On April 20, the New England power grid marked a historic milestone: electricity demand dropped to an all-time low of 5,318 megawatts. This event, driven by a mix of mild weather and unprecedented rooftop solar generation, represents a glimpse into the evolving energy landscape of the region—and perhaps, the future of power systems everywhere.

At the heart of this transformation is the growing adoption of behind-the-meter solar installations. On that spring afternoon, rooftop solar peaked at 6,600 megawatts, effectively reshaping the grid’s daily load profile. The result was a pronounced “duck curve,” where midday demand dipped sharply before rising again in the evening as the sun set and solar output faded.

This pattern underscores a fundamental shift in how and when power is consumed. Traditionally, electricity demand would peak in the afternoon or early evening, especially during hot summer days. But with increasing use of electric heating and rapid solar adoption, those peaks are now shifting—seasonally from summer to winter, and daily from afternoon to post-sunset.

Grid operators at ISO New England are actively adapting to these changes. As renewable energy sources like solar and wind become more integrated, and as electrification expands across sectors, the traditional dynamics of energy supply and demand are being redefined.

The April 20 low-demand milestone is more than just a record; it’s a signal. The structure of our energy systems is changing rapidly, and with it comes both challenges and opportunities. Flexibility, innovation, and forward-thinking policy will be key to ensuring that the grid can support a cleaner, more decentralized energy future.