Abstract
The life cycle phase of fossil fuel extraction is mainly considered in the life cycle assessment (LCA) when evaluating the energy production processes. It is then only one of many unit processes, which contribute to the blurring of mining-relevant results. There are few items in the literature focusing exclusively on the lignite mining phase and analysing the specific mining conditions and associated environmental impacts. The article focuses on the LCA of lignite mining processes on the basis of data coming from a Polish mine. The technology for opencast lignite mining is noted for its high production efficiency, high level of recovery and lower risk as regards the safety of workers when compared with underground mining systems. However, the need to remove large amounts of overburden to uncover the deposit contributes to a much greater degradation of the landscape. Analysing the results obtained, several key (hot spot) elements of the lignite mining operations were distinguished for modelling the environmental impact, i.e.: calorific value, the amount of electricity consumption, the manner in which waste and overburden are managed. As a result there is a high sensitivity of the final indicator to changes in these impacts.
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1 Introduction
The EU’s climate policy, including the European Green Deal announced in 2019, is intended to achieve climate neutrality for the continent. This is mainly to be achieved through the transformation of the energy sector by reducing the burning of fossil fuels and moving towards a net-zero emissions strategy (The European Parliament 2019) by supporting the development of renewable energy sources together with energy storage e.g. using hydrogen, CO2 offsetting, sustainable production and consumption practices ( European Commission 2020), etc.
EU has a significantly lower emissions intensity of power generation than other large economies. The carbon intensity was 270 grammes of CO2 per kilowatt-hour (g CO2/kW h) in 2018, compared with over 400 g CO2/kW h in the United States, over 500 g CO2/kW h in Japan, around 600 g CO2/kW h in the People’s Republic of China and over 700 g CO2/kW h in India and Australia (IEA 2020). Therefore, fossil fuels such as coal still constitute a significant source of energy in the world and in the EU. Coal consumption in the EU has fallen by 34% since 1995 and production by 53%. Dependence on coal imports, however, has increased to 40% with 30% of this demand coming from Russia, even though the share of coal in the EU energy mix has decreased to 15%. There are several factors affecting the future use of coal, these undoubtedly including climate considerations, but also security of supply. This factor has contributed to a reduction in coal use in some import-dependent countries which rely on this resource, but coal also provides energy security for those countries with their own resources like Poland. It should be pointed out that the Lisbon Treaty allows each Member State to decide on its energy mix. The European Council therefore recognises the need to ensure energy security and respect the right of Member States to decide on their energy mix and to choose the most appropriate technologies (Council of the European Union 2020). The recent announcements of a gradual phasing out of coal-fired power plants are expected to lead to a further reduction in demand for coal, which will affect the development of other energy carriers such as gas, renewable or nuclear. The “Coal Regions in Transition” platform (European Commission 2017) and dedicated policy instruments are expected to contribute to mitigating the social impact, especially for European regions associated with coal mining activities and therefore the transformation of coal-dependent regions will probably take several decades as coal-fired power plant still provides a high share of global capacity—38% in 2019 (IEA 2019). Analysing various scenarios prepared by the IEA (International Energy Agency) for the development of the energy sector until 2040, it can be seen that this share will decrease. However, under different scenarios it may still remain at a significant level of 25% (Stated Policies 2040 Scenario) or will be greatly reduced to 4% (Sustainable Development 2040 Scenario).
In the case of lignite, global consumption in 2018 was 793.5 million tonnes, with total demand for coal (brown, hard and coking coal) amounting to 5458 million tonnes (IEA 2019). In Poland, its share in electricity production in 2019 was 24.5% (41.5 TW h) which was 15% less than in 2018. This was associated, as in the global market, with a general decline in energy production (3.9%), with historically the lowest share of energy generated from coal in the domestic energy mix (74%) as well as the highest import of energy (10.6 TW h). This situation is mainly due to the increase in labour costs, lower quality of the fuel extracted (average calorific value below 7.9 MJ/kg) and high charges for CO2 emissions. These aspects translate into a decrease in the competitiveness of energy from coal in relation to other sources, including renewable ones.
In 2017, there were five opencast mines operating in Poland that supply fuel to five power plants. These mines were: Adamów, Belchatow, Konin, Turow and Sieniawa. Their total output in 2017 reached more than 61 million Mg of coal, with PGE GiEK S.A. KWB Belchaotw Branch being the largest producer, with output at 70% of domestic production. The total occupation area within the boundaries of this mine’s includes:
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(1) field Belchatow—1518 ha, with internal overburden dump—1755 ha,
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(2) field Szczercow—1415 ha, with external overburden dump—1061 ha,
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(3) Rogowiec support facility—212 ha,
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(4) Chabielice support facility—72 ha.
The share in the domestic lignite production of other companies in 2017 was as follows:
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(1) PAK KWB Konin S.A. at 14,
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(2) PGE GiEK S.A. KWB Turow 11,
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(3) PAK KWB Adamow S.A. 5,
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(4) Kopalnia Wegla Brunatnego Sieniawa Sp. z o.o. (about 100 thousand Mg).
Documented resources are being depleted in currently exploited deposits, In the currently exploited deposits documented resources are being exhausted and opening new deposits for exploitation meets with strong opposition of local communities due to transformation of landscape and hydrological system. Forecasts predict that after 2030 there will be a drastic decrease in lignite mining, and in 2050 its exploitation may stop altogether.
According to the current draft of the Energy Policy for Poland until 2040, it is predicted that in the next 10 years the share of coal in the production of electricity will drop to about 60%. Therefore, it is imperative to explore new theories and technologies that ensure high safety, low environmental pollution, and low damaging impact during coal mining (Ju et al. 2020)
LCA can also be used as a tool for long-term production planning in surface coal mines, taking into account the environmental conditions of the mine operations. The work presents such an approach presented by Pell et al. (2019). Author stated that LCA are useful to quantify the environmental costs of mining projects, however the application of LCA is often a retrospective environmental measurement of operating mines. Presented in the paper methodology use LCA to generate data that can form an environmental block model of a deposit. These spatially explicit data can then be used as a constraint within long-term mine scheduling simulations.
