Solar Power Has a Wildfire Smoke Problem

Wildfire smoke is choking renewable energy.

The plume of smoke billowing from Quebec down the East Coast of the United States isn’t just endangering people’s health, it’s reducing solar power production by darkening the sky. While the areas affected by the smoke are not greatly dependent on solar for power, both New York and New England have aggressive targets for more solar installation in the coming years, which means their grids could become more reliant on a form of generation that’s at risk during wildfires.

To find out how badly solar power was being hit, I reached out to grid operators who cover an area stretching from North Carolina to Maine, the Hamptons to Chicago. They all said something similar: the wildfire smoke meant less solar power production.

As the New England Independent System Operator put it in a release: The smoke was “significantly lowering production from solar resources in the region.”

But there was a wrinkle. The smoke isn’t just reducing the yield from photovoltaic panels, it’s also making forecasting power demand more difficult. That’s because the smoke cover also lowers temperatures, which can reduce demand for the air conditioning that is largely responsible for higher electricity usage in the summer months.

“These two factors — decreased production from solar resources and decreased consumer demand due to lower temperatures — has made forecasting demand for grid electricity challenging,” ISO New England explained, which made it hard to say exactly what factor won out over the other.

Similar effects were felt in the Midwest, Dan Lockwood, a spokesperson for the PJM Interconnection, the regional transmission organization that covers all or part of 13 states ranging from Northeast North Carolina to Chicago, told me in an email.

“Smoky conditions throughout the RTO this week have caused a reduction in visibility, reducing solar, and keeping temperatures several degrees lower than usual,” Lockwood said, although he also noted the uniqueness of the event made it “difficult to single out the effect of smoke alone.” He said the most comparable event was the summer of 2021, when western wildfire smoke floated through the Midwest and East Coast.

The New York Independent System Operator was able to put a figure on the solar production lost from the smoke. Andrew Gregory, a spokesperson for the New York ISO, said in an email that “total peak solar energy production … was 1,466 fewer megawatts than forecasted" on June 6 and 7, down about 25% from where they thought it would be. Those 1,466 megawatts would be enough to power around 250,000 homes, according to the Solar Energies Industries Association.

This is not unusual. California and Australia, which both have quickly growing solar sectors, have also experienced meaningful reductions in solar power production when they’ve been hit by severe wildfires.

One paper examining the 2020 wildfires on the West Coast found about “10%–30% reduction in solar power production during peak hours,” in California due to wildfire smoke. Not only did this mean a dirtier grid, it also wreaked havoc on planning done by the California Independent System Operation whose forecasts for electricity supply “did not include the effects of smoke and therefore overestimated the expected power production by [around] 10%–50%.”

These challenges will likely accumulate, the authors argue, as “a direct consequence of climate change is continued extreme biomass burning, which may lead to more frequent and intense smoke events.”

An Australian solar data company found that rooftop solar systems in Sydney and Canberra could see their output fall by 15 to 40 percent during hazy days. New South Wales, which includes Sydney, already gets 12.5 percent of its power from solar, according to the Australian Department of Climate Change, Energy, Environment, and Water.

While fossil fuel power is by no mean immune to extreme weather — just look at natural gas getting frozen out during cold snaps — a wide variety of carbon-free electricity can be diminished by the very climate events they are supposed to help solve, whether it’s the sun disappearing behind clouds of wildfire smoke or hydroelectric power getting choked off by drought or rivers getting too warm to cool nuclear reactors. This will only become a bigger problem as the world gets hotter.