Wildfires hit US West Coast solar performance with smoke cover

September 12, 2016
Facebook
Twitter
LinkedIn
Reddit
Email
Solar project revenues during this peak generation season are also estimated to have been seriously impacted. Flickr: Daria Devyatkina

Summer wildfires across the West Coast of the US have significantly impacted the output of solar PV projects in the region with smoke cover reducing irradiance levels, according to environmental and industrial measurement firm Vaisala.

Project revenues during this peak generation season are also estimated to have been seriously impacted, said Vaisala on the release of its ‘Solar Performance Maps’ for June to August this year.

This article requires Premium SubscriptionBasic (FREE) Subscription

Try Premium for just $1

  • Full premium access for the first month at only $1
  • Converts to an annual rate after 30 days unless cancelled
  • Cancel anytime during the trial period

Premium Benefits

  • Expert industry analysis and interviews
  • Digital access to PV Tech Power journal
  • Exclusive event discounts

Or get the full Premium subscription right away

Or continue reading this article for free

The West Coast is seeing an increasing number of large-scale forest and bush fires due to greater levels of heat and dry conditions during the summer.

California was cited as having “particularly severe” fires this year, with more than 180,000 acres covered, with several major fires still ablaze. As the most successful solar state in the US, with a fifteen-fold increase in capacity in five years, fires now pose a threat to both safety and profitability for California's solar project owners.

However, GTM Research's latets report did find that the key California market had experienced a slowdown.

Vaisala said the threat that fires pose to transmission infrastructure in terms of damage is well known and many project owners are able to enact precautionary site shutdowns for protection from fire. However, the threat that smoke poses to PV plant output is less apparent.

The ‘Solar Performance Maps’ for this summer, which demonstrate monthly resource variability from long-term averages, shows large areas of below-par resource in a number of regions across California and the southwest, which directly correlate with the sites of major wildfires throughout the region.

These California Solar Performance Maps show departures from average solar irradiance in GHI (or Global Horizontal Irradiance, the key variable for PV projects) and highlight the effects of recent wildfires. Vaisala conducted the study by comparing 2016 data with long-term averaged values from its continually updated global solar dataset. Credit: Vaisala

Kern County

One of the largest wildfires this summer was the Cedar Fire in Kern County, southern California, engulfing nearly 30,000 acres. Kern County has 4,881MW of installed solar power capacity yet its irradiance fell by between 1-4% in different areas during June.

Vaisala estimated US$940,000 in lost revenues for PV operators in the region based on a 1% loss in production during peak production and a tariff of US$150/MWh.

It is estimated that project operators in Los Angeles and San Bernardino counties, which both have large installed solar capacities, will have had similar losses.

Gwendalyn Bender, product manager, Vaisala, said: “Faced with the significant financial impact of performance fluctuations caused by regular wildfires, it’s clear that solar asset owners and operators in commonly affected areas need to start factoring this regional risk into their plans – particularly since these incidents typically coincide with the peak generation season.”

Bender added that the west coast wildfires show the importance of gathering long-term historical data at project locations, using satellite technology. Understanding such extreme events will help develop a “climate resilient portfolio”, which can account for variability in generation casued by such events.

16 June 2026
Napa, USA
PV Tech has been running PV ModuleTech Conferences since 2017. PV ModuleTech USA, on 16-17 June 2026, will be our fifth PV ModulelTech conference dedicated to the U.S. utility scale solar sector. The event will gather the key stakeholders from solar developers, solar asset owners and investors, PV manufacturing, policy-making and and all interested downstream channels and third-party entities. The goal is simple: to map out the PV module supply channels to the U.S. out to 2028 and beyond.
13 October 2026
San Francisco Bay Area, USA
PV Tech has been running an annual PV CellTech Conference since 2016. PV CellTech USA, on 13-14 October 2026 is our third PV CellTech conference dedicated to the U.S. manufacturing sector. The events in 2023, 2024 and 2025 were a sell out success and 2026 will once again gather the key stakeholders from PV manufacturing, equipment/materials, policy-making and strategy, capital equipment investment and all interested downstream channels and third-party entities. The goal is simple: to map out PV manufacturing in the U.S. out to 2030 and beyond.

Read Next

February 13, 2026
Inox Clean Energy has partnered with integrated renewable energy platform RJ Corp to expand into Africa’s renewable energy markets.
Premium
February 13, 2026
PV Talk: Charith Konda, energy specialist at IEEFA, says India’s 2026-27 budget aims to “establish a stronger supply chain within the solar and PV cell and module sector,” but warns that “execution is as important as the policy itself.”
February 13, 2026
Germany’s federal network agency (Bundesnetzagentur) has announced the results of its latest ground-mount solar auction, which closed with bids for more than twice as much capacity as was tendered.
February 13, 2026
AES Indiana, a subsidiary of US utility AES Corporation, has started commercial operations at a 250MW solar-plus-storage plant in Pike County, Indiana, US.
February 13, 2026
The US Treasury’s interim Foreign Entity of Concern (FEOC) guidance is “in line with expectations” according to a US renewable energy supply analyst.
February 12, 2026
US solar EPC SOLV Energy has issued its initial public offering (IPO) on the Nasdaq Global Select Market, priced at US$25 per share.

Upcoming Events

Upcoming Webinars
February 18, 2026
9am PST / 5pm GMT
Solar Media Events
March 24, 2026
Dallas, Texas
Solar Media Events
April 15, 2026
Milan, Italy
Solar Media Events
June 16, 2026
Napa, USA
Solar Media Events
October 13, 2026
San Francisco Bay Area, USA