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Strategies for reducing the costs of clean-energy technologies in buildings in Nigeria

Strategies for reducing the costs of clean-energy technologies in buildings in Nigeria Abstract The costs of clean-energy technologies are currently very high and their adoption in buildings is voluntary. This study evaluated strategies for improving the cost performance of photovoltaic (PV) electricity applied in buildings in Nigeria using a questionnaire survey involving 415 targets. The efficacy of each strategy and consensus in respondents’ perceptions were determined using Fuzzy Set Theory and Kruskal–Wallis tests. The top four strategies for achieving PV-cost reduction are mandating green buildings, standardization of building designs and PV components, facilitating import licensing and massive public education. Developing these strategies to improve the PV value chain will increase the supply capacity of clean energy in emerging markets. Graphical Abstract Open in new tabDownload slide buildings, cost reduction, photovoltaic, sustainable energy, sustainable development Introduction Buildings consume a significant proportion of global energy stock [1]. The main source of energy supply to buildings across developing countries is predominantly fossil-based electricity. The transmission of electricity to point-of-use involves an estimated loss of 6.8% and this proportion adds to the quantity of emitted carbon [2]. The environmental consequences of fossil-based electricity enhance the upsurge in the adoption of point-of-use-generated zero-carbon energy. Zero-carbon energy sources are renewable and various sources of renewable technologies exist, but solar photovoltaic (PV) energy has gained widespread approval in developing countries [3]. The expansion in renewable energy in Africa is further due to its contribution to increasing building energy efficiency, carbon reduction and aiding sustainable development goals [4–7]. The lack of reliability and non-availability of power supply are specific drivers supporting the penchant for the integration of PV technologies in buildings [5]. In Nigeria, power supply to buildings is not only low, but the spread is also low. The access to electricity by households in Nigeria was 60% in 2014 [8], with no significant growth in 2016 [9] and persistently declining [10]. The building sector in Nigeria consumes 55–60% of the current electricity output for 4–6 hours daily [10–12]. As in other nations, the energy demand by buildings in Nigeria is high but the efficiency of the current output is low. Strategic upscaling of the installed capacity of PV energy in this region is the desirable alternative for tackling energy poverty and the associated environmental problems [7, 13]. The potentials for solar energy and the applications of related technologies in buildings in Nigeria are compelling [4, 14], although accessibility and uptake of PV are laggard based on inferred high costs [15–17]. Despite advances in the dissemination of awareness relating to sustainable-energy development, most developing countries lack strategic policies for driving enabling technologies in the energy sector [9, 18]. Unlike related development in Asia [5, 19], the PV policies in Africa remain marginal after several decades [7]. The competition resulting from the niche created by the vast PV market in Africa seems inadequate as an incentive to improve the adoption of related technologies in the emerging markets. The high costs of PV systems continue to hinder the decision-making to adopt these technologies, replacing fossil-based electricity and fuel-based generators [15, 16, 20, 21]. Therefore, to thrive, several international intervention policies promoting PV adoption in this region, and clear and effective strategies for promoting cost reduction are imperative [7]. Various studies have appraised renewable-energy policies and strategies for improving access in Nigeria [14, 18, 22] and overseas [5–7, 19]. However, these studies focused on enablers, drivers, potentials and barriers, mainly using literature synthesis. The empirical evidence underlying the conclusions of these studies, in most cases, does not advance the severity and perceived performance of the relevance strategies for improving access to renewable energy along with regional variations. Therefore, despite the number of studies that evaluated the spread of PV technologies, the strategic mitigation policies to improving critical cost barriers are sketchy. PV-optimization studies researched the targeted selection process and building energy performance [23]. Other studies, amidst the empirical gap, focused on reforms aimed at solving national and regional energy problems [5, 19]. The inclination towards regional policies in past studies suggested that the critical problems inhibiting adoption require context-based solutions. Efforts to optimize the costs of Building-Integrated Photovoltaic (BIPV) systems [24] and the overall performance of the BIPV systems [24–27] also exist, but the adoption of PV technologies is currently very low due to the dearth of strategies to mitigate the perceived high costs. This paper argues that the cost of PV is a function of closely related drivers in the different phases of PV uses in buildings. A plethora of cost-related triggers such as component quality, low reliability, poor installation procedures and maintenance requirements are a few related concerns, which, when mitigated, would expedite PV adoption [26]. Chen and Riffat [28] reiterated the need for research to advance PV-cost mitigation to advance the sustainability of the built environment. This study, therefore, evolved practical steps to upscale the uptake of PV technologies in buildings, through empirical authentication of in-country perceived cost-mitigation strategies in Nigeria. The development of strategies to enhance point-of-use generation is capable of stimulating the supply of clean energy in emerging markets [4]. The research also provides desktop benchmarks for various actors in the PV value chain such as policy developers, industry partners and building developers to upscale adoption. The inability to generate data for policymaking in Nigeria is severe [29]; this study, therefore, contributes to resolving these problems in the energy sector. The objective of the study was to evaluate strategies for reducing the costs of PV technologies towards diffused integration in buildings in Nigeria. 1 The PV system The origin of the term ‘photovoltaic’ can be traced to Greek, in which ‘photo’ indicates light and ‘Volta’ was an Italian scientist who invented the chemical battery in 1800 [30]. The PV effect is therefore a direct conversion of solar energy into electricity. The panels are fabricated using material that allows electrons to energize in a free state from their atoms when subjected to light [30]. The current flows in one direction; hence, the electricity is direct current (DC). Photovoltaic systems, therefore, convert solar energy into electricity using PV cells combined in modules, and modules combined to form arrays. In developing countries, the most widely used method of deployment is to mount arrays on the roofs of buildings [15, 16, 19]. Solar PV is a member of the renewable-energy-technologies family. Renewable energy refers to energy obtained from sources that are replenished at a similar rate as used [28]. Other renewable sources include solar thermal, wind, biogas and hydroelectric technologies. There are three types of PV-cell technologies in the market across developing countries, namely mono-crystalline, silicon/polycrystalline silicon, amorphous silicon and thin-film technology of Copper Indium Diselenide (CIS) [30]. The mono-crystalline silicon is single-crystal silicon and has the highest efficiency rating of >26.7% [31]. The polycrystalline silicon is more expensive than mono-crystalline silicon; cells are fabricated from a block of cast silicon. Polycrystalline silicon has a conversion efficiency of 22.3% [31]. The amorphous silicon has the lowest conversion efficiency amongst all PV technologies (10–15%). However, mono-crystalline technology is readily available across market segments of the world, including Nigeria. The PV cell (panel) is the most significant component of the PV system, and the most significant cost driver [32]. The rooftop integration of PV across buildings accounts for >80% of applications across the globe [19, 33]. Current innovations to improve the cost management of PV adoption consider crystalline silicon technology to be more expensive and other technologies are economically viable substitutes [20]. 2 PV-cost-optimization strategies Global renewable-energy indices suggest a steady growth in the uptake of PV technology. Sustaining this growth trajectory requires reducing the costs (prices) of PV components, as an incentive to promote widespread adoption [3]. The vast proportion of extant literature links PV-cost mitigation with government actions as well as those of other stakeholders [3, 24, 34]. Yang and Zou [3] observed that strong government policy support and incentives are capable of motivating the adoption of PV technologies across sectors. This viewpoint leads to the postulation that effective, consistent and viable government policies are prerequisites to PV-costs reduction. Developing strategies for cost optimization must therefore focus on improving government policies to stimulate market growth. Lawton [34] established a relationship between the soft costs of PV and regional or local policies, while panel and module costs are affected by international trade regimes, the scale of technological development and production economics. The analysis of the causes of PV-cost reduction over 30 years revealed that enhanced module efficiency, increased research and development (R&D) and economies of scale could sustain the cost economy [35]. However, cost-mitigation solutions are pertinent through long-term policies and synergy between relevant stakeholders across the value chain. Cost-reduction strategies refer to drivers (policies) that contribute to lower PV costs by eliminating barriers and cost factors [5]. The effectiveness of cost-reduction strategies depends on the degree of their effectiveness to decimate cost factors and barriers. A Malaysian study showed that PV-integration policies must develop from the contexts of inherent drivers, enablers and barriers [6]. Enablers are facilitating policies, barriers are inhibitors, while drivers are strategies that can eliminate barriers [5]. Finance, incentives, policy, maintenance, promotion and housing-loan policies are focal drivers [6]. Therefore, market development and the provision of incentives are fundamental drivers to cost reduction [5]. Lawton [34] advanced five strategies for achieving economic competitiveness in the PV market. The five strategies focused on new corporate and public reforms and financing options, standardization of designs, streamlining permit issues, utility regulation and mandating green buildings. The study also proved that the early conception and incorporation of a photovoltaic system in the design stage are significant to mitigate the costs of remedial or retrofit works to roofs during installations. This study considers these strategies too generic to address the focal cost triggers predisposing high costs. Accordingly, standardizing panels, mandating solar homes, massive education and awareness campaigns can improve the costs of customer acquisition. Developing local technologies to aid the local manufacturing of PV components represents an enormous opportunity to improve the installed costs. The costs of PV modules and other components are consistent barriers to PV adoption across studies [15, 16]. The participants in these studies likewise agreed that interventions aimed at improving the reliability of PV components are essential to direct cost reduction. Similarly, mandating solar homes, the standardization of panels and relaxed permitting and inspection are strategic to improve installation costs. Encouraging and providing third-party financing is suitable to manage finance-related problems. Stimulating the local production of non-hardware components through the R&D of local content supports are imperative to lowering overall costs. Developing from the premise of innovation-system theory, Strupeit [36] revealed seven processes that could improve the soft costs in PV systems. The soft-cost-reduction policies include demand and market growth, supply-chain-agent interactions, knowledge acquisition and dissemination, producing variety and choice, and the development of institution capacity [36]. Improvement of the framework for supply-chain-based PV-cost governance is also significant to unbundle PV costs [3]. This strategy encompasses collaboration between key actors in the construction industry, namely government, professionals, manufacturers, clients, users and a league of others. The collective intervention of these stakeholders in their relevant sectors can eliminate knowledge gaps, provide subsidies, improve efficiencies and enhance market uptake. The roles of the identified stakeholders in PV-market uptake have been documented in past literature [37–39]. The strategies for the long-term cost optimization of BIPV also exist, namely the establishment of BIPV-information services, awareness and capacity-building programmes, the development of PV-market enhancement and infrastructure development, and improvement of policy and financial frameworks supportive for PV-market sustainability [24]. PV-market-development initiatives are needed to resolve technical feasibility and economic viability using demonstration projects, to promote a wider level of acceptance and to deepen understanding of the technology and its benefits [37, 38]. PV policies and financing programmes are adequate to advance activities directed at enhancing the ability of policymakers to institute appropriate, proactive and integrated plans, which can ensure the development and sustenance of a supportive business environment. Enhancing R&D is also a strategic way to develop, strengthen and organize the human-resource capacities of stakeholders [5]. Synergy through partnership with international joint ventures and companies can upgrade local firms, R&D institutions and the provision of technical infrastructures to test and standardize PV products. In Malaysia, Sopian [24] observed that the highlighted strategies improved PV-application rates by >300% over a 5-year strategic plan. The review of related literature in this section has shown that efforts to improve the cost-effectiveness of PV technologies require strategic planning, designed in phases to achieve short-, medium- and long-term cost-reduction targets. Table 1 provides a summary of theoretical cost-optimization variables for PV technologies from the literature. The strategies are categorized into three major groups, namely design; financing; and education, training and research. The postulation suggests the relevant policies for PV-cost reduction to enhance PV-system and building designs, financing, research, education and training. However, the existing PV-cost-reduction strategies are non-empirical and the product of institutional and technical literature. The scope of achievable cost reduction and the validity of the cost-reduction strategies are imminent empirical gaps in the literature. This study seeks to validate the potency of PV-cost-reduction strategies using empirical data, since the formative studies in the literature are non-empirical research. Table 1: Theoretical variables of PV-cost-reduction strategies Code . Strategies . Sources . Design strategies PCS1 Early conception and incorporation of photovoltaic system in the design stage [3, 40] PCS2 Mandate Green buildings [41] PCS3 Standardization of designs [34, 40] PCS4 Promotion of new business practices and developers [42] PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community [37, 43] PCS6 Simplifying permits and inspections [34] PCS7 Mandating solar power [3] PCS8 Relax level of inspection, permits and regulations policies [25] Financing strategies PCS9 Provide financing incentives [34, 42] PCS10 Develop and provide local content through research [26] PCS11 Facilitate import licensing to check & improve purchasing power benefits [39, 44] PCS12 Favourable tax policies [40, 45] Education, training and research PCS13 Massive public education and awareness campaign [24, 34] PCS14 Promote research to encourage local production of non-hardware components [35, 46, 47] PCS15 Provide real-time experiences for development in training and skills of stakeholders [26] PCS16 Institute relevant standards and update as at when required [26] PCS17 Set new guidelines for providing technical assistances to the industry [26, 38] PCS18 Detailed and document barriers and opportunities to cost efficiency to maximized shared experiences [26] PCS19 Promote installers licensing and certification [45] Code . Strategies . Sources . Design strategies PCS1 Early conception and incorporation of photovoltaic system in the design stage [3, 40] PCS2 Mandate Green buildings [41] PCS3 Standardization of designs [34, 40] PCS4 Promotion of new business practices and developers [42] PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community [37, 43] PCS6 Simplifying permits and inspections [34] PCS7 Mandating solar power [3] PCS8 Relax level of inspection, permits and regulations policies [25] Financing strategies PCS9 Provide financing incentives [34, 42] PCS10 Develop and provide local content through research [26] PCS11 Facilitate import licensing to check & improve purchasing power benefits [39, 44] PCS12 Favourable tax policies [40, 45] Education, training and research PCS13 Massive public education and awareness campaign [24, 34] PCS14 Promote research to encourage local production of non-hardware components [35, 46, 47] PCS15 Provide real-time experiences for development in training and skills of stakeholders [26] PCS16 Institute relevant standards and update as at when required [26] PCS17 Set new guidelines for providing technical assistances to the industry [26, 38] PCS18 Detailed and document barriers and opportunities to cost efficiency to maximized shared experiences [26] PCS19 Promote installers licensing and certification [45] Open in new tab Table 1: Theoretical variables of PV-cost-reduction strategies Code . Strategies . Sources . Design strategies PCS1 Early conception and incorporation of photovoltaic system in the design stage [3, 40] PCS2 Mandate Green buildings [41] PCS3 Standardization of designs [34, 40] PCS4 Promotion of new business practices and developers [42] PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community [37, 43] PCS6 Simplifying permits and inspections [34] PCS7 Mandating solar power [3] PCS8 Relax level of inspection, permits and regulations policies [25] Financing strategies PCS9 Provide financing incentives [34, 42] PCS10 Develop and provide local content through research [26] PCS11 Facilitate import licensing to check & improve purchasing power benefits [39, 44] PCS12 Favourable tax policies [40, 45] Education, training and research PCS13 Massive public education and awareness campaign [24, 34] PCS14 Promote research to encourage local production of non-hardware components [35, 46, 47] PCS15 Provide real-time experiences for development in training and skills of stakeholders [26] PCS16 Institute relevant standards and update as at when required [26] PCS17 Set new guidelines for providing technical assistances to the industry [26, 38] PCS18 Detailed and document barriers and opportunities to cost efficiency to maximized shared experiences [26] PCS19 Promote installers licensing and certification [45] Code . Strategies . Sources . Design strategies PCS1 Early conception and incorporation of photovoltaic system in the design stage [3, 40] PCS2 Mandate Green buildings [41] PCS3 Standardization of designs [34, 40] PCS4 Promotion of new business practices and developers [42] PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community [37, 43] PCS6 Simplifying permits and inspections [34] PCS7 Mandating solar power [3] PCS8 Relax level of inspection, permits and regulations policies [25] Financing strategies PCS9 Provide financing incentives [34, 42] PCS10 Develop and provide local content through research [26] PCS11 Facilitate import licensing to check & improve purchasing power benefits [39, 44] PCS12 Favourable tax policies [40, 45] Education, training and research PCS13 Massive public education and awareness campaign [24, 34] PCS14 Promote research to encourage local production of non-hardware components [35, 46, 47] PCS15 Provide real-time experiences for development in training and skills of stakeholders [26] PCS16 Institute relevant standards and update as at when required [26] PCS17 Set new guidelines for providing technical assistances to the industry [26, 38] PCS18 Detailed and document barriers and opportunities to cost efficiency to maximized shared experiences [26] PCS19 Promote installers licensing and certification [45] Open in new tab 3 Research methodology The research involved a survey research design. A self-study structured questionnaire was administered to targets drawn from relevant stakeholders associated with PV marketing, manufacturing, distribution, installation, design and promotion. The population of the study consisted of respondents from the Nigeria Energy Commission, construction professionals, PV contractors and electrical engineers. Preliminary inquiry data obtained from various databases of these bodies revealed a total population of 1010 targets. The Kish formula for sample-size determination [48] generated a sample of 415 respondents, including applied correction for non-response bias. The study was conducted in the six geo-political zones of Nigeria in eight cities: Abuja, Lagos, Port Harcourt, Dutse, Gombe, Calabar, Uyo and Enugu. The choice of survey research design using the questionnaire followed the trend in past studies [49, 50]. The survey therefore represents a strategic approach adapted to improved the existing theoretical data and knowledge of PV-cost-reduction strategies using key stakeholder experiences. The research instrument, the PV Cost Optimisation Strategies Questionnaire, was implemented to collect the study’s data. The questionnaire consisted of two parts: the first part contained questions relating to respondents’ background information including the role of respondents in the PV value chain, years of experience and educational qualifications; the second part elicited respondents’ perceived level of the effectiveness of identified PV-cost-mitigation strategies (Table 1). The respondents ranked their perceived level of effectiveness of the listed strategies on a five-point Likert scale. The five-point Likert scale was defined as 1 indicates that the strategy is not effective, the method has no potential to reduce costs; 2 indicates low effectiveness, the method has low potential to reduce cost; while 3 means medium effectiveness, a moderate effect on costs reduction; 4 indicates a high level of effectiveness, strategy is highly effective to mitigate PV cost; and 5 means very high effectiveness, the perceived level of the cost reduction of the strategy is very high. The administration of the research instrument involved a face-to-face survey and e-mails. The questionnaire-administration approaches yielded a response rate of 70% and an efficiency rate of 65% [51]. The study also determined the quality of the research design and measurement variables by conducting reliability tests because the literature review showed that the formative studies were non-empirical research. The result of the Cronbach’s alpha test indicated that the variables were indicative of optimization strategies for improving PV cost (Cronbach’s alpha = 0.78–0.92). Other data analysis involved Fuzzy Set Theory (FST) and the Kruskal–Wallis test. The Kruskal–Wallis test evaluated variance in the respondents’ perceptions of the effectiveness of PV-cost-reduction strategies, while FST determined the critical performance of each strategy following similar adoption in related studies [52, 53]. The effectiveness of each optimization strategy was therefore based on the critical-performance score obtained using FST. Studies [52] and [53] provide inclusive discussion about the theoretical dimensions of FST and its application in determining critical performance. The tool addresses fuzziness in the qualitative ranking and the analysis involves four steps: calculations of mean and standard deviation (SD), determination of Z score (Mean-3/Standard Deviation) and determination of the degree of membership using the Excel NORMDIST function. The degree of association forms the basis for setting a benchmark to select an effective strategy based on a 0.85 cut-off point [46] and scores in the range of 0.85–1.00 indicate full membership and a very high level of effectiveness. FST has diffused application in the determination of critical-performance indices within the research environment [54]. Overall, the research involved the five stages depicted in Fig. 1. Fig. 1: Open in new tabDownload slide Adopted research processes 4 Results 4.1 Characteristics of respondents The descriptive analysis of respondents’ characteristics validated the quality of the field data. The result in Table 2 shows that the lowest educational qualification of the respondents is Higher National Diploma (HND). The population of first- and higher-degree holders is also significant. The population of degree holders in the sample is 73%, while the combined population of degree holders and those with an HND is 90%. The composition of the sample with a valid academic qualification is therefore adequate to accept their perceptions about the effectiveness of identified PV-cost-reduction strategies. The majority of the respondents (57%) are design consultants, construction professionals and stakeholders in the PV-supply chain. The remaining 43% consists of vendors/distributors, building contractors and project managers. Fifty-one per cent operate in southern Nigeria and another 21% are in the northern part. Another 28% operate in Nigeria’s former and current capital cities (Lagos and Abuja). The sample is homogenous; 33% of respondents are in northern Nigeria, while 67% are in the southern part. Table 2: Respondent characteristics Educational qualifications . Professional qualifications . Years in related business . Variables . N . % . Variables . N . % . Variables . N . % . HND 24 13 Vendor/distributor 36 19 0–5 years 160 85 First degree 80 43 Design consultant 108 57 5–10 years 28 15 MSc and above 56 30 Project manager 24 13 10–15 – – Other qualifications 28 15 Building contractor 20 11 – – Total 188 100 Total 224 100 Total 188 100 Location South N % South N % Cosmopolitan N % Calabar 22 12 Jos 10 5 Abuja 23 12 Port Harcourt 38 20 Gombe 5 3 Lagos 30 16 Uyo 20 11 Dutse 10 5 - – Enugu 15 8 Kano 15 8 - - Educational qualifications . Professional qualifications . Years in related business . Variables . N . % . Variables . N . % . Variables . N . % . HND 24 13 Vendor/distributor 36 19 0–5 years 160 85 First degree 80 43 Design consultant 108 57 5–10 years 28 15 MSc and above 56 30 Project manager 24 13 10–15 – – Other qualifications 28 15 Building contractor 20 11 – – Total 188 100 Total 224 100 Total 188 100 Location South N % South N % Cosmopolitan N % Calabar 22 12 Jos 10 5 Abuja 23 12 Port Harcourt 38 20 Gombe 5 3 Lagos 30 16 Uyo 20 11 Dutse 10 5 - – Enugu 15 8 Kano 15 8 - - N, number. Open in new tab Table 2: Respondent characteristics Educational qualifications . Professional qualifications . Years in related business . Variables . N . % . Variables . N . % . Variables . N . % . HND 24 13 Vendor/distributor 36 19 0–5 years 160 85 First degree 80 43 Design consultant 108 57 5–10 years 28 15 MSc and above 56 30 Project manager 24 13 10–15 – – Other qualifications 28 15 Building contractor 20 11 – – Total 188 100 Total 224 100 Total 188 100 Location South N % South N % Cosmopolitan N % Calabar 22 12 Jos 10 5 Abuja 23 12 Port Harcourt 38 20 Gombe 5 3 Lagos 30 16 Uyo 20 11 Dutse 10 5 - – Enugu 15 8 Kano 15 8 - - Educational qualifications . Professional qualifications . Years in related business . Variables . N . % . Variables . N . % . Variables . N . % . HND 24 13 Vendor/distributor 36 19 0–5 years 160 85 First degree 80 43 Design consultant 108 57 5–10 years 28 15 MSc and above 56 30 Project manager 24 13 10–15 – – Other qualifications 28 15 Building contractor 20 11 – – Total 188 100 Total 224 100 Total 188 100 Location South N % South N % Cosmopolitan N % Calabar 22 12 Jos 10 5 Abuja 23 12 Port Harcourt 38 20 Gombe 5 3 Lagos 30 16 Uyo 20 11 Dutse 10 5 - – Enugu 15 8 Kano 15 8 - - N, number. Open in new tab 4.2 Critical performance of PV-cost-reduction strategies The level of effectiveness of the cost-mitigation strategies was analysed using FST. The result (Table 3) shows that 15 strategies (81%) out of 19 strategies evaluated are significant and effective to improve PV-cost performance. These strategies obtained λ-cut (Lambda Cut) values greater than the 0.85 benchmark adopted in the study (see the ‘Research methodology’ section). Further detail indicates that, overall, mandating green buildings emerged as the most effective strategy to improve PV-cost performance with a degree of association of 0.97. This strategy would ensure that newly built homes and major retrofitted homes adopt solar power and other passive design strategies towards energy efficiency. The spread of solar homes is capable of promoting the mass production of components to meet demand; the economies of scale would instruct cost reduction. The solar mandate would reduce costs by guaranteeing a customer base and promoting the benefit of economies of scale and design standardization. The second most effective strategy to optimize PV is to facilitate import licensing to check and improve purchasing-power benefits (λ-cut, 0.95). A massive public education and awareness campaign obtained a λ-cut score of 0.94 and emerged as the third most effective strategy to improve PV costs. Strategies with a low level of effectiveness represent 16% of the surveyed PV-cost-optimization strategies. This band of PV-cost-mitigation strategies obtained λ-cut values less than the 0.85 benchmark adopted by the study. The conclusion portrays their level of effectiveness to decimate the costs of PV technologies as low. Strategies in this category include PCS4 (the promoting of new business practices and developers), PCS16 (instituting relevant standards and updating them as and when required) and PCS17 (setting new guidelines for providing technical assistance to the industry). Growth drivers of PV-technologies adoption in the building sector are therefore unconnected to new business culture, new standards and guidelines based on the results of the study. Current and existing business practices, standards and guidelines are therefore adequate to support enabling policies towards adoption. Table 3: Effectiveness of PV-cost-reduction strategies Code . Strategies . SD . Z . M(xi) . Decision . PCS1 Early conception and incorporation of photovoltaic system in the design stage 0.92 1.22 0.89 ✓ PCS2 Mandate green buildings 1.32 1.79 0.97 ✓ PCS3 Standardization of designs 0.98 1.35 0.93 ✓ PCS4 Promotion of new business practices and developers 0.77 0.57 0.74 – PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community 1.01 1.10 0.87 ✓ PCS6 Simplifying permits and inspections 0.94 1.11 0.88 ✓ PCS7 Mandating solar power 1.11 1.42 0.93 ✓ PCS8 Relax level of inspection, permits and regulations policies 0.92 1.24 0.90 ✓ PCS9 Provide financing incentives 0.84 1.06 0.88 ✓ PCS10 Develop and provide local content through research 0.82 0.89 0.89 ✓ PCS11 Facilitate import licensing to check & improve purchasing power benefits 1.01 1.46 0.95 ✓ PCS12 Favourable tax policies 0.99 1.29 0.91 ✓ PCS13 Massive public education and awareness campaign 1.01 1.49 0.94 ✓ PCS14 Promote research to encourage local production of non-hardware components 0.89 0.98 0.86 ✓ PCS15 Provide real-time experiences for development in training and skills of stakeholders 1.04 1.32 0.93 ✓ PCS16 Institute relevant standards and update as at when required 0.89 0.36 0.67 – PCS17 Set new guidelines for providing technical assistances to the industry 0.87 0.77 0.25 – PCS18 Detail and document barriers and opportunities to cost-efficiency to maximize shared experiences 1.04 1.25 0.88 ✓ PCS19 Promote installers licensing and certification 0.95 1.42 0.91 ✓ Code . Strategies . SD . Z . M(xi) . Decision . PCS1 Early conception and incorporation of photovoltaic system in the design stage 0.92 1.22 0.89 ✓ PCS2 Mandate green buildings 1.32 1.79 0.97 ✓ PCS3 Standardization of designs 0.98 1.35 0.93 ✓ PCS4 Promotion of new business practices and developers 0.77 0.57 0.74 – PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community 1.01 1.10 0.87 ✓ PCS6 Simplifying permits and inspections 0.94 1.11 0.88 ✓ PCS7 Mandating solar power 1.11 1.42 0.93 ✓ PCS8 Relax level of inspection, permits and regulations policies 0.92 1.24 0.90 ✓ PCS9 Provide financing incentives 0.84 1.06 0.88 ✓ PCS10 Develop and provide local content through research 0.82 0.89 0.89 ✓ PCS11 Facilitate import licensing to check & improve purchasing power benefits 1.01 1.46 0.95 ✓ PCS12 Favourable tax policies 0.99 1.29 0.91 ✓ PCS13 Massive public education and awareness campaign 1.01 1.49 0.94 ✓ PCS14 Promote research to encourage local production of non-hardware components 0.89 0.98 0.86 ✓ PCS15 Provide real-time experiences for development in training and skills of stakeholders 1.04 1.32 0.93 ✓ PCS16 Institute relevant standards and update as at when required 0.89 0.36 0.67 – PCS17 Set new guidelines for providing technical assistances to the industry 0.87 0.77 0.25 – PCS18 Detail and document barriers and opportunities to cost-efficiency to maximize shared experiences 1.04 1.25 0.88 ✓ PCS19 Promote installers licensing and certification 0.95 1.42 0.91 ✓ ✓ = Effective; – = Not effective; MIS, mean item score; M(xi), degree of association to a set/critical performance. Open in new tab Table 3: Effectiveness of PV-cost-reduction strategies Code . Strategies . SD . Z . M(xi) . Decision . PCS1 Early conception and incorporation of photovoltaic system in the design stage 0.92 1.22 0.89 ✓ PCS2 Mandate green buildings 1.32 1.79 0.97 ✓ PCS3 Standardization of designs 0.98 1.35 0.93 ✓ PCS4 Promotion of new business practices and developers 0.77 0.57 0.74 – PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community 1.01 1.10 0.87 ✓ PCS6 Simplifying permits and inspections 0.94 1.11 0.88 ✓ PCS7 Mandating solar power 1.11 1.42 0.93 ✓ PCS8 Relax level of inspection, permits and regulations policies 0.92 1.24 0.90 ✓ PCS9 Provide financing incentives 0.84 1.06 0.88 ✓ PCS10 Develop and provide local content through research 0.82 0.89 0.89 ✓ PCS11 Facilitate import licensing to check & improve purchasing power benefits 1.01 1.46 0.95 ✓ PCS12 Favourable tax policies 0.99 1.29 0.91 ✓ PCS13 Massive public education and awareness campaign 1.01 1.49 0.94 ✓ PCS14 Promote research to encourage local production of non-hardware components 0.89 0.98 0.86 ✓ PCS15 Provide real-time experiences for development in training and skills of stakeholders 1.04 1.32 0.93 ✓ PCS16 Institute relevant standards and update as at when required 0.89 0.36 0.67 – PCS17 Set new guidelines for providing technical assistances to the industry 0.87 0.77 0.25 – PCS18 Detail and document barriers and opportunities to cost-efficiency to maximize shared experiences 1.04 1.25 0.88 ✓ PCS19 Promote installers licensing and certification 0.95 1.42 0.91 ✓ Code . Strategies . SD . Z . M(xi) . Decision . PCS1 Early conception and incorporation of photovoltaic system in the design stage 0.92 1.22 0.89 ✓ PCS2 Mandate green buildings 1.32 1.79 0.97 ✓ PCS3 Standardization of designs 0.98 1.35 0.93 ✓ PCS4 Promotion of new business practices and developers 0.77 0.57 0.74 – PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community 1.01 1.10 0.87 ✓ PCS6 Simplifying permits and inspections 0.94 1.11 0.88 ✓ PCS7 Mandating solar power 1.11 1.42 0.93 ✓ PCS8 Relax level of inspection, permits and regulations policies 0.92 1.24 0.90 ✓ PCS9 Provide financing incentives 0.84 1.06 0.88 ✓ PCS10 Develop and provide local content through research 0.82 0.89 0.89 ✓ PCS11 Facilitate import licensing to check & improve purchasing power benefits 1.01 1.46 0.95 ✓ PCS12 Favourable tax policies 0.99 1.29 0.91 ✓ PCS13 Massive public education and awareness campaign 1.01 1.49 0.94 ✓ PCS14 Promote research to encourage local production of non-hardware components 0.89 0.98 0.86 ✓ PCS15 Provide real-time experiences for development in training and skills of stakeholders 1.04 1.32 0.93 ✓ PCS16 Institute relevant standards and update as at when required 0.89 0.36 0.67 – PCS17 Set new guidelines for providing technical assistances to the industry 0.87 0.77 0.25 – PCS18 Detail and document barriers and opportunities to cost-efficiency to maximize shared experiences 1.04 1.25 0.88 ✓ PCS19 Promote installers licensing and certification 0.95 1.42 0.91 ✓ ✓ = Effective; – = Not effective; MIS, mean item score; M(xi), degree of association to a set/critical performance. Open in new tab 4.3 Test of variation in respondents’ perceptions of the significant cost-reduction strategies Data analysis also determined the consensus in respondents’ perception of the critical performance of cost-reduction strategies. The study assessed variance using the sectors of the respondents based on the Kruskal–Wallis test. The statistic determined the hypothesis which states that there is no significant variation in respondents’ perceptions about the efficacies of identified PV-cost-reduction strategies. The result presented in Table 4 indicates a lack of significant variance in the aggregated perceptions of respondents about the efficacies of the significant and insignificant PV-cost-reduction strategies (p, 0.323 > 0.05). The null hypothesis was accepted. The conclusion shows consensus in respondents’ perception and the inference means that tested strategies are imperative to PV-cost reduction. Table 4: Result of the Kruskal–Wallis test Respondents’ group . Mean rank . Chi square . df . Asymp. Sig. . Decision . Public authority 45.87 Construction professionals 43.90 60.460 2 0.323 Accepted PV contractors 15.67 Respondents’ group . Mean rank . Chi square . df . Asymp. Sig. . Decision . Public authority 45.87 Construction professionals 43.90 60.460 2 0.323 Accepted PV contractors 15.67 Open in new tab Table 4: Result of the Kruskal–Wallis test Respondents’ group . Mean rank . Chi square . df . Asymp. Sig. . Decision . Public authority 45.87 Construction professionals 43.90 60.460 2 0.323 Accepted PV contractors 15.67 Respondents’ group . Mean rank . Chi square . df . Asymp. Sig. . Decision . Public authority 45.87 Construction professionals 43.90 60.460 2 0.323 Accepted PV contractors 15.67 Open in new tab 5 Discussion The significant strategies for mitigating the cost of PV technologies in the building sector are summarized as promoting strong government incentives, a collaborative PV-supply chain and the provision of incentives and education, training and research. The level of effectiveness of PCS14 (to promote research to encourage local production of non-hardware components) is low, despite exceeding the targeted benchmark (0.85). The implication is that the impact of R&D relating to PV manufacturing using local resources is low. The result of PCS14 also indicates low valorization of academic research related to PV technologies in practice within the study area. It also indicates a lack of synergy between academia and industry in solving challenges associated with the diffusion of the PV market in the critical building sector. The study also draws attention to the high level of effectiveness of PCS18, PCS9, PCS6 and PCS5 (Table 3). The result of PCS18 (detail and document barriers and opportunities to cost-efficiency to maximize shared experiences) is not a surprise; it is therefore consistent with the perception of respondents about PCS14. Lack of academia–industry collaboration and the dearth of strategic research to promote PV technology underpin PCS18. The implication is that the barriers to achieving cost economy in the use of PV technology are less prioritized in research. Therefore, the PV-market policy towards improving cost performance in Nigeria must prioritize R&D. Lack of collaborative supply-chain practices in design, manufacturing, marketing and distribution are also insignificant, based on the result of PCS5. The PV market in Nigeria is largely fragmented, and dominated by traders and vendors instead of by professionals. The dearth of the capacity to undertake design, installation, maintenance and performance monitoring is significant [7]. Design consultants in the building sector must improve skills in these areas to benefit the cost and quality of PV systems towards improving adoption. In addition, strategies focusing on mitigating low access to finance, cumbersome permits and inspection regimes are focal international trade barriers in most places including Nigeria. The low effectiveness rating of PCS6 (simplifying permits and inspections) and PCS9 (provide financing incentives) are therefore consistent. 5.1 Promote strong government intervention The mitigation of PV costs revolves around strong government policy and programmes. This is missing, however, in most developing countries. Lawton [34] corroborated this position, noting that strong government support was essential to achieving a common level of economic competitiveness in the PV market in the USA [34]. Eleri et al. [22] also observed that a strong national agenda on renewable energy is a prerequisite to achieving efficiency. Government intervention is important to stimulate competition locally, as well as to galvanize funding for commercializing research in renewable technologies. A study interpreted this strategy as developing a renewable-energy industry towards achieving overall sustainable development [14]. Past studies including Hwang et al. [47] agreed concerning the role of government and its supporting agencies in ensuring cost-effective sustainable building features. As observed by Lawton [34], the costs of non-hardware (soft costs) are significant drivers of PV costs, accounting for >50% of the installed cost of PV systems. Eighty per cent of the drivers of soft costs are concerns that are solvable using local or national policies; examples include customer acquisition, permitting, inspection and interconnection, financing, installation costs, affiliated non-module hardware, and taxes [34]. Soft-cost reduction requires sectoral or regional innovation strategies [36]. Pertinent strategies for soft-cost reduction require demand and market growth, interactions between supply-chain agents, education and training, careful selection of systems and the production of varieties, and institutional-capacity development [36]. The seven strategies align the philosophies of PCS4, PCS5, PCS10, PCS13 and PCS17-19 in Table 3. The strongest links to reducing the soft costs of PV technologies are the local manufacturing of non-hardware accessories and human-capacity development. The study by Bizzarri et al. [55], judging from the sharp decrease in the price of PV systems over the years, posited that a cost-effective PV regime is possible through production efficiency and technology improvement. A related study by Bachellerie [41] also found that the extent of PV adoption depends on the extent to which technologies become affordable and readily efficient. The first mechanism to achieving affordability is to increase the level of technology adaptation and acquisition of related expertise by local manufacturers and scientists. This would mean creating requisite knowledge and skills as fundamental requirements of technological competences in the industrial development pathway. The second aspect deals with promoting the fitness and cost-efficiency of PV technology to local conditions, increasing R&D and initiating demonstration projects in order to create niches for the technology in the region. The primary cost driver of PV costs, namely modules, remains an imported component in emerging markets. Government incentives/subsidies, low-interest loans, the design of customized financing schemes for sustainable-energy development, subsidizing research in support of hardware development and tax relief are important to achieving cost economy in hardware components. Government intervention can also take the form of designed learning in renewable-energy educational courses and technical information. This dimension would improve the knowledge and skills essential to mitigating the cost of hardware in PV systems. A study by Eleri et al. [22] maintained that related information empowers communities, companies and civil-liberty society groups to make choices. Retzlaff [46] found that federal-government guidance, building a strong research agenda for renewable-energy policy, was significant to spur innovation and increase the adoption of PV. Access to information on available technologies, costs, benefits, government programmes and international support mechanisms in Nigeria are, however, inadequate. There is need for active engagement of the local media such as radio, TV, newspaper and the internet as part of environmental education. Festus and Ogoegbunam [56] recommended environmental education to enlighten the public on the benefits and the need to adopt renewable technologies to protect the environment. The pertinent viewpoints emerging from the Indian experience that can promote large-scale application are dependent on three fundamental goals. The three strategies were defined as prioritizing rooftop technologies, developing clear PV-integration policies and enforcing renewable-energy deployment mandates. The government can also provide incentives as the best strategy to enhance the spread of solar homes [15]. Fina et al. [57] concluded that government subsidies and financial incentives are imperative to promoting active building designs. 5.2 Encourage a collaborative PV-supply-chain management framework The first level of collaboration and integration must target multiple parties’ roles within the construction industry, including government, professionals, client, end-users (community) and manufacturers. The government role is to promote policies and generate funding, education and R&D, and increase awareness towards sustainable-energy uses [37]. Manufacturers must invest in R&D to upscale efficiency in order to reduce costs [3]. Azadian and Radzi [38] also considered skills and knowledge as being imperative to reducing the delays and costs associated with customized design. The client’s duty is to stimulate an environmentally friendly energy system by seeking knowledge about its benefits [43]. However, the quest for knowledge advocated by the literature also requires a commitment to investing in PV adoption [3]. Supply-chain collaboration would also ensure that shared experiences are fertilized across regional levels between project developers, PV contractors, policymakers and regulators. This level of collaboration would assist in the supply chain to examine cost structures and the influence of in-country circumstances on cost. Supply-chain collaboration would also enhance in-country strategy development based on applied lessons from unique experiences. However, the effectual analysis of the PV-cost structure would also require detailed documentation of barriers to and opportunities for efficient cost structures in the market. The use of regional dialogue through joint projects and workshops is also proficient to benefit cost-related learning [44]. This could also support shared perspectives and the identification of the responsibilities of each stakeholder in contributing to efficient implementation of cost-mitigation trails. 6 Education, training and increased awareness Appropriate information services, awareness and capacity-building programmes can be beneficial in a number of ways. They will improve the level of understanding and raise awareness for understanding the technology, its benefits and ecological significance. The results of PCS13 (massive public education and awareness campaign) and PCS15 (provide real-time experiences for development in training and skills of stakeholders) validate the importance of this dimension. Deep awareness relies on extensive education campaigns and capacity building. Studies have found seminars, workshops and information resource databases to be significant practices in achieving an appropriate level of penetration. Sopian et al. [24] supported these tools to improve stakeholders’ level of competence and the quality of work of the service providers. Information services will further situate decision-makers to gain market opportunities towards enhanced policy initiatives. Exemplar projects are also important to entrench deep learning and awareness in providing real-time experiences and increased efforts in R&D activities. Market-development policies are also important education and awareness-dissemination practices for ensuring that relevant standards are in place and are updated in a timely manner as a set of new guidelines for providing technical assistance to the industry. Market-development policies include appropriate legal, institutional, financial and fiscal measures for PV-market development. Education, training, research and increased awareness have benefited related market development in Asian countries [24]. The benefits of R&D would therefore stimulate an increase in installed capacity and a long-term cost reduction of technology through an increase in demand, economies of scale and competitive local manufacturing. Education, awareness, knowledge and skills improvement are also strategies for mitigating labour costs. The creation and dissemination of prerequisite knowledge relating to PV are drivers of soft costs within the PV system [36]. The study by Bachellerie [41] agreed that the PV labour market requires nationalization in order to regulate and mitigate the cost of labour. This understanding places PV-market development, for instance, with the development of national capital or local contents. Non-professionals dominate the existing market structure in most developing countries and these entrepreneurs lack the prerequisite expertise on the design and integration of PV systems into the building system. The drive to improve the labour costs of PV is unconnected with loss of jobs, and rather with promoting the efficiency, effectiveness and standardization of the work [34]. A study by Hwang et al. [47] also showed that improving the skills and experience of contractors and professionals is a strong driver of cost reduction towards the wider adoption of green-building technologies in Singapore. In addition to the education, awareness and skills development, past study identified technological innovation systems as one of the most important realms to unravel the institutional barriers bedevilling PV diffusion in Africa [7]. The issues of technology innovation within the context of education policy advocated in this research and in line with past studies concern the appropriate use of R&D [19]. The scope of R&D has no significant consequence on renewable-energy innovation [58]; therefore, research promotes growth in PV expansion in varying ways. The cost of PV systems is important for their selection and integration into building-project development. Cost determines the duration, quality of projects, profitability and the overall building costs [13]. This understanding places a premium on the need to achieve cost economy in the application of PV technologies to optimize project duration, quality, profitability and building costs. The significance of efficient regulatory apparatuses for PV-cost reduction is consistent with the norms established across previous studies [14, 28]. The three framings of strong government policy, collaborative supply chain and education, and training and increased awareness are veritable dimensions of cost-reduction applications in the PV market. Some policy dimensions advanced in this paper corroborate the positions in Shukla [5]. Shukla [5] posited that the mitigation of implementation barriers, deployment of incentives and advanced R&D are pertinent drivers of PV adoption. Therefore, R&D, appropriate regulatory governance and the mitigation of cost factors are coherent cost-reduction strategies for PV integration into buildings [14, 28]. Even though these cost-reduction policies are important, other critical cost factors and barriers impeding PV adoption in buildings must be mitigated. The understanding is that the incorporation of PV systems into buildings is conditioned to face cost barriers until policies and reforms become more effective, technologies become more affordable, awareness, education and training are upscaled, and every stakeholder is oriented to pursue energy efficiency as a part of sustainable development goals. Therefore, policymakers in developing markets must judiciously plan their future energy policies around strategies that optimize government intervention, education and training, supply-chain collaboration and awareness of energy efficiency, including how PV adoption can fast track sustainable development goals. The important strategies outlined above emphasize cooperation and a more active involvement of the public/private sector, professionals, professional bodies, regulatory agencies and households contextualized as a component of long-term strategic policies. 7 Conclusion Policies in the building sector to incorporate sustainable-energy systems in buildings in most developing countries have not been able to balance costs with the need to ensure diffused adoption. This study evaluated strategies for mitigating the costs of PV technologies applied in buildings in the typical context of a developing country: Nigeria. The results showed that strong government intervention, a collaborative PV-supply chain, and education, training and increased awareness are strategic to PV-cost reduction. These strategies are significant to drive mandatory green-building policies, the standardization of building designs/PV components, import-licensing facilitation, massive public education and the provision of real-time experience-based training for installers. The strategies are also adequate to optimize the cost drivers associated with customer acquisition, permitting, inspection and licensing, financing and the lack of incentives to importers, manufacturers and users. The development of future PV-market-penetration policies for developing countries should optimize these strategies for optimal results. The implementation of these strategies, however, requires phasing, and the specific comprehensive PV-diffusion goal should tie to the respective strategic phase. Further study is, however, important in designing a strategic framework for PV-cost-reduction implementation in developing countries, based on these drivers, needs and enablers. 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Published by Oxford University Press on behalf of National Institute of Clean-and-Low-Carbon Energy This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com © The Author(s) 2020. Published by Oxford University Press on behalf of National Institute of Clean-and-Low-Carbon Energy http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Clean Energy Oxford University Press

Strategies for reducing the costs of clean-energy technologies in buildings in Nigeria

Clean Energy , Volume 4 (4) – Dec 31, 2020

Strategies for reducing the costs of clean-energy technologies in buildings in Nigeria

Clean Energy , Volume 4 (4) – Dec 31, 2020

Abstract

Abstract The costs of clean-energy technologies are currently very high and their adoption in buildings is voluntary. This study evaluated strategies for improving the cost performance of photovoltaic (PV) electricity applied in buildings in Nigeria using a questionnaire survey involving 415 targets. The efficacy of each strategy and consensus in respondents’ perceptions were determined using Fuzzy Set Theory and Kruskal–Wallis tests. The top four strategies for achieving PV-cost reduction are mandating green buildings, standardization of building designs and PV components, facilitating import licensing and massive public education. Developing these strategies to improve the PV value chain will increase the supply capacity of clean energy in emerging markets. Graphical Abstract Open in new tabDownload slide buildings, cost reduction, photovoltaic, sustainable energy, sustainable development Introduction Buildings consume a significant proportion of global energy stock [1]. The main source of energy supply to buildings across developing countries is predominantly fossil-based electricity. The transmission of electricity to point-of-use involves an estimated loss of 6.8% and this proportion adds to the quantity of emitted carbon [2]. The environmental consequences of fossil-based electricity enhance the upsurge in the adoption of point-of-use-generated zero-carbon energy. Zero-carbon energy sources are renewable and various sources of renewable technologies exist, but solar photovoltaic (PV) energy has gained widespread approval in developing countries [3]. The expansion in renewable energy in Africa is further due to its contribution to increasing building energy efficiency, carbon reduction and aiding sustainable development goals [4–7]. The lack of reliability and non-availability of power supply are specific drivers supporting the penchant for the integration of PV technologies in buildings [5]. In Nigeria, power supply to buildings is not only low, but the spread is also low. The access to electricity by households in Nigeria was 60% in 2014 [8], with no significant growth in 2016 [9] and persistently declining [10]. The building sector in Nigeria consumes 55–60% of the current electricity output for 4–6 hours daily [10–12]. As in other nations, the energy demand by buildings in Nigeria is high but the efficiency of the current output is low. Strategic upscaling of the installed capacity of PV energy in this region is the desirable alternative for tackling energy poverty and the associated environmental problems [7, 13]. The potentials for solar energy and the applications of related technologies in buildings in Nigeria are compelling [4, 14], although accessibility and uptake of PV are laggard based on inferred high costs [15–17]. Despite advances in the dissemination of awareness relating to sustainable-energy development, most developing countries lack strategic policies for driving enabling technologies in the energy sector [9, 18]. Unlike related development in Asia [5, 19], the PV policies in Africa remain marginal after several decades [7]. The competition resulting from the niche created by the vast PV market in Africa seems inadequate as an incentive to improve the adoption of related technologies in the emerging markets. The high costs of PV systems continue to hinder the decision-making to adopt these technologies, replacing fossil-based electricity and fuel-based generators [15, 16, 20, 21]. Therefore, to thrive, several international intervention policies promoting PV adoption in this region, and clear and effective strategies for promoting cost reduction are imperative [7]. Various studies have appraised renewable-energy policies and strategies for improving access in Nigeria [14, 18, 22] and overseas [5–7, 19]. However, these studies focused on enablers, drivers, potentials and barriers, mainly using literature synthesis. The empirical evidence underlying the conclusions of these studies, in most cases, does not advance the severity and perceived performance of the relevance strategies for improving access to renewable energy along with regional variations. Therefore, despite the number of studies that evaluated the spread of PV technologies, the strategic mitigation policies to improving critical cost barriers are sketchy. PV-optimization studies researched the targeted selection process and building energy performance [23]. Other studies, amidst the empirical gap, focused on reforms aimed at solving national and regional energy problems [5, 19]. The inclination towards regional policies in past studies suggested that the critical problems inhibiting adoption require context-based solutions. Efforts to optimize the costs of Building-Integrated Photovoltaic (BIPV) systems [24] and the overall performance of the BIPV systems [24–27] also exist, but the adoption of PV technologies is currently very low due to the dearth of strategies to mitigate the perceived high costs. This paper argues that the cost of PV is a function of closely related drivers in the different phases of PV uses in buildings. A plethora of cost-related triggers such as component quality, low reliability, poor installation procedures and maintenance requirements are a few related concerns, which, when mitigated, would expedite PV adoption [26]. Chen and Riffat [28] reiterated the need for research to advance PV-cost mitigation to advance the sustainability of the built environment. This study, therefore, evolved practical steps to upscale the uptake of PV technologies in buildings, through empirical authentication of in-country perceived cost-mitigation strategies in Nigeria. The development of strategies to enhance point-of-use generation is capable of stimulating the supply of clean energy in emerging markets [4]. The research also provides desktop benchmarks for various actors in the PV value chain such as policy developers, industry partners and building developers to upscale adoption. The inability to generate data for policymaking in Nigeria is severe [29]; this study, therefore, contributes to resolving these problems in the energy sector. The objective of the study was to evaluate strategies for reducing the costs of PV technologies towards diffused integration in buildings in Nigeria. 1 The PV system The origin of the term ‘photovoltaic’ can be traced to Greek, in which ‘photo’ indicates light and ‘Volta’ was an Italian scientist who invented the chemical battery in 1800 [30]. The PV effect is therefore a direct conversion of solar energy into electricity. The panels are fabricated using material that allows electrons to energize in a free state from their atoms when subjected to light [30]. The current flows in one direction; hence, the electricity is direct current (DC). Photovoltaic systems, therefore, convert solar energy into electricity using PV cells combined in modules, and modules combined to form arrays. In developing countries, the most widely used method of deployment is to mount arrays on the roofs of buildings [15, 16, 19]. Solar PV is a member of the renewable-energy-technologies family. Renewable energy refers to energy obtained from sources that are replenished at a similar rate as used [28]. Other renewable sources include solar thermal, wind, biogas and hydroelectric technologies. There are three types of PV-cell technologies in the market across developing countries, namely mono-crystalline, silicon/polycrystalline silicon, amorphous silicon and thin-film technology of Copper Indium Diselenide (CIS) [30]. The mono-crystalline silicon is single-crystal silicon and has the highest efficiency rating of >26.7% [31]. The polycrystalline silicon is more expensive than mono-crystalline silicon; cells are fabricated from a block of cast silicon. Polycrystalline silicon has a conversion efficiency of 22.3% [31]. The amorphous silicon has the lowest conversion efficiency amongst all PV technologies (10–15%). However, mono-crystalline technology is readily available across market segments of the world, including Nigeria. The PV cell (panel) is the most significant component of the PV system, and the most significant cost driver [32]. The rooftop integration of PV across buildings accounts for >80% of applications across the globe [19, 33]. Current innovations to improve the cost management of PV adoption consider crystalline silicon technology to be more expensive and other technologies are economically viable substitutes [20]. 2 PV-cost-optimization strategies Global renewable-energy indices suggest a steady growth in the uptake of PV technology. Sustaining this growth trajectory requires reducing the costs (prices) of PV components, as an incentive to promote widespread adoption [3]. The vast proportion of extant literature links PV-cost mitigation with government actions as well as those of other stakeholders [3, 24, 34]. Yang and Zou [3] observed that strong government policy support and incentives are capable of motivating the adoption of PV technologies across sectors. This viewpoint leads to the postulation that effective, consistent and viable government policies are prerequisites to PV-costs reduction. Developing strategies for cost optimization must therefore focus on improving government policies to stimulate market growth. Lawton [34] established a relationship between the soft costs of PV and regional or local policies, while panel and module costs are affected by international trade regimes, the scale of technological development and production economics. The analysis of the causes of PV-cost reduction over 30 years revealed that enhanced module efficiency, increased research and development (R&D) and economies of scale could sustain the cost economy [35]. However, cost-mitigation solutions are pertinent through long-term policies and synergy between relevant stakeholders across the value chain. Cost-reduction strategies refer to drivers (policies) that contribute to lower PV costs by eliminating barriers and cost factors [5]. The effectiveness of cost-reduction strategies depends on the degree of their effectiveness to decimate cost factors and barriers. A Malaysian study showed that PV-integration policies must develop from the contexts of inherent drivers, enablers and barriers [6]. Enablers are facilitating policies, barriers are inhibitors, while drivers are strategies that can eliminate barriers [5]. Finance, incentives, policy, maintenance, promotion and housing-loan policies are focal drivers [6]. Therefore, market development and the provision of incentives are fundamental drivers to cost reduction [5]. Lawton [34] advanced five strategies for achieving economic competitiveness in the PV market. The five strategies focused on new corporate and public reforms and financing options, standardization of designs, streamlining permit issues, utility regulation and mandating green buildings. The study also proved that the early conception and incorporation of a photovoltaic system in the design stage are significant to mitigate the costs of remedial or retrofit works to roofs during installations. This study considers these strategies too generic to address the focal cost triggers predisposing high costs. Accordingly, standardizing panels, mandating solar homes, massive education and awareness campaigns can improve the costs of customer acquisition. Developing local technologies to aid the local manufacturing of PV components represents an enormous opportunity to improve the installed costs. The costs of PV modules and other components are consistent barriers to PV adoption across studies [15, 16]. The participants in these studies likewise agreed that interventions aimed at improving the reliability of PV components are essential to direct cost reduction. Similarly, mandating solar homes, the standardization of panels and relaxed permitting and inspection are strategic to improve installation costs. Encouraging and providing third-party financing is suitable to manage finance-related problems. Stimulating the local production of non-hardware components through the R&D of local content supports are imperative to lowering overall costs. Developing from the premise of innovation-system theory, Strupeit [36] revealed seven processes that could improve the soft costs in PV systems. The soft-cost-reduction policies include demand and market growth, supply-chain-agent interactions, knowledge acquisition and dissemination, producing variety and choice, and the development of institution capacity [36]. Improvement of the framework for supply-chain-based PV-cost governance is also significant to unbundle PV costs [3]. This strategy encompasses collaboration between key actors in the construction industry, namely government, professionals, manufacturers, clients, users and a league of others. The collective intervention of these stakeholders in their relevant sectors can eliminate knowledge gaps, provide subsidies, improve efficiencies and enhance market uptake. The roles of the identified stakeholders in PV-market uptake have been documented in past literature [37–39]. The strategies for the long-term cost optimization of BIPV also exist, namely the establishment of BIPV-information services, awareness and capacity-building programmes, the development of PV-market enhancement and infrastructure development, and improvement of policy and financial frameworks supportive for PV-market sustainability [24]. PV-market-development initiatives are needed to resolve technical feasibility and economic viability using demonstration projects, to promote a wider level of acceptance and to deepen understanding of the technology and its benefits [37, 38]. PV policies and financing programmes are adequate to advance activities directed at enhancing the ability of policymakers to institute appropriate, proactive and integrated plans, which can ensure the development and sustenance of a supportive business environment. Enhancing R&D is also a strategic way to develop, strengthen and organize the human-resource capacities of stakeholders [5]. Synergy through partnership with international joint ventures and companies can upgrade local firms, R&D institutions and the provision of technical infrastructures to test and standardize PV products. In Malaysia, Sopian [24] observed that the highlighted strategies improved PV-application rates by >300% over a 5-year strategic plan. The review of related literature in this section has shown that efforts to improve the cost-effectiveness of PV technologies require strategic planning, designed in phases to achieve short-, medium- and long-term cost-reduction targets. Table 1 provides a summary of theoretical cost-optimization variables for PV technologies from the literature. The strategies are categorized into three major groups, namely design; financing; and education, training and research. The postulation suggests the relevant policies for PV-cost reduction to enhance PV-system and building designs, financing, research, education and training. However, the existing PV-cost-reduction strategies are non-empirical and the product of institutional and technical literature. The scope of achievable cost reduction and the validity of the cost-reduction strategies are imminent empirical gaps in the literature. This study seeks to validate the potency of PV-cost-reduction strategies using empirical data, since the formative studies in the literature are non-empirical research. Table 1: Theoretical variables of PV-cost-reduction strategies Code . Strategies . Sources . Design strategies PCS1 Early conception and incorporation of photovoltaic system in the design stage [3, 40] PCS2 Mandate Green buildings [41] PCS3 Standardization of designs [34, 40] PCS4 Promotion of new business practices and developers [42] PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community [37, 43] PCS6 Simplifying permits and inspections [34] PCS7 Mandating solar power [3] PCS8 Relax level of inspection, permits and regulations policies [25] Financing strategies PCS9 Provide financing incentives [34, 42] PCS10 Develop and provide local content through research [26] PCS11 Facilitate import licensing to check & improve purchasing power benefits [39, 44] PCS12 Favourable tax policies [40, 45] Education, training and research PCS13 Massive public education and awareness campaign [24, 34] PCS14 Promote research to encourage local production of non-hardware components [35, 46, 47] PCS15 Provide real-time experiences for development in training and skills of stakeholders [26] PCS16 Institute relevant standards and update as at when required [26] PCS17 Set new guidelines for providing technical assistances to the industry [26, 38] PCS18 Detailed and document barriers and opportunities to cost efficiency to maximized shared experiences [26] PCS19 Promote installers licensing and certification [45] Code . Strategies . Sources . Design strategies PCS1 Early conception and incorporation of photovoltaic system in the design stage [3, 40] PCS2 Mandate Green buildings [41] PCS3 Standardization of designs [34, 40] PCS4 Promotion of new business practices and developers [42] PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community [37, 43] PCS6 Simplifying permits and inspections [34] PCS7 Mandating solar power [3] PCS8 Relax level of inspection, permits and regulations policies [25] Financing strategies PCS9 Provide financing incentives [34, 42] PCS10 Develop and provide local content through research [26] PCS11 Facilitate import licensing to check & improve purchasing power benefits [39, 44] PCS12 Favourable tax policies [40, 45] Education, training and research PCS13 Massive public education and awareness campaign [24, 34] PCS14 Promote research to encourage local production of non-hardware components [35, 46, 47] PCS15 Provide real-time experiences for development in training and skills of stakeholders [26] PCS16 Institute relevant standards and update as at when required [26] PCS17 Set new guidelines for providing technical assistances to the industry [26, 38] PCS18 Detailed and document barriers and opportunities to cost efficiency to maximized shared experiences [26] PCS19 Promote installers licensing and certification [45] Open in new tab Table 1: Theoretical variables of PV-cost-reduction strategies Code . Strategies . Sources . Design strategies PCS1 Early conception and incorporation of photovoltaic system in the design stage [3, 40] PCS2 Mandate Green buildings [41] PCS3 Standardization of designs [34, 40] PCS4 Promotion of new business practices and developers [42] PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community [37, 43] PCS6 Simplifying permits and inspections [34] PCS7 Mandating solar power [3] PCS8 Relax level of inspection, permits and regulations policies [25] Financing strategies PCS9 Provide financing incentives [34, 42] PCS10 Develop and provide local content through research [26] PCS11 Facilitate import licensing to check & improve purchasing power benefits [39, 44] PCS12 Favourable tax policies [40, 45] Education, training and research PCS13 Massive public education and awareness campaign [24, 34] PCS14 Promote research to encourage local production of non-hardware components [35, 46, 47] PCS15 Provide real-time experiences for development in training and skills of stakeholders [26] PCS16 Institute relevant standards and update as at when required [26] PCS17 Set new guidelines for providing technical assistances to the industry [26, 38] PCS18 Detailed and document barriers and opportunities to cost efficiency to maximized shared experiences [26] PCS19 Promote installers licensing and certification [45] Code . Strategies . Sources . Design strategies PCS1 Early conception and incorporation of photovoltaic system in the design stage [3, 40] PCS2 Mandate Green buildings [41] PCS3 Standardization of designs [34, 40] PCS4 Promotion of new business practices and developers [42] PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community [37, 43] PCS6 Simplifying permits and inspections [34] PCS7 Mandating solar power [3] PCS8 Relax level of inspection, permits and regulations policies [25] Financing strategies PCS9 Provide financing incentives [34, 42] PCS10 Develop and provide local content through research [26] PCS11 Facilitate import licensing to check & improve purchasing power benefits [39, 44] PCS12 Favourable tax policies [40, 45] Education, training and research PCS13 Massive public education and awareness campaign [24, 34] PCS14 Promote research to encourage local production of non-hardware components [35, 46, 47] PCS15 Provide real-time experiences for development in training and skills of stakeholders [26] PCS16 Institute relevant standards and update as at when required [26] PCS17 Set new guidelines for providing technical assistances to the industry [26, 38] PCS18 Detailed and document barriers and opportunities to cost efficiency to maximized shared experiences [26] PCS19 Promote installers licensing and certification [45] Open in new tab 3 Research methodology The research involved a survey research design. A self-study structured questionnaire was administered to targets drawn from relevant stakeholders associated with PV marketing, manufacturing, distribution, installation, design and promotion. The population of the study consisted of respondents from the Nigeria Energy Commission, construction professionals, PV contractors and electrical engineers. Preliminary inquiry data obtained from various databases of these bodies revealed a total population of 1010 targets. The Kish formula for sample-size determination [48] generated a sample of 415 respondents, including applied correction for non-response bias. The study was conducted in the six geo-political zones of Nigeria in eight cities: Abuja, Lagos, Port Harcourt, Dutse, Gombe, Calabar, Uyo and Enugu. The choice of survey research design using the questionnaire followed the trend in past studies [49, 50]. The survey therefore represents a strategic approach adapted to improved the existing theoretical data and knowledge of PV-cost-reduction strategies using key stakeholder experiences. The research instrument, the PV Cost Optimisation Strategies Questionnaire, was implemented to collect the study’s data. The questionnaire consisted of two parts: the first part contained questions relating to respondents’ background information including the role of respondents in the PV value chain, years of experience and educational qualifications; the second part elicited respondents’ perceived level of the effectiveness of identified PV-cost-mitigation strategies (Table 1). The respondents ranked their perceived level of effectiveness of the listed strategies on a five-point Likert scale. The five-point Likert scale was defined as 1 indicates that the strategy is not effective, the method has no potential to reduce costs; 2 indicates low effectiveness, the method has low potential to reduce cost; while 3 means medium effectiveness, a moderate effect on costs reduction; 4 indicates a high level of effectiveness, strategy is highly effective to mitigate PV cost; and 5 means very high effectiveness, the perceived level of the cost reduction of the strategy is very high. The administration of the research instrument involved a face-to-face survey and e-mails. The questionnaire-administration approaches yielded a response rate of 70% and an efficiency rate of 65% [51]. The study also determined the quality of the research design and measurement variables by conducting reliability tests because the literature review showed that the formative studies were non-empirical research. The result of the Cronbach’s alpha test indicated that the variables were indicative of optimization strategies for improving PV cost (Cronbach’s alpha = 0.78–0.92). Other data analysis involved Fuzzy Set Theory (FST) and the Kruskal–Wallis test. The Kruskal–Wallis test evaluated variance in the respondents’ perceptions of the effectiveness of PV-cost-reduction strategies, while FST determined the critical performance of each strategy following similar adoption in related studies [52, 53]. The effectiveness of each optimization strategy was therefore based on the critical-performance score obtained using FST. Studies [52] and [53] provide inclusive discussion about the theoretical dimensions of FST and its application in determining critical performance. The tool addresses fuzziness in the qualitative ranking and the analysis involves four steps: calculations of mean and standard deviation (SD), determination of Z score (Mean-3/Standard Deviation) and determination of the degree of membership using the Excel NORMDIST function. The degree of association forms the basis for setting a benchmark to select an effective strategy based on a 0.85 cut-off point [46] and scores in the range of 0.85–1.00 indicate full membership and a very high level of effectiveness. FST has diffused application in the determination of critical-performance indices within the research environment [54]. Overall, the research involved the five stages depicted in Fig. 1. Fig. 1: Open in new tabDownload slide Adopted research processes 4 Results 4.1 Characteristics of respondents The descriptive analysis of respondents’ characteristics validated the quality of the field data. The result in Table 2 shows that the lowest educational qualification of the respondents is Higher National Diploma (HND). The population of first- and higher-degree holders is also significant. The population of degree holders in the sample is 73%, while the combined population of degree holders and those with an HND is 90%. The composition of the sample with a valid academic qualification is therefore adequate to accept their perceptions about the effectiveness of identified PV-cost-reduction strategies. The majority of the respondents (57%) are design consultants, construction professionals and stakeholders in the PV-supply chain. The remaining 43% consists of vendors/distributors, building contractors and project managers. Fifty-one per cent operate in southern Nigeria and another 21% are in the northern part. Another 28% operate in Nigeria’s former and current capital cities (Lagos and Abuja). The sample is homogenous; 33% of respondents are in northern Nigeria, while 67% are in the southern part. Table 2: Respondent characteristics Educational qualifications . Professional qualifications . Years in related business . Variables . N . % . Variables . N . % . Variables . N . % . HND 24 13 Vendor/distributor 36 19 0–5 years 160 85 First degree 80 43 Design consultant 108 57 5–10 years 28 15 MSc and above 56 30 Project manager 24 13 10–15 – – Other qualifications 28 15 Building contractor 20 11 – – Total 188 100 Total 224 100 Total 188 100 Location South N % South N % Cosmopolitan N % Calabar 22 12 Jos 10 5 Abuja 23 12 Port Harcourt 38 20 Gombe 5 3 Lagos 30 16 Uyo 20 11 Dutse 10 5 - – Enugu 15 8 Kano 15 8 - - Educational qualifications . Professional qualifications . Years in related business . Variables . N . % . Variables . N . % . Variables . N . % . HND 24 13 Vendor/distributor 36 19 0–5 years 160 85 First degree 80 43 Design consultant 108 57 5–10 years 28 15 MSc and above 56 30 Project manager 24 13 10–15 – – Other qualifications 28 15 Building contractor 20 11 – – Total 188 100 Total 224 100 Total 188 100 Location South N % South N % Cosmopolitan N % Calabar 22 12 Jos 10 5 Abuja 23 12 Port Harcourt 38 20 Gombe 5 3 Lagos 30 16 Uyo 20 11 Dutse 10 5 - – Enugu 15 8 Kano 15 8 - - N, number. Open in new tab Table 2: Respondent characteristics Educational qualifications . Professional qualifications . Years in related business . Variables . N . % . Variables . N . % . Variables . N . % . HND 24 13 Vendor/distributor 36 19 0–5 years 160 85 First degree 80 43 Design consultant 108 57 5–10 years 28 15 MSc and above 56 30 Project manager 24 13 10–15 – – Other qualifications 28 15 Building contractor 20 11 – – Total 188 100 Total 224 100 Total 188 100 Location South N % South N % Cosmopolitan N % Calabar 22 12 Jos 10 5 Abuja 23 12 Port Harcourt 38 20 Gombe 5 3 Lagos 30 16 Uyo 20 11 Dutse 10 5 - – Enugu 15 8 Kano 15 8 - - Educational qualifications . Professional qualifications . Years in related business . Variables . N . % . Variables . N . % . Variables . N . % . HND 24 13 Vendor/distributor 36 19 0–5 years 160 85 First degree 80 43 Design consultant 108 57 5–10 years 28 15 MSc and above 56 30 Project manager 24 13 10–15 – – Other qualifications 28 15 Building contractor 20 11 – – Total 188 100 Total 224 100 Total 188 100 Location South N % South N % Cosmopolitan N % Calabar 22 12 Jos 10 5 Abuja 23 12 Port Harcourt 38 20 Gombe 5 3 Lagos 30 16 Uyo 20 11 Dutse 10 5 - – Enugu 15 8 Kano 15 8 - - N, number. Open in new tab 4.2 Critical performance of PV-cost-reduction strategies The level of effectiveness of the cost-mitigation strategies was analysed using FST. The result (Table 3) shows that 15 strategies (81%) out of 19 strategies evaluated are significant and effective to improve PV-cost performance. These strategies obtained λ-cut (Lambda Cut) values greater than the 0.85 benchmark adopted in the study (see the ‘Research methodology’ section). Further detail indicates that, overall, mandating green buildings emerged as the most effective strategy to improve PV-cost performance with a degree of association of 0.97. This strategy would ensure that newly built homes and major retrofitted homes adopt solar power and other passive design strategies towards energy efficiency. The spread of solar homes is capable of promoting the mass production of components to meet demand; the economies of scale would instruct cost reduction. The solar mandate would reduce costs by guaranteeing a customer base and promoting the benefit of economies of scale and design standardization. The second most effective strategy to optimize PV is to facilitate import licensing to check and improve purchasing-power benefits (λ-cut, 0.95). A massive public education and awareness campaign obtained a λ-cut score of 0.94 and emerged as the third most effective strategy to improve PV costs. Strategies with a low level of effectiveness represent 16% of the surveyed PV-cost-optimization strategies. This band of PV-cost-mitigation strategies obtained λ-cut values less than the 0.85 benchmark adopted by the study. The conclusion portrays their level of effectiveness to decimate the costs of PV technologies as low. Strategies in this category include PCS4 (the promoting of new business practices and developers), PCS16 (instituting relevant standards and updating them as and when required) and PCS17 (setting new guidelines for providing technical assistance to the industry). Growth drivers of PV-technologies adoption in the building sector are therefore unconnected to new business culture, new standards and guidelines based on the results of the study. Current and existing business practices, standards and guidelines are therefore adequate to support enabling policies towards adoption. Table 3: Effectiveness of PV-cost-reduction strategies Code . Strategies . SD . Z . M(xi) . Decision . PCS1 Early conception and incorporation of photovoltaic system in the design stage 0.92 1.22 0.89 ✓ PCS2 Mandate green buildings 1.32 1.79 0.97 ✓ PCS3 Standardization of designs 0.98 1.35 0.93 ✓ PCS4 Promotion of new business practices and developers 0.77 0.57 0.74 – PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community 1.01 1.10 0.87 ✓ PCS6 Simplifying permits and inspections 0.94 1.11 0.88 ✓ PCS7 Mandating solar power 1.11 1.42 0.93 ✓ PCS8 Relax level of inspection, permits and regulations policies 0.92 1.24 0.90 ✓ PCS9 Provide financing incentives 0.84 1.06 0.88 ✓ PCS10 Develop and provide local content through research 0.82 0.89 0.89 ✓ PCS11 Facilitate import licensing to check & improve purchasing power benefits 1.01 1.46 0.95 ✓ PCS12 Favourable tax policies 0.99 1.29 0.91 ✓ PCS13 Massive public education and awareness campaign 1.01 1.49 0.94 ✓ PCS14 Promote research to encourage local production of non-hardware components 0.89 0.98 0.86 ✓ PCS15 Provide real-time experiences for development in training and skills of stakeholders 1.04 1.32 0.93 ✓ PCS16 Institute relevant standards and update as at when required 0.89 0.36 0.67 – PCS17 Set new guidelines for providing technical assistances to the industry 0.87 0.77 0.25 – PCS18 Detail and document barriers and opportunities to cost-efficiency to maximize shared experiences 1.04 1.25 0.88 ✓ PCS19 Promote installers licensing and certification 0.95 1.42 0.91 ✓ Code . Strategies . SD . Z . M(xi) . Decision . PCS1 Early conception and incorporation of photovoltaic system in the design stage 0.92 1.22 0.89 ✓ PCS2 Mandate green buildings 1.32 1.79 0.97 ✓ PCS3 Standardization of designs 0.98 1.35 0.93 ✓ PCS4 Promotion of new business practices and developers 0.77 0.57 0.74 – PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community 1.01 1.10 0.87 ✓ PCS6 Simplifying permits and inspections 0.94 1.11 0.88 ✓ PCS7 Mandating solar power 1.11 1.42 0.93 ✓ PCS8 Relax level of inspection, permits and regulations policies 0.92 1.24 0.90 ✓ PCS9 Provide financing incentives 0.84 1.06 0.88 ✓ PCS10 Develop and provide local content through research 0.82 0.89 0.89 ✓ PCS11 Facilitate import licensing to check & improve purchasing power benefits 1.01 1.46 0.95 ✓ PCS12 Favourable tax policies 0.99 1.29 0.91 ✓ PCS13 Massive public education and awareness campaign 1.01 1.49 0.94 ✓ PCS14 Promote research to encourage local production of non-hardware components 0.89 0.98 0.86 ✓ PCS15 Provide real-time experiences for development in training and skills of stakeholders 1.04 1.32 0.93 ✓ PCS16 Institute relevant standards and update as at when required 0.89 0.36 0.67 – PCS17 Set new guidelines for providing technical assistances to the industry 0.87 0.77 0.25 – PCS18 Detail and document barriers and opportunities to cost-efficiency to maximize shared experiences 1.04 1.25 0.88 ✓ PCS19 Promote installers licensing and certification 0.95 1.42 0.91 ✓ ✓ = Effective; – = Not effective; MIS, mean item score; M(xi), degree of association to a set/critical performance. Open in new tab Table 3: Effectiveness of PV-cost-reduction strategies Code . Strategies . SD . Z . M(xi) . Decision . PCS1 Early conception and incorporation of photovoltaic system in the design stage 0.92 1.22 0.89 ✓ PCS2 Mandate green buildings 1.32 1.79 0.97 ✓ PCS3 Standardization of designs 0.98 1.35 0.93 ✓ PCS4 Promotion of new business practices and developers 0.77 0.57 0.74 – PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community 1.01 1.10 0.87 ✓ PCS6 Simplifying permits and inspections 0.94 1.11 0.88 ✓ PCS7 Mandating solar power 1.11 1.42 0.93 ✓ PCS8 Relax level of inspection, permits and regulations policies 0.92 1.24 0.90 ✓ PCS9 Provide financing incentives 0.84 1.06 0.88 ✓ PCS10 Develop and provide local content through research 0.82 0.89 0.89 ✓ PCS11 Facilitate import licensing to check & improve purchasing power benefits 1.01 1.46 0.95 ✓ PCS12 Favourable tax policies 0.99 1.29 0.91 ✓ PCS13 Massive public education and awareness campaign 1.01 1.49 0.94 ✓ PCS14 Promote research to encourage local production of non-hardware components 0.89 0.98 0.86 ✓ PCS15 Provide real-time experiences for development in training and skills of stakeholders 1.04 1.32 0.93 ✓ PCS16 Institute relevant standards and update as at when required 0.89 0.36 0.67 – PCS17 Set new guidelines for providing technical assistances to the industry 0.87 0.77 0.25 – PCS18 Detail and document barriers and opportunities to cost-efficiency to maximize shared experiences 1.04 1.25 0.88 ✓ PCS19 Promote installers licensing and certification 0.95 1.42 0.91 ✓ Code . Strategies . SD . Z . M(xi) . Decision . PCS1 Early conception and incorporation of photovoltaic system in the design stage 0.92 1.22 0.89 ✓ PCS2 Mandate green buildings 1.32 1.79 0.97 ✓ PCS3 Standardization of designs 0.98 1.35 0.93 ✓ PCS4 Promotion of new business practices and developers 0.77 0.57 0.74 – PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community 1.01 1.10 0.87 ✓ PCS6 Simplifying permits and inspections 0.94 1.11 0.88 ✓ PCS7 Mandating solar power 1.11 1.42 0.93 ✓ PCS8 Relax level of inspection, permits and regulations policies 0.92 1.24 0.90 ✓ PCS9 Provide financing incentives 0.84 1.06 0.88 ✓ PCS10 Develop and provide local content through research 0.82 0.89 0.89 ✓ PCS11 Facilitate import licensing to check & improve purchasing power benefits 1.01 1.46 0.95 ✓ PCS12 Favourable tax policies 0.99 1.29 0.91 ✓ PCS13 Massive public education and awareness campaign 1.01 1.49 0.94 ✓ PCS14 Promote research to encourage local production of non-hardware components 0.89 0.98 0.86 ✓ PCS15 Provide real-time experiences for development in training and skills of stakeholders 1.04 1.32 0.93 ✓ PCS16 Institute relevant standards and update as at when required 0.89 0.36 0.67 – PCS17 Set new guidelines for providing technical assistances to the industry 0.87 0.77 0.25 – PCS18 Detail and document barriers and opportunities to cost-efficiency to maximize shared experiences 1.04 1.25 0.88 ✓ PCS19 Promote installers licensing and certification 0.95 1.42 0.91 ✓ ✓ = Effective; – = Not effective; MIS, mean item score; M(xi), degree of association to a set/critical performance. Open in new tab 4.3 Test of variation in respondents’ perceptions of the significant cost-reduction strategies Data analysis also determined the consensus in respondents’ perception of the critical performance of cost-reduction strategies. The study assessed variance using the sectors of the respondents based on the Kruskal–Wallis test. The statistic determined the hypothesis which states that there is no significant variation in respondents’ perceptions about the efficacies of identified PV-cost-reduction strategies. The result presented in Table 4 indicates a lack of significant variance in the aggregated perceptions of respondents about the efficacies of the significant and insignificant PV-cost-reduction strategies (p, 0.323 > 0.05). The null hypothesis was accepted. The conclusion shows consensus in respondents’ perception and the inference means that tested strategies are imperative to PV-cost reduction. Table 4: Result of the Kruskal–Wallis test Respondents’ group . Mean rank . Chi square . df . Asymp. Sig. . Decision . Public authority 45.87 Construction professionals 43.90 60.460 2 0.323 Accepted PV contractors 15.67 Respondents’ group . Mean rank . Chi square . df . Asymp. Sig. . Decision . Public authority 45.87 Construction professionals 43.90 60.460 2 0.323 Accepted PV contractors 15.67 Open in new tab Table 4: Result of the Kruskal–Wallis test Respondents’ group . Mean rank . Chi square . df . Asymp. Sig. . Decision . Public authority 45.87 Construction professionals 43.90 60.460 2 0.323 Accepted PV contractors 15.67 Respondents’ group . Mean rank . Chi square . df . Asymp. Sig. . Decision . Public authority 45.87 Construction professionals 43.90 60.460 2 0.323 Accepted PV contractors 15.67 Open in new tab 5 Discussion The significant strategies for mitigating the cost of PV technologies in the building sector are summarized as promoting strong government incentives, a collaborative PV-supply chain and the provision of incentives and education, training and research. The level of effectiveness of PCS14 (to promote research to encourage local production of non-hardware components) is low, despite exceeding the targeted benchmark (0.85). The implication is that the impact of R&D relating to PV manufacturing using local resources is low. The result of PCS14 also indicates low valorization of academic research related to PV technologies in practice within the study area. It also indicates a lack of synergy between academia and industry in solving challenges associated with the diffusion of the PV market in the critical building sector. The study also draws attention to the high level of effectiveness of PCS18, PCS9, PCS6 and PCS5 (Table 3). The result of PCS18 (detail and document barriers and opportunities to cost-efficiency to maximize shared experiences) is not a surprise; it is therefore consistent with the perception of respondents about PCS14. Lack of academia–industry collaboration and the dearth of strategic research to promote PV technology underpin PCS18. The implication is that the barriers to achieving cost economy in the use of PV technology are less prioritized in research. Therefore, the PV-market policy towards improving cost performance in Nigeria must prioritize R&D. Lack of collaborative supply-chain practices in design, manufacturing, marketing and distribution are also insignificant, based on the result of PCS5. The PV market in Nigeria is largely fragmented, and dominated by traders and vendors instead of by professionals. The dearth of the capacity to undertake design, installation, maintenance and performance monitoring is significant [7]. Design consultants in the building sector must improve skills in these areas to benefit the cost and quality of PV systems towards improving adoption. In addition, strategies focusing on mitigating low access to finance, cumbersome permits and inspection regimes are focal international trade barriers in most places including Nigeria. The low effectiveness rating of PCS6 (simplifying permits and inspections) and PCS9 (provide financing incentives) are therefore consistent. 5.1 Promote strong government intervention The mitigation of PV costs revolves around strong government policy and programmes. This is missing, however, in most developing countries. Lawton [34] corroborated this position, noting that strong government support was essential to achieving a common level of economic competitiveness in the PV market in the USA [34]. Eleri et al. [22] also observed that a strong national agenda on renewable energy is a prerequisite to achieving efficiency. Government intervention is important to stimulate competition locally, as well as to galvanize funding for commercializing research in renewable technologies. A study interpreted this strategy as developing a renewable-energy industry towards achieving overall sustainable development [14]. Past studies including Hwang et al. [47] agreed concerning the role of government and its supporting agencies in ensuring cost-effective sustainable building features. As observed by Lawton [34], the costs of non-hardware (soft costs) are significant drivers of PV costs, accounting for >50% of the installed cost of PV systems. Eighty per cent of the drivers of soft costs are concerns that are solvable using local or national policies; examples include customer acquisition, permitting, inspection and interconnection, financing, installation costs, affiliated non-module hardware, and taxes [34]. Soft-cost reduction requires sectoral or regional innovation strategies [36]. Pertinent strategies for soft-cost reduction require demand and market growth, interactions between supply-chain agents, education and training, careful selection of systems and the production of varieties, and institutional-capacity development [36]. The seven strategies align the philosophies of PCS4, PCS5, PCS10, PCS13 and PCS17-19 in Table 3. The strongest links to reducing the soft costs of PV technologies are the local manufacturing of non-hardware accessories and human-capacity development. The study by Bizzarri et al. [55], judging from the sharp decrease in the price of PV systems over the years, posited that a cost-effective PV regime is possible through production efficiency and technology improvement. A related study by Bachellerie [41] also found that the extent of PV adoption depends on the extent to which technologies become affordable and readily efficient. The first mechanism to achieving affordability is to increase the level of technology adaptation and acquisition of related expertise by local manufacturers and scientists. This would mean creating requisite knowledge and skills as fundamental requirements of technological competences in the industrial development pathway. The second aspect deals with promoting the fitness and cost-efficiency of PV technology to local conditions, increasing R&D and initiating demonstration projects in order to create niches for the technology in the region. The primary cost driver of PV costs, namely modules, remains an imported component in emerging markets. Government incentives/subsidies, low-interest loans, the design of customized financing schemes for sustainable-energy development, subsidizing research in support of hardware development and tax relief are important to achieving cost economy in hardware components. Government intervention can also take the form of designed learning in renewable-energy educational courses and technical information. This dimension would improve the knowledge and skills essential to mitigating the cost of hardware in PV systems. A study by Eleri et al. [22] maintained that related information empowers communities, companies and civil-liberty society groups to make choices. Retzlaff [46] found that federal-government guidance, building a strong research agenda for renewable-energy policy, was significant to spur innovation and increase the adoption of PV. Access to information on available technologies, costs, benefits, government programmes and international support mechanisms in Nigeria are, however, inadequate. There is need for active engagement of the local media such as radio, TV, newspaper and the internet as part of environmental education. Festus and Ogoegbunam [56] recommended environmental education to enlighten the public on the benefits and the need to adopt renewable technologies to protect the environment. The pertinent viewpoints emerging from the Indian experience that can promote large-scale application are dependent on three fundamental goals. The three strategies were defined as prioritizing rooftop technologies, developing clear PV-integration policies and enforcing renewable-energy deployment mandates. The government can also provide incentives as the best strategy to enhance the spread of solar homes [15]. Fina et al. [57] concluded that government subsidies and financial incentives are imperative to promoting active building designs. 5.2 Encourage a collaborative PV-supply-chain management framework The first level of collaboration and integration must target multiple parties’ roles within the construction industry, including government, professionals, client, end-users (community) and manufacturers. The government role is to promote policies and generate funding, education and R&D, and increase awareness towards sustainable-energy uses [37]. Manufacturers must invest in R&D to upscale efficiency in order to reduce costs [3]. Azadian and Radzi [38] also considered skills and knowledge as being imperative to reducing the delays and costs associated with customized design. The client’s duty is to stimulate an environmentally friendly energy system by seeking knowledge about its benefits [43]. However, the quest for knowledge advocated by the literature also requires a commitment to investing in PV adoption [3]. Supply-chain collaboration would also ensure that shared experiences are fertilized across regional levels between project developers, PV contractors, policymakers and regulators. This level of collaboration would assist in the supply chain to examine cost structures and the influence of in-country circumstances on cost. Supply-chain collaboration would also enhance in-country strategy development based on applied lessons from unique experiences. However, the effectual analysis of the PV-cost structure would also require detailed documentation of barriers to and opportunities for efficient cost structures in the market. The use of regional dialogue through joint projects and workshops is also proficient to benefit cost-related learning [44]. This could also support shared perspectives and the identification of the responsibilities of each stakeholder in contributing to efficient implementation of cost-mitigation trails. 6 Education, training and increased awareness Appropriate information services, awareness and capacity-building programmes can be beneficial in a number of ways. They will improve the level of understanding and raise awareness for understanding the technology, its benefits and ecological significance. The results of PCS13 (massive public education and awareness campaign) and PCS15 (provide real-time experiences for development in training and skills of stakeholders) validate the importance of this dimension. Deep awareness relies on extensive education campaigns and capacity building. Studies have found seminars, workshops and information resource databases to be significant practices in achieving an appropriate level of penetration. Sopian et al. [24] supported these tools to improve stakeholders’ level of competence and the quality of work of the service providers. Information services will further situate decision-makers to gain market opportunities towards enhanced policy initiatives. Exemplar projects are also important to entrench deep learning and awareness in providing real-time experiences and increased efforts in R&D activities. Market-development policies are also important education and awareness-dissemination practices for ensuring that relevant standards are in place and are updated in a timely manner as a set of new guidelines for providing technical assistance to the industry. Market-development policies include appropriate legal, institutional, financial and fiscal measures for PV-market development. Education, training, research and increased awareness have benefited related market development in Asian countries [24]. The benefits of R&D would therefore stimulate an increase in installed capacity and a long-term cost reduction of technology through an increase in demand, economies of scale and competitive local manufacturing. Education, awareness, knowledge and skills improvement are also strategies for mitigating labour costs. The creation and dissemination of prerequisite knowledge relating to PV are drivers of soft costs within the PV system [36]. The study by Bachellerie [41] agreed that the PV labour market requires nationalization in order to regulate and mitigate the cost of labour. This understanding places PV-market development, for instance, with the development of national capital or local contents. Non-professionals dominate the existing market structure in most developing countries and these entrepreneurs lack the prerequisite expertise on the design and integration of PV systems into the building system. The drive to improve the labour costs of PV is unconnected with loss of jobs, and rather with promoting the efficiency, effectiveness and standardization of the work [34]. A study by Hwang et al. [47] also showed that improving the skills and experience of contractors and professionals is a strong driver of cost reduction towards the wider adoption of green-building technologies in Singapore. In addition to the education, awareness and skills development, past study identified technological innovation systems as one of the most important realms to unravel the institutional barriers bedevilling PV diffusion in Africa [7]. The issues of technology innovation within the context of education policy advocated in this research and in line with past studies concern the appropriate use of R&D [19]. The scope of R&D has no significant consequence on renewable-energy innovation [58]; therefore, research promotes growth in PV expansion in varying ways. The cost of PV systems is important for their selection and integration into building-project development. Cost determines the duration, quality of projects, profitability and the overall building costs [13]. This understanding places a premium on the need to achieve cost economy in the application of PV technologies to optimize project duration, quality, profitability and building costs. The significance of efficient regulatory apparatuses for PV-cost reduction is consistent with the norms established across previous studies [14, 28]. The three framings of strong government policy, collaborative supply chain and education, and training and increased awareness are veritable dimensions of cost-reduction applications in the PV market. Some policy dimensions advanced in this paper corroborate the positions in Shukla [5]. Shukla [5] posited that the mitigation of implementation barriers, deployment of incentives and advanced R&D are pertinent drivers of PV adoption. Therefore, R&D, appropriate regulatory governance and the mitigation of cost factors are coherent cost-reduction strategies for PV integration into buildings [14, 28]. Even though these cost-reduction policies are important, other critical cost factors and barriers impeding PV adoption in buildings must be mitigated. The understanding is that the incorporation of PV systems into buildings is conditioned to face cost barriers until policies and reforms become more effective, technologies become more affordable, awareness, education and training are upscaled, and every stakeholder is oriented to pursue energy efficiency as a part of sustainable development goals. Therefore, policymakers in developing markets must judiciously plan their future energy policies around strategies that optimize government intervention, education and training, supply-chain collaboration and awareness of energy efficiency, including how PV adoption can fast track sustainable development goals. The important strategies outlined above emphasize cooperation and a more active involvement of the public/private sector, professionals, professional bodies, regulatory agencies and households contextualized as a component of long-term strategic policies. 7 Conclusion Policies in the building sector to incorporate sustainable-energy systems in buildings in most developing countries have not been able to balance costs with the need to ensure diffused adoption. This study evaluated strategies for mitigating the costs of PV technologies applied in buildings in the typical context of a developing country: Nigeria. The results showed that strong government intervention, a collaborative PV-supply chain, and education, training and increased awareness are strategic to PV-cost reduction. These strategies are significant to drive mandatory green-building policies, the standardization of building designs/PV components, import-licensing facilitation, massive public education and the provision of real-time experience-based training for installers. The strategies are also adequate to optimize the cost drivers associated with customer acquisition, permitting, inspection and licensing, financing and the lack of incentives to importers, manufacturers and users. The development of future PV-market-penetration policies for developing countries should optimize these strategies for optimal results. The implementation of these strategies, however, requires phasing, and the specific comprehensive PV-diffusion goal should tie to the respective strategic phase. Further study is, however, important in designing a strategic framework for PV-cost-reduction implementation in developing countries, based on these drivers, needs and enablers. 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Published by Oxford University Press on behalf of National Institute of Clean-and-Low-Carbon Energy This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com © The Author(s) 2020. Published by Oxford University Press on behalf of National Institute of Clean-and-Low-Carbon Energy

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Abstract

Abstract The costs of clean-energy technologies are currently very high and their adoption in buildings is voluntary. This study evaluated strategies for improving the cost performance of photovoltaic (PV) electricity applied in buildings in Nigeria using a questionnaire survey involving 415 targets. The efficacy of each strategy and consensus in respondents’ perceptions were determined using Fuzzy Set Theory and Kruskal–Wallis tests. The top four strategies for achieving PV-cost reduction are mandating green buildings, standardization of building designs and PV components, facilitating import licensing and massive public education. Developing these strategies to improve the PV value chain will increase the supply capacity of clean energy in emerging markets. Graphical Abstract Open in new tabDownload slide buildings, cost reduction, photovoltaic, sustainable energy, sustainable development Introduction Buildings consume a significant proportion of global energy stock [1]. The main source of energy supply to buildings across developing countries is predominantly fossil-based electricity. The transmission of electricity to point-of-use involves an estimated loss of 6.8% and this proportion adds to the quantity of emitted carbon [2]. The environmental consequences of fossil-based electricity enhance the upsurge in the adoption of point-of-use-generated zero-carbon energy. Zero-carbon energy sources are renewable and various sources of renewable technologies exist, but solar photovoltaic (PV) energy has gained widespread approval in developing countries [3]. The expansion in renewable energy in Africa is further due to its contribution to increasing building energy efficiency, carbon reduction and aiding sustainable development goals [4–7]. The lack of reliability and non-availability of power supply are specific drivers supporting the penchant for the integration of PV technologies in buildings [5]. In Nigeria, power supply to buildings is not only low, but the spread is also low. The access to electricity by households in Nigeria was 60% in 2014 [8], with no significant growth in 2016 [9] and persistently declining [10]. The building sector in Nigeria consumes 55–60% of the current electricity output for 4–6 hours daily [10–12]. As in other nations, the energy demand by buildings in Nigeria is high but the efficiency of the current output is low. Strategic upscaling of the installed capacity of PV energy in this region is the desirable alternative for tackling energy poverty and the associated environmental problems [7, 13]. The potentials for solar energy and the applications of related technologies in buildings in Nigeria are compelling [4, 14], although accessibility and uptake of PV are laggard based on inferred high costs [15–17]. Despite advances in the dissemination of awareness relating to sustainable-energy development, most developing countries lack strategic policies for driving enabling technologies in the energy sector [9, 18]. Unlike related development in Asia [5, 19], the PV policies in Africa remain marginal after several decades [7]. The competition resulting from the niche created by the vast PV market in Africa seems inadequate as an incentive to improve the adoption of related technologies in the emerging markets. The high costs of PV systems continue to hinder the decision-making to adopt these technologies, replacing fossil-based electricity and fuel-based generators [15, 16, 20, 21]. Therefore, to thrive, several international intervention policies promoting PV adoption in this region, and clear and effective strategies for promoting cost reduction are imperative [7]. Various studies have appraised renewable-energy policies and strategies for improving access in Nigeria [14, 18, 22] and overseas [5–7, 19]. However, these studies focused on enablers, drivers, potentials and barriers, mainly using literature synthesis. The empirical evidence underlying the conclusions of these studies, in most cases, does not advance the severity and perceived performance of the relevance strategies for improving access to renewable energy along with regional variations. Therefore, despite the number of studies that evaluated the spread of PV technologies, the strategic mitigation policies to improving critical cost barriers are sketchy. PV-optimization studies researched the targeted selection process and building energy performance [23]. Other studies, amidst the empirical gap, focused on reforms aimed at solving national and regional energy problems [5, 19]. The inclination towards regional policies in past studies suggested that the critical problems inhibiting adoption require context-based solutions. Efforts to optimize the costs of Building-Integrated Photovoltaic (BIPV) systems [24] and the overall performance of the BIPV systems [24–27] also exist, but the adoption of PV technologies is currently very low due to the dearth of strategies to mitigate the perceived high costs. This paper argues that the cost of PV is a function of closely related drivers in the different phases of PV uses in buildings. A plethora of cost-related triggers such as component quality, low reliability, poor installation procedures and maintenance requirements are a few related concerns, which, when mitigated, would expedite PV adoption [26]. Chen and Riffat [28] reiterated the need for research to advance PV-cost mitigation to advance the sustainability of the built environment. This study, therefore, evolved practical steps to upscale the uptake of PV technologies in buildings, through empirical authentication of in-country perceived cost-mitigation strategies in Nigeria. The development of strategies to enhance point-of-use generation is capable of stimulating the supply of clean energy in emerging markets [4]. The research also provides desktop benchmarks for various actors in the PV value chain such as policy developers, industry partners and building developers to upscale adoption. The inability to generate data for policymaking in Nigeria is severe [29]; this study, therefore, contributes to resolving these problems in the energy sector. The objective of the study was to evaluate strategies for reducing the costs of PV technologies towards diffused integration in buildings in Nigeria. 1 The PV system The origin of the term ‘photovoltaic’ can be traced to Greek, in which ‘photo’ indicates light and ‘Volta’ was an Italian scientist who invented the chemical battery in 1800 [30]. The PV effect is therefore a direct conversion of solar energy into electricity. The panels are fabricated using material that allows electrons to energize in a free state from their atoms when subjected to light [30]. The current flows in one direction; hence, the electricity is direct current (DC). Photovoltaic systems, therefore, convert solar energy into electricity using PV cells combined in modules, and modules combined to form arrays. In developing countries, the most widely used method of deployment is to mount arrays on the roofs of buildings [15, 16, 19]. Solar PV is a member of the renewable-energy-technologies family. Renewable energy refers to energy obtained from sources that are replenished at a similar rate as used [28]. Other renewable sources include solar thermal, wind, biogas and hydroelectric technologies. There are three types of PV-cell technologies in the market across developing countries, namely mono-crystalline, silicon/polycrystalline silicon, amorphous silicon and thin-film technology of Copper Indium Diselenide (CIS) [30]. The mono-crystalline silicon is single-crystal silicon and has the highest efficiency rating of >26.7% [31]. The polycrystalline silicon is more expensive than mono-crystalline silicon; cells are fabricated from a block of cast silicon. Polycrystalline silicon has a conversion efficiency of 22.3% [31]. The amorphous silicon has the lowest conversion efficiency amongst all PV technologies (10–15%). However, mono-crystalline technology is readily available across market segments of the world, including Nigeria. The PV cell (panel) is the most significant component of the PV system, and the most significant cost driver [32]. The rooftop integration of PV across buildings accounts for >80% of applications across the globe [19, 33]. Current innovations to improve the cost management of PV adoption consider crystalline silicon technology to be more expensive and other technologies are economically viable substitutes [20]. 2 PV-cost-optimization strategies Global renewable-energy indices suggest a steady growth in the uptake of PV technology. Sustaining this growth trajectory requires reducing the costs (prices) of PV components, as an incentive to promote widespread adoption [3]. The vast proportion of extant literature links PV-cost mitigation with government actions as well as those of other stakeholders [3, 24, 34]. Yang and Zou [3] observed that strong government policy support and incentives are capable of motivating the adoption of PV technologies across sectors. This viewpoint leads to the postulation that effective, consistent and viable government policies are prerequisites to PV-costs reduction. Developing strategies for cost optimization must therefore focus on improving government policies to stimulate market growth. Lawton [34] established a relationship between the soft costs of PV and regional or local policies, while panel and module costs are affected by international trade regimes, the scale of technological development and production economics. The analysis of the causes of PV-cost reduction over 30 years revealed that enhanced module efficiency, increased research and development (R&D) and economies of scale could sustain the cost economy [35]. However, cost-mitigation solutions are pertinent through long-term policies and synergy between relevant stakeholders across the value chain. Cost-reduction strategies refer to drivers (policies) that contribute to lower PV costs by eliminating barriers and cost factors [5]. The effectiveness of cost-reduction strategies depends on the degree of their effectiveness to decimate cost factors and barriers. A Malaysian study showed that PV-integration policies must develop from the contexts of inherent drivers, enablers and barriers [6]. Enablers are facilitating policies, barriers are inhibitors, while drivers are strategies that can eliminate barriers [5]. Finance, incentives, policy, maintenance, promotion and housing-loan policies are focal drivers [6]. Therefore, market development and the provision of incentives are fundamental drivers to cost reduction [5]. Lawton [34] advanced five strategies for achieving economic competitiveness in the PV market. The five strategies focused on new corporate and public reforms and financing options, standardization of designs, streamlining permit issues, utility regulation and mandating green buildings. The study also proved that the early conception and incorporation of a photovoltaic system in the design stage are significant to mitigate the costs of remedial or retrofit works to roofs during installations. This study considers these strategies too generic to address the focal cost triggers predisposing high costs. Accordingly, standardizing panels, mandating solar homes, massive education and awareness campaigns can improve the costs of customer acquisition. Developing local technologies to aid the local manufacturing of PV components represents an enormous opportunity to improve the installed costs. The costs of PV modules and other components are consistent barriers to PV adoption across studies [15, 16]. The participants in these studies likewise agreed that interventions aimed at improving the reliability of PV components are essential to direct cost reduction. Similarly, mandating solar homes, the standardization of panels and relaxed permitting and inspection are strategic to improve installation costs. Encouraging and providing third-party financing is suitable to manage finance-related problems. Stimulating the local production of non-hardware components through the R&D of local content supports are imperative to lowering overall costs. Developing from the premise of innovation-system theory, Strupeit [36] revealed seven processes that could improve the soft costs in PV systems. The soft-cost-reduction policies include demand and market growth, supply-chain-agent interactions, knowledge acquisition and dissemination, producing variety and choice, and the development of institution capacity [36]. Improvement of the framework for supply-chain-based PV-cost governance is also significant to unbundle PV costs [3]. This strategy encompasses collaboration between key actors in the construction industry, namely government, professionals, manufacturers, clients, users and a league of others. The collective intervention of these stakeholders in their relevant sectors can eliminate knowledge gaps, provide subsidies, improve efficiencies and enhance market uptake. The roles of the identified stakeholders in PV-market uptake have been documented in past literature [37–39]. The strategies for the long-term cost optimization of BIPV also exist, namely the establishment of BIPV-information services, awareness and capacity-building programmes, the development of PV-market enhancement and infrastructure development, and improvement of policy and financial frameworks supportive for PV-market sustainability [24]. PV-market-development initiatives are needed to resolve technical feasibility and economic viability using demonstration projects, to promote a wider level of acceptance and to deepen understanding of the technology and its benefits [37, 38]. PV policies and financing programmes are adequate to advance activities directed at enhancing the ability of policymakers to institute appropriate, proactive and integrated plans, which can ensure the development and sustenance of a supportive business environment. Enhancing R&D is also a strategic way to develop, strengthen and organize the human-resource capacities of stakeholders [5]. Synergy through partnership with international joint ventures and companies can upgrade local firms, R&D institutions and the provision of technical infrastructures to test and standardize PV products. In Malaysia, Sopian [24] observed that the highlighted strategies improved PV-application rates by >300% over a 5-year strategic plan. The review of related literature in this section has shown that efforts to improve the cost-effectiveness of PV technologies require strategic planning, designed in phases to achieve short-, medium- and long-term cost-reduction targets. Table 1 provides a summary of theoretical cost-optimization variables for PV technologies from the literature. The strategies are categorized into three major groups, namely design; financing; and education, training and research. The postulation suggests the relevant policies for PV-cost reduction to enhance PV-system and building designs, financing, research, education and training. However, the existing PV-cost-reduction strategies are non-empirical and the product of institutional and technical literature. The scope of achievable cost reduction and the validity of the cost-reduction strategies are imminent empirical gaps in the literature. This study seeks to validate the potency of PV-cost-reduction strategies using empirical data, since the formative studies in the literature are non-empirical research. Table 1: Theoretical variables of PV-cost-reduction strategies Code . Strategies . Sources . Design strategies PCS1 Early conception and incorporation of photovoltaic system in the design stage [3, 40] PCS2 Mandate Green buildings [41] PCS3 Standardization of designs [34, 40] PCS4 Promotion of new business practices and developers [42] PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community [37, 43] PCS6 Simplifying permits and inspections [34] PCS7 Mandating solar power [3] PCS8 Relax level of inspection, permits and regulations policies [25] Financing strategies PCS9 Provide financing incentives [34, 42] PCS10 Develop and provide local content through research [26] PCS11 Facilitate import licensing to check & improve purchasing power benefits [39, 44] PCS12 Favourable tax policies [40, 45] Education, training and research PCS13 Massive public education and awareness campaign [24, 34] PCS14 Promote research to encourage local production of non-hardware components [35, 46, 47] PCS15 Provide real-time experiences for development in training and skills of stakeholders [26] PCS16 Institute relevant standards and update as at when required [26] PCS17 Set new guidelines for providing technical assistances to the industry [26, 38] PCS18 Detailed and document barriers and opportunities to cost efficiency to maximized shared experiences [26] PCS19 Promote installers licensing and certification [45] Code . Strategies . Sources . Design strategies PCS1 Early conception and incorporation of photovoltaic system in the design stage [3, 40] PCS2 Mandate Green buildings [41] PCS3 Standardization of designs [34, 40] PCS4 Promotion of new business practices and developers [42] PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community [37, 43] PCS6 Simplifying permits and inspections [34] PCS7 Mandating solar power [3] PCS8 Relax level of inspection, permits and regulations policies [25] Financing strategies PCS9 Provide financing incentives [34, 42] PCS10 Develop and provide local content through research [26] PCS11 Facilitate import licensing to check & improve purchasing power benefits [39, 44] PCS12 Favourable tax policies [40, 45] Education, training and research PCS13 Massive public education and awareness campaign [24, 34] PCS14 Promote research to encourage local production of non-hardware components [35, 46, 47] PCS15 Provide real-time experiences for development in training and skills of stakeholders [26] PCS16 Institute relevant standards and update as at when required [26] PCS17 Set new guidelines for providing technical assistances to the industry [26, 38] PCS18 Detailed and document barriers and opportunities to cost efficiency to maximized shared experiences [26] PCS19 Promote installers licensing and certification [45] Open in new tab Table 1: Theoretical variables of PV-cost-reduction strategies Code . Strategies . Sources . Design strategies PCS1 Early conception and incorporation of photovoltaic system in the design stage [3, 40] PCS2 Mandate Green buildings [41] PCS3 Standardization of designs [34, 40] PCS4 Promotion of new business practices and developers [42] PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community [37, 43] PCS6 Simplifying permits and inspections [34] PCS7 Mandating solar power [3] PCS8 Relax level of inspection, permits and regulations policies [25] Financing strategies PCS9 Provide financing incentives [34, 42] PCS10 Develop and provide local content through research [26] PCS11 Facilitate import licensing to check & improve purchasing power benefits [39, 44] PCS12 Favourable tax policies [40, 45] Education, training and research PCS13 Massive public education and awareness campaign [24, 34] PCS14 Promote research to encourage local production of non-hardware components [35, 46, 47] PCS15 Provide real-time experiences for development in training and skills of stakeholders [26] PCS16 Institute relevant standards and update as at when required [26] PCS17 Set new guidelines for providing technical assistances to the industry [26, 38] PCS18 Detailed and document barriers and opportunities to cost efficiency to maximized shared experiences [26] PCS19 Promote installers licensing and certification [45] Code . Strategies . Sources . Design strategies PCS1 Early conception and incorporation of photovoltaic system in the design stage [3, 40] PCS2 Mandate Green buildings [41] PCS3 Standardization of designs [34, 40] PCS4 Promotion of new business practices and developers [42] PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community [37, 43] PCS6 Simplifying permits and inspections [34] PCS7 Mandating solar power [3] PCS8 Relax level of inspection, permits and regulations policies [25] Financing strategies PCS9 Provide financing incentives [34, 42] PCS10 Develop and provide local content through research [26] PCS11 Facilitate import licensing to check & improve purchasing power benefits [39, 44] PCS12 Favourable tax policies [40, 45] Education, training and research PCS13 Massive public education and awareness campaign [24, 34] PCS14 Promote research to encourage local production of non-hardware components [35, 46, 47] PCS15 Provide real-time experiences for development in training and skills of stakeholders [26] PCS16 Institute relevant standards and update as at when required [26] PCS17 Set new guidelines for providing technical assistances to the industry [26, 38] PCS18 Detailed and document barriers and opportunities to cost efficiency to maximized shared experiences [26] PCS19 Promote installers licensing and certification [45] Open in new tab 3 Research methodology The research involved a survey research design. A self-study structured questionnaire was administered to targets drawn from relevant stakeholders associated with PV marketing, manufacturing, distribution, installation, design and promotion. The population of the study consisted of respondents from the Nigeria Energy Commission, construction professionals, PV contractors and electrical engineers. Preliminary inquiry data obtained from various databases of these bodies revealed a total population of 1010 targets. The Kish formula for sample-size determination [48] generated a sample of 415 respondents, including applied correction for non-response bias. The study was conducted in the six geo-political zones of Nigeria in eight cities: Abuja, Lagos, Port Harcourt, Dutse, Gombe, Calabar, Uyo and Enugu. The choice of survey research design using the questionnaire followed the trend in past studies [49, 50]. The survey therefore represents a strategic approach adapted to improved the existing theoretical data and knowledge of PV-cost-reduction strategies using key stakeholder experiences. The research instrument, the PV Cost Optimisation Strategies Questionnaire, was implemented to collect the study’s data. The questionnaire consisted of two parts: the first part contained questions relating to respondents’ background information including the role of respondents in the PV value chain, years of experience and educational qualifications; the second part elicited respondents’ perceived level of the effectiveness of identified PV-cost-mitigation strategies (Table 1). The respondents ranked their perceived level of effectiveness of the listed strategies on a five-point Likert scale. The five-point Likert scale was defined as 1 indicates that the strategy is not effective, the method has no potential to reduce costs; 2 indicates low effectiveness, the method has low potential to reduce cost; while 3 means medium effectiveness, a moderate effect on costs reduction; 4 indicates a high level of effectiveness, strategy is highly effective to mitigate PV cost; and 5 means very high effectiveness, the perceived level of the cost reduction of the strategy is very high. The administration of the research instrument involved a face-to-face survey and e-mails. The questionnaire-administration approaches yielded a response rate of 70% and an efficiency rate of 65% [51]. The study also determined the quality of the research design and measurement variables by conducting reliability tests because the literature review showed that the formative studies were non-empirical research. The result of the Cronbach’s alpha test indicated that the variables were indicative of optimization strategies for improving PV cost (Cronbach’s alpha = 0.78–0.92). Other data analysis involved Fuzzy Set Theory (FST) and the Kruskal–Wallis test. The Kruskal–Wallis test evaluated variance in the respondents’ perceptions of the effectiveness of PV-cost-reduction strategies, while FST determined the critical performance of each strategy following similar adoption in related studies [52, 53]. The effectiveness of each optimization strategy was therefore based on the critical-performance score obtained using FST. Studies [52] and [53] provide inclusive discussion about the theoretical dimensions of FST and its application in determining critical performance. The tool addresses fuzziness in the qualitative ranking and the analysis involves four steps: calculations of mean and standard deviation (SD), determination of Z score (Mean-3/Standard Deviation) and determination of the degree of membership using the Excel NORMDIST function. The degree of association forms the basis for setting a benchmark to select an effective strategy based on a 0.85 cut-off point [46] and scores in the range of 0.85–1.00 indicate full membership and a very high level of effectiveness. FST has diffused application in the determination of critical-performance indices within the research environment [54]. Overall, the research involved the five stages depicted in Fig. 1. Fig. 1: Open in new tabDownload slide Adopted research processes 4 Results 4.1 Characteristics of respondents The descriptive analysis of respondents’ characteristics validated the quality of the field data. The result in Table 2 shows that the lowest educational qualification of the respondents is Higher National Diploma (HND). The population of first- and higher-degree holders is also significant. The population of degree holders in the sample is 73%, while the combined population of degree holders and those with an HND is 90%. The composition of the sample with a valid academic qualification is therefore adequate to accept their perceptions about the effectiveness of identified PV-cost-reduction strategies. The majority of the respondents (57%) are design consultants, construction professionals and stakeholders in the PV-supply chain. The remaining 43% consists of vendors/distributors, building contractors and project managers. Fifty-one per cent operate in southern Nigeria and another 21% are in the northern part. Another 28% operate in Nigeria’s former and current capital cities (Lagos and Abuja). The sample is homogenous; 33% of respondents are in northern Nigeria, while 67% are in the southern part. Table 2: Respondent characteristics Educational qualifications . Professional qualifications . Years in related business . Variables . N . % . Variables . N . % . Variables . N . % . HND 24 13 Vendor/distributor 36 19 0–5 years 160 85 First degree 80 43 Design consultant 108 57 5–10 years 28 15 MSc and above 56 30 Project manager 24 13 10–15 – – Other qualifications 28 15 Building contractor 20 11 – – Total 188 100 Total 224 100 Total 188 100 Location South N % South N % Cosmopolitan N % Calabar 22 12 Jos 10 5 Abuja 23 12 Port Harcourt 38 20 Gombe 5 3 Lagos 30 16 Uyo 20 11 Dutse 10 5 - – Enugu 15 8 Kano 15 8 - - Educational qualifications . Professional qualifications . Years in related business . Variables . N . % . Variables . N . % . Variables . N . % . HND 24 13 Vendor/distributor 36 19 0–5 years 160 85 First degree 80 43 Design consultant 108 57 5–10 years 28 15 MSc and above 56 30 Project manager 24 13 10–15 – – Other qualifications 28 15 Building contractor 20 11 – – Total 188 100 Total 224 100 Total 188 100 Location South N % South N % Cosmopolitan N % Calabar 22 12 Jos 10 5 Abuja 23 12 Port Harcourt 38 20 Gombe 5 3 Lagos 30 16 Uyo 20 11 Dutse 10 5 - – Enugu 15 8 Kano 15 8 - - N, number. Open in new tab Table 2: Respondent characteristics Educational qualifications . Professional qualifications . Years in related business . Variables . N . % . Variables . N . % . Variables . N . % . HND 24 13 Vendor/distributor 36 19 0–5 years 160 85 First degree 80 43 Design consultant 108 57 5–10 years 28 15 MSc and above 56 30 Project manager 24 13 10–15 – – Other qualifications 28 15 Building contractor 20 11 – – Total 188 100 Total 224 100 Total 188 100 Location South N % South N % Cosmopolitan N % Calabar 22 12 Jos 10 5 Abuja 23 12 Port Harcourt 38 20 Gombe 5 3 Lagos 30 16 Uyo 20 11 Dutse 10 5 - – Enugu 15 8 Kano 15 8 - - Educational qualifications . Professional qualifications . Years in related business . Variables . N . % . Variables . N . % . Variables . N . % . HND 24 13 Vendor/distributor 36 19 0–5 years 160 85 First degree 80 43 Design consultant 108 57 5–10 years 28 15 MSc and above 56 30 Project manager 24 13 10–15 – – Other qualifications 28 15 Building contractor 20 11 – – Total 188 100 Total 224 100 Total 188 100 Location South N % South N % Cosmopolitan N % Calabar 22 12 Jos 10 5 Abuja 23 12 Port Harcourt 38 20 Gombe 5 3 Lagos 30 16 Uyo 20 11 Dutse 10 5 - – Enugu 15 8 Kano 15 8 - - N, number. Open in new tab 4.2 Critical performance of PV-cost-reduction strategies The level of effectiveness of the cost-mitigation strategies was analysed using FST. The result (Table 3) shows that 15 strategies (81%) out of 19 strategies evaluated are significant and effective to improve PV-cost performance. These strategies obtained λ-cut (Lambda Cut) values greater than the 0.85 benchmark adopted in the study (see the ‘Research methodology’ section). Further detail indicates that, overall, mandating green buildings emerged as the most effective strategy to improve PV-cost performance with a degree of association of 0.97. This strategy would ensure that newly built homes and major retrofitted homes adopt solar power and other passive design strategies towards energy efficiency. The spread of solar homes is capable of promoting the mass production of components to meet demand; the economies of scale would instruct cost reduction. The solar mandate would reduce costs by guaranteeing a customer base and promoting the benefit of economies of scale and design standardization. The second most effective strategy to optimize PV is to facilitate import licensing to check and improve purchasing-power benefits (λ-cut, 0.95). A massive public education and awareness campaign obtained a λ-cut score of 0.94 and emerged as the third most effective strategy to improve PV costs. Strategies with a low level of effectiveness represent 16% of the surveyed PV-cost-optimization strategies. This band of PV-cost-mitigation strategies obtained λ-cut values less than the 0.85 benchmark adopted by the study. The conclusion portrays their level of effectiveness to decimate the costs of PV technologies as low. Strategies in this category include PCS4 (the promoting of new business practices and developers), PCS16 (instituting relevant standards and updating them as and when required) and PCS17 (setting new guidelines for providing technical assistance to the industry). Growth drivers of PV-technologies adoption in the building sector are therefore unconnected to new business culture, new standards and guidelines based on the results of the study. Current and existing business practices, standards and guidelines are therefore adequate to support enabling policies towards adoption. Table 3: Effectiveness of PV-cost-reduction strategies Code . Strategies . SD . Z . M(xi) . Decision . PCS1 Early conception and incorporation of photovoltaic system in the design stage 0.92 1.22 0.89 ✓ PCS2 Mandate green buildings 1.32 1.79 0.97 ✓ PCS3 Standardization of designs 0.98 1.35 0.93 ✓ PCS4 Promotion of new business practices and developers 0.77 0.57 0.74 – PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community 1.01 1.10 0.87 ✓ PCS6 Simplifying permits and inspections 0.94 1.11 0.88 ✓ PCS7 Mandating solar power 1.11 1.42 0.93 ✓ PCS8 Relax level of inspection, permits and regulations policies 0.92 1.24 0.90 ✓ PCS9 Provide financing incentives 0.84 1.06 0.88 ✓ PCS10 Develop and provide local content through research 0.82 0.89 0.89 ✓ PCS11 Facilitate import licensing to check & improve purchasing power benefits 1.01 1.46 0.95 ✓ PCS12 Favourable tax policies 0.99 1.29 0.91 ✓ PCS13 Massive public education and awareness campaign 1.01 1.49 0.94 ✓ PCS14 Promote research to encourage local production of non-hardware components 0.89 0.98 0.86 ✓ PCS15 Provide real-time experiences for development in training and skills of stakeholders 1.04 1.32 0.93 ✓ PCS16 Institute relevant standards and update as at when required 0.89 0.36 0.67 – PCS17 Set new guidelines for providing technical assistances to the industry 0.87 0.77 0.25 – PCS18 Detail and document barriers and opportunities to cost-efficiency to maximize shared experiences 1.04 1.25 0.88 ✓ PCS19 Promote installers licensing and certification 0.95 1.42 0.91 ✓ Code . Strategies . SD . Z . M(xi) . Decision . PCS1 Early conception and incorporation of photovoltaic system in the design stage 0.92 1.22 0.89 ✓ PCS2 Mandate green buildings 1.32 1.79 0.97 ✓ PCS3 Standardization of designs 0.98 1.35 0.93 ✓ PCS4 Promotion of new business practices and developers 0.77 0.57 0.74 – PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community 1.01 1.10 0.87 ✓ PCS6 Simplifying permits and inspections 0.94 1.11 0.88 ✓ PCS7 Mandating solar power 1.11 1.42 0.93 ✓ PCS8 Relax level of inspection, permits and regulations policies 0.92 1.24 0.90 ✓ PCS9 Provide financing incentives 0.84 1.06 0.88 ✓ PCS10 Develop and provide local content through research 0.82 0.89 0.89 ✓ PCS11 Facilitate import licensing to check & improve purchasing power benefits 1.01 1.46 0.95 ✓ PCS12 Favourable tax policies 0.99 1.29 0.91 ✓ PCS13 Massive public education and awareness campaign 1.01 1.49 0.94 ✓ PCS14 Promote research to encourage local production of non-hardware components 0.89 0.98 0.86 ✓ PCS15 Provide real-time experiences for development in training and skills of stakeholders 1.04 1.32 0.93 ✓ PCS16 Institute relevant standards and update as at when required 0.89 0.36 0.67 – PCS17 Set new guidelines for providing technical assistances to the industry 0.87 0.77 0.25 – PCS18 Detail and document barriers and opportunities to cost-efficiency to maximize shared experiences 1.04 1.25 0.88 ✓ PCS19 Promote installers licensing and certification 0.95 1.42 0.91 ✓ ✓ = Effective; – = Not effective; MIS, mean item score; M(xi), degree of association to a set/critical performance. Open in new tab Table 3: Effectiveness of PV-cost-reduction strategies Code . Strategies . SD . Z . M(xi) . Decision . PCS1 Early conception and incorporation of photovoltaic system in the design stage 0.92 1.22 0.89 ✓ PCS2 Mandate green buildings 1.32 1.79 0.97 ✓ PCS3 Standardization of designs 0.98 1.35 0.93 ✓ PCS4 Promotion of new business practices and developers 0.77 0.57 0.74 – PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community 1.01 1.10 0.87 ✓ PCS6 Simplifying permits and inspections 0.94 1.11 0.88 ✓ PCS7 Mandating solar power 1.11 1.42 0.93 ✓ PCS8 Relax level of inspection, permits and regulations policies 0.92 1.24 0.90 ✓ PCS9 Provide financing incentives 0.84 1.06 0.88 ✓ PCS10 Develop and provide local content through research 0.82 0.89 0.89 ✓ PCS11 Facilitate import licensing to check & improve purchasing power benefits 1.01 1.46 0.95 ✓ PCS12 Favourable tax policies 0.99 1.29 0.91 ✓ PCS13 Massive public education and awareness campaign 1.01 1.49 0.94 ✓ PCS14 Promote research to encourage local production of non-hardware components 0.89 0.98 0.86 ✓ PCS15 Provide real-time experiences for development in training and skills of stakeholders 1.04 1.32 0.93 ✓ PCS16 Institute relevant standards and update as at when required 0.89 0.36 0.67 – PCS17 Set new guidelines for providing technical assistances to the industry 0.87 0.77 0.25 – PCS18 Detail and document barriers and opportunities to cost-efficiency to maximize shared experiences 1.04 1.25 0.88 ✓ PCS19 Promote installers licensing and certification 0.95 1.42 0.91 ✓ Code . Strategies . SD . Z . M(xi) . Decision . PCS1 Early conception and incorporation of photovoltaic system in the design stage 0.92 1.22 0.89 ✓ PCS2 Mandate green buildings 1.32 1.79 0.97 ✓ PCS3 Standardization of designs 0.98 1.35 0.93 ✓ PCS4 Promotion of new business practices and developers 0.77 0.57 0.74 – PCS5 Encourage PV supply chain cost framework collaboration of actors in the building sector, professionals, manufacturers, vendors, clients, users and community 1.01 1.10 0.87 ✓ PCS6 Simplifying permits and inspections 0.94 1.11 0.88 ✓ PCS7 Mandating solar power 1.11 1.42 0.93 ✓ PCS8 Relax level of inspection, permits and regulations policies 0.92 1.24 0.90 ✓ PCS9 Provide financing incentives 0.84 1.06 0.88 ✓ PCS10 Develop and provide local content through research 0.82 0.89 0.89 ✓ PCS11 Facilitate import licensing to check & improve purchasing power benefits 1.01 1.46 0.95 ✓ PCS12 Favourable tax policies 0.99 1.29 0.91 ✓ PCS13 Massive public education and awareness campaign 1.01 1.49 0.94 ✓ PCS14 Promote research to encourage local production of non-hardware components 0.89 0.98 0.86 ✓ PCS15 Provide real-time experiences for development in training and skills of stakeholders 1.04 1.32 0.93 ✓ PCS16 Institute relevant standards and update as at when required 0.89 0.36 0.67 – PCS17 Set new guidelines for providing technical assistances to the industry 0.87 0.77 0.25 – PCS18 Detail and document barriers and opportunities to cost-efficiency to maximize shared experiences 1.04 1.25 0.88 ✓ PCS19 Promote installers licensing and certification 0.95 1.42 0.91 ✓ ✓ = Effective; – = Not effective; MIS, mean item score; M(xi), degree of association to a set/critical performance. Open in new tab 4.3 Test of variation in respondents’ perceptions of the significant cost-reduction strategies Data analysis also determined the consensus in respondents’ perception of the critical performance of cost-reduction strategies. The study assessed variance using the sectors of the respondents based on the Kruskal–Wallis test. The statistic determined the hypothesis which states that there is no significant variation in respondents’ perceptions about the efficacies of identified PV-cost-reduction strategies. The result presented in Table 4 indicates a lack of significant variance in the aggregated perceptions of respondents about the efficacies of the significant and insignificant PV-cost-reduction strategies (p, 0.323 > 0.05). The null hypothesis was accepted. The conclusion shows consensus in respondents’ perception and the inference means that tested strategies are imperative to PV-cost reduction. Table 4: Result of the Kruskal–Wallis test Respondents’ group . Mean rank . Chi square . df . Asymp. Sig. . Decision . Public authority 45.87 Construction professionals 43.90 60.460 2 0.323 Accepted PV contractors 15.67 Respondents’ group . Mean rank . Chi square . df . Asymp. Sig. . Decision . Public authority 45.87 Construction professionals 43.90 60.460 2 0.323 Accepted PV contractors 15.67 Open in new tab Table 4: Result of the Kruskal–Wallis test Respondents’ group . Mean rank . Chi square . df . Asymp. Sig. . Decision . Public authority 45.87 Construction professionals 43.90 60.460 2 0.323 Accepted PV contractors 15.67 Respondents’ group . Mean rank . Chi square . df . Asymp. Sig. . Decision . Public authority 45.87 Construction professionals 43.90 60.460 2 0.323 Accepted PV contractors 15.67 Open in new tab 5 Discussion The significant strategies for mitigating the cost of PV technologies in the building sector are summarized as promoting strong government incentives, a collaborative PV-supply chain and the provision of incentives and education, training and research. The level of effectiveness of PCS14 (to promote research to encourage local production of non-hardware components) is low, despite exceeding the targeted benchmark (0.85). The implication is that the impact of R&D relating to PV manufacturing using local resources is low. The result of PCS14 also indicates low valorization of academic research related to PV technologies in practice within the study area. It also indicates a lack of synergy between academia and industry in solving challenges associated with the diffusion of the PV market in the critical building sector. The study also draws attention to the high level of effectiveness of PCS18, PCS9, PCS6 and PCS5 (Table 3). The result of PCS18 (detail and document barriers and opportunities to cost-efficiency to maximize shared experiences) is not a surprise; it is therefore consistent with the perception of respondents about PCS14. Lack of academia–industry collaboration and the dearth of strategic research to promote PV technology underpin PCS18. The implication is that the barriers to achieving cost economy in the use of PV technology are less prioritized in research. Therefore, the PV-market policy towards improving cost performance in Nigeria must prioritize R&D. Lack of collaborative supply-chain practices in design, manufacturing, marketing and distribution are also insignificant, based on the result of PCS5. The PV market in Nigeria is largely fragmented, and dominated by traders and vendors instead of by professionals. The dearth of the capacity to undertake design, installation, maintenance and performance monitoring is significant [7]. Design consultants in the building sector must improve skills in these areas to benefit the cost and quality of PV systems towards improving adoption. In addition, strategies focusing on mitigating low access to finance, cumbersome permits and inspection regimes are focal international trade barriers in most places including Nigeria. The low effectiveness rating of PCS6 (simplifying permits and inspections) and PCS9 (provide financing incentives) are therefore consistent. 5.1 Promote strong government intervention The mitigation of PV costs revolves around strong government policy and programmes. This is missing, however, in most developing countries. Lawton [34] corroborated this position, noting that strong government support was essential to achieving a common level of economic competitiveness in the PV market in the USA [34]. Eleri et al. [22] also observed that a strong national agenda on renewable energy is a prerequisite to achieving efficiency. Government intervention is important to stimulate competition locally, as well as to galvanize funding for commercializing research in renewable technologies. A study interpreted this strategy as developing a renewable-energy industry towards achieving overall sustainable development [14]. Past studies including Hwang et al. [47] agreed concerning the role of government and its supporting agencies in ensuring cost-effective sustainable building features. As observed by Lawton [34], the costs of non-hardware (soft costs) are significant drivers of PV costs, accounting for >50% of the installed cost of PV systems. Eighty per cent of the drivers of soft costs are concerns that are solvable using local or national policies; examples include customer acquisition, permitting, inspection and interconnection, financing, installation costs, affiliated non-module hardware, and taxes [34]. Soft-cost reduction requires sectoral or regional innovation strategies [36]. Pertinent strategies for soft-cost reduction require demand and market growth, interactions between supply-chain agents, education and training, careful selection of systems and the production of varieties, and institutional-capacity development [36]. The seven strategies align the philosophies of PCS4, PCS5, PCS10, PCS13 and PCS17-19 in Table 3. The strongest links to reducing the soft costs of PV technologies are the local manufacturing of non-hardware accessories and human-capacity development. The study by Bizzarri et al. [55], judging from the sharp decrease in the price of PV systems over the years, posited that a cost-effective PV regime is possible through production efficiency and technology improvement. A related study by Bachellerie [41] also found that the extent of PV adoption depends on the extent to which technologies become affordable and readily efficient. The first mechanism to achieving affordability is to increase the level of technology adaptation and acquisition of related expertise by local manufacturers and scientists. This would mean creating requisite knowledge and skills as fundamental requirements of technological competences in the industrial development pathway. The second aspect deals with promoting the fitness and cost-efficiency of PV technology to local conditions, increasing R&D and initiating demonstration projects in order to create niches for the technology in the region. The primary cost driver of PV costs, namely modules, remains an imported component in emerging markets. Government incentives/subsidies, low-interest loans, the design of customized financing schemes for sustainable-energy development, subsidizing research in support of hardware development and tax relief are important to achieving cost economy in hardware components. Government intervention can also take the form of designed learning in renewable-energy educational courses and technical information. This dimension would improve the knowledge and skills essential to mitigating the cost of hardware in PV systems. A study by Eleri et al. [22] maintained that related information empowers communities, companies and civil-liberty society groups to make choices. Retzlaff [46] found that federal-government guidance, building a strong research agenda for renewable-energy policy, was significant to spur innovation and increase the adoption of PV. Access to information on available technologies, costs, benefits, government programmes and international support mechanisms in Nigeria are, however, inadequate. There is need for active engagement of the local media such as radio, TV, newspaper and the internet as part of environmental education. Festus and Ogoegbunam [56] recommended environmental education to enlighten the public on the benefits and the need to adopt renewable technologies to protect the environment. The pertinent viewpoints emerging from the Indian experience that can promote large-scale application are dependent on three fundamental goals. The three strategies were defined as prioritizing rooftop technologies, developing clear PV-integration policies and enforcing renewable-energy deployment mandates. The government can also provide incentives as the best strategy to enhance the spread of solar homes [15]. Fina et al. [57] concluded that government subsidies and financial incentives are imperative to promoting active building designs. 5.2 Encourage a collaborative PV-supply-chain management framework The first level of collaboration and integration must target multiple parties’ roles within the construction industry, including government, professionals, client, end-users (community) and manufacturers. The government role is to promote policies and generate funding, education and R&D, and increase awareness towards sustainable-energy uses [37]. Manufacturers must invest in R&D to upscale efficiency in order to reduce costs [3]. Azadian and Radzi [38] also considered skills and knowledge as being imperative to reducing the delays and costs associated with customized design. The client’s duty is to stimulate an environmentally friendly energy system by seeking knowledge about its benefits [43]. However, the quest for knowledge advocated by the literature also requires a commitment to investing in PV adoption [3]. Supply-chain collaboration would also ensure that shared experiences are fertilized across regional levels between project developers, PV contractors, policymakers and regulators. This level of collaboration would assist in the supply chain to examine cost structures and the influence of in-country circumstances on cost. Supply-chain collaboration would also enhance in-country strategy development based on applied lessons from unique experiences. However, the effectual analysis of the PV-cost structure would also require detailed documentation of barriers to and opportunities for efficient cost structures in the market. The use of regional dialogue through joint projects and workshops is also proficient to benefit cost-related learning [44]. This could also support shared perspectives and the identification of the responsibilities of each stakeholder in contributing to efficient implementation of cost-mitigation trails. 6 Education, training and increased awareness Appropriate information services, awareness and capacity-building programmes can be beneficial in a number of ways. They will improve the level of understanding and raise awareness for understanding the technology, its benefits and ecological significance. The results of PCS13 (massive public education and awareness campaign) and PCS15 (provide real-time experiences for development in training and skills of stakeholders) validate the importance of this dimension. Deep awareness relies on extensive education campaigns and capacity building. Studies have found seminars, workshops and information resource databases to be significant practices in achieving an appropriate level of penetration. Sopian et al. [24] supported these tools to improve stakeholders’ level of competence and the quality of work of the service providers. Information services will further situate decision-makers to gain market opportunities towards enhanced policy initiatives. Exemplar projects are also important to entrench deep learning and awareness in providing real-time experiences and increased efforts in R&D activities. Market-development policies are also important education and awareness-dissemination practices for ensuring that relevant standards are in place and are updated in a timely manner as a set of new guidelines for providing technical assistance to the industry. Market-development policies include appropriate legal, institutional, financial and fiscal measures for PV-market development. Education, training, research and increased awareness have benefited related market development in Asian countries [24]. The benefits of R&D would therefore stimulate an increase in installed capacity and a long-term cost reduction of technology through an increase in demand, economies of scale and competitive local manufacturing. Education, awareness, knowledge and skills improvement are also strategies for mitigating labour costs. The creation and dissemination of prerequisite knowledge relating to PV are drivers of soft costs within the PV system [36]. The study by Bachellerie [41] agreed that the PV labour market requires nationalization in order to regulate and mitigate the cost of labour. This understanding places PV-market development, for instance, with the development of national capital or local contents. Non-professionals dominate the existing market structure in most developing countries and these entrepreneurs lack the prerequisite expertise on the design and integration of PV systems into the building system. The drive to improve the labour costs of PV is unconnected with loss of jobs, and rather with promoting the efficiency, effectiveness and standardization of the work [34]. A study by Hwang et al. [47] also showed that improving the skills and experience of contractors and professionals is a strong driver of cost reduction towards the wider adoption of green-building technologies in Singapore. In addition to the education, awareness and skills development, past study identified technological innovation systems as one of the most important realms to unravel the institutional barriers bedevilling PV diffusion in Africa [7]. The issues of technology innovation within the context of education policy advocated in this research and in line with past studies concern the appropriate use of R&D [19]. The scope of R&D has no significant consequence on renewable-energy innovation [58]; therefore, research promotes growth in PV expansion in varying ways. The cost of PV systems is important for their selection and integration into building-project development. Cost determines the duration, quality of projects, profitability and the overall building costs [13]. This understanding places a premium on the need to achieve cost economy in the application of PV technologies to optimize project duration, quality, profitability and building costs. The significance of efficient regulatory apparatuses for PV-cost reduction is consistent with the norms established across previous studies [14, 28]. The three framings of strong government policy, collaborative supply chain and education, and training and increased awareness are veritable dimensions of cost-reduction applications in the PV market. Some policy dimensions advanced in this paper corroborate the positions in Shukla [5]. Shukla [5] posited that the mitigation of implementation barriers, deployment of incentives and advanced R&D are pertinent drivers of PV adoption. Therefore, R&D, appropriate regulatory governance and the mitigation of cost factors are coherent cost-reduction strategies for PV integration into buildings [14, 28]. Even though these cost-reduction policies are important, other critical cost factors and barriers impeding PV adoption in buildings must be mitigated. The understanding is that the incorporation of PV systems into buildings is conditioned to face cost barriers until policies and reforms become more effective, technologies become more affordable, awareness, education and training are upscaled, and every stakeholder is oriented to pursue energy efficiency as a part of sustainable development goals. Therefore, policymakers in developing markets must judiciously plan their future energy policies around strategies that optimize government intervention, education and training, supply-chain collaboration and awareness of energy efficiency, including how PV adoption can fast track sustainable development goals. The important strategies outlined above emphasize cooperation and a more active involvement of the public/private sector, professionals, professional bodies, regulatory agencies and households contextualized as a component of long-term strategic policies. 7 Conclusion Policies in the building sector to incorporate sustainable-energy systems in buildings in most developing countries have not been able to balance costs with the need to ensure diffused adoption. This study evaluated strategies for mitigating the costs of PV technologies applied in buildings in the typical context of a developing country: Nigeria. The results showed that strong government intervention, a collaborative PV-supply chain, and education, training and increased awareness are strategic to PV-cost reduction. These strategies are significant to drive mandatory green-building policies, the standardization of building designs/PV components, import-licensing facilitation, massive public education and the provision of real-time experience-based training for installers. The strategies are also adequate to optimize the cost drivers associated with customer acquisition, permitting, inspection and licensing, financing and the lack of incentives to importers, manufacturers and users. The development of future PV-market-penetration policies for developing countries should optimize these strategies for optimal results. The implementation of these strategies, however, requires phasing, and the specific comprehensive PV-diffusion goal should tie to the respective strategic phase. Further study is, however, important in designing a strategic framework for PV-cost-reduction implementation in developing countries, based on these drivers, needs and enablers. 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Published by Oxford University Press on behalf of National Institute of Clean-and-Low-Carbon Energy This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com © The Author(s) 2020. Published by Oxford University Press on behalf of National Institute of Clean-and-Low-Carbon Energy

Journal

Clean EnergyOxford University Press

Published: Dec 31, 2020

References