SALEM, Ore. (KIFI/KIDK)-PacifiCorp, the parent company of Rocky Mountain Power, may be understating the financial case for early retirement of the Naughton, Jim Bridger, and Dave Johnston coal-fired electricity plants. That is the assessment of the Sierra Club in its filing regarding PacifiCorp’s long-range electricity plan.

The Sierra Club believes the proposal could leave cost savings on the table by “slow-walking” the plant retirements. The filing points out the company’s plan needs approval from regulators in the six states in which it operates. It voices concern that the company may be forced to retire the plants on an even quicker timeline than currently proposed.

According to the Sierra Club, workers and community members in Kemmerer, Rock Springs, and Glenrock deserve an honest assessment of how many years the plants have left, so that they can begin economic transition planning as soon as possible. Putting off the discussion about their future, it argues, could put the communities at risk of sudden closures and job losses, like those that recently happened in the Blackjewel bankruptcy.

In its filing, the Sierra Club claims the company overstated the amount of generating capacity it will need in the mid 2020’s without adequate justification. They say PacifiCorp arbitrarily added 500 megawatts to its capacity projections.

The filing also claims the plan underestimates the true cost of operating the Jim Bridger plant. The plant is one of the company’s most expensive sources of electricity. The company claims it will run until 2037. The Sierra Club claims PacifiCorp is underestimating the increasing cost of coal, which it claims could double between 2009 and 2018.

You can see the club’s comments, filed with the Oregon Public Utility Commission this month, here. (Parts were redacted because they include proprietary PacifiCorp data.)