Summer Blackout Fears Fuel 300% Jump in Gauge of US Power-Plant Profit

US power plants are poised to reap their best summertime profits in nearly two decades thanks to soaring electricity prices that are outpacing the high costs of natural gas and coal.

On America’s largest grid, stretching from New Jersey to Illinois, a key metric for gauging the profitability of coal plants has nearly quadrupled from a year ago to $43 per megawatt-hour, according to Energy Aspects Ltd., an electricity research and data provider. In Texas, it’s up almost 10-fold for gas plants, said BloombergNEF.

While a potential windfall for power-plant owners, the wide margins suggest trouble for the country’s strained grids. They reflect concerns among wholesale power traders that extreme heat in the weeks ahead will drive electricity demand to record levels, making supplies perilously tight. State and federal officials have already warned that electric grids could be pushed to the brink of blackouts. Now the market is sending its own unambiguous distress signal.