Officials said the power stations due to be closed under the administration were the saving grace during the polar vortex that hit this past winter.

Senators from the most coal-dependent states have raised their concerns, questioning whether the grid will be able to handle consumption during extreme weather situations once the power stations are closed.

Pro-coal states, such as West Virginia and Minnesota, claim that the administration’s focus on the environmental agenda puts huge pressure on the reliability of the nation’s power grid.

EPA regulations imposed five years ago have closed around 20% of the country’s power stations. Coal advocates predict upcoming regulations will shutter a further 20%, nearly halving the number of coal plants within a decade.

The EPA said government studies showed that despite the closures, the grid was able to produce more than enough power to support energy needs in the coming decades.

EPA administrator Gina McCarthy told Fox News that the agency was doing everything it could to avoid compromising the reliability of power supply.

“Nothing we do can threaten reliability," McCarthy says.

“We have to recognise that in a changing climate like the one we have recently been experiencing, it is an increasing challenge to maintain a reliable energy supply.”

West Virginia Senator Joe Minchin said the EPA’s updated performance standards would halt the building of any new coal-fired power stations and suggested that doing so would put lives at risk.

Minnesota Democrat Al Franken said state flexibility was needed on the EPA guidelines to ensure reliability.

The EPA regulations will come into effect in June 2014.