Wildfire smoke may have a significant impact on the
efficiency of solar panels and the overall effort to transition nation’s energy
production from fossil fuels to more solar based systems, according to research
published by Long Zhao, Ph.D., an assistant professor in the Department of
Electrical Engineering and Computer Science at South Dakota Mines and director
of the Smart Grid and Energy Research Lab at South Dakota Mines.
Zhao’s work, conducted over the last two years when
wildfire smoke blanketed parts of the American West, shows that widespread
smoke can reduce the output of individual solar panels by nearly 50% -- even on
days when smoke is present at high altitudes and air quality near the ground is
not significantly impacted.
“It depends on where you are,” says Zhao. It makes
sense that solar energy production is negatively impacted on very smoky days, but
Zhao’s team was surprised to see reductions in solar energy output when wildfire
smoke was aloft higher in atmosphere. “This makes it harder to quantify days
when smoke will impact solar energy production based on air quality monitoring
systems we have in place,” he says. His
work will be published in the Journal IEEE Transactions on Industry Applications.
Unlike passing clouds, that can reduce solar energy generation
for a short duration, wildfire smoke can settle over a region for an extended
period. This summer, for example, saw thick layers of Canadian wildfire smoke
inundate the East Coast of the United States.
“I think one special thing about wildfire smoke is
it can travel thousands of miles and cover lots of land mass and last for days
or even weeks,” says Zhao.
Furthermore, smoke from wildfires often varies in
intensity with pockets of heavier and lighter coverage that can cause
fluctuations in solar panel output. Zhao calls these fluctuations “the wiggle effect,”
and he described this phenomena in a paper published by IEEE that was
shared in the publication IEEE Spectrum. “These
fluctuations can have a significant impact on our power supply if we are
relying on solar systems as a major part of our energy grid,” says Zhao.
Electric grids across the nation operate on thin
margins between supply and demand, and Zhao’s work shows fluctuations in solar
energy generation caused by wildfire smoke could be enough to destabilize parts
of the grid that are more reliant on solar power. In California, for example,
the U.S. Energy Information Administration reports that 25% of all electricity in 2022 was solar generated. Across the United
States, 92.5 gigawatts were generated by solar systems in the same year. Zhao’s
research shows that as the country moves toward more reliance on solar
generated electricity, wildfire smoke must be a factor taken into
consideration.
“Bigger photovoltaic systems will have bigger
problems with the wiggle effect,” Zhao says. “We have not yet seen widespread problems
because we do not yet have solar widely installed across the country. As we
move to rely on more solar power in the future, and as wildfires continue, this
is going to be a serious problem we need to address.”
Zhao says this research would not have been possible
without the support of the Edwin E. Clark Professorship through the South
Dakota Mines Center for Alumni Relations and Advancement (CARA). “Most of the
research equipment in the Smart Grid and Energy Research Lab was purchased
using funds from this professorship,” he says. He is seeking graduate students
and more funding for his ongoing research.