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Revista Minelor – Mining Revue ISSN-L 1220-2053 / ISSN 2247-8590 vol. 29, issue 1 / 2023, pp. 63-78 THE EMERGENCE OF NON-ENERGY USES OF COAL AND THE FUTURE OF LIGNITE MINING IN A REGION OF LOW CARBON FOOTPRINT, A CASE STUDY 1* 2 3 Francis PAVLOUDAKIS , Evangelos KARLOPOULOS , Chrisoula PAGOUNI Department of Mineral Resources Engineering, University of Western Macedonia, Kozani, Greece, firstname.lastname@example.org Chemical Processes and Energy Resources Institute, Centre for Research and Technology HELLAS (CERTH), Ptolemaida, Greece, email@example.com Department of Mineral Resources Engineering, University of Western Macedonia, Kozani, Greece, firstname.lastname@example.org DOI: 10.2478/minrv-2023-0005 Abstract: The rapid development of renewable energy sources, which has been going on for the last two decades, allows now the elimination of the coal use for power generation. Nevertheless, coal will continue to be used in key-industrial sectors, such as steel and cement production, which are crucial for maintaining the living standards of modern society. The future remains doubtful for coals of poor quality characteristics, such as lignite, which is used almost exclusively for power generation purposes. The present study aims to show that, even in the case of lignite, the transition to a zero-carbon economy must be decoupled from the mines closure. In this context, a combined SWOT–AHP analysis was conducted in order to compare seven potential non-energy uses of the lignite produced in the mines of Western Macedonia region, based on six criteria that are in line with the framework set by the European Union for the selection of the best technologies for every site-specific case. This comparison showed that the most promising technologies are related to the production of organic fertilizers and soil amendments, raw materials and products for the construction industry, activated carbon, and graphene. These technologies may contribute to the achievement of socioeconomic and environmental targets that are critical for the just transition of Western Macedonia region to a new, sustainable productive model. Keywords: lignite, energy transition, non-energy uses, SWOT analysis, MCDA, Western Macedonia 1. Introduction The technological developments in energy storage systems, the emergence of decentralised power generation technologies, the need to adapt energy management to the digital economy and, above all, the global challenge of tackling the climate crisis, define the new framework for the entire energy economy at both national and European level. In this context, the clean energy transition refers to the shift of the energy sector from fossil fuel-based power generation systems to renewable energy sources . On the other hand, in 2020 the global fossil coal market amounted to $ 698 billion maintaining 7 million jobs, while the assets of the forty largest companies that are active in coal mining and trade were estimated at a staggering $1.16 trillion . Nevertheless, given that the economically recoverable coal reserves worldwide exceed 1.16 trillion tons , most countries are looking for alternative technologies for harnessing coal and lignite in non-energy uses. This means that the global target of the energy transition and decarbonisation of the power mix do not necessarily result to the definitive closure of coal and lignite mines. The capitalization of infrastructure and know-how accumulated by the coal value chain at regional level, the need of creating a safe "bridge" for the transition of local communities to the new productive model and, above all, the multiple prospects offered by coal as a raw material, define new conditions in the global coal economy . Corresponding author: Francis Pavloudakis, Assoc. Professor, Department of Mineral Resources Engineering, University of Western Macedonia, Kozani, Greece, Contact details: email@example.com 63 Revista Minelor – Mining Revue vol. 29, issue 1 / 2023 ISSN-L 1220-2053 / ISSN 2247-8590 pp. 63-78 This development, however, exposes many countries and regions to severe economic, social, and environmental impacts. Unless properly managed, the clean energy transition may lead the areas still heavily dependent on fossil fuels extraction to a long period of economic crisis . Considering that the countries and regions affected more by energy transition have limited capacities to implement the required socio-economic transformations, it is inevitable that decarbonisation will be a process with numerous implications, delays, and harmful side effects [1, 6, 7]. This is also the case of Western Macedonia region (Figure 1), given that 25% of its regional GDP results from the extraction and combustion of lignite for power generation purposes. Lignite mining in Western Macedonia has been going on since the 1920s. Since 1956, the exploitation of lignite deposits was launched at an intensive pace and fully industrialized. With the involvement of the Public Power Corporation of Greece, the capacity of lignite-fired power plants reached a total of 4,300MW. In the decade of 1990, the mines provided 5,600 permanent jobs and the power plant more than 2,500. Up to now, 1.7 billion tons of lignite have been produced, and more than 8.5 billion cubic meters of rocks have been excavated. According to the mines operator, the exploitable lignite reserves that will remain after the closure of the last thermal power plant (2028) will exceed 3.1 billion tons . Western Macedonia Region Figure 1. EU regions affected by energy transition classified based on the number of employees in coal industry  The lignite produced in the mines of Western Macedonia was almost exclusively used for power generation purposes. This is the typical case for all the low-rank coals. Only limited quantities of lignite were used by metallurgies in Greece and Northern Macedonia and for the heating of residences, small industries and greenhouses. However, many non-energy uses of coal and lignite are known and firmly established for decades while innovative uses are still emerging. The most prevalent non-electric use of coal is in steel metallurgy. Coal is used in 70% of the world’s steel production. Steel manufacture delivers the goods and services that growing economies need. For instance, it plays a significant role in delivering renewable energy. Each wind turbine requires 260 tons of steel made from 170 tons of coking coal and 300 tons of iron ore. In 2019, global metallurgical coal consumption rose 3.2% to 1,080 Mt with China being by far the largest consumer accounting for 64% (691 Mt) of the global total. Since there is no near-term substitute for coal in steel production, it can be safely predicted that coal demand for steel production will remain constant . 64 Revista Minelor – Mining Revue vol. 29, issue 1 / 2023 ISSN-L 1220-2053 / ISSN 2247-8590 pp. 63-78 Furthermore, because of its relative affordability, coal is the most widely used source of energy in the manufacturing process of other energy intensive materials such as cement, aluminium and lime. However, in these cases coal utilization is also subjected to CO emissions control restrictions. Coal is also used for the production activated carbon, carbon fibres, hydrogen, liquid fuels, silicon metal, coal tar and many other chemicals . These materials are vital in transport, infrastructures and modern life in general. In addition, the production of soil amendments and fertilizers  as well as the extraction of rocks, such as sands and clays contained in the overburden strata of coal deposits, provide new products that may have various applications in the agriculture and the construction materials and ceramics industry. The development of the aforementioned non-electric uses requires coal of strict quality standards. Therefore, a question still remains about what could be the future uses of low rank coals with widely varying quality characteristics, such as lignite and peat. Although not included in the scope of this study, it is worth mentioning the co-combustion of lignite and biomass to meet the thermal needs of residential, industrial and agricultural activities. This option is ideally combined with the utilization of the energy content of farm residues and municipal solid waste that would otherwise disposed of in landfills, since the costs and logistics for their collection, transport and storage are infeasible. In fact, these projects can be carried out with small, decentralized combustion plants on a local scale, minimizing fuel transport costs and promoting the idea of energy democracy. At the same time, it would be possible to find synergies in the exploitation of reclaimed lignite mining areas by growing certain plant species that maximize biomass production. This specific land use of the reclaimed mine surfaces has many advantages, taking into consideration probable problems of soil fertility and high content of toxic elements, limited water quantities for irrigation, restrictions relevant to the cultivation of edible plants, etc. Essentially, it incorporates some of the basic principles of the circular economy and the rational management of natural and energy resources . In this context, the main objective of this paper is to analyse the opinion of experts regarding the commercially mature and emerging technologies of lignite non-energy uses, which are the most appropriate in the case of Western Macedonia, taking into account a series of criteria that have been proposed for decision- making procedures of this category. Directing the interest of the research community, local authorities and other stakeholders to the most promising technologies, this paper aspires to take the first step towards the development of a roadmap for the exploitation of the remaining lignite deposits, after the phase out of power generation units, for the production of high added value products. 2. Materials and methods The applied methodology is a strategic management process applicable in various decision making problems. It incorporates Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis for the qualitative evaluation of the compared alternatives, Analytical Hierarchy Process (AHP) for interpreting qualitative evaluation to quantitative, and the engagement of a group of eight experts that guarantee its participatory character. Similar methodologies combining SWOT and AHP methods are referred in the literature as decision-making tools in project management , mining industry [14-16], manufacturing , natural resources management , and in the post-mining land uses planning and redesign . In the case of the selection of the most appropriate non-energy uses of the lignite produced in Western Macedonia region, the methodology is applied in eight steps analysed as follows: a. Creation of a working group For the purposes of the present study, the Department of Western Macedonia of the Technical Chamber of Greece set up a working group consisting of seven engineers with adequate scientific background and long- term professional experience in lignite mines planning and operation, energy technologies and environmental management. The working group members had the following specialties of engineering: surveying (MSc), architecture (MSc), mechanical engineering, mineral resources (PhD), environment, spatial planning (MSc), and chemistry (MSc). The group was joined by an eighth member, a chemist (PhD), who is expert in nanotechnologies. b. Selection of lignite non-energy uses of particular interest for the Region of Western Macedonia Based on their knowledge and experience and a thorough review of the literature and previous research projects and studies relevant to non-energy uses of Greek lignite, the members of the working group decided to investigate further the following non-energy uses of lignite: Production of liquid and gaseous fuels and raw materials for the chemical industry 65 Revista Minelor – Mining Revue vol. 29, issue 1 / 2023 ISSN-L 1220-2053 / ISSN 2247-8590 pp. 63-78 Recovery of rare earth elements Production of activated carbon Production of graphene nanomaterials Production of organic fertilisers and soil amendments Production of hydrogen Production of raw materials and products for the construction sector c. Implementation of SWOT analysis for each of the examined non-energy uses of lignite The SWOT analysis has introduced in strategic management research in early 1960s. As a method, investigates the internal factors, known as strengths and weaknesses, as well as the external factors, known as opportunities and threats, which have influence in an organization, an industrial service, a plan of action or a project [20, 21]. In the case under investigation, the internal factors are within the control of local authorities, which undertake the responsibility to select and develop the non-energy uses of lignite, while the external factors are out of the control of these organisations (e.g. legal framework, competition, financial support). Other peculiarities in this case are the following: Regarding the internal environment, each non-energy use can be applied with several methods, techniques, and capacities and in different locations that differentiate critical characteristics for their assessment, such as costs and environmental impacts. These differences must be taken into account in any decision-making. For instance, in case of gasification, the evaluation results presented in the following sections was based on the assumption that it will take place in-situ. Regarding the external environment, the one-dimensional economic development of Western Macedonia region, with the energy industry as the central pillar for more than 5 decades, has suspended economic activity at the level of small and medium-sized enterprises and has increased dependence on the public investments. d. Conduct of a preliminary environmental impact assessment The investigation of the above non-energy uses of lignite took into account their expected impacts on numerous components of the environment, including components relevant to economic growth, quality of life, and social prosperity. A total number of 47 components of the environment were assessed. e. Selection of the criteria for evaluating the non-energy uses of lignite The evaluation of the seven non-energy uses of lignite under consideration was based on six criteria that are in line with the framework set by the European Union for the selection of the best technologies from the proposed toolkit (https://energy.ec.europa.eu/topics/oil-gas-and-coal/eu-coal-regions_en), based on the specific characteristics of each region in energy transition. In particular, these criteria are the following: Technological maturity Suitability of domestic lignite in terms of quality characteristics and critical mining sizes Eligibility of investment Capitalization of infrastructure and know-how Positive impact on employment Degree of circularity, as an indication of environmental performance f. Application of AHP to determine the relative importance of the criteria The AHP is a groupware multi-criteria decision-making method (MCDM), widely developed in academic research, industry, manufacturing, finance, businesses and project management . The method is a simple, well-understood and easy problem-solving tool and does not require complex or costly software for its application . AHP is structured in a hierarchical model synthesizing the decision-making problem goal, the evaluation criteria and the alternative solutions enabling evaluators to express and transform their knowledge, professional experience and judgements, in form of numerical data. The evaluators perform a series of pairwise comparisons to construct reciprocal matrices and to define the relative weight of factors and the performance of each alternative over each of these factors [24-26]. The SWOT analysis is usually used in combination with the AHP method in order the relative importance (weight) of each evaluation factor of the SWOT analysis to take a specific numerical value, and then, to be introduced in the calculations for ranking of the alternative strategies. 66 Revista Minelor – Mining Revue vol. 29, issue 1 / 2023 ISSN-L 1220-2053 / ISSN 2247-8590 pp. 63-78 In the examined case, the importance (weight) of each of the evaluation criteria of the non-energy lignite uses, which were selected in the previous step, was determined by applying the AHP method using as evaluators the eight members of the working group. Their opinions were recorded and processed using the spreadsheets developed by the company Creative Commons based in San Francisco, USA http://creativecommons.org/licenses/by-nc/3.0/sg/ and freely accessible from the internet. In Table 1, the input table used by the members of the working group for expressing their opinions about the relative importance of the six criteria is presented. The input table is based on the comparison of the six criteria in pairs, where each time the strongest criterion is determined by a letter while the superiority of one over the other by a number, according to the instructions provided in Table 2. Table 1. Comparison of the non-energy lignite uses evaluation criteria using the AHP method (example of a table, as it was filled in by a member of the working group) Criteria …and to what extent Which criterion is this criterion more is more important … A B i j important? Lignite quality characteristics 1 2 A 3 and critical mining sizes 1 3 Eligibility of investment A 2 Technological maturity Capitalisation of infrastructure 1 4 A 3 and know-how 1 5 Positive impact on employment A 2 1 6 Degree of circularity A 2 2 3 Eligibility of investment A 3 Lignite quality Capitalisation of infrastructure 2 4 A 3 and know-how characteristics and 2 5 critical mining sizes Positive impact on employment B 2 2 6 Degree of circularity A 1 Capitalisation of infrastructure 3 4 B 3 Eligibility of and know-how 3 5 investment Positive impact on employment B 3 3 6 Degree of circularity B 3 4 5 Capitalisation of Positive impact on employment B 2 infrastructure and 4 6 Degree of circularity B 2 know-how Positive impact on 5 6 Degree of circularity A 1 employment Table 2. Numerical definition of the relative importance of a criterion compared with the others Intensity of importance Definition 1 Equal importance 3 Moderate importance 5 Strong Importance 7 Very strong importance 9 Extreme importance The intensity numbers 2,4,6,8 can be used for expressing intermediate degrees of importance g. Comparative assessment of the non-energy uses of lignite Each one of the examined non-energy lignite uses is characterized by its own advantages and disadvantages, which can be interpreted as evaluation factors. Some of these factors are internal and depend on the performance capabilities and deficiencies of the lignite deposits and the mines. Some other factors are external and have to be effectively managed by the authorised parties for minimization of risks and maximization of the new business opportunities, so that the non-energy uses of lignite to be proven beneficial from the social, environmental and economical point of view. In this context, the role of the experts, in this case the members of the working group, was crucial for the decision-making procedure. The combination of SWOT and AHP methods provided the basis of a creative aggregation of knowledge, empirical evidence and various judgements and opinions expressed for the development of non-energy uses for the lignite produced in the mines of Western Macedonia. Moreover, the members of the working group had the opportunity to make their personal judgement and to take, under various 67 Revista Minelor – Mining Revue vol. 29, issue 1 / 2023 ISSN-L 1220-2053 / ISSN 2247-8590 pp. 63-78 ways, consultation from representatives of companies, local authorities, NGOs and other stakeholders and afterwards, to quantify and introduce this information in the rating of the compared technologies. h. Review of results The working group members highlighted the pros and cons of the methodology by analysing the way with each criterion or factor of the SWOT and AHP methods shaped the outputs of the procedure. Moreover, they compared the results, as these were reflected in the ranking of the examined technologies, based on the professional judgement of each one and tried to review and disseminate the knowledge gained from this project. 3. Results 3.1. The selected non-energy uses of lignite The seven non-energy lignite uses that were selected to be further investigated are presented in Figure 2. In view of the ongoing debate on whether the closure of the lignite-fired steam power plants will be combined with the closure of lignite mines, these non-energy uses have been divided into three categories, depending on whether or not their development requires active lignite mines. Apart from in-situ gasification and graphene production, all other uses are based on active mines, albeit of limited production capacity compared to the existing ones, either for the production of lignite or for the recovery of ash and clays from the waste heaps. In the following paragraphs, a brief review of the basic characteristics of the considered non-energy lignite uses is presented. • Soil amendments and organic fertilizers Lignite • Activated carbon production in an active • Chemical industry mine products • Hydrogen production • In-situ gasification Closed • Nanomaterials and mines graphene • Production of raw materials for contruction Dumps industry • Recovery of REE Figure 2. Connection of the operational status of lignite mines with the development of non-energy lignite uses In-situ coal gasification also known as underground coal gasification appears to be both technically and economically feasible and exhibits many potential advantages over the conventional mining methods. The gasification process creates synthesis gas that can be used as fuel, or feedstock for further chemical processes. An oxidant (usually air, oxygen, or steam) is injected into the coal seam and reacts with the coal and water present in the seam to produce synthesis gas that is extracted through a production well. In-situ gasification has less environmental impacts compared with conventional mining including no discharge of tailings, reduced sulphur emissions and reduced discharge of ash. Thus, in the coming years it is expected to compete against other fuels not just on an economic basis but also on the basis of overall environmental performance, after improvements in hydraulic control of the process, which is crucial to prevent groundwater pollution, and incorporation of carbon capture and sequestration technologies [27, 28]. 68 Revista Minelor – Mining Revue vol. 29, issue 1 / 2023 ISSN-L 1220-2053 / ISSN 2247-8590 pp. 63-78 In addition, Greek lignite is an excellent raw material for the production of soil improvement and organohumic fertilizers . In Greece, due to the Mediterranean climate and intensive agricultural crops, a significant degradation of the soils supporting the primary agricultural production has occurred, due to the loss of organic humus. The consumption of mineral fertilizers does not solve the problem, but exacerbates the nitrate pollution of aquifers, while the search for methods of preserving organic matter in soils is becoming increasingly expensive. Consequently, it emerges as a necessity to support investment plans aimed at exploiting small lignite deposits for application either as soil conditioners or as raw material for the production of organohumic fertilizers, ingredients rich in humic and fulvic acids. Studies done with humic components isolated from lignite, have shown that these have a beneficial effect on seed germination, nutrient absorption by plant tissues, stem and root system growth, as well as increasing the production and quality of a wide variety of crops. At international level, lignite is used as a raw material for the production of organohumic fertilizers in the form of salts of humic acids or humic acids enriched in nitrogen and potassium. Typical examples of successful use of lignite for the production of soil conditioners are the NOVIHUM® and actosol® products of Novihum (Germany) and Arctech (USA), respectively, creating extremely successful and profitable investments [29, 30]. The production of activated carbon from lignite is an additional commercially mature technology. The most important property of active carbons, due to their porous structure, is their ability to adsorb and retain on their surface substances that are in the gaseous or liquid phase. An important advantage for the use of lignite as a raw material for the production of activated carbon is its low cost, since activated carbon is a product with high demand in water management and the chemical industry. The majority of activated carbon applications are related to discoloration, odour removal, cleaning, dechlorination, removal of toxic substances, solvent recovery and as a substrate in catalysts. In tertiary wastewater treatment systems, activated carbon is used to remove residual substances and other toxic organic compounds after primary filtration and secondary biological treatment process . An emerging but promising technology concerns the production of lignite-based graphene nanomaterials. Graphene is a material consisting of pure carbon, similar to graphite but with characteristics that make it extremely light and strong. A sheet of one square meter of graphene weighs 0.77 mg, while its strength is 200 times greater than that of steel, and its density is similar to that of carbon fibre. It is one of the most conductive materials for electricity and heat, which makes it the most suitable material for electronics and many other industrial uses. For many experts, graphene is the material of the future, since its applications are practically limitless and promise to revolutionize in many areas. It is characteristic that while the production of graphene in 2010 was 28 tons, it is projected to increase to over 750 tons by 2025. The value of this nanomaterial is extremely high and amounts to 862,000 €/kg. There are already multinational companies active in graphene research and development (e.g. Intel and IBM in the IT sector, Dow Chemicals and BASF as suppliers of basic graphene hardware and Samsung in consumer electronics). One of the biggest challenges we face today in the commercialization of graphene is how to produce high-quality material, on a large scale at low cost and in a reproducible way. The quality of graphene plays a decisive role, since the presence of residues, impurities, granules, multiple sheets, structural disorders, "wrinkles / cracks" in the graphene sheet can have an adverse effect on its electronic and optical properties. A research team in Greece succeeded in manufacturing high purity graphene from lignite with a specific methodology based on the conversion of lignite into humic acid and later into graphene oxide before the manufacture of the final product [32, 33]. The case of rare earths concerns a category of high-demand mineral raw materials that is expected to escalate further in the future. Rare earth elements are used in critical technologies for the digital age, including many that find application in armament systems. This, combined with the small number of exploitable deposits and China's control of the global market, makes the recovery of rare earths from secondary sources a top priority technological challenge for global industry. Therefore, it is appropriate to strengthen research by local scientific bodies, with the aim of both ascertaining the rock content of rare earth elements that occur in the lignite mines of Western Macedonia and in the by-products produced by the combustion of lignite, and assessing their recoverability at an acceptable cost. In case the first investigations give promising signals, it is highly likely that there will be international interest in the commercial exploitation of rare earths associated with the lignite deposits of Western Macedonia . In any case, it is already established that the recovery of rare earths from lignite is easier than in the case of hard coal, while the ash content of rare earth elements is increased by 6-10 times compared to lignite. What is commonly accepted by the scientific community is that there is still no method for recovering rare earth elements from lignite and its by-products, capable of being applied on an industrial scale on economically viable terms [35, 36]. Regarding the use of lignite for hydrogen production, it is worth noting that 98% of the world's hydrogen 69 Revista Minelor – Mining Revue vol. 29, issue 1 / 2023 ISSN-L 1220-2053 / ISSN 2247-8590 pp. 63-78 production today results from fossil hydrocarbons. About 130 coal gasification plants for hydrogen production are in operation, while more than 80% of them are located in China. Given that in China gas prices are almost three times higher than in the United States, this country's huge coal reserves are the most attractive source of hydrogen production. The cost of producing fossil-based hydrogen is about €1.5/kg, the estimated cost of production based on minerals and simultaneously capturing and storing carbon dioxide is about €2/kg, while the cost of green hydrogen is €2.5-5.5/kg. Indicatively, it is mentioned that from 1 ton of Ptolemaida lignite, about 18 kg of hydrogen can be produced [37, 38]. Finally, rocks mined together with lignite and by-products of its combustion can be used as raw material in the construction industry. To the products and by-products of this category belong barren materials, fly ash, bottom ash, slag and gypsum. The above materials can be sold untreated or after being processed into building materials. Especially fly ash has many applications in mines and the cement industry, as a weak pozzolanic material. In addition, it can replace Portland cement in unarmed concretes, in the manufacture of cement products (pavement blocks, pavement slabs, etc.), in the construction of elements of unarmed or lightly reinforced concrete (safety barriers, etc.), in the construction of concrete dams with RCC (rolling concrete) technology, in the construction of rigid pavements, self-compacting concretes, in tunnel cladding, in cementing, in the production of ready-made mortars and in the manufacture of utilitarian objects (pots, etc.). It can also be applied in soil treatment and stabilization, in the production of synthetic zeolites, in road construction (for the construction of embankments, bases and bases and as a component of asphalt concrete) and in waste management facilities for the absorption of toxic elements [39, 40]. 3.2. The SWOT analysis results For the above-presented non-energy lignite uses, a SWOT analysis was carried out. For space saving reasons, in Table 3 are presented only the major strengths, weaknesses, opportunities and threats of each of the compared technologies. In any case, taking into account all the findings of this analysis, it seems that there are factors that apply to more than one technology, which are decisive and largely predetermine the future of the non-energy lignite uses. High investment costs, lack of know-how, and competition from other countries with cheaper production factors are characteristics of the internal and external environment that hinder the promotion of specific technologies. On the contrary, technologies that combine the creation of a large number of jobs with qualitative advantages of the domestic lignite seem to have the best prospects and are expected to be eligible for funding by the just transition programmes. Thus, these factors are included in the criteria that will be used for the comparative evaluation of technologies. Table 3. Major Strengths (cyan), Weaknesses (orange), Opportunities (green) and Threats (rose) of the examined non- energy uses of the lignite produced in Western Macedonia region Production of raw materials for the chemical industry (gasification, in-situ gasification, liquefaction) Possible production of various products High investment cost High energy efficiency Lack of know-how in local companies Symbiosis with other industries Similar products can be produced from other, low-cost sources Large number of jobs Rare Earth Elements Easier recovery or REE from lignite, compared to hard There is no commercial method for REE recovery from coal lignite Possible enrichment in fly ashes Lack of know-how Limited number of REE deposits The global market is dominated by China Continuously increased demand Possible recovery of REE from waste in the near future Activated Carbon Variety of products and uses High investment cost Low production cost from lignite with chemical Measures required for control of environmental impacts activation method Mature technology possible to be transferred in local Competition from companies in developing countries companies that produce AC from coconut cells Large market, further increased of demand is expected Existence of strong players in global market from developing countries 70 Revista Minelor – Mining Revue vol. 29, issue 1 / 2023 ISSN-L 1220-2053 / ISSN 2247-8590 pp. 63-78 Nanomaterials - Graphene High added value High cost of technological development Possible production of by-products: humic acid, The existence of lignite deposits is not a competitive absorbents advantage Numerous high-tech applications Graphene production from graphite Attractive field of research, new developments are Existence of strong players in global market expected in the near future Soil amendments and Organic Fertilizers Lignite deposits favourable for soil amendments Need for developing a sales network production Caution from many stakeholders due to the closure of a local fertilizer company Mature technology possible to be transferred in local Strong lobbing by companies that import similar companies products Large number of jobs due to the higher lignite Strong competition from neighboring countries production demanded, compared to other technologies Hydrogen Hydrogen fuel has zero carbon dioxide emissions Production line that requires high-tech safety systems Hydrogen production from lignite is more efficient Hydrogen production from lignite is not a sustainable compared to hard coal technology for the long-term Mature technology possible to be transferred in local The hydrogen production cost from RES is high but is companies expected to be reduced Increased demand is expected in the near future Construction materials Technology compatible with the skills of local Probable reduction of raw materials quantities (e.g. fly workforce ash) after the closure of thermal power plants Possible exploitation of numerous raw materials, by- Lack of a market oriented cost – benefit analysis products and waste Existence of technical specification for the use of lignite Limited interest by companies of the constructions fly-ash sector Numerous technical studies and pilot-scale test results Legal implications related to the use of by-products are available 3.3. Preliminary assessment of environmental impacts In order to assess the environmental impact of the non-energy uses of lignite, the natural and anthropogenic environment was analysed in 16 main and 47 secondary environmental components. For each of these components, the potential impacts were identified and assessed in terms of frequency and severity, and the mitigation measures that can be implemented were determined and assessed based on their cost and expected effectiveness. In Table 4, with the help of a colour scale, the impact of each of the examined non- energy technologies of lignite use on the 16 main components of the environment are presented. The intensity of the impact shown in the table corresponds to the maximum intensity recorded among the secondary components included in each main component. 71 Revista Minelor – Mining Revue vol. 29, issue 1 / 2023 ISSN-L 1220-2053 / ISSN 2247-8590 pp. 63-78 Table 4. Environmental impacts of the non-energy lignite uses on various components of the natural and anthropogenic environment Non-energy uses: Environmental components: Soil Ambient air Water Land uses Flora Fauna Natural resources Disturbances Risk of extreme events Population Transport Energy Infrastructures, public utilities Health Quality of life Disturbance of protected areas Definition of the colour scale: Severe impacts requiring continuous monitoring and mitigation measures Impacts requiring continuous monitoring and probable action for risk minimization Limited impacts, monitoring in regular basis is required Minor impacts, no mitigation measures are required Not concerned 3.4. The criteria weights In Figure 3, the results of the AHP method regarding the relative importance of the six criteria used for the evaluation of non-energy lignite uses are presented. It is obvious that, according to the judgement of the members of the working group, technological maturity has the greatest importance to all (28.5%). In fact, its weight is more than double the weights of all the other criteria, except the criterion of positive impact on employment (20.5%). The later criterion is expected to affect positively technologies that either create new jobs or maintaining a large part of the existing ones (e.g. by continuing the operation of the lignite mines). Its high weight value is directly related to the high unemployment rates affecting the Region of Western Macedonia, which threaten social cohesion due to the migration of people of working age, especially those with higher qualifications (brain-drain). Gasification, liquefaction, etc. Recovery of REE Activated carbon Nanomaterials and graphene Fertilizers, soil amendments Hydrogen Construction materials Revista Minelor – Mining Revue vol. 29, issue 1 / 2023 ISSN-L 1220-2053 / ISSN 2247-8590 pp. 63-78 Figure 3. Relative importance (weights) of the criteria used for evaluating the non-energy lignite uses 3.5. Rating of alternative non-energy uses Finally, the experts were asked to rate each of the seven alternative technologies for the non-energy lignite use based on the selected criteria. The results of this scoring are presented in Table 5. The technologies that received the highest score are the following: Production of organic fertilisers and soil amendments: 7,63 Production of raw materials and products for the construction sector: 7,31 Production of activated carbon: 7,14 Production of graphene nanomaterials: 6,27 As it was foreseen in the previous section, the top three non-energy uses of lignite owe their rating to the high score they received for the criterion of technological maturity, which had the greatest weight. Nanomaterial technologies and graphene production gained a narrow lead over gasification mainly due to the high eligibility for funding from European programs. The low scores of gasification and hydrogen production were results of their environmental impacts and the little support from EU funds that receive now investments in this type of industrial facilities. The recovery of rare earths elements from lignite received by far the lowest score due to the absence of an economically feasible method for processing lignite and fly ash of such a low initial concentrations of rare earth elements as this determined in the case of Western Macedonian deposits. Nevertheless, even the technologies that received relatively lower scores should not be ignored by the local research institutions, since many researchers around the world work intensively in areas such as in-situ gasification and critical raw materials production, and the economic and technical data are very likely to change in the near future. 4. Discussion Based on the above-presented results, it is concluded that the examined technologies of non-energy lignite uses exhibit various degrees of technological maturity. For some of them, their application on an industrial scale has a history of decades, such as gasification and production of soil amendments, while others have not yet reached the threshold level of being economically feasible, such as the recovery of rare earth elements. The hitherto limited interest of the business sector in the development of these technologies in Greece may be partly due to the inherent ineffectiveness of the state governance to attract relevant investments, but it is also decisively influenced by various weaknesses of these technologies. For instance, gasification, liquefaction, production of soil amendments and activated carbon from lignite has to compete with technologies, which produce equivalent and sometimes better quality products at a significantly lower cost. In 73 Revista Minelor – Mining Revue vol. 29, issue 1 / 2023 ISSN-L 1220-2053 / ISSN 2247-8590 pp. 63-78 addition, the production of soil amendments and building materials will confront the strong lobbing of the agricultural supplies dealers and cement industry, respectively, which are capable to prevent any attempted change in domestic market. Concerning the production of high value-added products, such as graphene and activated carbon, the harsh reality is that the existence of large lignite deposits does not add any advantage to Western Macedonia region. The raw material quantities required, especially for the production of graphene, are so small that it is practically not a real problem to transport them from the most remote part of the world, where a deposit with the best quality characteristics exist. For these reasons, other parameters must be taken into account in order to proceed with the development of non-energy lignite technologies. These parameters may concern the lignite qualitative and technological advantages and low production costs. Table 5. Evaluation results of seven alternative technologies for the non-energy use of the lignite produced in Western Macedonia mines Non-energy lignite uses Technological maturity 28.5% 7.25 3.75 8.63 4.88 8.25 7.38 8.50 Suitability of domestic lignite in terms of 13.7% 6.38 6.25 6.75 6.88 7.88 5.88 6.38 quality characteristics and critical mining sizes Eligibility of investment 12.4% 4.63 6.50 7.13 9.00 7.75 5.00 6.00 Capitalisation of infrastructure and know-how 11.5% 6.00 6.63 6.88 7.00 7.50 6.25 7.13 Positive impact on employment 20.5% 7.00 5.25 5.75 5.25 6.63 6.50 6.88 Degree of circularity, as an indication of 13.5% 4.63 6.75 6.75 7.00 7.63 4.13 7.75 environmental performance Total score: 6.26 5.47 7.14 6.27 7.63 6.13 7.31 The legal and regulatory framework can also be decisive in favour of one technology or another. The European Union clearly favours of producing hydrogen from renewable energy sources and is burdening energy technologies that are based on fossil fuels with the obligation to purchase carbon dioxide emission allowances. Moreover, the lack of technical specifications may limit the range of applications of lignite combustion by-products in construction works. Finally, the absence of any reference to technologies with specific site-selection requirements in the spatial planning prepared for the region of Western Macedonia may create obstacles for their development in the future. From the above analysis, it becomes clear that the development of the non-energy uses of the Greek lignite is not a prospect without any risk. Therefore, it must be supported by the decisions made in the frame of the National programme of just development transition, taking, at the same time, advantage of the funds available through the European Commission’s just transition mechanism, which aims at the transition towards a climate-neutral economy in a fair way for territories that were dependent on fossil fuels exploitation. This support should cover the following actions: Criteria Weights Production of liquid and gaseous fuels and chemical products Recovery of rare earth elements Production of activated carbon Production of graphene nanomaterials Production of organic fertilisers and soil amendments Production of hydrogen Production of materials and products for the construction sector Revista Minelor – Mining Revue vol. 29, issue 1 / 2023 ISSN-L 1220-2053 / ISSN 2247-8590 pp. 63-78 The promotion of scientific research for (a) the evaluation of the suitability of Greek lignite and its by- products, in terms of quality specifications, for each different non-energy use, and (b) the development of technological advantage; The amortisation of the business risk for the local enterprises that want to invest in non-energy lignite technologies and, at the same time, the attraction of enterprises outside the region, which are willing to get involved in relevant projects that will be implemented in Western Macedonia. Expanding further the discussion, the development of non-energy lignite uses is closely related to the mine lands repurposing scenarios. The early closure of the lignite mines, as a result of the energy transition strategy, caused a failure of the environmental protection and land reclamation programme according to the laws and regulations that are in force. Many works that were planned to be carried out in the next decades must have been completed within a period of few years, requiring increased efforts from all the involved parties and of course funding. Regardless of the above, the mine operators and the state-owned company that acquired a large part of the mining land, after the relinquishment of any legal liability by the Public Power Corporation of Greece, hold a broad portfolio of potential land uses that range from those maximizing profits to those trying to balance ecological restoration and mild productive activities. The development of photovoltaic parks, an investment opportunity that lately attracts both giant enterprises of the energy sector and small investors organized in various forms of cooperative schemes, is classified in the category of land uses that are focused on financial results. In the same category are classified most of the examined non-energy lignite uses, which should occupy large parts of the reclaimed mining land for the installation of industrial plants and/or the extraction of the lignite quantities that will be supplied to those plants. Concerning the category of land uses that focus on ecological restoration, this includes interventions that are compatible with many non-energy lignite uses and in some cases may have a symbiotic character. Forestation is usually carried out in sloped surfaces, aiming at the improvement of the landscape aesthetics, control of soil erosions and, beyond these, at the production of biomass. Mild agricultural and livestock activities are hosted in flat areas on the top of waste heaps, where large quantities of soil amendments can be applied for enhancing soil fertility. 5. Conclusions In the context of energy transition and decarbonisation of the power generation sector, the challenge for coal and lignite mining enterprises and all the involved stakeholders is the development of a new, sustainable and just production model. The obstacles encountered due to the one-dimensional growth model that dominated the lignite mining areas make this effort particularly difficult. In the middle of last century, most of the lignite-producing regions were rural areas with limited potential to develop their secondary and tertiary sectors. The rapid shift to the lignite industry and the long-lasting dependence on it, has has resulted in the suspension of any other economic development efforts, especially those related to innovation. For the above reasons, the continuation of the exploitation of coal deposits during and after the energy transition period is considered necessary for addressing effectively the threats of poverty, unemployment, social exclusion, migration, and degradation of the life quality in general. It will also provide the time required to develop a regulatory framework that will quickly and effectively manage the changes of the production model. In any case, the importance of lignite mining operations is reflected on the relative weights that the members of the working group gave to the comparison criteria of the alternative technologies. The continuation of the lignite mines operation, in turn, can be based on the development of non-energy uses of lignite. For many of these uses, intensive research is being carried out globally, since they can make a decisive contribution to tackling major problems, such as environmental pollution, reduction of arable land, and lack of raw materials for digital technologies. For this reason, they are expected to be at the peak of the investors’ interest. As far as the future of the lignite mines of Western Macedonia region is of concern, the combined SWOT–AHP analysis that was conducted in this study showed that the most promising technologies are related to the production of organic fertilizers and soil amendments, raw materials and products for the construction industry, activated carbon, and graphene. The development of these technologies depends on the support they will receive at various decision-making levels as well as from their eligibility for funding by financial resources granted for the purposes of just transition. It worth to be noticed that non-energy lignite uses provide many opportunities for synergies and diversification, characteristics that help to widen the group of beneficiaries, while, at the same time, some of them take advantage of the accumulation of knowledge and technical skills of local workforce in the operation of mines and steam power plants. 75 Revista Minelor – Mining Revue vol. 29, issue 1 / 2023 ISSN-L 1220-2053 / ISSN 2247-8590 pp. 63-78 The next step, which is proposed for the investigation of the possibility of developing non-energy uses of lignite in Western Macedonia region, is the implementation of an extensive sampling and analysis program to evaluate the suitability of all lignite deposits, even those that have not been exploited to date, in relation to the quality characteristics that favour each different lignite use. 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Mining Revue – de Gruyter
Published: Mar 1, 2023
Keywords: lignite; energy transition; non-energy uses; SWOT analysis; MCDA; Western Macedonia
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