America is retiring coal plants slowly and steadily. The boilers are cut up for scrap, the smokestacks get dropped on camera and the land tends to sit in permitting limbo for a decade. But in Becker, Minnesota, the state’s biggest coal plant is being used, not for all this hardware but for a plug.On July 21, Xcel Energy announced it had completed the third phase of Sherco Solar, pushing the site to 710 megawatts generated by 1.7 million panels. This makes it the largest solar facility in Minnesota and one of the biggest in the Upper Midwest, by the utility’s own careful scoping. But this is not the most interesting part.What is making headlines is the fact that Sherco Solar feeds the grid through the transmission infrastructure and interconnection rights of the Sherburne County Generating Station, the coal giant next door that has been pushing power into the same wires since 1976. The solar plant borrowed that connection to let 710 megawatts of solar go through.
The plug that matters
Any new power plant that wants onto the US transmission grid has to join an interconnection queue, where grid operators study what upgrades the system needs before anything gets energised. According to Lawrence Berkeley National Laboratory’s latest count, published July 1, some 2,061 gigawatts of proposed generation and storage are sitting in those queues. That is more capacity than every power plant currently operating in the country, combined.But Sherco Solar almost sidestepped this entire process. The Midcontinent Independent System Operator, which runs the grid across the middle of the country, gives the owner of a retiring plant three years to reuse its interconnection rights for a replacement resource. Those rights cannot be sold to anyone else, so they are strictly use it or lose it.Xcel used it. The nonprofit RMI estimates this generator replacement route can cut connection time from the five-year average to under one year. Rob Gramlich, CEO of the consulting firm Grid Strategies, put it more bluntly when CNN visited the site in 2024, saying “somebody just has this Disney pass to skip the line.”Transmission is a scarce asset underneath all this. There is seldom a spare line sitting around anywhere on a modern grid, which is why Tasmania is currently rebuilding 287 towers on a corridor it is not allowed to switch off. A live connection with real capacity behind it is close to priceless, and a retiring coal plant has exactly that.
