PacifiCorp subsidiary Rocky Mountain Power is planning on potentially longer operations for its coal-fired power plants in Wyoming and Utah.
The utility's preferred scenario proposed in an updated integrated resource plan (IRP) released today envisions running seven coal-fired units in Utah and Wyoming as long as 2042.
"PacifiCorp's coal resources will continue to play a pivotal role in following fluctuations in renewable energy as the remaining coal units approach retirement dates," the company said in its updated plan.
The updates also reflect legislative and regulatory changes, including the US Environmental Protection Agency's (EPA) approval of Wyoming's ozone plan and the stay of EPA's disapproval of Utah's ozone plan results in fewer restrictions on coal-fired operation than were assumed in the 2023 IRP.
The most dramatic extension is for PacifiCorp's Hunter and Huntington coal plants, with the company bringing the plans for those plants back to what it had modeled in 2021.The utility now plans to retire all three units of Hunter in 2042 instead of the 2031-32 retirements laid out in the original 2023 IRP. The plan filed today also maps out retiring Huntington units 1 and 2 in 2036, four years later than expected a year ago.
Both Utah and Wyoming passed legislation recently aimed at preserving coal-fired generation in those states. PacifiCorp is currently reviewing and analyzing the new legislation, and the specific effects the laws will have. That analysis will be part of the 2025 IRP now underway, PacifiCorp said.
But the company's final plan for compliance with Wyoming's revised low-carbon energy portfolio standard, which was submitted to the state's utility commission on 29 March, included a proposed pre-front end engineering and design study for an amine-based carbon capture retrofit at Jim Bridger units 3 and 4. According to the updated 2023 IRP, these units are now expected be retrofitted with carbon capture (CCS) technology in 2028 and operate through 2039. The company previously expected to convert both of the units to natural gas in 2030 and to close them in 2037.
PacifiCorp subsidiary Rocky Mountain Power also announced separately on 29 March that it has formalized a memorandum of understanding with energy technology firm 8 Rivers Capital to consider a carbon capture project at either the Dave Johnston or Wyodak coal-fired power plants. The work will be also supported by South Korea's SK Group, a conglomerate of more than 175 tech innovation companies.
Dave Johnston's four coal-fired units, which were built between 1959 and 1972, can generate 745MW of electricity. PacifiCorp's updated IRP keeps the retirement dates for three out of four coal-fired units of the plant as 31 December 2027-31 December 2028 and still has the last unit of the plant closing in 2039.
Wyodak, which is 80pc owned by PacifiCorp and 20pc by Black Hills Energy in South Dakota, is also expected to close in 2039, the same as PacifiCorp modeled last year.
The project being considered by Rocky Mountain Power would use a technology that would include synthetic gas generation with inherent carbon capture.
Wyoming governor Mark Gordon (R), who has been a proponent of CCS projects in the state, said that PacifiCorp's announcement gives an extended life to the state's coal-fired power plants. "This decision to take this action comes as a result of the Wyoming Legislature and me working closely together in both policy and legislation in support of keeping our coal as a base fuel for dependable, dispatchable energy." Earlier in March, Gordon signed a bill into law that extends the compliance deadline for coal plant carbon capture and storage (CCS) technology requirements and loosens some regulations around low-carbon energy generation standards.
