Yet even the most efficient coal-fired power plants only operate at around 44% efficiency, meaning that 56% of the energy content of the coal is lost. These plants emit 15 times more carbon dioxide than renewable energy systems and twice as much CO2 as gas-fired power plants.

How cost efficient is coal?

Of all the fossil-fuel sources, coal is the least expensive for its energy content and is a major factor in the cost of electricity in the United States. However, burning coal in electric power plants is a major source of carbon dioxide (CO2) emissions, and its use has other repercussions as well.

What is the most efficient coal power plant?

The most efficient coal-fired unit in the country is the 665-MW John Turk Jr. plant in Arkansas ( POWER's Plant of the Year in 2013), which achieves an efficiency of 42%. It is the nation's only ultrasupercritical unit.