On March 27, 2012, the Environmental Protection Agency (EPA) proposed  greenhouse gas emission limits for newly constructed power plants. The New Source Performance Standards would specifically limit carbon dioxide emissions from new power plants to 1,000 pounds of carbon dioxide per megawatt-hour of electricity produced.
The proposed standard applies to fossil fuel-fired electric utility generating units larger than 25 megawatts, but would not apply to existing power plants or new permitted plants that start construction within the next twelve months.
EPA expects that new natural gas combined cycle power plants will be able to meet the proposed standard without additional controls; new coal-fired or petroleum coke-fired plants could meet the standard by implementing carbon dioxide emission reduction technology such as carbon capture and storage (CCS). New power plants that employ CCS are given the flexibility to meet the proposed standard on average over a 30-year period to allow for phasing in new technology over time.