**1. Introduction**

The European Green Deal is the response of the European Union (EU) to the climate and environmental-related challenges that are the defining task of this generation. It is a new development strategy that aims to transform the EU into a fair and prosperous society with a strong and competitive economy, where growth is decoupled from intensive resource use and there are no net emissions of greenhouse gases [1]. By signing the Paris Agreement, the EU made an official commitment to undertake certain measures for limiting global warming to "well below 2 ◦C" [1–3]. Then, in November 2018, the European Commission released a long-term strategic vision to reduce greenhouse gas emissions, between 80% and 100% compared to 1990. In fact, the ambitious goal of a 100% reduction of greenhouse gases represents a climate-neutral economy [4].

In order to achieve this goal, the EU will need to rapidly decarbonise its power sector. However, the implementation of this strategy poses significant technological, economic, and social challenges [4]. Coal infrastructures exist in 108 European regions. It is estimated that the coal sector currently employs about 237,000 people (185,000 work in coal/lignite mines). Poland employs about half of the workforce of coal/lignite mines and thermal power plants, followed by Germany, the Czech Republic, Romania, Bulgaria, Greece, and Spain [2].

Coal and lignite-fired thermal power plants face overwhelming regulatory pressures to lower greenhouse gas emissions. Power plants also face increasing competition from growing renewable-power capacity and from lower natural gas prices, trends that are developing against a backdrop of stagnating demand. While European year-ahead (2019) coal prices have dropped to about \$66 per ton from more than \$100 a year ago, EU carbon permits have escalated fivefold since 2017. As a consequence, the current cost of burning coal is significantly higher [5] and coal-fired power plants are becoming unprofitable as they have experienced losses worth €6.6 billion in 2019, according to a new study by the British think tank "Carbon Tracker" [6]. The most exposed utilities are the German RWE, the Czech EPH, and the Greek Public Power Corporation SA (PPC) who could haemorrhage about €2 billion in 2019 [2,7].

The above-described situation is particularly true for the lignite-intensive regions of the Balkan countries that have to be prepared for the reduction or phasing-out of mining and lignite power generation activities [7]. The dependency of these regions on the lignite exploitation resulted in limited growth of other economic sectors. This is related to a socioeconomic phenomenon known as "lock-in": A tendency for incumbent industries to actively resist the diversification of the local economy in order to avoid competition for economic resources [8]. This fact, combined with indirect impacts of mining on the quality of environment, properties' value, and health, leads to a vicious cycle, whereby the deteriorating attractiveness of the regions for new investments makes them ever more reliant on the lignite exploitation [8]. However, many coal dependent regions perceive decarbonisation driven by environmental considerations only as a process with adverse socioeconomic impacts, which expose local communities to unnecessary turbulence with unpredictable flow-on effects [7].

Despite the aforementioned obstacles, the reduction or phasing-out of mining and coal power generation activities is considered as one of the most cost-effective methods to achieve emissions reduction due to both market-driven and regulatory trends [6]. Under these circumstances, the economic importance of coal mining has decreased. Coal mining regions have lost a considerable part of their economic base and are facing structural changes [3]. Wuppertal Institute has published an analysis of common characteristics and site-specific differences of four coal-dependant European regions: Silesia PL, western Macedonia EL, Aragon ES, and Lusatia DE [9]. The analysis is focused on the distinction between the hard coal-producing region of Silesia and the lignite-producing regions. Silesia exhibits a high level of urbanisation. It is also strongly industrialised, with many sectors having considerable shares in regional GDP. On the contrary, lignite-producing regions remain rural areas with low population densities, where mines and thermal power plants are the main providers of jobs [9].

In this context, the Greek government announced the abolition of lignite-based electricity generation by 2028 and the increase in electricity generation via RES to 35% by 2030. Under the new strategy, there will be an ambitious program to accelerate the reduction of lignite-based power generation over the next decade [10]. Given the fact that 69% (2019) of Greece's lignite production takes place in the region of western Macedonia, this area will be at the heart of the energy transition, with all the threats but also opportunities that this entails [7,10].

Taking into account the fact that the climate mitigation is a collective effort in Europe, it seems fair that coal/lignite mining regions should receive support to master the challenges of this transition [2,3]. The Greek government is currently preparing a new comprehensive action plan for this purpose [10]. An essential part of this plan are the contributions granted via various European resources, such as the Fair Transition Fund and other financial mechanisms. However, the success of this plan relies on the decisions made by local and regional authorities regarding the development of new sustainable economic activities in the post-mining era [11]. Although actions aiming at the diversification from existing economic activities depending on lignite are necessary, first and foremost, the development of the optimum mix of land uses on the reclaimed mining areas is critical for achieving sustainability targets at the local and regional level.

The main objectives of this contribution are the determination of a series of sustainability criteria and indicators and, to a next stage, the development of an evaluation process for various land rehabilitation scenarios. This process is validated in the case of the western Macedonia lignite centre, a complex of surface mines that was the main pillar of the energy sector of Greece for more than six decades. More specifically, the paper is organized as follows: The second section provides background information on the evolution of the lignite industry in the western Macedonia region, the current situation and the perspectives of the local economy during and after the transition to a zero-lignite era, and the results of the mine land reclamation works carried out so far. The third section proposes a series of land uses that are considered to fit better in the examined case for amortising decarbonisation stresses, based on the circular economy principles and the founding tools available in the frame of the European Just Transition Mechanism. The fourth section describes a procedure for the evaluation of various land rehabilitation scenarios based on a PEST analysis and an optimisation algorithm that takes into account the criteria of revenues, investment cost, conservation of nature, and equity. In addition, the third section and the initial paragraphs of the fourth section provide references supplementary to these presented in the introduction, which strengthen the author's claims and suggestions. Finally, the last two sections provide a short discussion and conclusions.

#### **2. Background**

#### *2.1. The Lignite Mines of Western Macedonia*

Starting in the early 1950s, the lignite industry has critically shaped the development of western Macedonia. The decision to intensify the exploitation of domestic lignite deposits has been a central political option, supported by all Greek governments over the years. Up to now, 1.7 billion tons of lignite have been produced and more than 8.5 billion cubic metres of rocks have been excavated from four surface mines (Figure 1). The remaining exploitable reserves in the lignite field under exploitation by Public Power Corporation SA are estimated to be 820 million tons, while private mines reserves are 120 million tons. Public Power Corporation SA also has the rights to exploit 460 million tons of lignite located in areas where mining activities have not been developed so far [12].

**Figure 1.** Lignite production of the western Macedonia Lignite Centre [12].

The lignite deposits of western Macedonia belong to an elongated sedimentary basin with a length of 250 km, which extends to NW into the SW territories of north Macedonia (Figure 2) [13]. The basin is divided into two elongated grabens with different stratigraphic evolution and subsurface morphology. The basin formation occurred at the end of the Tertiary era and its creation is considered to be a consequence of subsidence in large NW–SE fault zones [14,15]. The different sedimentation rates of

the basin resulted in frequent intercalation between the lignite layers and the sterile, which consist, mainly, of marls and subsequently from clay and sand. As a consequence, the lignite deposits are characterised by a multiple-layered form, which deteriorated considerably the quality characteristics of excavated lignite compared to these of geological lignite due to the unavoidable co-excavation of sterile. The basement underlying the sedimentary basin includes Paleozoic schists, ophiolites, and granites. Above the basement lays the Pelagonian Structural Zone, which consists from Mesozoic dolomitic limestones, interlaying with volcanic sediments with ophiotic blocks, and flysch. The basin itself consists from Tertiary and Quaternary sediments with a maximum thickness of 1000 m. The upper part of the basin is filled with Miocene to Pliocene sand, sandy clay, lignite, and marl, mainly of fluvial to lacustrine origin. More specifically, in the surface lies the Quaternary sediments, then the Plio-Pleistocene unit that has a thickness of 20–100 m and consists of sand and clay, which intercalate with marls and conglomerates. Below this sequence lies the Plio-Miocene deposits consisting of layers of lignite and sand. These sediments are rich in CaCO3 since it can be found in all the sediments of the sequence, including the lignite [14].

**Figure 2.** Geological map of the western Macedonia Lignite Centre (Ptolemaida mines) [13].

Nowadays, the mines occupy 17,000 ha (Figure 3). The area that was gradually expropriated for mine development purposes was mainly agricultural. Forests covered limited areas, usually close to watercourses. Moreover, several villages that were located in close proximity to the mines have been resettled [12].

**Figure 3.** Satellite view of the western Macedonia Lignite Centre, with the red curves indicating the two mining areas: Amynteon (NW) and Ptolemaida (SE).

The mines have been equipped with 42 bucket wheel excavators, 250 km of belt conveyors and 17 spreaders, while shovels and trucks are used for the excavation and transportation of the hard rocks that are present in the overburden strata. These formations usually require blasting. In the last year (2019), 17.7 million tons of lignite and 130 million cubic metres of rocks were excavated from the four active open-cast lignite pits. This production rate is significantly lower than the record figures of 55.8 million tons of lignite (2002) and 332 million cubic metres of rocks (2005). The mines meet the fuel demand of 11 thermal power units with a total installed capacity of 3737 MW, which should be gradually reduced due to the EU decarbonisation targets that are fully adopted by the Greek government [12].

Regarding water management, this is a critical issue for the operation of the surface mines and the implementation of the environmental protection and land reclamation programme. For this reason, a complex system of seven pumping stations, which also serve as sedimentation ponds, and numerous wells, which are responsible for the drop of the groundwater table around the pits, have been developed [14]. A small river that flows into Lake Vegoritis receives surface water and groundwater discharges pumped from the mines. The river has already been relocated a few times for the needs of the expansion of the mine's exploitation. Under normal operating and weather conditions, the river receives annually more than 40 million cubic metres [14]. The quality characteristics of the water allow its use for dust depression in-pit, irrigation, or even for water supply purposes. Deviations from water quality standards usually refer to the concentrations of suspended solids and

electric conductivity values. Problems with acidic drainages have never been detected due to the presence of minerals rich in CaO in the entire lignite-bearing basin [15].

#### *2.2. Western Macedonia Decarbonisation Impacts*

The lignite industry has critically shaped the development of western Macedonia. For many decades, more than 25% of the regional GDP (gross domestic product) and more than 22,000 direct and indirect jobs have been unilaterally supported by local lignite activity needs [16].

Based on Hellenic Statistical Authority data, the use of an input-output model methodology for the period 2000–2016 showed that there is a direct correlation between lignite production and jobs. For every million tons of lignite produced, 185 jobs are maintained in the mining-energy sector and 725 jobs are created in the local labour market; this is a ratio of 1:3.9. The correlation of annual lignite production rates and employment in the western Macedonia region is illustrated in Figure 4. Although the R2 value of the linear regression line of total employment is not high, the number of jobs in western Macedonia in 2028, when the lignite output will be zero, is estimated to exceed marginally 70,000 (i.e., 24% compared to year 2014), unless strong impact mitigation interventions are implemented [17].

**Figure 4.** Lignite production and employment in western Macedonia.

Moreover, the regional GDP was very sensitive to the slight increase of lignite production during the period 2000–2005 (Figure 5). In the next years, when lignite production collapsed from 55.0 million tons in 2005 to 25.6 million tons in 2016, this correlation weakened (i.e., the slope of the blue regression line in Figure 5 is smaller than the one of the red line). This is probably due to deterioration of the stripping ratio, which kept the total rock excavations almost constant until 2013. The strong correlation of regional GDP with the excavated rock volumes is illustrated in Figure 6. In particular, this figure demonstrates how the regional economy is affected by the rock-moving works carried out by subcontractors of Public Power Corporation SA [16,17].

**Figure 5.** Correlation of GDP of the western Macedonia region and annual lignite production.

**Figure 6.** Correlation of GDP of the western Macedonia region and annual excavations carried out by subcontractors operating in lignite mines.

Based on the data presented in Figures 5 and 6, it can be predicted that, with zero lignite production and zero excavations in 2028, the GDP of west Macedonia will be moved between €3.2 billion (linear regression) and €1.5 billion (power regression). In the first case, if regional GDP is €3.2 billion, the wealth loss of the region of west Macedonia will reach 27%. In the second case, if regional GDP shrinks to €1.5 billion, urgent political intervention will be necessary to minimise demographic changes and to reduce economic and social impacts in the long term [17].

Summarising the effects of decarbonisation in the western Macedonia region and having as a reference the year 2013, the zero lignite production in 2028 is expected to bring the following consequences [11,16,17]:


Jobs loss and regional GDP reduction as a consequence of the withdrawal of lignite plants in the period 2009–2016 are presented in Figure 7, combined with a prediction for the year 2028, when lignite production is expected to be zero [17]. The above-presented Figures 4–7 make clear that western Macedonia's long-term dependence on the lignite cancelled every developmental effort, which was quantitatively reflected in low productivity diversification and low innovation rates. Moreover, it has created conditions that cannot be addressed by corrective interventions but require long-term productive restructuring policies, based on the competitive advantages of the wider region of west Macedonia. A key component of these policies should be the rehabilitation of the surface lignite mines.

**Figure 7.** Forecast of GDP—employment progression in Western Macedonia.
