Almost all countries have issued laws and regulations to promote renewable energy (RE). However, the applications and motivations of such laws as well as achievements have been different. Currently, the Japanese government has announced its targets to expand the electricity feed-in tariff scheme for solar power, along with other energy sources, within two years to meet the goal set by the Japanese Prime Minister who, in the 15th United Nations Climate Change Conference (COP15) held in September 2009, proclaimed to cut 25% of greenhouse gas (GHG) emissions from the 1990 levels by 2020. In this paper, the current Japanese energy policies and measures for promoting RE in comparison to popular methods followed worldwide are explored. Furthermore, a Least Cost Feed-in Tariff (LCFIT) Simulation Model for Japanese case was developed to calculate the optimal mix of technologies to reach certain targets. The LCFIT also calculates the tariff that should be proposed for each technology and the total cost for the program with and without a carbon tax and estimates the premium added to the bill of the customer every month. (C) 2012 Elsevier Ltd. All rights reserved.