Nuclear power has long been a cornerstone of energy policy in Japan, a country with few natural resources of its own. However, following on from the Fukushima Daiichi accident, the Japanese government is now in the throes of reviewing its nuclear power policy. On the other hand, under continuing policies of greenhouse gas reduction, it is crucial to consider scenarios for the country to realize an economic, safe and low-carbon power generation system in the future. Therefore, in the present study, economic and environmental analysis was conducted on the power generation system in Japan up to 2030 using a multi-objective optimization methodology. Four nuclear power scenarios were proposed in light of the nuclear accident: (1) actively anti-nuclear; (2) passively negative towards nuclear; (3) conservative towards nuclear; and (4) active expansion of nuclear power. The obtained capacity mix, generation mix, generation cost. CO2 emissions and fuel consumption of the scenarios were compared and analysed. The obtained results show that the large scale penetration of PV (photovoltaic), wind and LNG (Liquefied Natural Gas) power can partly replace nuclear power, however, removing nuclear power entirely was not suggested from economic, environmental and energy security perspectives. (C) 2012 Elsevier Ltd. All rights reserved.