The power grid in the Central United States could be forced to impose rotating blackouts on some of the hottest days of the summer due to rising demand and plant retirements, federal energy officials said in an online energy comment on Friday. Extreme weather is causing increasing challenges for power grids across the United States, and officials are concerned that record heat and drought could result in rotating blackouts in several regions in the western half of the country. In addition to the shutdown of coal and nuclear plants over the past year, the Midwest’s summer generating capacity is threatened by planned maintenance and forced outages, as well as seasonal factors like low wind conditions. The region’s grid operator, the Midcontinent Independent System Operator (MISO), has already warned of potential capacity shortfalls and other reliability concerns in the north and central regions of its coverage […]