Colorado’s rapid switch to renewable energy is having a surprising side effect: The closure of coal-fired power plants is freeing up precious water.

Any newfound source of water is a blessing in a state routinely stricken by drought and wildfire, where rural residents can be kept from washing a car or watering a garden in summer, and where farm fields dry up after cities buy their water rights.

State water planners long assumed that the amount of water needed to cool major power plants would increase with the booming population. Planners in 2010 predicted that, within 25 years, major power plants would be consuming 104,000 acre-feet per year of their own water. The Colorado Sun found that their annual consumption will end up closer to 10% of that figure.

The 94,000 acre-feet of water that major power plants won’t be consuming is enough to cover the needs of 1.25 million people, according to figures included in the Colorado Water Plan of 2015. (That’s counting water permanently consumed in cities, and not counting water consumed by agriculture and certain giant industries, or water returned to rivers through runoff and wastewater treatment plants.)

Already, water once used by now-defunct power plants is flowing to households, shops and factories in Denver, Colorado Springs, Boulder and Palisade, because the local water utilities owned the water and supplied the plants. When the plants closed, the cities just put their own water back into municipal supplies, officials in those cities said.

“Chances are, new customers are in line” to buy that water, said Natalie Eckhart of Colorado Springs Utilities, which provides water to the city and runs two coal-burning power plants, as well as gas, solar and hydro generation systems.

The Pueblo Riverwalk along the Arkansas River in Pueblo. (Jesse Paul, The Colorado Sun)

In Pueblo, Black Hills Energy shut down a 100-year-old, coal-then-gas-fired power plant downtown. After decommissioning stations 5 and 6 near the Arkansas River in 2012, Black Hills donated the water to public use. Water that once cooled the plant now flows in the Arkansas through the city’s Historic Riverwalk, where gondoliers paddle and picnickers gather in the sun for art and music. Renowned Denver historic preservationist Dana Crawford has partnered with a local developer on plans to revive the art deco power plant as an anchor for an expansion of the Riverwalk, with shops and restaurants.

In Cañon City, water that cooled the closed W.N. Clark power plant is going down the Arkansas River as well, Black Hills Energy spokeswoman Julie Rodriguez said. It is likely being picked up by the user with the next legal right in line.

The San Miguel River on the Western Slope is gaining some water from closure of the coal power plant in Nucla — at least temporarily until Tri-State Generation and Transmission Association, which owns the plant, finishes the tear down and reclamation, which requires some water. Spokesman Mark Stutz said Tri-State has made no decision on what to do with the water rights after that, but “we will listen to the input of interested stakeholders.”

Major power plants’ water consumption peaked in 2012 at about 60,000 to 70,000 acre-feet. It has dropped to about 47,000 acre-feet now and will fall further to about 27,000 acre-feet over the next 15 years, just from closures already announced. By the time the last coal plant closes, major power plant water consumption will have plummeted to about 10,000 acre-feet.

“There’s a potential for that big chunk of water to really benefit Colorado,” said Stacy Tellinghuisen, senior climate policy analyst at Western Resource Advocates, which works to protect the West’s land, air and water. Agriculture and endangered species could both be helped by it, she said.

In the past 10 years, 13 coal power plant units in Colorado have shut down. Another 10 will close by 2036 or much earlier. The remaining four units are under review by their owners.

The last gas power plant built in Colorado was in 2015, according to the U.S. Energy Information Administration. All new power generation in Colorado since then has been renewable.

Platte River Power Authority’s Rawhide Energy Station north of Wellington, generates electricity using coal, natural gas and solar. It serves Fort Collins and other Northern Colorado municipalities. (Ed Kosmicki, Special to The Colorado Sun)

Technology has driven down the cost of wind and solar, and they now can provide power at a lower price per kilowatt-hour than coal-fired power in Colorado. Even accounting for the need to store electricity, bids to provide renewable energy have come in lower than the cost of coal-fired power.

Closure dates have been accelerating. Utilities are running scenarios on how they could shut down the last four coal-burning units in Colorado not already set for closure. They are Xcel Energy’s Pawnee in Brush and Comanche 3 in Pueblo, Platte River Power Authority’s Rawhide 1 near Wellington, and Colorado Springs Utilities’ Ray D. Nixon unit 1 south of the city.

Emissions controls and customers’ climate concerns are also driving the change, utility officials said.

For example, Platte River Power Authority already expects to be 60% wind, solar and hydro by 2023, and its board said it wants to reach 100% by 2030, spokesman Steve Roalstad said. A public review process started March 4 to discuss how best to achieve that. Closing the coal plant at Rawhide and even the adjacent gas plants by 2030 are options, but not certain, he said.

Early closing dates set for other coal plants could move up. PacifiCorp, a partial owner of three coal power units in Craig and Hayden in northwest Colorado, is pushing its partners, Tri-State and Xcel, for faster shut-downs. It wants to move more quickly to cheaper renewables.

MORE: Tri-State Generation to close all of its Colorado, New Mexico coal-fired power plants and coal mines — 3 locations — by 2030

The changes are not occurring without pain. Some areas of the state dependent on coal mining and associated coal power plants, like Hayden and Craig, are worried about the loss of jobs and money. But newly freed water might help.

Even as late as last year, water plans could not keep up with the changes. The 2019 update to the Colorado Water Plan predicted that the power plants in the Yampa Valley would raise their water use to 30,000 acre-feet in the coming decades, apparently to cover once-planned expansions of the coal power plants in Craig and Hayden. In reality, the entire Craig power station and one of two units at Hayden will be closed by 2030, cutting water use to a few thousand acre-feet.

The Colorado Sun collected these figures from electric and water utilities, state, federal and local governments. Some figures conflicted, so the totals are approximate. Water use also varies with power production. Colorado needs extra electricity for air-conditioning in the summer heat, which makes power plants produce more energy and use more water.

Colorado is extremely short on water. More than 60% of the state’s river water goes to downstream states like California and Kansas, so Colorado reuses water many times, according to the state water plan.

That’s why the amount consumed and never returned to rivers through runoff and treatment plants is crucial, Tellinghuisen explained. Power plant water in Colorado is largely consumed, lost to the air through cooling towers and evaporation.

MORE: Even after a rush of snow and rain, the thirsty Colorado River Basin is “not out of the woods yet”

As more power plants close in coming years, much of the water no longer needed will be water owned by the power companies themselves. Many were reluctant to talk about their water rights in detail.

Water court records show Xcel owns water from wells all over the metro area, and draws from Clear Creek. Xcel also owns 5,000 to 10,000 acre-feet in the Colorado River. That water is diverted to northern Colorado through the Colorado-Big Thompson tunnel under the mountains.

Xcel did say it is holding onto its water rights for now. It has been cutting its water purchases from cities, switching to its own water as power plants close.

On a smaller scale, Tri-State is now switching its J.M. Shafer power plant in Fort Lupton from city well water to its own water rights, city administrator Chris Cross said.

Water court records show another example of what can happen to utility-owned water: Xcel wants to use some of its Clear Creek water rights at a hydroelectric plant above Georgetown that is being renovated to produce more megawatts.

Some water might become available for other uses as more Xcel coal plants close, spokeswoman Michelle Aguayo said.

That could be a substantial asset. Water rights are selling for $20,000 per acre-foot and even more, according to published reports. That could amount to hundreds of millions of dollars of water rights held by utilities.

“If a power plant was no longer using its consumptive water, it could potentially sell that,” said Bart Miller, healthy rivers program director for Western Resource Advocates. And if a new user was downstream, the water would stay in a Colorado river for a little longer, he said.

But that’s only if Colorado’s complex water law allows the change. Owners must use their water to maintain their rights, and water court must approve new uses.

Closure of the power plants could open up arguments over where that water should go instead, explained Erin Light, state water engineer for the northwestern district.

“Every water right is decreed for an amount, a use and a place of use,” Light said. With the power plant gone, utilities can try to sell their rights, but other water users may dispute that in court.

Xcel, for example, owns 35,000 acre-feet of conditional water rights in reservoirs in the Yampa Valley that have never been built, she said. But “conditional” means the company gets the water only if it is actually needed, she explained. So when the Hayden power plant closes in the 2030s, Xcel would have to go back to water court to change the use or sell the rights, she said.

“Those conditional water rights become a lot more speculative if they are not operating a power plant,” she said. “Arguably, they would lose their conditional rights.”

Legislators are sufficiently concerned about speculators making money on Colorado’s water shortage that in March they passed Senate Bill 48 asking water officials to give them suggestions on how to strengthen current law against it.

