The coal-fired Jim Bridger power plant northeast of Rock Springs is undergoing a major retrofit to improve efficiency and reduce pollution.

The improvements by PacifiCorp, which operates in Wyoming as Rocky Mountain Power, are part of environmental improvements the utility is undertaking throughout its six-state region.

In Wyoming, improvements also are planned or underway at Rocky Mountain Power’s Dave Johnston plant at Glenrock and the Naughton plant outside Kemmerer.

They’re part of the reason why Rocky Mountain Power is seeking a $35 million rate increase in Wyoming that would add nearly 14 percent to customers’ electricity rates. The proposal is pending before the Wyoming Public Service Commission.

State Sen. Cale Case, R-Lander, has filed as an intervening party to the rate case.

“They will be back. I feel it’s kind of frustrating, like you’re painting the ship while it’s in motion,” Case said.

But even if the commission approves the increase, the utility plans to return with another rate increase proposal for 2011. In coming years, PacifiCorp expects to ask customers to share the cost of improving the grid to tap wind energy.

“As these projects are brought into service, the company will request approval to begin including their costs in the prices customers pay for electricity,” said Rocky Mountain Power spokesman Jeff Hymas.

That includes the current rate and additional requests over several years, he said.

Improvements to the Unit 1 boiler at the Jim Bridger plant include a new Hitachi generator shaft to increase efficiency and reduce sulfur dioxide and nitrogen oxide emissions.

“Anything you do for efficiency, you reduce emissions,” said Paul Fahlsing, the plant’s engineering and environmental manager.

By the end of 2014, PacifiCorp expects to retrofit 16 units at power plants with low-nitrogen oxides burners, sulfur dioxide scrubbers and fabric bag houses to capture particulate matter.

Information from: Casper Star-Tribune - Casper, www.trib.com