When Stephen Gordon installed solar panels on his two-story house in Webster last year, several contractors remarked that his home was perfect for solar. He has a big south-facing roof and no tall trees obscuring the sunlight.
But even with the ideal set up, he saw his power production drop dramatically this week as smoke from Canadian wildfires blew into New England.
In the two days before the first big plume arrived, Gordon’s solar array produced about 53 kilowatt-hours of power per day — an amount he said is typical for a warm summer day, and more than covers his household needs during daylight hours.
Then came Wednesday, when people throughout New England woke up to gray or even orange-tinted skies. Gordon’s total output that day was just under 23 kilowatt hours, less than half of what his panels generated the previous day.
Elsewhere in the state, Scott Wahlstrom of Holden said his solar panels also underperformed with the hazy conditions.
“My rough estimation is the wildfire smoke cut production of our solar array in half yesterday,” he wrote in an email.
And down in Warwick, R.I., a large rooftop array that produced 1,833 kilowatt-hours of power last Wednesday, produced only 599 kilowatt-hours a week later.
“Peak generation value was down by over 50% [Wednesday] and the total output for the whole of the day was down 60%,” said John Fitzgerald Weaver, president and owner of the solar firm, Commercial Solar Guy.
According to ISO New England, the organization that manages New England’s electric grid, these were not isolated cases. All that smoke caused a big drop in solar production in the region, the vast majority of which is known as “behind-the-meter,” or small projects that power individual homes and buildings.
“We’ve seen, at points, up to a 40% drop in what we would have expected from behind-the-meter solar due to that smoke,” said ISO spokesperson Matt Kakley.
At peak hours, the solar fleet in the region produced 2,500 megawatts less than had been forecasted, Kakley said.
“That’s essentially like losing a resource greater than Millstone Power Plant,” he said, referring to the nuclear power plant in Connecticut. “It’s a big drop.”
As for New England’s utility-scale solar projects, Kakley said production was down there too, though the ISO doesn’t have hard numbers yet about this.
Even so, there was plenty of power and the reliability of the grid was never in question, he made clear.
In fact, the wildfire smoke helped dampen electricity demand in the region. By blocking the sun, the the temperature on land was several degrees cooler than anticipated, and people’s air conditioners didn’t have to work as hard.
“So you have one major factor increasing demand on the system — that being the drop in solar production — and then you have another factor that’s bringing it way down, and that’s the lower temperatures,” Kakley said. “And what it kind of adds up to is a very challenging week for our forecasters.”
The issue is that there isn’t a lot of historical data to help experts determine how smokey conditions can impact the grid here in New England. We had a lot of smoke a few summers ago, which also affected temperature and solar output, Kakley said, but this week’s smoke has been more intense.
Climate change has made wildfires in the Western U.S. and Canada bigger, hotter and more destructive. Hundreds of wildfires are actively burning in Canada, including at least 109 fires deemed “out of control.” These fires, plus some burning in Minnesota, are largely to blame for the smokey — and unhealthy — conditions in the Northeast.
As smokey days likely become more of a typical part of a New England summer, Kakley said his team is working to better understand how these conditions affect the electric grid — both in the demand for power and the production of it.
“It’s certainly something that we are, unfortunately, getting more experience with,” Kakley said. “However, the more experience we do get dealing with these challenging conditions, the better we’ll have a handle on exactly what levels of concentration mean and how different portions of of the region experience it more or less.”
This article was originally published on WBUR.org.
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