CO2 capture: towards cleaner energy
Fossil fuel is still the most widely used energy source globally. At the same time, it is the major source of greenhouse gas (GHG) emissions responsible for global warming. To reduce CO2 emission, technologies have been developed to capture CO2 either before or after fuel combustion. Along that path, the EU-funded ‘Enhanced capture of CO2’ (ENCAP) project aimed to develop and validate a number of CO2 pre-combustion technologies and processes for power generation based on fossil fuels – mainly hard coal, lignite and natural gas. The consortium brought together field experts and stakeholders to research and develop technologies with a 90 % CO2 capture rate and reduction in cost by 50 %. Among the processes that were investigated during the Encap project were pre-combustion decarbonisation, oxyfuel combustion, chemical looping combustion (CLC) and novel pre-combustion concepts. The ultimate aim was to ensure integration of these technologies in current energy systems. The pre-combustion decarbonisation concept of integrated gasification combined cycle (IGCC) for hard coal and lignite and the integrated reforming combined cycle (IRCC) for natural gas were tested with integrated CO2 capture. Hard coal and lignite met the ENCAP capture and cost targets while natural gas did not. During oxyfuel combustion, fuel is burnt in the presence of oxygen without nitrogen generating flue gas that feeds back into the system to moderate temperature. The consortium tested a number of oxygen carriers and managed to capture 90 % of the generated CO2 and also meet the ENCAP CO2 avoidance cost target. Promising results were obtained for CLC with small energy penalties. However, the technology lacks technical maturity and is far from being implemented in large power plants. Regarding novel pre-combustion technologies, project members tested numerous process concepts to find that although coal and gas cycles achieved the 90 % CO2 capture rate, the cost reduction was only reached with coal IGCC systems. In summary, the ENCAP project contributed to the creation of a European Research Area (ERA) for CO2 capture and enhanced European competitiveness in the field. Project deliverables have the potential for wide commercial exploitation in the industry and a significant positive impact for the environment.
