Bonneville, the Northwest’s biggest clean-power supplier, faces promise and perils in changing energy markets

 July 21, 2019 at 6:00 am By Hal Bernton  Seattle Times staff reporter GRAND COULEE DAM — When workers started pulling apart the three largest hydroelectric units in North America — capable of supplying more than enough power for all of Seattle — they found the damage far worse than expected. They encountered large cracks, worn-out bearings …