Pacific Power has an idea of how much money it could save customers by hastening retirement of its coal-burning power plants, but it won’t make public the results of that analysis.

Release of the coal study, performed at the request of Oregon regulators, is the latest front in an ongoing struggle between the Sierra Club and the electric utility over the pace of its transition to renewable energy.

The Sierra Club recently appealed to the Oregon Public Utility Commission a decision by an administrative law judge allowing PacifiCorp — the parent company of Pacific Power — to keep that study under wraps.

The analysis compares the cost of continuing PacifiCorp’s plan to retire all its coal plants by 2046 with speeding the retirement date up to 2022.

PacifiCorp presented the results to regulators, Sierra Club staff members and other stakeholders who signed nondisclosure agreements, but key portions are redacted.

PacifiCorp worries that the wide release of the study would affect its business relationships, and that it would mislead the public about the true cost of retiring multiple coal-burning units.

“You can’t just look at the cost of a megawatt of renewable and the cost of a megawatt of coal,” PacifiCorp spokesman Bob Gravely said. Closing coal units ahead of schedule could have side effects on transmission lines that connect to the grid and vendor contracts, he said. “There’s a lot more that goes into the true cost.”

The Sierra Club’s push to publicize the details of the cost comparison suggest that it backs up the organization’s own report on coal versus renewable energy sources.

The organization and consumer watchdogs are tracking the development of PacifiCorp’s 2019 integrated resource plan, which lays out all the utility’s power sources over the next 20 years.

Work on that plan is under way, and the disputed coal study could factor into it.

“It remains to be seen where there’s going to be accountability from PacifiCorp on the cost of their coal fleet,” said Cesia Kearns, Northwest deputy director of Sierra Club’s Beyond Coal campaign.

The study Sierra Club wants released isn’t PacifiCorp’s last look at coal’s cost.

Another analysis is slated for release in early November, Public Utility Commission spokeswoman Kandi Young said.

“The updated analysis is important because it will identify potential economic early retirements of coal resources,” Young said.

A special public meeting for Oregon stakeholders to review the results is scheduled for Nov. 8, Young said. The commission on Nov. 20 will formally address the results of the second analysis and how it should factor into the 2019 integrated resource plan.

PacifiCorp’s six coal-burning power plants are in Wyoming and Utah, but Oregon customers share the cost of retrofits and upgrades. Each plant can have multiple coal-burning units.

Oregon residents served by Pacific Power paid 11.5 cents per kilowatt hour for electricity in 2017, according to statistics published by the Public Utility Commission. That’s up 33 percent from 8.63 cents per kilowatt hour in 2008.

The utility typically only analyzes the cost of operating coal units when it’s faced with making required upgrades, said Bob Jenks, executive director of the nonprofit consumer advocacy group Citizens Utility Board.

This is the first time PacifiCorp has looked at every single unit its fleet, he said.

Jenks is one of the people who signed a non-disclosure agreement and saw the results of the coal study presented over the summer.

“I think (the) public ought to know more about this stuff,” he said. At the same time, he said, Citizens Utility Board doesn’t have the money to fight over one document.

Jenks said he’s concentrating on the 2019 integrated resource plan. If any of PacifiCorp’s coal plants are non-economic, they should be closed, he said.

The utility’s 2017 integrated resource plan would retire 16 of 24 coal-fired units by the end of 2036, Gravely said. That’s the equivalent of about 3,600 megawatts of coal generation, which means coal’s share of the power generation portfolio would drop from 58 percent to 30 percent.

— Reporter: 541-617-7860,kmclaughlin@bendbulletin.com