Evaluation of Carbon Sequestrations in Japan with a Mathematical Model

Publisher Summary CO 2 sequestrations are considered to be one of the key technologies to reduce net CO 2 emissions in Japan, because high energy efficiencies that are economically acceptable have already been achieved and large potentials of renewable energies, for example, wind power, cannot be expected in Japan. However, CO 2 sequestration, in parallel with other carbon mitigation options, has not yet been evaluated adequately. Cost effectiveness of CO 2 sequestration, especially into aquifers, strongly depends on the sequestration capacities and the routes to connect their sites and CO 2 recovery sites. This site dependency of CO 2 sequestration makes their evaluations difficult. Explicit modeling is made for energy systems and also CO 2 recoveries from fossil fuel power plants, CO 2 transportation and sequestration processes. To pay due consideration to the site dependency, the land area of Japan is divided into 20 regions and the off-shore area also into 20 regions. The land regions have various types of electric power plants and other energy systems. On the other hand, the off-shore regions have aquifers for CO 2 sequestration. In addition, CO 2 sequestration into the ocean is taken into account. These model regions are inter-linked to each other to evaluate CO 2 transportation between the CO 2 sources and the reservoirs. The total costs of energy systems and CO 2 sequestration in Japan between the year of 2000 and 2050 is minimized in this model. This chapter describes the structure of this new model for evaluation of CO 2 sequestrations in Japan, and presents optimized solutions as to when, where, and how much CO 2 sequestration and other carbon mitigation options should be implemented under assumed carbon mitigation policy options using this new model.