Evaluation of improvements on techno-economic performance of a supercritical oxy-fuel combustion power plant.

To meet the global target for lowering greenhouse gas emissions and preventing climate change, the power sector has to be decarbonised by 2050. Since coal is projected to play a critical role in the future energy portfolio, carbon capture and storage (CCS) technology has taken on the role of decarbonisation. To find the ways potentially improve defects of the state-of-art oxy-fuel combustion power plant regarding worse techno-economic performance, the oxy-fuel combustion power plant coupling with recuperated supercritical carbon dioxide (sCO₂) cycle has the potential to surpass the state- of-art oxy-fuel combustion power plant. Its net electricity efficiency and levelised cost of electricity (LCOE) is 29.73% and 97.7 €/MWelh, respectively, at operating conditions of 593°C and 240 bar. Further study of chemical looping combustion (CLC) power plant with recompression sCO₂ power cycle achieved 35.49% of net electricity efficiency and 96.8 €/MWelh of LCOE for the manganese ore as the natural oxygen carrier. Conversely, an LCOE of 109.2 €/MWelh was obtained owing to selecting the manufactured oxygen carrier of nickel oxide. Particularly worth mentioning is the excellent decarbonisation ability by fuelling the biomass in the two processes with -1255 gCO₂/kWelh and - 1066 gCO₂/kWelh (Mn₃O₄ case) of specific carbon dioxide (CO₂) emission, respectively. However, it showed significantly higher LCOE with around 2.3%HHV and 3.8%HHV (Mn₃O₄ case) of net efficiency penalty, respectively, compared with the coal-fuelled cases. In the emission trading system with the uncertainty of carbon tax, the two processes fuelled by biomass have the potential to achieve lower costs than the coal-fuelled cases. Finally, the probability assessment is conducted in the proposed cases, showing a higher cumulative probability of LCOE in the coal-fuelled CLC case than in the oxy- coal case. Hence, this study revealed that technologies of CLC and the sCO₂ power cycle have the potential to improve the techno-economic performance of the state-of-art oxy-fuel combustion technology.