During the autumn months of 2020, wildfire smoke blanketed Washington, Oregon, and California at unprecedented levels. The particle counts were so high some days that all people were encouraged to stay inside, even if they had breathing protection to wear.

This smoke eventually made its way across the country and worldwide, but the first two weeks of September were miserable. In the coming decades, climate scientists expect these wildfires to be larger, burn longer, and occur throughout more of the year. [1]

The haze from wildfire smoke in California was enough to dampen solar collection activities by one-third. Even though sunlight scatters more on the days when thick smoke hangs over a specific region, Kimberley Corwin discovered that the same levels of solar energy made it to the planet’s surface.

We Need to Take a Global, Not a Local Look at Solar Production

Corwin is a doctoral thesis candidate at Colorado State University. She presented the information regarding solar energy collection during the American Geophysical Union fall meeting. [2]

She discovered that the amount of direct sunlight reaching a specific square meter of the planet’s surface dropped by 8% when comparing September 2019 with the same month in 2020. The information also showed that the levels of direct and diffuse light hitting that area only dropped by 2%.

“Solar panels don’t care whether they are getting photons from a direct beam or through diffuse radiation,” said Elizabeth Weatherhead, an atmospheric scientist at the Cooperative Institute for Research in Environmental Sciences at the University of Colorado in Boulder. Weatherhead was not involved in the study, but has received several awards for her work on climate, UV radiation, and stratospheric ozone.

The heat from wildfires can drive smoke high into the atmosphere. Winds at that altitude can push it thousands of miles away. In 2020, Washington residents got to experience hazy conditions from a burn in Siberia. [3]

The United States aims to ramp up solar energy production from 3% today to 45% in 2050. Those efforts will be hampered if wildfire smoke prevents photovoltaic (PV) panels from collecting the energy that shines down on the planet each day. [4]

Although the outcomes aren’t as possible for solar collection efforts that use mirrors or other methods, PV panels don’t slow down their efforts when there is haze in the sky. That means the push toward more renewables through these technologies makes sense.

More Work Is Needed Before Drawing Definitive Conclusions

Corwin’s goal is to have her research contribute to utility-scale energy production, but she says her analysis requires additional information points. The initial presentation didn’t include direct estimates of power generation or the tilt of the PV panels.

She’s hoping to extend the information analysis of direct and diffuse sunlight to at least 2006 to ensure there is enough data to show that photovoltaics can keep generating power during smoky days.

The Fourth National Climate Assessment estimates that the annual area burned by lightning strikes in the Southeastern US could rise by more than 30% by 2060. In the West, where wildfires are already a yearly problem due to megadrought conditions, the area burned could be six times higher than it is today by 2050. [5]

Are Photovoltaic Panels an Environmentally Friendly Solution?

Solar energy is experiencing a significant surge of interest as a renewable energy source, with an annual average growth rate that reaches 50% in some years. The reasons behind its popularity touch on three points.

• The cost of photovoltaic panels has dropped significantly over the past ten years.
• Once created, the energy produced with this method doesn’t contribute greenhouse gases to the atmosphere.
• Government incentives have helped to grow the economic power of this industry.

Solar panels are traditionally manufactured with quartz, which provides silicon and oxygen atoms. Since mining this natural resource can cause health issues, the industry is moving toward using quartz sand in the production process. This material is then refined into metallurgical-grade silicon for solar panels.

The issue is that the quartz material must convert to polysilicon for it to be usable. This process creates a silicon tetrachloride byproduct that requires proper disposal to avoid soil acidification or exposure to harmful fumes.

Regulations require at least 98.5% of this waste to be recycled in China, where most of today’s photovoltaic manufacturing occurs. [6]

Some products in PV panels require fossil fuels to complete the manufacturing process, but the net gains from energy production offset those emissions significantly.

“It is somewhat comforting to know that the impacts of smoke on energy production are only notable if the solar panels are right near the fires,” said Weatherhead.

[1] https://eos.org/articles/potentially-good-news-for-solar-energy-during-wildfires ; [2] https://www.agu.org/Fall-Meeting/Pages/About ; [3]https://ecology.wa.gov/Blog/Posts/September-2020/A-smoky-siege ; [4] https://www.energy.gov/eere/solar/solar-futures-study ; [5]https://nca2018.globalchange.gov/chapter/6/ ; [6] https://spectrum.ieee.org/green-tech/solar/solar-energy-isnt-always-as-green-as-you-think