Solar is causing a dramatic shift in electricity demand

Demand for electricity from the New England power grid fell to an all-time low on Easter Sunday, another telling sign that solar power continues to expand across the region.

Solar is an energy source that can be hard to track, in part because much of the electricity is generated and used behind the power meter of a home or business and never makes it on to the grid.

But the power grid operators at ISO-New England are seeing more and more evidence of solar’s growth. Traditionally, demand for power from the grid is lowest at night when most people are sleeping. But increasingly the low point of power demand is shifting to earlier in the day when solar panels on homes and businesses are generating the most electricity.

The first time demand for power from the grid was lower in the afternoon than at night was on April 21, 2018. It happened 35 more times through the end of 2021, 45 times in 2022, and is expected to happen even more times this year.

On May 1 last year, demand for power from the grid fell to its lowest level since ISO-New England took over operation of the grid 25 years ago. Demand fell to 7,580 megawatts on a Sunday when the sun was shining (generating more solar energy) and overall demand for electricity was low. Temperatures were in that sweet spot where neither air conditioning nor heat were needed.  

On Easter Sunday this year, demand fell even lower — to 6,814 megawatts between 2 and 3 p.m. As a point of reference, power demand from the grid was 10,929 megawatts six years ago on Sunday, May 6, 2017.

Less demand for power from the grid means less need to fire up power plants that rely on fossil fuels to generate electricity. It’s a virtuous cycle that should accelerate in the coming years.

“The previous record lasted less than a year, and this one likely won’t last long either,” said Steven Gould, ISO-New England’s director of operations. “Each day, our system operators are seeing the clean energy transition play out in real time.”