How the EPA plans to regulate power plants going forward

The U.S. Environmental Protection Agency is taking drastic measures to limit pollutants coming from industries that cause the most environmental harm in an effort to bring the country closer to its climate goals.

The EPA announced Thursday new regulation to dramatically reduce greenhouse gas emissions from power plants, which are currently unregulated despite being the second-largest source of emissions in the country.

The new rule will apply to some, but not all, existing natural gas power plants. It will also apply to any new natural gas plants as well as facilities that burn coal or oil, according to the EPA.

"The proposed limits and guidelines would require ambitious reductions in carbon pollution based on proven and cost-effective control technologies that can be applied directly to power plants," EPA Administrator Michael Regan said in a briefing with reporters on Wednesday.

The power sector produced 25% of the country's greenhouse gas emissions in 2021. The rule, which is expected to go into effect in 2030, allows power plants to use carbon capture to reduce their emissions while continuing to burn fossil fuels.

The administration says tax credits under the Inflation Reduction Act will help reduce the cost of carbon capture technology, which up to this point has been seen as too expensive for wide-scale deployment.

The rule will prevent up to 617 million metric tons of carbon dioxide emissions through 2042, the equivalent of reducing the emissions of half the cars in the U.S., the EPA said. It would also generate an estimated $85 billion in net benefits to the climate and health benefits from reducing other types of pollution.

The power sector has reduced its emissions 35% since 2005, according to the EPA.

The federal rule is another push toward making the country's power sector completely carbon-free, Brian Murray, director of Nicholas Institute for Energy, Environment & Sustainability at Duke University, told reporters on Wednesday.

"I think this is going to lead to, over the next two decades, fossil units that are still around ... are going to have adopted some technology to keep carbon dioxide out of the atmosphere," Murray added.

This is not the first time the federal government has attempted to regulate greenhouse gas emissions from power plants but there are no current regulations in place. The centerpiece proposal from the Obama administration, the Clean Power Plan, never went into effect.

The Supreme Court ruled last year that law went too far and exceeded EPA's authority by telling utilities they had to shift power generation away from fossil fuels.

Under the Biden Administration the EPA, is taking a more straightforward approach by saying that power plants must reduce their emissions, but leaving the decision of how to do that up to companies. EPA projects that some coal power plants will retire as a result of this rule, but those decisions will be made by the companies, not the government.

That decision forced EPA to focus on more traditional approaches to controlling pollution, Jay Duffy, litigation director for Clean Air Task Force, told ABC News.

"EPA has authority under the Clean Air Act to reduce emissions commensurate with the best technologies that are available," Duffy said. "That's the end of its authority."

The EPA expects a negligible impact on energy prices as a result of this rule, Regan said.

Even though the benefits from the proposal are described as through 2042, Regan and National Climate Advisor Ali Zaidi said they're confident it will help the country reach the climate commitments under the Paris Climate Agreement -- and set by President Joe Biden -- to reduce emissions 50% to 52% by 2030.

The proposal reinforces the country's ability to meet the goal in a critical sector of the economy, the power sector, Zaidi said.

"Every action that we take that reinforces that trajectory, firms up our footing, firms up our path to achieve that goal and increases the odds that we will unlock the full economic upside and public health gains associated with meeting that target," Zaidi said on a call with reporters.

ABC's Andy Field reports:

ABC News' Kelly Livingston contributed to this report.