Economic evaluation toward zero CO2 emission power generation system after 2050 in Japan

Abstract

The costs of renewable energy and battery systems have been reduced. However, further technological developments are required to establish an economical, stable and reliable power grid system through the large-scale introduction of renewable energy systems. This study aims to evaluate the power costs for a high ratio of renewable energy and close to zero CO2 emissions by considering the stability of the electric grid system in Japan. An optimal multi-region power generation model had been developed that based on the system stability of this analysis. For future technological and economic evaluation of renewable energy, a technological evaluation method was used that was based on a manufacturing technology database developed by the Center for low carbon society strategy (LCS) and the following results were obtained. In 2050 CO2 emissions from the electric power system can be reduced by 85% at almost the same power cost as that incurred in 2013. Even if the renewable energy technology stagnates by that time, an 80% CO2 emission reduction can be achieved at low cost. In particular, photovoltaic power systems (PVs) and battery systems will contribute to the establishment of a cost effective and low carbon power generation system. Scenarios in which the annual power consumptions are as high as 800 TWh, PVs accounting for more than 300 GW have been installed which are equivalent to over 30% of total power consumption. The capacity of installed battery systems is taken as 300-500 GWh, and supplies 10%-30 % of the total power consumption. However, the power cost sharply increases when CO2 emissions are reduced by more than 90%. To achieve a zero emission power generation system after 2050, it is necessary to develop hot dry rock geothermal power generation, to reduce power demand and to establish the rationalization of the grid system. These results show the effectiveness of the quantitative evaluation and planning of a low carbon power supply system when the system stability is considered in this methodology.