STEVE INSKEEP, HOST:
Coal plants have been closing across the country, which is good for the climate, not good for certain communities that need jobs and property taxes. In Hayden, Colo., with a population of 2,000 people, a power plant is slated to close down in the coming years. Now instead of demolishing the facility, it could become a new kind of renewable energy storage.
Sam Brasch of Colorado Public Radio reports.
SAM BRASCH, BYLINE: It's happy hour when Hayden town manager Mathew Mendisco walks into Yampa Valley Brewing Company. Before heading to the bar, he gets his own personal mug off a wall.
So you got your own mug. Is that how it works here?
MATHEW MENDISCO: Yeah. It's a mug club.
BRASCH: Mendisco and I take a seat outside. He says the brewery is a glimmer of a new Hayden, the hip, cheaper neighbor of Steamboat Springs, a ski town with skyrocketing housing costs. But that's the future. At the moment, the bedrock of Hayden's tax base is Hayden Generating Station, a decades-old coal-fired power plant.
MENDISCO: It's 55% for the school...
BRASCH: Wow.
MENDISCO: ...And our hospital district, our cemetery district, our library district. I mean, take your pick.
BRASCH: And it's going away soon. Last year, Mendisco says he got a call from executives at Xcel Energy, Colorado's largest power company. They said they planned to stop burning coal at the plant eight years ahead of schedule.
MENDISCO: It wasn't some, oh, we're going to transition you all, and, you know, yeah, we're going to retrain you to go be this or whatever. They're like, hey, we think we can do this right.
BRASCH: In this case, doing it right meant preserving part of the plant as a molten-salt energy storage system. I know it's a mouthful. But Xcel executive Jack Ihle says it's really about the biggest problem with renewable energy.
JACK IHLE: Which is, how do we get through long periods of time without burning fossil fuels and emitting carbon dioxide emissions?
BRASCH: See, the wind and the sun have this annoying tendency to disappear with the weather. That's why energy storage is crucial for any transition to renewables. It ensures electricity will be there when people need it. Ihle says this molten-salt technology could be a new way to build energy storage out of the guts of an old coal plant.
IHLE: And so you would reuse the steam turbine. You'd reuse the transmission facilities that are connecting that plant to our grid - and then just the footprint and the land around the plant.
BRASCH: The key addition would be a massive tank full of regular old salt. Don't try this in your kitchen, but if you apply enough heat, salt melts into a liquid. At Hayden, that'd be done with extra renewable energy. Then when the grid needs power, the liquid salt would make steam to run a turbine and generate electricity.
CRAIG TURCHI: Yeah. So technically it makes good sense.
BRASCH: Craig Turchi is an engineer at the National Renewable Energy Laboratory. He says the advantage of the plan is it repurposes existing tech. But the challenge...
TURCHI: I think, one, it's going to be just the integration of this. You know, all the individual pieces are existing technology - proven - but putting it all together is going to be a first-of-a-kind unit.
BRASCH: And a lot needs to happen before molten salt gives new life to the Hayden plant. A final plan isn't even expected until next year. But Hayden town manager Mathew Mendisco says, so far, it seems like the company isn't backing away. After all, it came to him with the plan, not the other way around.
MENDISCO: So that, to me at least, was a step forward...
BRASCH: OK.
MENDISCO: ...And a step of trust. And as long as we all maintain that, I think we'll be great.
BRASCH: And someday, he thinks Hayden might actually go from coal town to molten-salt hot spot.
For NPR News, I'm Sam Brasch in Denver. Transcript provided by NPR, Copyright NPR.