Greenhouse gas emissions by the United States of Energy's Energy Information Administration (EIA). Electricity generation increased by 2.5%, and carbon dioxide emissions from the power sector increased even more, at 3%, indicating that U.S. utilities shifted towards energy sources that emitted more carbon. That shift was partially caused by a 40 billion kilowatt-hour decrease in hydropower production causing a greater reliance on fossil fuels like natural gas and coal. Carbon dioxide emissions from power plants fueled with natural gas increased by 10.5%, while coal-burning power plants increased their emissions by 1.8%. Paper is the fourth largest contributor to greenhouse gas emissions in the United States and one
Supercritical carbon dioxide heat pumps are commercially marketed in Asia. EcoCute systems from Japan, developed by Mayekawa, develop high temperature domestic water with small inputs of electric power by moving heat into the system from the surroundings. Supercritical has been used since the 1980s to enhance recovery in mature oil fields. "Clean coal" technologies are emerging that could combine such enhanced recovery methods with carbon sequestration. Using gasifiers instead of conventional furnaces, coal and water is reduced to hydrogen gas, carbon dioxide and ash. This hydrogen gas can be used to produce electrical power In combined cycle gas turbines, is captured, compressed to