Techno-economic assessment of CO2 capture possibilities for oil shale power plants

Oil shale is a calcium-rich fossil fuel, and its combustion in power plants generates high CO2 emissions, which must be reduced drastically. Thus, this study conducts a comparative techno-economic analysis of adding CO2 capture technologies, namely, post- and oxy-fuel combustion technologies, to existing oil shale power plants in Estonia. Estonia's energy sector is unique due to its heavy reliance on oil shale. The study's technical analysis indicates that oxy-fuel combustion capture would outperform post-combustion capture in oil shale power generation. However, integration of CO2 capture technology would result in reductions in power units' heat rate performances by more than 10% points due its energy requirements. From a financial perspective, the feasibility of Estonian oil shale power plant CO2 capture depends upon the long-term trends in the electricity market and CO2 emissions trading system. Full-capacity operation over an assumed 24-year lifetime would cost at least 89 euros per ton of CO2 captured and stored in 2021 values. The actual cost might exceed paying CO2 emission allowance fees and environmental charges or result in a competitive disadvantage. Thus, only in the event that the negative externalities resulting from CO2 emissions and national energy security concerns cannot be feasibly mitigated with alternative, stable, and controllable energy sources should state aid be used for CO2 capture technologies for oil shale power plants. The need to impose higher taxes, ceteris paribus, to cover the state aid or transfer the CO2 capture costs to the private sector might reduce the Estonian economy's overall competitiveness.