Wildfires engulfing large swathes of the U.S. West Coast this summer have had a significant impact on the performance of solar photovoltaic projects operating in the region. Irradiance shortfalls caused by smoke cover are clearly visible on monthly performance maps produced by Vaisala, a global leader in environmental measurement. These are estimated to have caused a substantial impact on project revenues during peak generation season.
Large-scale forest and bush fires have become a common occurrence throughout the American southwest, driven by a number of factors, including increasingly hot and dry conditions in the summer months. In California, this year's fires have been particularly severe, covering an area greater than 180,000 acres. A number of fires continue to rage throughout the state, putting lives, homes, and other key infrastructure at risk.
Californian solar is a national success story, having experienced impressive growth over the past five years. A fifteen-fold increase in capacity has seen it surpass wind as the leading form of renewable energy generation in the state. For the owners and operators of these projects, however, the increasing intensity of seasonal wildfires will provide cause for concern - posing a dual threat to the safety and profitability of their sites.
The physical risk of fire damage to solar assets and their transmission infrastructure is well known and many project owners in hot and dry regions worldwide implement fire protection and prevention measures - including precautionary site shutdowns - to mitigate this potential impact.
What is less immediately apparent is the risk posed by smoke resulting from wildfires to the operational performance of solar sites in the vicinity. While it is inevitable that smoke will contribute to reduced irradiance at ground level, assessing the scale and financial impact of this effect can be difficult to achieve.
Vaisala's June, July, and August 2016 California Solar Performance Maps, released today, provide a visual illustration of monthly resource variability from long-term averages. The maps clearly show 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.
One of the largest such areas surrounds the site of the Cedar Fire in Kern County, Southern California; a sizeable wildfire covering close to 30,000 acres. Kern County boasts an installed capacity of 4,881 MW of solar power - and saw average irradiance fall by between 1 and 4% in different parts of the county in the month of June.
Based on a $150 MWh power purchase price, Vaisala estimates that a 1% loss in production in Kern County during this typical month of peak production would equate to over $940,000 in lost revenues for operators across the region.
A similar impact is likely to have been felt by project operators in Los Angeles and San Bernardino counties, both areas with a high volume of installed capacity, where major wildfires in July and August have contributed to visible irradiance shortfalls on Vaisala's monthly maps.
"Irradiance fluctuations are typically linked almost exclusively to changing weather patterns, and the effects of other seasonal environmental conditions such as wildfires aren't always considered when it comes to financial modeling and forecasting" said Gwendalyn Bender, Product Manager, Vaisala.
"However, 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."
"The West Coast wildfires are a further illustration of the importance of gaining a long-term historical record at a project location that captures these kinds of events using satellite technology. Understanding these extreme events, weather or otherwise, is critical for creating a climate resilient portfolio, which helps smooth portfolio revenues by countering the impact of variability with projects that are geographically and technologically diverse."