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A tractor-trailer heads through the gates into Xcel Energy's Cherokee Station power plant north of downtown Denver on March 26, 2010. A plan to clean up Colorado's air is pitting two powerful industries, natural gas and coal, against each other in what could be a warm-up for a national fight over confronting climate change. (David Zalubowski, AP Photo)

Switching to natural gas from coal cut pollution at the Arapahoe and Cherokee electric generating stations nearly in half, but activists are now pushing for their early closure to speed the climate change battle and promote environmental justice. 

The Sierra Club issued a report Tuesday in partnership with community groups asking why the massive smokestacks are scheduled to operate for decades even though Xcel Energy has pledged to generate electricity carbon-free by 2050. 

They also point out Denver has pledged to use 100% renewable electricity by 2030, while some of the turbines at Xcel’s Cherokee plant in Adams County are scheduled to burn gas through 2055. Xcel’s contract to buy electricity from Arapahoe expires in 2023, but there is no indication yet whether Xcel will renew the deal or walk away from the south Denver plant.

The Sierra Club report calls on state regulators to seek closure of the two gas-fired plants by at least 2030, helping to fulfill state laws requiring 50% greenhouse gas cuts from 2005 levels by that year. The report details ongoing annual pollution at the sites: 2 million tons of climate change-contributing CO2, more than 1 million pounds of asthma-inducing nitrogen oxide, and more than 20,000 pounds of the respiratory irritant sulfur dioxide. 

Despite no longer burning coal, the Denver power plants rank near the top of Colorado polluters in every category.

“The lesser of two evils is still evil,” said Katara Burrola, a community organizer for Mi Familia Vota in the neighborhoods surrounding the power plants. Some of the affected neighborhoods include Globeville and Elyria-Swansea, southern Commerce City, Overland and Ruby Hill. “And it’s producing all these toxins which causes for my people higher levels of asthma, cancer and other diseases. That we are all bearing the brunt of unfairly.”

Xcel responded Monday that while it had not studied the Sierra Club report, the on-demand power sources are needed while it builds out a renewable supply system.

“Since 1995, through initiatives that were supported by Sierra Club and other key stakeholders, we have reduced emissions from Arapahoe and Cherokee by more than 90%, including emissions of nitrogen oxides, sulfur dioxide and mercury,” Xcel’s Michelle Aguayo said in an emailed statement. “Premature retirement of these plants would impose significant costs on our customers, reduce our ability to deliver renewable energy to our customers, and make it harder to maintain reliability.”

The report also signals conservation groups’ political — and potentially legal — strategy after three successful years lobbying for environmental justice provisions in new state laws. Multiple bills since 2019 require climate change policies that repair historic disproportionate impacts of greenhouse gases and local air pollution on communities of color and low-income neighborhoods, where major polluters are concentrated. 

The Sierra Club report calls on Denver and the Public Utilities Commission to push Xcel for earlier plant closures and to replace the power with clean, renewable sources. The PUC was instructed by the legislature in a 2021 bill to “prioritize benefits to disproportionately impacted communities and address historical inequalities” when it reviews utility plans.

“We are tired of the sacrifice zones, tired of environmental racism,” said Ean Tafoya, Colorado director of GreenLatinos, who grew up looking at the Cherokee plant just north of Denver. “Our communities aren’t going to continue for another 10 or 15 years without fighting like hell to shut those places down.”

The Sierra Club report details the nearly 220,000 people who live within a 3-mile radius of the two plants. The EPA uses a 3-mile screening tool accounting for 11 environmental factors within the radius to assess environmental justice in its policy and enforcement decisions. (The report begins by saying the plants’ offenses began at their naming, when Xcel used the names without the consent of the Cherokee or Arapaho tribes. The plants are located on former Arapaho land taken in the 1851 Treaty of Fort Laramie.) 

In a “textbook example” of environmental racism, the report says, people of color make up 71% of those living around the Cherokee plant and 45% of those around the Arapahoe plant, compared to 32% of the statewide population. People without a high school education make up 31% around Cherokee and 16% around Arapahoe, compared to 9% of the overall state population. 

Health indicators within that same radius are also wildly disproportionate, the report said. Around the Cherokee plant, 48% of the population has high blood pressure, according to CDC statistics cited in the report. For Colorado overall, the high blood pressure rate is 24.5%. 

Diabetes affects 19% of the population around the Cherokee plant and nearly 11% around Arapahoe,  compared with the Colorado average of 7.3%. Cancer rates around Cherokee are more than twice as high, though they are slightly less than the state average around Arapahoe. Asthma rates are 11.1% around Cherokee and 10.2% around Arapahoe, compared with 9.4% in the state as a whole. 

The Sierra Club and supporting advocates say the gas-fired plants can be replaced by 2030 with solar and wind plants that produce energy at roughly the same cost. 

Cherokee currently consists of two gas turbine plants. Three Cherokee coal-fired units were previously shut down, and Cherokee 4 was converted to natural gas in 2017. The Air Quality Control Commission will require Cherokee 4 to shut down in 2028 as part of the Regional Haze State Implementation Plan. The haze plan is meant to comply with EPA requirements to reduce visible pollution suffered by Rocky Mountain National Park and other natural areas. 

Three new gas-fired units at Cherokee came online in 2015 as the Cherokee Combined Cycle plant, one of the largest gas-fired electricity plants in the state at 600 megawatts. Xcel’s 2021 Electric Resource Plan, required every four years by the PUC, says those units of Cherokee are likely to be retired in 2055. 

That’s where the Sierra Club is demanding answers. Xcel has said elsewhere it will deliver 100% carbon-free electricity in Colorado in 2050, and Denver has said it wants to hit 100% renewable electricity in 2030

The PUC is still reviewing Xcel’s Electric Resource Plan.

Arapahoe to the south also previously burned coal, then put gas-fired turbines online between 2000 and 2003. It is owned and operated by Onward Energy and Xcel has a contract to buy the electricity until 2023. 

Closing all the gas units of Cherokee and Arapahoe by 2030, the Sierra Club said, would promote the “transition off of fossil fuels to a more equitable, clean energy future that promotes healthy neighborhoods for everyone, in accordance with several state laws.” 

Michael Booth is The Sun’s environment writer, and co-author of The Sun’s weekly climate and health newsletter The Temperature. He and John Ingold host the weekly Sun-Up podcast on The Temperature topics every Thursday. He is co-author with...