The Martin Drake Power Plant will burn its last load of coal Friday, ending a century of coal-burning near downtown Colorado Springs. All but one of Colorado’s remaining coal plants will also close in this decade.
What will replace the electricity generated by coal combustion in times when neither the wind blows nor the sun shines? The answers remain unclear.
In the case of Colorado Springs, six gas-burning units have been erected on the ground of the power plant along Interstate 25. But these are temporary units, as Colorado Springs Utilities has made clear. Like Xcel Energy and Tri-State Generation and Transmission and other utilities, Colorado Springs continues to wait for technological and perhaps political breakthroughs.
Coal has been a mainstay for the last century. At first, the plants were small. A practiced eye can see those brick buildings erected along rivers in Fort Morgan and Fort Collins.
Then coal plants grew and grew. For example, Cameo Station, located along the Colorado River east of Grand Junction, had a generating capacity of 73 megawatts in the late 1950s. At Hayden, the two units that went online in the ‘60s and ‘70s together have 441 megawatts of capacity. Then came the true behemoths at Craig and Pueblo, the former with 1,283 megawatts of generating capacity and the latter, called Comanche, with 1,410 megawatts.
Now the closings have started. The smaller and older ones came first, and Cherokee, located north of downtown Denver, was converted from coal to natural gas. By 2030, only Comanche 3 is planned to remain in operation, but that is far from a certainty.
What a lot of change: In 2010, utilities were still tentatively clinging to the past, unsure how much renewable generation they could absorb and still ensure your refrigerator had juice. Renewables were also still expensive.
A profound shift occurred in 2014-2018: Prices of wind and solar generation plummeted, both of them aided by federal tax breaks. Coal has become the expensive fuel.
Utilities also learned to integrate higher levels of renewables without sacrificing reliability. This was easier done in the middle of the night, when wind was blowing hard across Colorado’s eastern plains, but it applied to all hours of the day too.
A hallmark of this progression came in December 2018, when Xcel Energy assembled Colorado’s political leaders, reporters and others at the Denver Museum of Nature and Science to announce a goal worthy of national attention: The company said it would cut carbon emissions from its electrical generation 80% by 2030 as compared to 2005 levels.
A week later, directors of Platte River Power Authority—the power provider for Fort Collins, Longmont, Loveland and Estes Park—announced a 100% goal for 2030, with a list of caveats.
Tri-State, Colorado’s second largest electrical distributor, with 18 member cooperatives from Cortez to Holyoke, in January 2020 announced coal plant closings to reduce emissions 80%.
Colorado Springs Utilities in June 2020 announced that first Drake and then the Ray Nixon Plant, the latter a newer power plant, would close. The passage of Drake will be marked Friday afternoon with remarks by Colorado Springs Mayor John Suthers and Aram Benyamin, the chief executive of Colorado Springs Utilities since 2015.
How far can this go? Xcel says it believes it can hit 100% emissions-free energy by mid-century, even if it doesn’t know how it will cover that last 20%. Holy Cross Energy, the electrical cooperative serving Vail, Aspen, and Rifle areas, made its goal of 100% by 2030 unconditioned.
Renewables, however, can be problematic: The vulnerability of the electrical grid was exposed by the windless days of February. Xcel Energy spent $600 million in suddenly expensive natural gas to cover the gap, meaning customers can expect sharp increases in bills. Tri-State spent only $11 million, but turned to burning fuel oil when wind farms that produced an average of 51.2 megawatts of electricity delivered just 0.9 megawatts.
Storage has become the Holy Grail of the 100% quests. Lithium-ion batteries, which have about a four-hour storage life, are inadequate: We will need a lot more backup for when the wind doesn’t blow several days in a row on the Eastern Plains.
A regional transmission organization that allows Colorado to use electricity being generated in California or Arizona or even Iowa might help a lot. Tri-State wants such an organization. So does Holy Cross Energy and, it would appear, Colorado Springs Utilities.
Other storage technologies may deliver the answers. Xcel Energy says molten salt tops the list of storage technologies when it closes its coal units at Hayden in 2027 and 2028. It also is considering green hydrogen, which can use electricity to create hydrogen from water (venting the oxygen into the atmosphere). In this way, excess renewable generation can be stored using existing transmission. That technology faces a high cost and other hurdles.
Tri-State has the backing of Colorado’s state government in seeking to make the power plant at Craig a demonstration site for research and development of green hydrogen, as I explained in a story posted to Big Pivots earlier in August.
As for Comanche 3, Colorado’s largest and youngest coal plant. . Xcel Energy wants to keep it operating until 2040 at about a third of capacity. Pueblo and Pueblo County have also registered their support. They want the tax base.
But will a new energy storage technology make Comanche 3 obsolete? Maybe not, but that’s a bet I’d like to take.
Allen Best publishes Big Pivots, an e-journal that focuses on the energy and other transitions provoked by the changing climate. More can be found at bigpivots.com