Blackout risk rises as heatwave stresses largest US electric grids

US energy department warns of potential for outages in PJM Interconnection, serving 67 million from DC to Chicago

The risk of power outages is expected to escalate across a broad swath of the United States on Wednesday as intense heat will test the capacity of electricity supplies serving millions of homes and businesses from the midwest through the mid-Atlantic.

The USDepartment of Energy warned of the potential for heightened blackout risks in the PJM Interconnection, the largest US electric grid, which serves 67 million people in a territory stretching from Washington DC to Chicago.