Regulators "acknowledged what we feel: That it's still in the best interests of our customers and the company, from a cost perspective, to install the emissions control equipment," Shawver said.
In a partial victory for environmental groups, however, the Idaho regulator declined to approve a request from the utility that would have virtually guaranteed that Idaho Power could recover the full $130 million investment, once the project was completed.
Had that been granted, the commission wrote in its 13-page decision, it would have made it more difficult for Idaho Power to abandon these investments, even if stricter federal greenhouse gas limits made the controls a bad deal for ratepayers.
"A tipping point could be reached making them uneconomic," regulators wrote. "As the project moves toward completion ... we direct Idaho Power to return to the commission if viable alternatives ... become available."
Zack Waterman, director of the Sierra Club in Idaho and a key organizer of opposition to the utility's proposal, joined other coal-plant foes including the Snake River Alliance group in lauding the commission's decision not to lock in recovery of the $130 million.
He's hopeful forcing Idaho Power to justify its upgrades every three months, coupled with the possibility of new greenhouse gas emission limits on the horizon, will prompt the utility to "completely rethink" its investment in the upgrades.
"We're still thrilled with this," Waterman said. "We think this gives us an opportunity to continue the discussion. We don't think all of the costs of running these coal plants have been accounted for. And we don't think that an adequate range of alternatives has been presented to ratepayers."