In January 2012 the Renewable Portfolio Standard (RPS) replaced previously in place feed-in tariff system in order to accelerate Korea's renewable energy deployment with a goal to create a competitive market environment for the sector. RPS programme requires 13 largest power companies (with installed power capacity larger than 500 MW) to steadily increase their renewable energy mix in total power generation in period of 2012-2024. Obliged power companies to participate in RPS system: Korea Hydro & Nuclear Power Co., Ltd., Korea South-East Power Co., Korea Midland Power Co., Korea Western Power Co., Korea Southern Power Co., Korea East-West Power Co., Korea District Heat Corporation, Korea Water Resources Corporation, Posco Energy, SK E&S, GS EPS, GS Power, MPC Yulchon. Yearly RPS targets (% of RE power generation): RPS targets will be reviewed and adjusted every 3 years. Target can be met by electricity generated from the following renewable energy sources: Wind, solar, biomass, biogas, waste-to-energy, landfill gas, tidal, hydro, integrated gasification combined cycle (IGCC) . Power producers involved in RPS system receive certain amount of Renewable Energy Certificates (RECs). Number of RECs allocated for produced electricity from renewable sources varies depending on the technology used.