U.S. Midwest in Danger of Rotating Power Blackouts This Summer

According to federal energy officials, the Central United States’ power grid may face rolling blackouts on some of the hottest days this summer as plant retirements and rising demand continues. 

Weather extremes are causing increasing challenges for power grids across the U.S. Officials are concerned that drought and record heat may result in rotating blackouts in several regions in the country’s west.

The Midwest’s summer generating capacity has been threatened by forced outages and planned maintenance in addition to the shutdown of nuclear and coal plants over the past year and seasonal factors, including low wind speeds.

Midcontinent Independent System (MISO), the region’s grid operator, has already warned of reliability concerns and potential capacity shortfalls in the central and north regions of its areas of coverage. MISO operates the power grid for 15 central U.S. states as well as the Canadian province of Manitoba. Forty-two million people rely on MISO’s power supply.

According to MISO, the central and northern regions it provides for are at “increased risk of temporary, controlled outages to preserve the integrity of the bulk electric system.” The U.S. Energy Information Administration (EIA) agreed, saying on its website that the forecast demand in MISO could reach 125.2 gigawatts (GW) in extreme conditions and 118.2 GW under normal conditions.

MISO optimistic it can meet summer peak demand

MISO expects to have 143.2 GW of capacity available to meet the peak demand this summer. However, forced outages and planned maintenance could reduce that capacity. Those reductions could leave just 114.9 GW of generating capacity available for MISO, less than the summer demand forecasts. On a hot summer day, as few as 200,000 U.S. homes can be powered on a hot summer day, compared with about a million on an average day.

Over the past five years, MISO’s summer capacity has been reduced by 14.4 GW of forced outages, 9.6 GW of seasonal derates like low-wind conditions, fuel supply limitations, drought, and an average of 6.7 GW of maintenance outages.

One of MISO’s largest power plants shut down over the past year. Entergy Corporation’s 0.8 GW Palisades nuclear reactor, located in Michigan, retired in May after more than 50 years of operation.

According to MISO, member utilities are prepared to take actions to maintain grid reliability and have trained for worst-case scenarios. Actions taken include limiting transmission line and power plant maintenance during heatwaves, imposing blackouts, and conserving energy.