Sen. Joe Manchin urged the Federal Energy Regulatory Commission on Monday to subsidize coal and nuclear plants, as Energy Secretary Rick Perry has proposed.

"I encourage you to ensure that coal-fired and nuclear baseload units, which make our electric delivery system more resilient and provide essential reliability services, are appropriately valued and compensated for their beneficial attributes," Manchin, D-W.Va., wrote in a letter to FERC.

Manchin, who represents one of the top coal producing states, is the first Democrat to explicitly support Perry's plan.

Perry submitted a proposal to FERC late last month to create regulations that would change regional power market pricing to reward the "reliability and resilience attributes" of plants that have 90 days of fuel supply on site, meaning coal and nuclear.

The grid operators that FERC oversees would pay the power plants for storing the fuel.

A wide swath of the energy industry, from oil and natural gas companies to solar and wind farms, oppose the proposed rule and the expedited timeline under which Perry wants FERC, an independent agency, to make a decision.

Critics have derided Perry's proposal for its potential to upset the last two decades of electricity generation, which have been marked by free competition and little intrusion by the government.

The Trump administration has expressed concern that the growth in natural gas and renewables has harmed the economic viability of "baseload" coal and nuclear power plants that provide around-the-clock power.

Perry issued his proposal to FERC on Sept. 28 in a peculiar way that broke with 40 years of commission precedent. FERC typically doesn't issue rule-makings at the behest of a Cabinet-level agency.

The energy secretary gave FERC a 60-day timeline to consider the proposed rule.