One of the world’s largest renewable energy projects, largest project’s period, was constructed in the 1930’s. The Grand Coulee Dam.
Not without controversy, it was also the beneficiary of some terrific luck when, with the attack on Pearl Harbor and outbreak of WWII, President Roosevelt and other supporters looked like geniuses for having had the foresight to push through such a crazy-expensive project. Hydro-electric power from the dam made possible the building of planes by Boeing and ships in Portland, not to mention the transformations of Seattle and Portland from outposts into major Northwestern cities.
This, really well-done, documentary tells a lot of the story, including choice bits about Woody Guthrie being paid to come up with promotional tunes for public energy (!) [who has that gig now?] and environmental consequences like the interruption of salmon runs on the Columbia River, the restoration of which have been probably more feel good and window dressing for preserving regional identity than anything. Anyway, recommended.