Thailand, electricity production form biogas has been interested for replacement nuclear and fossil power plants. Current status of electricity production from biogas is 155 MWe, and more potential of current capacity is 380 MWe. Additional, energy crops have a potential for another source of biogas. For this study, electricity production to 1000 MW was determined. Napier grass was considered, high growth rate and high production yield. Napier grass 190,000 acre can produce 1000 MW electricity. And economic analysis of electricity production 1 MW was studied, these results show that biogas for electricity 1MW power plant project is not economic under current condition in Thailand.