PacifiCorp would close 16 of its 24 coal units, add nearly 7,000 MW of new renewable energy and build 400 miles of transmission line over the next decade to accelerate decarbonizing its system, according to its draft 2019 integrated resource plan.
The utility said Oct. 3 that the 16 coal closures would take place by 2030, and another four by 2038. The retirements would cut nearly 2,800 MW from the company's 6,000 MW coal portfolio by 2030, and nearly 4,500 MW by 2038.
The draft IRP calls for divesting PacifiCorp's ownership in Jim Bridger Unit 1 in 2023, rather than 2037, with Bridger Unit 2 leaving the portfolio in 2028. The utility would retire its shares of Colstrip units 3 and 4 in 2027. Craig Unit 2 would also be out of the portfolio in 2026, after Naughton units 1 and 2 retire in 2025.
Under a recently passed Wyoming state law, PacifiCorp must try to sell the Wyoming-based coal units before closing them.
Chad Teply, senior VP for business policy and development at PacifiCorp, said the utility will be working with employees and communities impacted by the closures.
"We will facilitate advancing economic development, and will be sitting down with state and local leadership to identify ways that we can move this plan forward," Teply said.
Rick Link, PacifiCorp VP of resource planning and acquisitions, said the coal units that remain in operation would primarily be used to help integrate renewables, rather than function as baseload resources. He added that the staggered closure dates would help the utility maintain reliability of its system.
A spokesman for the Sierra Club called the draft IRP a "good sign," but noted it would keep about one-third of the coal fleet running well past the mid-2030s, leaving retirement schedules for another one-third of the fleet untouched.
"The utility is slow walking coal plant retirements despite spending the last year showing how much money it can save customers with a speedier transition. Leaving the retirement schedule for almost two thirds of its coal fleet untouched is out of step with other utilities and the clear economic trends," Thomas Young, spokesman for the Sierra Club, said in a statement.
The draft long-term resource plan also calls for adding 3,500 MW of new wind generation by 2025, including 1,500 MW currently under construction, as well as 1,920 MW of new wind in Wyoming by 2024. The IRP shows the utility also adding 1,100 MW of new wind in Idaho between 2030 and 2032.
Also planned are 3,000 MW of new solar energy by 2025, to be backed by 600 MW of battery storage, which is making its first appearance in a PacifiCorp IRP and would be in addition to another 2,800 MW of storage planned to come on line by 2038. All the storage resources planned by 2025 are paired with new solar generation, and the plan adds nearly 1,400 MW of stand-alone storage resources starting in 2028.
The draft IRP shows 3,000 MW of new solar in Utah paired with 635 MW of battery storage built between 2020 and 2037, and 1,415 MW of new solar in Wyoming paired with 354 MW of battery storage built between 2024 and 2038.
Oregon is scheduled to host 1,075 MW of new solar development that would be paired with 244 MW of battery storage built between 2020 and 2033. An estimated 814 MW of new solar has been identified for Washington that would be paired with 204 MW of battery storage built between 2024 and 2036.
The utility is also planning to develop the 400-mile Gateway South transmission line that would connect southeastern Wyoming and northern Utah.
PacifiCorp would rely on 366 MW of market purchases during summer peak periods during 2020-2027, down 60 percent from market purchases identified in the 2017 IRP preferred portfolio.
PacifiCorp didn't provide a total cost estimate on the plan, but Link said the cost of developing the wind portfolio would be "somewhere north of $2 billion" with the price tag for the Gateway South transmission line costing about $1.8 billion.
"The resource plan sets a very clear direction on how to reliably serve customers going forward," Link said. "We will manage this transition in a way that keeps costs as affordable as possible, maintains system reliability and has the least impacts on our communities and employees."
The company plans to file the final 2019 IRP with regulators in its six-state territory on Oct. 18.