Massachusetts Loosened Its Clean Energy Rule — Now 53% Fewer Batteries

Massachusetts has a rule called the Clean Peak Standard. It requires electricity suppliers to buy a growing share of their power from clean sources during the busiest hours of the day — roughly the late afternoon and early evening, when everyone's lights, ovens and air conditioners are running. To meet it, developers build big batteries that charge up when power is cheap and clean, then sell that electricity back to the grid at peak. In 2026, the state recalibrated the rule: it lowered the minimum requirements and expanded a bonus for storage projects built soon.

Two researchers ran an hour-by-hour computer simulation of the New England power grid from 2026 through 2030, comparing the original rule with the relaxed one. Both versions technically comply with the law. But the relaxed version leads to 53.1% fewer new batteries being built and cuts the modeled cost of running the whole system by 3.7%. The amount of clean electricity discharged during peak hours falls 30.4%.

The catch: fossil-fuel generation during those peak hours rises 11.7%. That sounds bad for the climate, but total emissions stay nearly flat. Why? Because of the Regional Greenhouse Gas Initiative, a cap-and-trade program covering power plants across the Northeast. The cap sets a hard ceiling on total pollution, so extra gas burned at peak hours gets offset by reductions elsewhere. The state stays under the cap, so the atmosphere doesn't notice much.

Still, the tradeoff is real. Massachusetts gets a cheaper system and builds fewer batteries, but its physical ability to actually clean up peak hours weakens. If the pollution cap tightens in future years, or if new gas plants get built to fill the gap, that lost storage capacity could be harder and more expensive to replace. Think of it as paying less for a gym membership you rarely use — fine today, awkward if you suddenly need to get in shape.