CO2 emission reduction strategy and roles of nuclear energy in Japan

An analysis was made on the potential and cost of reducing carbon dioxide (CO2) emissions from Japan's long-term energy systems by using the MARKAL model, developed in the Energy Technology Systems Analysis Programme (ETSAP) of International Energy Agency (IEA). Assuming future growths of GDP, the demand for energy services was estimated for the analytical time horizon 1990-2050. Assumptions were made also on prices and availability of fossil fuels, and on availability of nuclear and renewable energy. CO2 emissions and system costs were compared between energy demand and supply scenarios defined with different assumptions on nuclear energy, a CO2 disposal option, and natural gas imports. Main results were as follows. Without nuclear energy, the CO2 emissions will hardly be reduced because of the increases of coal utilization. CO2 disposal will be effective in reducing the emissions, however at much higher costs than the case with nuclear energy. The expansion of natural gas imports alone will not reduce the emissions at enough low levels. (author)