U.S. President Donald Trump on Wednesday signed several executive orders and proclamations focused on deregulating markets, including one aimed at ensuring federal regulations do not block entrants from entering new markets.

Energy Secretary Chris Wright acknowledged during his confirmation hearing in January that the burning of fossil fuels — coal, oil and natural gas — causes climate change. That’s because the combustion of fossil fuels is drastically increasing the amount of carbon dioxide in the atmosphere, warming the planet.

The median age of the retired plants is 56 years and as coal plants age, maintenance costs also rise, subsequently pushing up generation costs. In addition to these costs, any uni