Rooftop solar drives down electricity demand to record low in New England
New England’s power grid experienced a record-low demand for electricity on April 9th, and the main reason is rooftop solar. The combination of sunny skies, mild temperatures, and the holiday of Easter reduced the demand to an average of 6,814 megawatts of power between 2 and 3 p.m., which is the lowest on record. This figure is also 10% less than the previous record of 7,580 MW set on May 1, 2022. The output available at the time was over twice the amount needed, reflecting the challenge traditional power plants face from the increasingly cheaper solar and wind energy.
According to Steven Gould, the director of operations at ISO-New England, which oversees the six-state power grid, the new record is a result of the continued evolution of New England’s power system, and he expects the record to be broken again soon. During the record-low demand on April 9th, around 4,500 megawatts of electricity, which is approximately four times the output of the Seabrook Station nuclear power plant, was produced by rooftop solar. This type of solar power generation is “behind the meter” and is not directly measured by ISO-NE, but its output shows up as a reduction in demand. ISO-NE measured around 500 MW of electricity produced by large-scale industrial solar plants.
New England’s solar output tends to peak in spring because of the combination of sunny days and cooler temperatures, which electronic systems prefer. The demand decreased on Easter Sunday when many businesses were closed, which also contributed to the record. In the middle of summer when it is cloudy, bulk demand can exceed 20,000 MW.
The increase of rooftop solar during the day has changed the traditional pattern of power production. Previously, New England's power needs increased in the morning, remained stable during the day, increased slightly when people returned home from work, and then fell, reaching a low point after midnight. However, on sunny days, demand falls sharply during the day as it gets replaced by rooftop solar, creating what is known as a “duck curve.” On extreme days known as “duck curve days,” the bulk power system's demand is at its lowest in the afternoon rather than overnight. These days are becoming increasingly common in the spring and fall.
Source: vermontbiz.com