Sources of renewable energies (e.g., landfill gas, wind, and solar energy) are environmentally friendly and electricity generation or electricity supply in Korea has concentrated on new and renewable energy technologies. The economic and environmental influence of renewable energies on existing electricity generation market of Korea was studied with energy-economic model Long-range Energy Alternative Planning system and the associated Technology and Environmental Database. Different alternative scenarios were considered, i.e., the base case with existing electricity facilities, technological improvement of different annual growth and process dispatch rule according to merit order change. In each alternative scenario analysis, alternation trend of existing electricity generation facilities was analyzed and the cost of installed renewable energy plants and CO 2 reduction potential was evaluated. This is an abstract of a paper presented at the 7th World Congress of Chemical Engineering (Glasgow, Scotland 7/10-14/2005).