ABSTRACT
To meet targets for reducing greenhouse gas emissions, many countries, including Estonia, must transition to low-emission electricity sources. Based on current circumstances, the most likely options in Estonia are renewables with energy storage, oil shale power plants with carbon capture and storage (CCS), or the combination of renewables and either oil shale or nuclear power plants. Here we compare these different scenarios to help determine which would be the most promising based on current information. For the comparison we performed simulations to assess how various systems meet the electricity demand in Estonia and at what cost. Based on our simulation results and literature data, combining wind turbines with thermal power plants would provide grid stability at a more affordable cost. Using nuclear power to compliment wind turbines would lead to an overall levelized cost of electricity (LCOE) in the range of 68 to 150 EUR/MWh (median of 103 EUR/MWh). Using oil shale power plants with CCS would give a cost between 91 and 163 EUR/MWh (median of 118 EUR/MWh). By comparison, using only renewables and energy storage would have an LCOE of 106 to 241 EUR/MWh (median of 153 EUR/MWh).
Subject(s)
Carbon Dioxide/analysis , Electricity , Energy-Generating Resources , Power Plants , Renewable Energy , Carbon , Computer Simulation , Costs and Cost Analysis , Estonia , Greenhouse Gases , Monte Carlo MethodABSTRACT
Oxyfuel combustion can reduce CO2 emissions from fossil fuels. Hence, it is currently being investigated for potential use in oil shale-fired power plants, which currently produce most of Estonia's electricity. Here, experiments were performed with kukersite oil shale for both oxyfuel and conventional combustion in a 60 kWth circulating fluidized bed combustor. In this paper, we provide data on the ash composition including mineral compositions and heavy metal concentrations. Oxyfuel conditions did not noticeably influence the concentrations of heavy metals in the ash but did have significantly lower amounts of free lime because of inhibition of the carbonate decomposition reactions. The results suggest that oxyfuel combustion would produce no significant problems in terms of the behavior of the ash or the fate of heavy metals contained in the ash.
