CO2 mitigation with new energy systems

CO2 emission rates from commercial and residential sectors, as well as transportation, are high. Applications of solar energy as a fuel-switching measure and of fuel cells for energy-efficiency improvement can reduce CO2 emissions from these sectors. Photovoltaic (PV) energy systems using roof-top cells, cogeneration systems with solid oxide fuel cells (SOFCs), and electric vehicles with a hybrid system of SOFCs and batteries are considered and their utility in CO2 mitigation is discussed. Possible reductions in CO2 emissions are estimated to be 43 million tons per year as carbon (Mt-C/y) in Japan.