Electric utility PacifiCorp proposed closing 20 of its 24 coal-fired generating units by 2038 and adding 6,500 megawatts (MW) of wind and solar generating capacity by 2025.

The proposals were part of the utility's draft “preferred portfolio” for its 2019 Integrated Resource Plan (IRP). PacifiCorp said it will file its final 2019 IRP with state regulatory commissions by October 18.

PacifiCorp proposed building a 400 mile long transmission line to connect southeastern Wyoming and northern Utah. Source: PacifiCorpThe draft resource plan includes a number of additional renewable energy resources distributed across the West:

• More than 3,500 MW of new wind generation by 2025, including resources acquired through customer partnerships, and a total of more than 4,600 MW of new wind generation by 2038.
• More than 1,500 MW of new wind generation that is currently under construction, including new wind projects in Wyoming.
• 1,920 MW of additional new wind generation in Wyoming by 2024.
• 1,100 MW of new wind generation in Idaho in the 2030 to 2032 timeframe.
• Nearly 3,000 MW of new solar by 2025, including resources acquired through customer partnerships, and more than 6,300 MW of new solar by 2038.
• Nearly 600 MW of battery storage by 2025 and more than 2,800 MW of battery storage by 2038.

The utility said its 2019 draft resource plan identified battery storage as part of a least-cost portfolio for the first time. All of the storage resources planned by 2025 are paired with new solar generation. The plan adds nearly 1,400 MW of standalone storage resources starting in 2028.

The proposed new solar and storage resources that could be added include:

• 3,000 MW of new solar in Utah paired with 635 MW of battery storage, phased in between 2020 and 2037.
• 1,415 MW of new solar in Wyoming paired with 354 MW of battery storage, phased in between 2024 and 2038.
• 1,075 MW of new solar in Oregon paired with 244 MW of battery storage, phased in between 2020 and 2033.
• 814 MW of new solar in Washington paired with 204 MW of battery storage, phased in between 2024 and 2036.

Coal unit retirements

Of the 24 coal units currently serving PacifiCorp load, the draft plan envisions retiring 16 of the units by 2030 and 20 of the units by the end of 2038. The unit retirements would reduce coal-fueled generation capacity by nearly 2,800 MW by 2030 and by nearly 4,500 MW by 2038.

Coal unit retirements scheduled under the resource plan are:

• Jim Bridger 1 in 2023 instead of 2037
• Naughton 1 and 2 in 2025 instead of 2029
• Craig 2 in 2026 instead of 2034
• Colstrip 3 and 4 in 2027 instead of 2046
• Jim Bridger 2 in 2028 instead of 2037

The 2019 draft plan also assumes the following units will continue to run until the retirement dates assumed in the 2017 IRP: Naughton 3 (2019); Cholla 4 (2020); Dave Johnston 1-4 (2027); Hayden 1-2 (2030); Huntington 1-2 (2036) and Jim Bridger 3-4 (2037).

The draft preferred portfolio also includes a proposal to convert Naughton 3 to natural gas in 2020.

Transmission

PacifiCorp also is proposing building a 400-mile-long transmission line known as Gateway South connecting southeastern Wyoming and northern Utah. The new transmission line would be in addition to the 140-mile Gateway West transmission segment in Wyoming currently under construction. The plan also includes several other transmission upgrades across PacifiCorp’s system that the utility said would enable new renewables and increase supply reliability and resilience.