Energy Secretary Rick Perry told House lawmakers Thursday that his controversial proposal to prop up coal and nuclear plants is not the "be-all-end-all" and is meant to be a conversation starter.

Appearing before the House Energy and Commerce energy subcommittee, Perry did not defend the proposal as aggressively as in his prepared remarks in which he said the plan "is just a first step" in his efforts to ensure the reliability of the nation's electric grid, suggesting he could take additional action in the future.

He didn't mention the proposal in the opening statement that he delivered to lawmakers, and he softened what he said it was intended to do.

"I want to hear both sides of this [debate] and have a very robust and open conversation," Perry told lawmakers in response to questions from Democrats critical of his proposal. "I don't have any idea if there are better options. I am not saying my [proposal] is the be-all-end-all. But obviously, it's been very successful in getting a conversation started."

Perry submitted a proposal to the Federal Energy Regulatory Commission 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.

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 the Federal Energy Regulatory Commission, which is independent, 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.

Republicans asking questions at the hearing mostly supported Perry's proposal, although Rep. Fred Upton, R-Mich., the chairman of the energy subcommittee, said he would "reserve judgment."

Democrats, meanwhile, were uniformly opposed to the grid proposal.

Rep. Kathy Castor, D-Fla., highlighted studies by experts that show Perry's proposal could cost consumers "billions."

"There is just no rational basis for this FERC rule you are trying to move through as quickly as possible," Castor said. "I am concerned a discussion about how this will increase prices for consumers is being short circuited. How do you give voice to consumer concerns about massive price increases?"

Perry opened the door to FERC rejecting his recommendations.

"If the letter to FERC is what you say it is, they won't go forward with [the proposed rule]," Perry said.

The energy secretary, repeating a point he made at a veterans event last week, asserted that the concept of free markets in the energy industry is a "fallacy" that exists in a "mythical" world.

He criticized the Obama administration for having its "thumb on the scale" for renewable energy sources, which he said provides precedent for the Energy Department to subsidize coal and nuclear plants.

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.

"I don't think you have this perfect free market world," Perry said. "We subsidize a lot of different energy sources. We subsidize wind, ethanol, solar, oil, and gas. That was my goal, to get us talking about the idea we have had a subsidized energy industry for a long time, and I frankly don't have a problem with that. The question is how do you make it as fair as you can. I don't know if I want to bet my grandmother's safety and security and whether the lights will come on to ensure a totally unregulated market."

Rep. Paul Tonko, D-N.Y., asked Perry if he had considered whether subsidizing struggling energy sources would increase costs for consumers.

"I think you take costs into account, but what's the cost of freedom?" Perry replied. "What's it cost to make America free? I'm not sure I want to leave that up to the free market."

But Perry struggled to describe how the Obama administration had unfairly subsidized renewable power sources.

Tonko noted the Republican-controlled Congress voted to extend tax credits for the wind and solar industries in 2015. The wind industry's tax credit begins phasing down this year before expiring in 2020. The solar industry's tax credit ends in 2022.

"Are you upset with production tax credits?" Tonko asked. "Is that an example of what you mean by thumb on the scale?"

"I am not upset with them," Perry said. "I am not sure what you mean."

"Weren't they passed by Congress?" Tonko asked of the tax credits.

"That doesn't mean everything done by Congress I agree with," Perry responded.

Perry wouldn't say if he supported ending the tax credits for renewables before they phase out, but he colorfully acknowledged that wind and solar power have become viable energy providers.

"I look at wind and solar the way I see my kids," Perry said. "I supported them in their growing years, but when they're out of college, they are on their own. They have become very good at what they do. Innovation has allowed them to be incredibly efficient."

Yet, Perry said wind, solar, and natural gas need help in keeping the grid resilient and reliable, by the way of promoting coal and nuclear power. At least two FERC members, Democrat Cheryl LaFleur and Republican Robert Powelson, have cast doubt publicly on whether Perry's proposal is the best way to do that.

Perry gave FERC a 60-day timeline to consider the proposed rule.

"I respect the FERC members' views," Perry said. "Their picture is one of a snapshot in time. There is blue skies. The sun is shining. The wind is blowing. The pipelines are carrying gas. In that scenario, our grid is reliable and resilient. But that is not the world I have been asked to participate in."