A different kind of holiday: Thanksgiving grid demand peaks in the afternoon

For the first time since at least 2000, and possibly ever, Thanksgiving didn’t see its usual morning peak for grid demand this year. The change wasn’t caused by New Englanders suddenly deciding to change their cooking habits, but rather the further influence of solar power in the region.

Only a tiny fraction of the region’s 2,700 MW (nameplate) of solar power is sold in the region’s wholesale electricity marketplace. Instead, almost all regional solar power is “distributed”—generated locally or installed directly on site at retail customers’ homes or businesses. New Englanders using distributed solar power use commensurately less electricity from the regional power system. As the grid operator, ISO New England experiences distributed solar power as a reduction in grid demand.

This Thanksgiving, despite seeing historical cold temperatures, was bright and sunny, with power from the region’s more than 150,000 solar installations displacing demand for grid electricity, as seen in the graph below.

The afternoon Thanksgiving peak comes just a few months after solar power pushed midday grid demand below overnight demand for the first time in New England, and further highlights the growing impact of solar energy on the region’s power system.