Oregon Live: Follow Share this story Story tools Facing a Sierra Club lawsuit and heightened federal scrutiny of its Boardman coal-fired generating plant, Portland General Electric has drafted a much firmer proposal to close Oregon’s only coal plant by Dec. 31, 2020, at least 20 years earlier than anticipated. The new plan also tightens controls on sulfur dioxide pollution from 2018 to 2020. And it has backing from the Oregon Environmental Council, the Citizens’ Utility Board and other groups, raising the…