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.