Offshore wind’s first heat wave trimmed New England’s oil burn

New England’s grid hit its highest demand of the year, 25,351 megawatts, on July 2, as a heat dome parked over the Northeast. The oil-fired plants that traditionally drag the region through its worst hours ran, but less hard: oil supplied roughly 10% of power at the peak, versus nearly 15% during the comparable June 2025 heat wave, according to an analysis of Grid Status data published Monday by Canary Media’s Maria Gallucci. A big part of the difference is offshore wind capacity that, as Grid Status analysts wrote during last June’s heat wave, the region wasn’t expected to see “for at least another year.”

It arrived.

Vineyard Wind, rated at 806 megawatts, finished construction in March, with 49 of its 62 turbines active as of early May. Revolution Wind, 704 megawatts, began delivering power the same month and expects full commercial operation later this year. Together with the smaller, older South Fork Wind, the projects put hundreds of megawatts on the grid through the July 1–4 heat wave, per Grid Status. Over those four days the region’s oil-fired plants generated 42.2 gigawatt-hours, down 37% from the June 23–25 heat wave last year.

What survives the check

The topline holds up against public data, with one asterisk. ISO New England warned on July 2 of “little surplus generating capacity” and forecast a 25,850-megawatt evening peak; the actual figure came in about 500 megawatts under, and the operator’s hourly fuel mix is public in its daily generation-by-fuel-type reports. For the 2025 baseline, the U.S. Energy Information Administration’s post-mortem of ISO-NE data put the June 24, 2025, peak at 25,898 megawatts, the region’s highest since 2013, with petroleum at 12% of the peak-hour mix. Not 15%.

That is a denominator quarrel, not a contradiction. Measured at each year’s demand peak using EIA’s figures, oil fell from roughly 3.1 gigawatts to about 2.5, a drop closer to 600 megawatts than the “more than 1 gigawatt” Canary Media cites, which compares each day’s maximum oil burn. The direction survives either cut. The size depends on which hour you slice and what counts as supply.

What no slice can isolate is how much credit belongs to the turbines. The two peak days had different weather, and 2026 demand ran about 550 megawatts lighter. Plant-outage profiles differ year to year in ways the public record doesn’t expose. Offshore wind also had help: the New England Clean Energy Connect line has been moving Canadian hydropower into Maine since January, and the region’s roughly 6 gigawatts of distributed solar covered more than a quarter of demand at moments on July 2, according to the Acadia Center’s grid report. Canary Media’s own sourcing concedes as much.

“Even if total demand was in line with last year, we would still be hundreds of megawatts below what the total [peak oil] burn would’ve been,” Grid Status analyst Tim Ennis told the outlet.

Hundreds of megawatts is the defensible number. It is also the first real-world peak-performance data from projects the federal government spent last year trying to stop. The Trump administration ordered construction halted on Revolution Wind in August 2025, when the project was 80% complete; a federal judge granted an injunction that September allowing construction to resume. In December, the Bureau of Ocean Energy Management paused the leases of all five large U.S. offshore wind projects then under construction, per Canary Media, before courts intervened again.

The industry spent a decade making its case with capacity-factor projections and interconnection studies. Its strongest evidence to date turned out to be four days in July, when day-ahead power cleared as high as $934.98 a megawatt-hour and the oil fleet, for once, throttled back.