But the National Park Service and a coalition of environmental groups that includes the Sierra Club say the proposal doesn't make PGE go far enough or fast enough. The plant, opened in 1977, has avoided tight controls for more than three decades, they said.
Ratepayer advocates worry that the utility could spend millions to control sulfur dioxide and nitrogen oxide emissions, then end up closing the plant if regulation of carbon dioxide emissions kicks in to combat global warming.
"The worst-case scenario for customers is they're being asked to make a $500 million investment in a plant that's going to be shut down because of climate change in a few years," said Bob Jenks, executive director of the Citizens' Utility Board.
The proposal, up for approval by the Oregon Environmental Quality Commission on June 19, was first floated in December, generating more than 1,200 public comments. The staff recommendation includes few changes from the initial proposal.
An earlier agreement with PGE will cut mercury emissions by 90 percent by 2012, although a proposal in the new rules could allow PGE to extend that deadline to 2014.
The Boardman plant, 150 miles east of Portland, is the largest stationary source of sulfur dioxide and nitrogen oxides in Oregon. It also generates a fifth of PGE's power.
It's responsible for more than half of the haze in the eastern gorge at certain times in the winter, a study concluded in 2008. The pollution also contributes to acid rain in the gorge, on Mount Hood and Mount Adams, and increases haze in 10 national parks and wilderness areas, from Hells Canyon to Mount Rainier.
The new proposal requires PGE, by 2014, to install updated burners and new scrubbers that would reduce emissions of sulfur dioxide by 80 percent and nitrogen oxides by 46 percent, at a cost of $280 million. That part of the plan is similar to what PGE proposed in 2007.
By 2018, the company would have to install a more advanced catalytic reduction system that would chop nitrogen oxide emissions by 84 percent at a cost of $191 million. That goes beyond PGE's proposal.
The coalition of environmental groups, which is suing PGE to try to force more pollution control, said regulators should set earlier deadlines with all controls installed by 2014. PGE should also be held to pollution reductions of 90 percent or more, the group said.
The equipment PGE will install "can provide dramatically lower pollution than this plan requires," said Aubrey Baldwin, an attorney with the Pacific Environmental Advocacy Center.
The National Park Service, U.S. Forest Service and the Southwest Clean Air Agency in Washington State also called for quicker action.
The Boardman plant impairs visibility as far away as North Cascades National Park in northern Washington state, the Park Service said, "the greatest magnitude and extent of visibility impairment" of any single source subject to pollution retrofits under the haze rule.
Andy Ginsburg, DEQ air quality administrator, said the schedules are realistic. PGE has to do a lot of prep work and will need to get in line for pollution scrubbers as other states update their haze plans and require more controls.
The equipment can achieve greater reductions than called for, Ginsburg agreed, but a 90 percent reduction standard would generate too many violations given the age of PGE's plant. Other Oregon laws will require that PGE run the equipment at its highest performance level, he said.
PGE asked regulators to allow two "decision points" when it could opt to close the plant instead of installing the pollution controls. Combined with plans to reduce mercury emissions, spending on pollution controls will increase rates by 3 percent, PGE predicts.
The first decision point, in 2012, would have allowed PGE to forego further spending on controls if it closed the plant by 2020. The second, in 2015, would have allowed fewer controls if the company committed to closure by 2029.
But DEQ staff rejected that request, saying PGE can request a rule change later if it wants to close the plant.