By Curtis Tate

A federal court has declined to put President Barack Obama's Clean Power Plan on hold, meaning Kentucky and other states that sued to block it must comply with it until the legal challenges are resolved.

Under the plan, states must reduce their carbon dioxide emissions by one-third by 2030, meaning states that are heavy users of coal to produce electricity face having to move toward natural gas or renewable energy.

Kentucky is a heavy producer and consumer of coal, which generates more than 90 percent of its electricity.

Kentucky was one of 27 states that sued the Environmental Protection Agency to block Obama's plan. They also asked the U.S. Court of Appeals for the District of Columbia to put the plan's requirements on hold while the challenge moved through the courts.

On Thursday, however, the appeals court denied the request.

A spokesman for Kentucky Attorney General Andy Beshear, a Democrat, could not be reached to comment.

Beshear's predecessor, Jack Conway, joined the challenge to the plan, filed in October. Conway, also a Democrat, lost the Kentucky governor's race in November to Republican Matt Bevin, in part because even pro-coal Democrats have become associated with Obama's energy policies.

Last month, Bevin appointed Charles Snavely, a former Arch Coal executive, to lead the state's Energy and Environment Cabinet. Snavely has petitioned the EPA to reconsider the Clean Power Plan.

Kentucky's coal industry, particularly in its mountainous eastern region, has been battered by economic forces. It is more expensive to mine coal in eastern Kentucky, and it must compete with cheaper coal from western Kentucky, Indiana, Illinois and Wyoming.

Eastern Kentucky coal isn't even competitive within the state. In 2015, only 4 percent of the coal burned by its power plants came from the region, down from 32 percent in 1983, according to state data. Meanwhile, 39 percent of the coal Kentucky used last year came from other states.

Coal itself faces competition from cheap and abundant natural gas produced through hydraulic fracturing, known as fracking. This month, Arch Coal, the second-largest coal producer in the country, filed for bankruptcy protection. Including Arch, four major coal producers have entered bankruptcy in the past year, and the largest, Peabody Energy, is not faring well.

Elected officials in Kentucky and elsewhere have blamed Obama's policies for coal's decline. Last week, the Interior Department issued a moratorium on new coal leases on federal lands, a move decried by lawmakers from coal-producing and consuming states.

(c)2016 McClatchy Washington Bureau