WASHINGTON (Reuters) - U.S. President Donald Trump on Wednesday nominated a proponent of his administration’s plan to subsidize aging coal and nuclear plants to a federal agency that regulates power transmission, a move criticized by environmental groups who questioned his independence on the issue.

Trump nominated Bernard McNamee to the vacant seat of the five-member Federal Energy Regulatory Commission (FERC), an independent office of the Department of Energy, for a term expiring June 30, 2020. McNamee, a Republican, is now the head of the policy office at the department.

McNamee helped to roll out last year a plan by Energy Secretary Rick Perry to subsidize aging coal and nuclear plants. The coal industry is suffering because of an abundance of cheap natural gas and an expansion of wind and solar power.

Coal and nuclear plants are integral to making the power grid reliable and resilient, or able to bounce back quickly from storms, hacking or physical attacks, the Energy Department has said.

An unusual coalition of natural gas drillers, renewable power groups, power grid operators and consumer advocates opposed Perry’s plan. FERC rejected it in January in a setback for Trump.

Environmentalists decried McNamee’s nomination. The Sierra Club’s Mary Anne Hitt said the Trump administration is “trying to use FERC to manipulate America’s electricity markets to bail out dirty and expensive coal plants ... while locking in a fossil fuel future for communities across the country.”

Neither the White House, nor the Department of Energy immediately responded to requests for comment about criticism that McNamee could not be independent in any commission votes on plant bailout plans.

In June, Trump ordered Perry to take emergency measures to slow down the closure of coal and nuclear plants, arguing those facilities boost U.S. energy security because they can store months of fuel on site.

Perry told reporters last week that he was waiting for the executive branch to respond to his agency’s ideas on the emergency measures, saying they were still being “bandied about” at the White House.

Coal mining and mining and industrial communities form part of Republican Trump’s base and he has returned the favor of their support by overturning Obama-era regulations. His administration axed a moratorium on coal mining on federal lands, proposed a weaker plan to reduce carbon emissions from power plants, and announced its intent to withdraw the United States from the 2015 Paris agreement on curbing greenhouse gases.

McNamee needs to be confirmed by the Senate. He would replace Robert Powelson, a Republican, who resigned. The Commission currently has two Democrats and two Republicans.