Techno-Economic Assessment of a Biomass-Based Cogeneration Plant with CO2 Capture and Storage

Reduction of CO2 emissions from energy systems could be achieved through: CO2 capture and storage, energy savings, fuel switching among fossil fuels, increased use of renewable energy sources, and nuclear power. In addition, atmospheric CO2 reduction could also be achieved through increasing the carbon stock in soils and standing biomass. The CO2 capture and storage option for mitigating CO2 emissions from biomass-based cogeneration plants, considering critical aspects such future development of technologies, economies of scale. carbon price, site-specific analysis, and future energy systems has received little attention in scientific studies. With the overall objective of improved understanding of the potential scope for its large-scale implementation, a techno-economic assessment of biomass-based cogeneration plants with CO2 capture and storage was carried out. Most of the above-mentioned critical aspects have been considered for the techno-economic assessment of cogeneration plants with CO2 capture and storage technology. The results show the optimal scale of the conversion systems with respect to cost of electricity (COE). The optimal size for steam turbine-based cogeneration (CHP-ST) technologies without CO2 capture lies in the range 98-106 MWe (COE is 5.7 USD/MWh) when fueled by forest/logging residues, but the optimal size increases to 200-227 MWe for integrated gasification combined cycle based cogeneration (CHP-IGCC) (COE is 16.73 USD/MWh). The optimal size increases considerably to 249-288 MWe (COE 15.70 USD/MWh) for Salix fueled CHP-ST technology without CO2 capture and 441-504 MWe (COE 27.52 USD/MWh) for CHP-IGCC technology. With the additional feature of CO2 capture, transport, and storage (here we assume 100 km CO2 transport distance from the plant site) the unit capital cost for CHP-ST and CHP-IGCC technology increases around 70 and 30 percent, respectively. If one considers revenues from trading emission quotas earned through negative emissions one can estimate a market price of CO2 (PC) at which the COE becomes negative (i.e. all capital and operating costs are covered by revenues from heat and negative emissions delivered). Scale effects significantly influence the economic feasibility of CO2 capture. According to the model calculation, the PC at which the COE becomes negative significantly drops from 75 USD/tCO2 for 10 MWe CHP-ST plants to 32 USD/tCO2 for 90 MWe CHP-ST plants when fueled by Salix. The PC drop from 65 USD/tCO2 for 10 MWe CHP-ST plants to 25 USD/tCO2 for 90 MWe CHP-ST plants when fueled by forest/logging residues. For CHP-IGCC plants, the PC decreases from 72.5 USD/tCO2 for 30 MWe to 37.5 USD/tCO2 for 170 MWe when fueled by Salix. When fueled by forest/logging residue, the PC decreases from 62.5 USD/tCO2 for 30 MWe plants to 30 USD/tCO2 for 170 MWe. The techno-economic assessment was based on electrical capacity of the plants and revenues from cogenerated heat and captured CO2 were credited. In practice, the implementation of any cogeneration should be optimized based on site-specific context