The unanimous vote ended a multi-year process to reduce haze pollution in scenic and wildlife areas, as required by federal law.
New filters and scrubbers at the Boardman power plant will reduce both acid rain and the haze clouding the Columbia River Gorge, Mount Hood and Hells Canyon.
Combined with plans to reduce mercury emissions, spending on pollution controls will increase rates by 3 percent, PGE predicts.
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 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 plan requires PGE, by 2014, to install updated burners and new scrubbers that will 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 will 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.