A sweeping heatwave across the United States is intensifying concerns about the country's ability to meet surging electricity and water demands driven by the rapid expansion of artificial intelligence data centres. PJM Interconnection (the nation's largest power grid operator, covering 13 states and Washington, DC) has asked the Department of Energy to require data centres to switch to backup generators within 15 minutes of an emergency signal, freeing capacity for homes and businesses as temperatures in some eastern cities approach or break decade-long records. The pressure is fuelling rare cross-partisan backlash: data centres currently account for 4 percent of US power consumption — a share the Department of Energy expects to nearly double by 2030 — and seven in ten Americans oppose new facilities in their communities, according to a recent Gallup survey.