Do Wildfires Affect Solar Energy Systems?

Wildfires mean short-term large losses of solar power, a study found.

Cameron Peak fire Kimberly Corwin credit Colorado State University

As wildfires are sweeping through areas near Los Angeles, California, new research from Colorado State University shows that while wildfire smoke increasingly covers large parts of the U.S. it does not have much of an impact on overall, long-term solar power generation activity.

The paper – published in Nature Communications – shows that losses of average, or background, photovoltaic solar resources due to wildfire smoke remain modest outside of the areas immediately surrounding active fires, where plumes are dense. The researchers also found that power generated from photovoltaics remained relatively stable across the U.S. even in extreme fire seasons.

For the project, the CSU-led research team used both modeled and historic data from multiple seasons to better understand changes in baseline solar resource availability related to wildfire smoke.
 
CSU Postdoctoral Fellow Kimberley Corwin is the first author on the paper. She said that as the U.S. looks to increase the amount of solar it uses from 3% to 45% of its total energy portfolio, these findings could be used to make informed decisions around where to build collection sites.

“There has been similar research into specific events – particularly around the larger fires in California. Our work, however, goes further and quantifies the effects over large timescales and geographies,” she said. “We show there are significant impacts to solar power resources near these fires, but that when smoke is transported farther away, as we have seen in the Midwest and along the East Coast recently, it presents much less of a concern in terms of prolonged solar losses. That has implications for where upcoming facilities should be placed for long-term efficiency as well as stability with the grid.”

Solar power generation can be hindered by a variety of factors beyond smoke, such as cloud cover and air pollution. The research team was interested in specifically understanding wildfire smoke’s impact on irradiance – the amount of solar light making its way to the surface of a panel to be collected. They specifically focused on Global Horizontal Irradiance (GHI) which includes both direct sunlight and diffuse sunlight scattered by the atmosphere. GHI is most relevant for the flat-plate photovoltaic systems that account for most of the solar production in the U.S. 

Corwin said they leveraged daily case studies from both the particularly active 2020 wildfire season in California and the much quieter 2019 season to offer short- and long-term context for upcoming wildfire seasons. They also looked at monthly and yearly aggregations on impacts at the state, regional and national levels, and used satellite-based tools like the NOAA Hazard Mapping System Smoke product to understand impacts at different scales.

The paper's abstract read:

By 2050, the U.S. plans to increase solar energy from 3% to 45% of the nation’s electricity generation. Quantifying wildfire smoke’s impact on solar photovoltaic (PV) generation is essential to meet this goal, especially given previous studies documenting sizable PV output losses due to smoke. We quantify smoke-driven changes in baseline solar resource availability [i.e., amount of direct normal (DNI) and global horizontal (GHI) irradiance] at different spatial and temporal scales using radiative transfer model output and satellite-based smoke, aerosol, and cloud observations. We show that irradiance decreases as smoke frequency increases at the state, regional, and national scale. DNI is more sensitive to smoke with sizable losses persisting downwind of fires. Large reductions in GHI–the main PV resource–are possible close to fires, but mean GHI declines minimally (<5%) due to transported smoke. PV resources remain relatively stable across most of CONUS even in extreme fire seasons.

In 2020, smoke from wildfires burning in California, Colorado and Oregon eventually arrived on the East Coast. Corwin said those plumes can still result in large losses over short time scales, however longer-term impacts remain modest since the smoke is not as persistent.

“While you do see large reductions close to active fires, that drops off quickly with distance. Substantial losses are specific to the area directly around the fire where the smoke column is denser and therefore blocks more of the light,” she said. “Meanwhile, the impact of the large, transported plumes that can linger for days but are dilute, is relatively modest compared to the average solar resource change you may see under other conditions. The decreases from transported smoke are only about 5% and – in some places – even less than 2% versus the average in low smoke years.”

Corwin added that improved battery storage should help further limit short-term impacts to power collection near wildfires. By switching to reserves from batteries, operators could avoid having to use natural gas to make up for power losses from local fires.

Corwin began working on the project as a graduate student in the Department of Atmospheric Sciences with Professor Emily Fischer. She started the work as part of her now finished Ph.D. with funding and support through a CSU Food-Energy-Water Systems graduate program, a NASA grant, and a CSU SoGES GCRT grant. Other CSU-affiliated researchers involved in the paper include faculty members Jesse Burkhardt, Amit Munshi and Fischer.

Fischer said Kimberley’s work is a “critical step in understanding the full implications of climate-driven increases in wildfire smoke.” 

“This paper, and the other chapters of Kimberley’s dissertation, have radically expanded our understanding of how smoke impacts the light at the ground needed for photosynthesis, solar power generation, and also the impacts on other aspects of air quality,” said Fischer, who is part of the Walter Scott, Jr. College of Engineering at CSU.

The federal government has spent billions of dollars in subsidizing the solar energy industry in recent years. Consumers who opt to install solar energy systems can count on tax credits and can apply for a loan of up to $25,000, payable in 20 years. Federal subsidies for renewable energy producers more than doubled between 2016 and 2022, forming nearly half of all federal energy-related support in that period, according to the Energy Information Administration. Those subsidies rose from $7.4 billion in fiscal year 2016 to $15.6 billion in fiscal year 2022, according to the Biden administration. In April 2024, the Biden administration pledged another $7 billion in grants to low-income households for renewable energy schemes.

Topic tags:
Colorado california wildfire alternative energy solar power