AMNA NAWAZ: The Environmental Protection Agency has finalized a long-awaited set of regulations regarding proposed limits on fossil-fueled power plant emissions.

But these new rules could mean the end of the coal industry as a source of electricity generated in the United States.

Stephanie Sy has more.

STEPHANIE SY: Fossil fuel power plants account for more than one quarter of all greenhouse gas emissions in the U.S.

The Biden administration is trying to crack down on the worst polluters, and that's the remaining coal-powered plants, which emit the most carbon dioxide.

The new EPA rules require coal plants to reduce their greenhouse gas emissions by 90 percent by 2039, or close.

There are about 200 coal-burning power plants and operations in the U.S. And, last year, coal-fired plants generated a little over 16 percent of the nation's electricity.

For more on these rules and the reactions to them, I'm joined by Bloomberg's Jennifer Dlouhy, who reports on energy and environmental issues.

Jennifer, thanks so much for joining the "NewsHour."

As you know, the coal industry has already been in decline for decades in this country.

Will these new rules make an enormous difference when it comes to climate change and public health?

JENNIFER DLOUHY, Bloomberg: Well, we're already expecting about half of the nation's capacity of coal-fired power to go offline by 2039, which is essentially a stoppage date in this rule as well.

So that's already happening.

We're already seeing that decline.

This rule, however, will encourage more coal plants to close.

That's clearly an expectation here.

And it will do that by basically saying that coal plants, if they want to keep running after January 1, 2039, will have to be capturing nearly all of their greenhouse gas emissions.

And they will have to start doing that, actually, by 2032, seven years earlier.

Those systems are expensive.

There are utility owners, power plant owners that may decide it's simply not wise to expend that much money trying to retrofit an existing coal-fired power plant to keep it operating into the 2040s.

So this will absolutely hasten coal plant retirements that we're already seeing.

And it will affect new natural gas plants that are coming online as well.

STEPHANIE SY: You talked about the expense of meeting these standards.

Carbon sequestration is listed in the rules as one way that coal plants, for example, can reduce their emissions.

But where is that technology in being able to meet those targets?

JENNIFER DLOUHY: Carbon capture and technology has been around for decades, and yet it has not been deployed widely at a commercial scale, especially in the power sector.

And that's really one of the big concerns that we're hearing from power plant owners and from utilities and grid operators right now, is that, frankly, carbon capture systems may not be ready to deploy at the scale this rule would require to keep coal plants and even large new gas plants online.

STEPHANIE SY: So, besides coal, one of the new standards, and you mentioned this, requires that new gas-fired power plants control 90 percent of their carbon pollution.

However, that doesn't apply to existing gas power plants.

Why did the Biden decision -- the Biden administration ultimately decide not to have tougher standards on the gas industry?

JENNIFER DLOUHY: Yes, it really was a matter of pushing that decision off until later.

The administration looked at this rule and looked at some of the inevitable legal challenges to it, the challenges in designing this measure, and they decided to put off the decision for existing gas plants and do it as part of a separate rule they're hoping to advance later this year.

That is a big disappointment.

There are environmentalists who are really concerned about getting at not just the new gas plants that will be built, but a huge source of pollution coming from the existing fleet.

And, for now, they're going to have to wait at least another year for that to be completed, for that process to be finished.

STEPHANIE SY: There are also critics of the new rules in the coal industry.

And to hear them talk about it, they say that, when you're really looking at extreme demand, say, on a very cold day or a very hot day, that the most reliable power is still fossil fuel power.

Is there validity to those concerns, as far as what we know about the reliability of renewables?

JENNIFER DLOUHY: Yes, there are very real concerns about reliability that are being voiced by those interests.

And the EPA, the administration tried to respond to some of those concerns.

The rule has a safety valve, essentially, for demand emergencies.

So when power spikes and you really need to have those coal plants, really gas plants running, they're going to make sure that they have the ability to keep running under this rule.

So that is seen as addressing some of those concerns.

But you're right.

This is coming at a time when power demand is expected to grow tremendously, because we have got A.I.

demand.

We have data centers.

We have electrification of our cars.

All of that is going to be requiring more power from the grid.

And there are many folks today wondering if they can get enough renewable zero-emission supplies on the grid in the next few years to offset what will be a decline of coal power that provides kind of an always-on power source today.

STEPHANIE SY: And, quickly, Jennifer, do you believe that these rules will be enacted any time soon?

Or are they going to face the same type of legal and political scrutiny that we have seen other big announcements on carbon emissions face?

JENNIFER DLOUHY: Yes, this is, frankly, the third attempt by the EPA under three different administrations to set these kind of limits on the power sector.

It's difficult to do.

It faces inevitable legal challenges.

And, frankly, if another -- if President Trump is elected, this whole effort will probably be a target for elimination or at least a rollback.

The next few years will be a challenge in both the court of -- in legal courts and in the court of public opinion.

And, really, we will see what happens with the election.

This is clearly an attempt by the EPA and even by the folks they were working for in the industry to create a more durable rule that will stand and last the test of time.

STEPHANIE SY: We will see.

Bloomberg's Jennifer Dlouhy, thank you so much.

JENNIFER DLOUHY: Thank you.