Two more utilities in Arizona and Colorado are moving to accelerate closure of coal plants and replace them with renewable energy backed by batteries, joining a broader push in both states to shift to more cost-effective clean energy optionsÂ even in the absence of state mandates.Â
Tucson Electric Power on Friday released a long-term energy plan that calls for closing its remaining coal plants by 2032, on the way to 70 percent renewables by 2035. Arizona’s biggestÂ utility, Arizona Public Service, recently announcedÂ its own plan to achieve carbon-free energy by 2050, despite a lack of state mandates requiring such a transition.Â
Meanwhile, Colorado Springs Utilities said it would close its remaining coal plants by 2030. Along with accelerated coal closure plans from two other Colorado utilities, this will leave multistate utility Xcel Energy, which has committed to 100 percent carbon-free electricity by 2050, the only one to keep coal plants open past the end of the decade.
Colorado wants to get half of its power from renewable sources by 2030 and 90 percent by 2050.
Tucson Electric Powerâ€™sÂ 2020 integrated resourceÂ planÂ calls for a steady phase-down of itsÂ coal-fired Springerville Generating Station: The plant would startÂ operating on a seasonal basis in 2023, close down one of its 425-megawattÂ units in 2027Â and halt operation of the other remaining unit by 2032.Â
At the same time, the plan would see Tucson Electric PowerÂ adding 1.7 gigawatts of solar, 850 megawatts of wind and nearly 1.4 gigawatts of energy storage by 2035. Alongside a big boost in its energy efficiency efforts, TEP says the plan would allow it to avoid building any new natural-gas plants.Â
TEP, which serves about 430,000 customers, had already exited the Navajo Generating Station coal plant owned by Arizona utility Salt River Project, whichÂ closed down last year. It is also planning to exit the San Juan and Four Corners coal plants in New Mexico, owned by utilities Public Service Co. of New Mexico and Arizona Public Service, respectively.Â Both plants are in the Navajo Nation, which hasÂ asked Arizona regulatorsÂ to require the utility to pay up to $62 million to compensate for resulting economic losses.Â
Springervilleâ€™s remaining two units are owned by electric cooperative Tri-State Generation and Salt River Project. Tri-State, which servesÂ 43 electric co-op membersÂ and more than 1 million people acrossÂ four Western states,Â plans to abandon coalÂ andÂ add more than 1 gigawatt of utility-scale renewable generation to its portfolioÂ by 2030.
Arizona Public Service has committed toÂ 100 percent clean power by 2050, including an interim target of 65 percent by 2030. That target will make use of the roughly 25 percent of its capacity provided by the Palo Verde nuclear power plant, as well as 45 percent renewable energy, largely solar power.Â
The Arizona Corporation CommissionÂ hasnâ€™t imposed any clean-energy or carbon-reduction mandates on the stateâ€™s utilities, and it allowed aÂ moratorium on new natural-gasÂ power plant construction toÂ lapse last year. But falling prices for solar power and lithium-ion batteriesÂ in the sun-soaked state have made that combinationÂ a cost-effective alternativeÂ to dispatchable fossil-fired power â€”Â although aÂ fire at Arizona Public Serviceâ€™s McMicken batteryÂ facility last year has halted new battery installations until the state concludes an investigation into broader safety issues.Â
Fridayâ€™s 7-2 vote by the Colorado Springs UtilitiesÂ Board approves a plan to close its 208-megawatt Martin Drake coal plant by 2023, 12 years earlier than initially planned, and to shut down its 283-megawatt Ray Dixon coal plant by 2030.Â
The plan won approval by beating outÂ alternatives that would have replaced Martin Drakeâ€™s coal generators with permanent natural-gas generation, relying instead on temporary natural-gas generators until new transmission lines can be built to replace its capacity. Under itsÂ 2020 Electric Resource Plan, the municipal utility serving about 222,000 customersÂ will replace its 416 megawatts of coal-fired power with about 500 megawatts of new wind energy, aboutÂ 150 megawatts of solar powerÂ and more thanÂ 400 megawatts of battery storage.Â
Colorado Springsâ€™ decision comes on the heels of two other Colorado utilities pledging early retirements of their coal plants. Earlier this month, the Platte River Power Authority decided to shut down its 280-megawatt Rawhide coal-fired plant by 2030, 16 years ahead of its previously targeted closure date. And in January, Tri-State said it would close its remaining units at the Craig coal plant in 2030Â as part of its broader decarbonization plans.Â
These decisions come as state leaders are considering a push beyond its mandate for 50 percent renewables by 2030 and 90 percent by 2050 signed into law last year. Gov. Jared Polis won the 2018 election on his call for the state to adopt a target ofÂ 100 percent renewables by 2040Â and continues to press lawmakers for a more aggressive policy.Â
Xcel Energy, which owns Public Service Co. of Colorado, the stateâ€™s biggest utility with about 1.4 million customers, has pledged to reduce carbon emissions 80 percent by 2030 andÂ 100 percent by 2050;Â it plans to closeÂ its last two coal-fired power plantsÂ in Minnesota by 2030.Â
In 2018, Public Service Co. submitted a plan toÂ replace 660 megawatts of coalÂ generation at its Comanche coal-fired power plant withÂ 1,131 megawatts of wind, 707 megawatts of solar PV and 275 megawatts of battery storage, and wonÂ record-low price contractsÂ for battery-backed renewables in 2018.Â But it hasnâ€™t yet altered plans to keep the 750-megawatt Comanche 3 coal plant operating through 2070 or to keep the 552-megawatt Pawnee coal plantÂ running until 2041.Â