ISO New England’s Winter Peak Shift

ISO New England's outlook has become more specific and somewhat more confident: demand is still rising, but the forecast now quantifies about 9% growth by 2035 and puts more emphasis on the timing challenge of roughly equal summer and winter peaks. The updated framing also gives batteries a clearer role in summer shaving while downplaying their winter usefulness.

The story has shifted from a general upward-load forecast to a more specific downgrade in near-term growth expectations, driven by weaker heat pump and EV adoption after policy changes. It also adds clearer detail on winter-peak dynamics and the first modeled inclusion of small behind-the-meter batteries, though their impact remains limited.

• Near-term heat pump and EV adoption is weaker than previously expected.
• Small behind-the-meter batteries are modeled in ISO New England's forecast for the first time.
• Massachusetts is expected to drive much of incremental storage growth.
• Vermont and Maine show the fastest winter peak growth rates.

The story has shifted from a narrower demand-forecast update to a broader framing about how electrification and customer-sited resources are reshaping New England’s load profile. The biggest new emphasis is uncertainty around winter peak timing and the limits of batteries and solar in reducing that risk.

• Winter peak timing is now the main uncertainty in regional planning.
• Customer-sited batteries may have limited value if winter peaks shift unpredictably.
• Behind-the-meter solar and batteries are increasingly embedded in forecast planning.
• The story now explicitly includes Massachusetts storage policy.
• Forecast horizons now extend through 2046 in some planning updates.

ISO New England now projects roughly 9% electricity demand growth across New England over the next decade, a slower outlook than in prior forecasts. The main drivers remain electrification of heating and transportation, while revised assumptions reflect expiring federal incentives, updated heat-pump modeling, and new estimates for data centers, solar, and battery storage. The forecast matters because it will shape utility planning, winter peak preparation, and grid investment decisions in Maine and the wider region.