Decarbonizing the Peak: A Roadmap for Retiring and Replacing Massachusetts’ Fossil Fuel Peaker Plants by 2050

Massachusetts has committed to achieve net-zero emissions by 2050, a goal that requires retiring the state’s fossil fuel peaker power plants and replacing them with clean, reliable alternatives. This report by the Massachusetts Clean Peak Coalition, with analysis from Synapse Energy Economics, shows that net-zero technologies can meet the state’s peak electricity demand by 2050 while maintaining reliability and containing costs.

The analysis finds that full peak decarbonization is feasible, reliable, and cost-effective, even as electrification drives a shift to higher, longer, winter-peaking demand. A least-cost portfolio of clean resources combines demand-side measures, energy storage, and wind generation to meet 2050 peak demand. When climate and public health benefits are accounted for, this clean portfolio is less costly than continued reliance on gas peaker plants or combustion-based alternatives such as hydrogen or renewable natural gas.

Based on these findings, the Massachusetts Clean Peak Coalition advances four core recommendations:

1. Incentivize demand-side measures to reduce the cost of decarbonization, with a focus on reducing summer and winter peaks.
2. Prioritize the development of medium- and long-duration energy storage technologies to maintain reliability during winter peaks.
3. Consider local siting constraints and community concerns in building out wind capacity.
4. Account for externalities, such as climate and public health impacts, when evaluating the cost-effectiveness of peak decarbonization.

Taken together, the analysis confirms that decarbonizing peak demand is not an abstract aspiration but a practical and necessary component of Massachusetts’ clean energy transition. With deliberate policy choices centered on zero-emissions solutions, equity, and community engagement, the Commonwealth can retire its most harmful power plants, protect public health, and build a cleaner, more resilient electric system by 2050.

The Massachusetts Peak Coalition is comprised of Clean Energy Group, the Berkshire Environmental Action Team (BEAT), and Slingshot.