Solar Risk Assessment: 2022

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  Section 2


















Topics Covered:

  • Inverter OEM and performance data
  • Terrain impacts
  • System complexity and quality trends
  • Degradation rates

Inverters perform 40% worse during two-year warranty period compared to remaining years of operation


      By: Frank Kelly, VP  


NovaSource operates 20GW of utility-scale PV systems. Based on its experience and industry knowledge, NovaSource has observed that inverters when covered by their original equipment manufacturer's warranty are underperforming and not meeting proforma availability targets compared to the same inverters when they are operating out-of-warranty.


Inverters are critical components to the performance of PV sites and on average account for ~60% of a site's total lost energy[1]. To measure the performance of inverters, we look at two key metrics: (1) failure rate and (2) mean- time-to-repair ("MTTR"). A lower failure rate and shorter MTTR are key to projects achieving their availability targets.


After reviewing the GWs of inverters we operate, we found that on average, inverter failure incidences that impact generation occur 0.8 to 1.4 times per inverter per year. To quantify the severity and complexity of repairs necessary to bring systems back online, we also review the MTTR associated with inverter failure incidences.

While in many cases the complexity to repair is low (e.g. requiring a reset, tightening connections, or replacing parts), other repairs require significant spare parts lead times and technical fixes.


Surprisingly, the NovaSource team identified significant deviation of site technical availability driven by failure rate and MTTR when comparing inverters under warranty (first two years) vs. the same inverters out-of-warranty (plant age 2+). Figure 1 shows that assets within their first two years of operations had the lowest technical availability[2] and began to perform better overtime as inverters fell out of their warranty timelines and constraints. This is corroborated with the review of inverter failure rates and MTTR in Figure 2. Failure rates dropped by ~40% between Year 0 and Year 8 of operations. Similarly, the average MTTR (days) dropped ~45% within the same timeframe.

Figure 1. Technical Availability Figure 2. Inverter Failure Rate and MTTR



To help owners improve their asset availability during the warranty period, we recommend owners:


  1. Improve inverter qualification process on new inverters by performing field tests to confirm performance prior to large scale installation and establish requirements for defect response and remediation times.
  2. Develop a reliable inventory strategy by establishing inverter inventory onsite or within central inventory to enable next day repairs for medium to high frequency failures. Use OEM recommended spares lists for new inverters and O&M expertise on inverters with operational history.
  3. Align warranty incentives by enabling O&M providers to perform first responder, level 1, and level 2 repairs and establishing availability and/or time to repair requirements within the warranty.


  1. NovaSource GADS classification of fleetwide downtime events
  2. Technical Availability = Measured Energy / (Measured Energy + Lost Energy)

45% of inverters are “abandoned” (from discontinued

manufacturers) just 4 years after construction


      By: Noel Myers, Sr. Business Development Manager & Cliff Myers, Co-Founder, Chief Engineering Officer     


Based on operational data from 2017-2018, 9,984 MWac of PV capacity was powered using inverters made by discontinued manufacturers. These systems reflect "abandoned inverters" whose Original Equipment Manufacturer (OEM) is no longer in business.


Per NovaSource's 2021 SRA publication, the O&M company's research found that solar facilities with equipment from discontinued inverter manufacturers saw average inverters perform at 85% technical availability. In contrast, industry standard aims for 97%-99% power plant availability. Technical availability for a PV power plant is defined as the amount of time a system is producing energy, divided by the total amount of time in that period.


Using operational data from 2017-2018, Solar Support estimates that PV plants operating with abandoned inverters lost between 1.9 million and 2.7 million MWh in production per year, costing investors $97m -

$174m in missed revenue[1]. Unfortunately, the lost revenue is unrecoverable due to production limits in

interconnect agreements.


Owners who are exposed to PV assets powered by abandoned inverters face tremendous pressure to make operational decisions that triage current and future losses. Without active and ongoing inverter OEM help, PV power plants fail to receive sufficient technical support, and battle to find and procure replacement parts as old equipment fails. Of all sites that were operating in 2018, 45% are powered with inverters made by manufacturers who are now discontinued.


Solar repowering - the process of removing old PV technology and replacing it with new - is increasingly becoming the best long-term solution for investors exposed to sites with abandoned inverters. By developing business cases and performing engineering analyses, strategic asset owners are beginning to implement repowering projects through finance and partnership with experienced repowering Engineering, Procurement, Construction (EPC) teams.


As solar PV fleets age and inverter OEMs continue to go out of business, asset owners are forced to develop and deploy new solutions. Industry thought-leaders are refining solutions for the lowest-cost and least-disruptive methods for boosting plant performance. Repowering is now a proven method for addressing discontinued products and project stakeholders have a great opportunity to capitalize on the lost production but acting quickly is paramount before aging Power Purchase Agreements expire.


[1] Model evaluated five scenarios: 1) high production x high PPA price; 2) low production x high PPA price; 3) high production x low PPA price; 4) low production x low PPA price; 5) average production x median PPA price. Solar Support estimated 1800 MWh per MW per year high production; 1300 MWh per MW per year low production; 1550 MWh per MW per year average production; $150 high PPA price; $40 low PPA price; $75 median PPA price.

Uneven terrain driving up to 6% of performance losses; new tracking tech and modelling software help assets recover


      By: MinWah Leung, Senior Engineer, Mark Mikofski, Principal Engineer, & Anat Razon, Head of Solar IE & Tech     


In the 2021 SRA, DNV reported from a validation study of 20 sites that uneven terrain at solar projects had caused up to 6% losses compared to preconstruction estimates. Previously, the impact of uneven terrain was not a significant concern because for many years US solar projects were sited on relatively flat terrain. However, DNV has observed increased development in regions with hilly topography. Luckily, several leading tracker manufacturers have deployed advanced backtracking algorithms that claim to substantially reduce uneven terrain losses. In response to these new tracker technologies, DNV has developed a modeling method that predicts both uneven terrain losses and the possible recovery by using an advanced backtracking algorithm.This methodology is designed to accompany PVsyst, the industry-standard solar energy modeling software, which doesn't fully accommodate modeling of these variables.


As reported by M. Leung et al.[1], DNV has developed a proprietary method to calculate losses from complex terrain and the expected benefit of deploying advanced tracking algorithms. The method has been validated with operational data provided by tracker manufacturers as well as publicly available data from a DOE funded site.

DNV has further compared the methodology against results from DNV's proprietary SolarFarmer solar energy assessment software, which does enable three-dimensional modeling of trackers on any terrain with either standard or user-specified advanced backtracking algorithm. Table 1 summarizes results comparing the two methods and shows agreement in production gains and losses for the site analyzed in the article.


Table 1. Comparison between DNV uneven terrain method and SolarFarmer



DNV uneven terrain method


Uneven terrain loss



N-S gain



Net terrain effect



Advanced backtracking






Net advanced backtracking effect




In summary, losses attributable to terrain will be higher for sites with more complex topography and will be a key point of investigation for project developers who wish to evaluate the cost versus benefit of implementing advanced backtracking algorithms for their projects. DNV implemented the methodology for complex terrain evaluation in early 2021 as part of its baseline methodology.











[1] "Tracker Terrain Loss Part Two," in IEEE Journal of Photovoltaics, vol. 12, no. 1, pp. 127-132, Jan. 2022

Complex installations and BOS anomalies increased total affected power to 2.63% in 2021 from 1.85% in 2020


      By: Nikhil Vadhavkar, CEO, Eddie Obropta, CTO, & Shane Carey, Marketing Specialist  


As the solar industry rapidly expands, PV systems are becoming increasingly anomalous. Over the last 4 years, Raptor Maps has built digital twins for 53 GW of solar PV assets spread across 40 countries. The 2021 dataset spans 20.24 GW of utility, commercial, and industrial PV systems across 32 countries, captured from 2,943 aerial inspections.


Overall power affected - as a percentage of nameplate capacity - increased from 1.74% in 2018 to 2.63% in 2021 (Figure 1). The upward trend in 2021 is largely driven by increases in several balance of system (BOS) anomalies associated with strings, inverters, combiners and trackers in addition to module and sub-module level issues.



 Figure 1. Power Affected by Anomaly[1]


String anomalies, which stayed constant at 0.5% of total power affected in 2018 and 2019, increased in 2020 and 2021 to 0.8% and 0.9% respectively. The next four most common anomalies were inverters, combiners, module level anomalies, and trackers. Together in 2021, these five categories contributed 2.5% of lost power production as a percent of power inspected.



Increasing BOS anomalies are correlated with solar installations becoming increasingly large and complex, with wider varieties and greater numbers of parties involved in their design, construction, and maintenance. On average the number of unique contributors shared on an aerial inspection report grew from 22 in 2020 to 27 in 2021.

Faulty BOS components can affect power production (e.g., defective fuses causing string outages) and can also be subject to installation issues (e.g., miswiring) that can go unnoticed at commissioning without a thorough inspection.

The 2.5 GW of commissioning inspections that occurred within an asset's first operating year found that 1.2% of

power was affected primarily due to combiner, string, inverter, and module anomalies.



With regards to module-level anomalies, the prevalence of cracking has been increasing since 2018 (Figure 2). There was a 3X increase in 2021 compared to 2020. Cracking has several root causes such as mishandling of modules during transportation or installation, debris from vegetation management, or weather events such as hailstorms. The significant increase in 2021 is suspected to be correlated with increased utility-scale solar PV in regions where hailstorms are more common.


Inspection data in this report was collected with unmanned aerial vehicles (aka UAVs or drones) and manned aircraft (aka planes) with high-resolution color (RGB) and infrared (thermal) cameras. Raptor Maps' open-source data collection methods are recorded at a range of 3 cm/pixel, 5.5 cm/pixel, and 15.0 cm/pixel depending on inspection level. Power figures in this report are based on manufacturer rated power (or nameplate capacity). JinkoSolar, First Solar, Trina Solar, Canadian Solar, and JA Solar were the five most common module manufacturers.

  1. Raptor Maps 2022 Global Solar Inspection Report
  2. Raptor Maps database



 Figure 2. Total Power Affected by Year[2]




























Commercial and utility-scale PV systems are degrading at - 0.75%/yr after accounting for availability issues


      By: Dirk Jordan, Senior Reliability Engineer  


The long-term gradual performance loss of PV technologies is of great financial importance. Many studies have focused on this topic, yet, confusion often surrounds the subject because of module versus system and recoverable versus nonrecoverable losses.


In the PV Fleet initiative, high frequency data from a large number of commercial and utility-scale systems is collected. To date, more than 1,700 sites, with ca. 19,000 individual inverter data streams provide a high-level perspective of the long-term performance of PV systems. The total monitored capacity has surpassed 7.2 gigawatts (GW) or roughly 6% of the entire commercial and utility market in the US.


The open-source freely available software package RdTools[1] is used to determine the performance loss rate (PLR) of the system in the database. The aggregated PLR distribution from the entire fleet is displayed in blue in Figure 1 (a) with a histogram of individual inverter-level PLRs. The median PLR for the fleet is found to be -0.75

%/year based on 4,915 inverters passing automated data quality checks[2].


This is lower than other recent publications (e.g. Bolinger 2020)[3] that have established higher system PLR values around 1 %/yr. Because of our high frequency data we are better able to account for availability issues. It is also possible that a difference in the portfolio or makeup of systems could include faster degrading systems. In addition, soiling deposition can contribute to annual performance loss even if cleaning events bring the system back up to full production. Identifying and isolating soiling performance loss trends remains an active area of work for the PV Fleet initiative.


 Figure 1. System PLR (blue) and predominantly module degradation (red) (a) and example illustration of module versus system losses (b)














A second histogram is shown in red displaying previously published literature values from our 2016 degradation summary paper. The vast majority of the data points in that previous study were based on module-level degradation and did not present system loss. The example in Figure 1 (b) illustrates how recoverable (fixable) losses such as inverter outages, stalled trackers, outages due to fuses, breaker or even curtailment, can explain a higher PLR than module-level degradation. Because of the high-fidelity of our data, we can now better account for availability issues and obtain a more accurate estimation of system losses. It is essential to differentiate between module and systems losses and use the appropriate number for the most accurate financial models.

  1. RdTools:
  2. Jordan DC, Anderson K, Perry K, et al. Photovoltaic fleet degradation insights. Prog Photovolt Res Appl. 2022;1-10. doi:10.1002/pip.3566
  3. Bolinger M, Gorman W, Millstein D, Jordan D, J. Renewable Sustainable Energy 12, 2020.

PVEL’s 2022 results show 5x increase in median degradation

rates following damp heat tests for mono PERC modules


      By: Tristan Erion-Lorico, VP Sales & Marketing  


For the past decade PV Evolution Labs ("PVEL") has subjected PV modules to our Product Qualification Program ("PQP"), a series of extended-duration reliability and performance tests that help address the gap between module certification and the due diligence needs of the sophisticated PV site developer and investment community. During that time, we have tested over 500 different bill of material ("BOM") combinations from more than 50 PV module manufacturers.


Many procurement misconceptions have been literally put to test by PVEL, and the results have repeatedly shown that country of origin and manufacturer size is not an indicator of module reliability; relying on module certification alone will not protect the module purchasers' long-term interests; and seemingly minor changes to the BOM can have major impacts on test results[1].


Another trend observed in recent results is that changes to proven technology may result in unintended consequences. This is evidenced in recent damp heat ("DH") results, particularly for mono PERC glass backsheet modules. The PQP damp heat test places modules in a climate chamber at +85°C and 85% relative humidity for 2,000 hours, followed by a 48-hour stabilization step. This test reveals corrosion and/or delamination in susceptible modules. For the last few years most of the power loss seen in mono PERC modules following DH was erased during the stabilization step, as cells were  doped using boron.


The switch from boron to gallium dopant has been widespread across the population of PQP-tested mono PERC modules, and has solved previous destabilization concerns. It has also resulted in record low light-induced degradation rates, as stated in the 2022 PV Module Reliability Scorecard. However, in gallium-doped mono PERC modules across multiple manufacturers PVEL is now seeing higher rates of DH power loss that is not recoverable during stabilization. Research is ongoing to determine if this is related to the gallium dopant, a change in cell metallization, or other module properties.


Figure 1. Mono PERC Module Degradation Post-DH


Technology in our industry moves fast, and while changes to what may be considered mature products bring potential benefits, they also present inherent risks. Buyers need to exercise caution and ensure the products they are procuring have been properly vetted.

  1. PVEL, "Minute differences in raw materials impact system performance by up to 5%", SRA 2021

Frequency of high-risk quality concerns found in module

purchase contracts has increased 20x from ‘20H1 to ‘22H1


      By: Frederic Dross, VP Strategic Development  


The PV quality assurance community is witnessing an "earthquake" of module quality issues. The number of high-risk deviations requested by suppliers during the contracting process has gone up by a factor of 20 in the last two years. These requests by module suppliers intend to waive quality controls from their module purchase agreement with buyers. As a result, it is hard to imagine that there will be no impact on field degradation and failure rates over the next few years; The question remains: will this "earthquake" trigger a tsunami, or just a little ripple on the slowly rising sea of risks taken by developers today?


During contract negotiations, STS advises procurement teams through a diligent risk assessment process. STS has established "best practice" quality requirements (STS-STD-PVM1 Standard) and records the deviations away from this safe zone, labeling each risk as "low", "medium" or "high" based on the nature of the risks, their probability, severity and detectability (Risk Priority Number). While in the first half of 2020, the number of high-risk deviations requested by suppliers was on average of 0.25 per contract (one every four contracts), this average reaches 5.75 high-risk deviations per contract in the first half of 2022; a 20 times increase compared to two years ago. These additional high-risk deviations may have a significant impact on the performance of the modules in the field. For instance, modules with more cracks or more soldering defects (which happen to be the two main high-risk deviations observed recently), are more likely to develop hotspots, which require immediate replacement, and expose owners to safety risks.


Because of the current "seller's market" conditions, some manufacturers have lowered the quality specifications of their products. STS clients are made aware of the additional risks associated with these deviations and may therefore push back. Many other developers, however, may end up at an increased risk of purchasing low quality items.


Figure 1: Average number of “high-risk” deviations requested by manufacturers

during the negotiation of the module purchase contracts[1]


Today's supply chain situation parallels the shortage between 2010 and 2012. The PV module industry demand was growing faster than the supply of materials, cornering manufacturers into using new, unproven materials in their modules. Quality checks were dropped, and risks were taken to quench the thirsty demand. One example is the Isovoltaics AAA backsheet. Used in an estimated 12GW worth of modules, this backsheet had an 88% failure rate in the field at the 10-year mark.


Unfortunately, the story seems destined to repeat itself, and the quality assurance community is bracing for what may be the next module quality tsunami, unless developers are able to course correct by introducing more rigorous inspection plans to the procurement process.


[1] STS 2022

  Section 3

















Topics Covered:

  • Property insurance trends
  • Hail mitigation strategies
  • Soiling impact from wildfire
  • Irradiance impact from wildfire

Property insurance market experience beneficial, yet limited

reprieve from last year’s 10%+ rate increases in premiums


      By: Darryl Harding, Senior Underwriter  


Insurance in the renewable industry has gained significant attention for lenders and project developers. Insurance carriers have experienced significant losses recently and the market has shifted in response. Premiums, limits, deductibles, and the ability to obtain coverage have all been impacted by this shift. For some, there are signs that this shift is ending, but for others, the shift has not slowed down.


Insurance Premium Rates and Terms


kWh Analytics surveyed leading insurance brokers to learn about the latest trends. Overall, projects that are less exposed to extreme weather are getting more favorable terms. Many projects that experienced 10%+ rate increases year-over-year in 2021 and 2020 are now approaching renewal rates with no increase at all. However, projects with exposure to extreme weather will continue to see higher rates and restrictive terms from carriers, especially for projects exposed to hail, severe convective storm, and wildfire risk.


Per Alex Post, SVP at Lockton Power, "Insurance carriers have higher confidence levels in traditional NAT CAT exposures (earthquake, hurricane, and flood). Non-traditional NAT CAT perils including severe convective storm, and wildfire, are more challenging as various risk models are not as mature and results range widely between models. It is challenging for insurers or lenders consultants to have a high degree of confidence especially in regions like Texas following recent large loss events."


Placing Coverage with Carriers


Carriers are also shifting their risk appetite and taking a larger share of each insurance contract despite limiting the maximum amount of risk they hold. For developers, this could mean your broker can find the same level of coverage for your project with fewer carriers involved.


One secondary effect of this is that the time needed for placing coverage has decreased about 15%. As different approaches to renewables have been tested for a few years, lenders are getting more comfortable with the language and policy terms being offered. As consistency is being found in the insurance market, renewal policies are seeing only mild changes, requiring less time to quote and bind policies. As term standardization increases, the number of exceptions needing to be approved for loans are down about 5% from last year.


Although the industry is constantly evolving, some things remain the same. Large projects still require multiple carriers to provide coverage, carriers are not offering full limits, and deductibles are still high across all perils. Todd Burack, insurance broker with McGriff Insurance Services, Inc., stated, "When the US renewable marketplace has approximately 300 million in gross written premiums, yet you have several significant, high-dollar losses, you quickly realize the conservatism being expressed by insurers."


Innovations in equipment manufacturing and asset management help mitigate risk, however, incumbent carriers are not recognizing changing technology and resilient designs nor are they providing rates and terms to reflect the mitigated risk. Alistair Barnes of AMWINS Group, Inc shared that, "Different insurers have different approaches to site specific hardware and design with some insurers providing no credit for superior physical attributes and few providing more than 15% credit. Insurance carriers need to become better educated and reward those efforts to incentivize the development of a more resilient and sustainable sector." New entrants to the markets are beginning to disrupt the underwriting process by rewarding owners with well managed risk with favorable policies. Traditional carriers are taking a larger portion of the risk, but they are struggling to underwrite individual projects rather than view each project as "average" for the industry. The renewable and insurance industries will benefit long term from resilient and well-maintained projects which is why smart carriers should incentivize such behaviors. Regardless of your view of insurance, the renewables industry needs insurance to allow investment and growth.

Informed hail mitigation strategies reduce probable maximum loss by up to 80%


      By: John Sedgwick, President     


Last year Texas led the nation in utility scale PV installations. As development in the state rapidly expands, so does the risk of exposure to extreme weather events. In response to the increased number of hail-related claims, the insurance market has hardened. Premiums have increased and hail risk is subject to significant sub-limits and deductibles, pushing more risk onto owners and investors. How do owners and investors assess the risk and the value proposition of mitigation measures for setting insurance strategy and optimal financial performance?


Utility scale PV development in severe hail prone regions has been limited to date, yielding a small sample of PV actuarial loss data. At the same time, module technology is evolving rapidly. This makes the task of projecting financial impact due to hail difficult. Fortunately, there is another approach, a "bottom-up" risk assessment based on engineering and science considering the multiple factors which drive Probable Maximum Loss (PML) - the maximum value an insurer is expected to lose - in a given time period and Average Annual Loss (AAL) due to hail, two values which are used today not just for risk analysis, but which also play a critical role in the pricing of insurance premiums.


Risk Assessment


A "bottom-up" model of hail risk includes two primary components:


    1. High Quality hail frequency and severity data. As shown in Figure 1, depending on hail diameter, the Return Interval of hail can vary significantly from one location to another. Even from one location in Texas to another the frequency of hail can vary by a factor of two and compared to an example location in California itn can vary by an order of magnitude or more.
    2. Detailed physical modeling. Best in class loss estimation recognizes that some modules are more resilient than others depending on glass thickness and temper. Losses also depend heavily on the ability of trackers to move to a mitigating tilt angle ahead of an imminent severe hail event.



Risk Mitigation


VDE estimates that, at a typical Texas location, module resilience (thickness and temper) can influence losses by 30%. However, the single most important mitigation action an owner can take is to tilt modules away from the horizontal, reducing estimated losses by up to 80%. Advanced tracking technology is required as well as warnings of impending severe weather. To ensure movement without compromise, operators must also consider hail stow movement in relation to other safety stow protocols such as wind stow.


Using the above methodology, investors, operators, suppliers, insurers and their advisors can evaluate the risk of hail specific to the location and estimate the PML and AAL for a given system design and operation. This enables specific quantification of the value proposition of selected equipment and chosen sub-limits based on the 500-year PML, while the AAL informs the component of premium based on hail risk.



Figure 1. Comparison of Return Interval by Hail Size for three sample sites


Wildfires caused up-to-3% annual soil–related performance losses at solar PV sites in California between 2018 and 2020


      By: Stephen Lightfoote, Technical Director     


Wildfires have major detrimental effects on the performance of solar PV arrays in nearby areas in two ways. They make atmospheric conditions smokier or hazier; and they also deposit particulates on the solar PV panels, known as 'soiling'. This reduces the sunlight reaching the panels.


Research from Power Factors shows that the wildfires in 2020 led to excess soiling-related performance losses of between 1% and 3% annually at affected sites. We learned this by analyzing data from 150 solar PV arrays that represent 1.3GW of AC capacity in California from 2018 to 2020. Operators can clean the panels to mitigate the effects of soiling, but they need accurate project performance data to know when this makes financial sense.


Degraded Performance


Operators can decide when it makes sense to clean soiled panels using the degraded performance methodology of Power Factors. This looks at the actual performance of solar PV projects compared to their theoretical performance, and shows operators when projects are underperforming.


Further analysis can show operators the likely reasons that the projects are underperforming, by comparing their performance to signatures that show how four common types of degradation affect project performance.


For example, underperformance caused by dirt, dust or ash will result in steady drops in project performance over time until panels are cleaned. It is a different profile to underperformance caused by snow, combiner outages and stalled trackers. This shows when soiling causes losses.


Wildfire Impacts


Our research showed that soiling rates were significantly worse in 2020 during months when wildfires were at their worst (Figure 1). It shows a clear correlation between wildfires, soiling, and underperformance. The research showed that projects most affected by soiling were in counties in California most affected by wildfires, such as Kern County.


Figure 1: Soiling Rate by Month



Wildfires are likely to become more common and more severe as a result of climate change. By better understanding this trend, operators can mitigate their losses in the years ahead.

Days where wildfire smoke impacted solar doubled in 2020, 2021 compared to historic wildfire years of 2017, 2018


      By: Patrick Keelin, Lead Product Manager     


According to a new analysis by Clean Power Research, California's solar potential was down 17% in September 2020-the peak of the worst wildfire season in recent history-relative to the long-term average for the month. Smoke clouds and aerosols from wildfires block sunlight and thus reduce PV output. Across

California, resulting losses were 27 kWh/kWDC. Increased PV soiling from soot and ash also reduced yield (Clean Power Research estimates a median loss of 3% based on models utilizing concurrent particulate matter and precipitation data). Total impacts exceeding 30% were seen in regions surrounding large fires (Figure 1).


Figure 1. September 2020 PV yield relative to

long-term average for September (%)[1]


Figure 2. Number of days impacted by




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The 2020 wildfires were extreme by historical standards: September 2020 yield across California was nearly three standard deviations from the long-term average (i.e., < P99). Unfortunately, hotter, drier conditions are increasing US wildfire risk.


If further proof was needed that 2020 was an indication of things to come, 2021 provided it. The 2021 wildfires burned 7.1 million acres and caused $10.6 billion of damages in the United States (10.2 million acres burned in 2020). The number of days where aerosols dimmed sunlight more than doubled in 2020 and 2021 compared to historic wildfire years of 2017 and 2018 (Figure 2).


For stakeholders needing to forecast solar yield and asset value, observations from recent years provide new information on the risks to solar projects. First, some locations will be more impacted by smoke than others. Intuitively, proximity to wildfire fuel increases risk. But in addition, it's been observed that smoke traps itself in valleys by blocking sunlight and air circulation, creating a self-reinforcing temperature inversion. The effect is apparent in the California Central Valley, the Columbia River Basin, the Po valley in Northern Italy and the Sichuan Basin in China, for example.


Second, there is increased risk to solar-powered generation during wildfire season throughout Western North America. Interestingly, annual deviations for both 2020 and 2021 were moderated by unusually sunny spring weather. A shift in the seasonal yield profile is possible.


NOAA's seasonal outlook predicts that June - August 2022 will be hot and dry. The stage is set for another active fire season. While we will hope for the best, stakeholders must prepare for the possibility that wildfires will materially impact solar assets for the foreseeable future.



  1. Deviations show the impact of wildfire smoke and soiling
  2. Days considered impacted if clear sky DNI was at least 35% below 2001-2015 averages

kWh Analytics: kWh Analytics is the market leader in solar risk management. By leveraging the most comprehensive performance database of solar projects in the United States (30% of the US market) and the strength of the global insurance markets, kWh Analytics' customers are able to minimize risk and increase equity returns of their projects or portfolios. Website


BloombergNEF: BloombergNEF (BNEF) is a strategic research provider covering global commodity markets and the disruptive technologies driving the transition to a low-carbon economy. Our expert coverage assesses pathways for the power, transport, industry, buildings and agriculture sectors to adapt to the energy transition. We help commodity trading, corporate strategy, finance and policy professionals navigate change and generate opportunities. Website


Clean Power Research: Clean Power Research has delivered award-winning cloud software solutions to the solar industry and utilities for more than 20 years. Our SolarAnywhere®, PowerClerk® and WattPlan® product families allow customers to make sense of and thrive amid the energy transformation. Website


DNV: DNV provides assurance to the entire energy value chain through its advisory, monitoring, verification, and certification services. As the world's leading resource of independent energy experts and technical advisors, the assurance provider helps industries and governments to navigate the many complex, interrelated transitions taking place globally and regionally, in the energy industry. DNV is committed to realizing the goals of the Paris Agreement, and supports customers to transition faster to a deeply decarbonized energy system. Website


NREL: The National Renewable Energy Laboratory (NREL) is the nation's primary laboratory for renewable energy and energy efficiency research and development (R&D). NREL develops technologies and practices, advances related science and engineering, and transfers knowledge and innovations to address the nation's energy and environmental goals. NREL has forged a focused strategic direction to increase its impact on the US Department of Energy's (DOE) and our nation's energy goals by accelerating the research path from scientific innovations to market-viable alternative energy solutions.



Novasource Power Services: Novasource Power Services is a diversified national solar services company, delivering unparalleled expertise to the nation's distributed generation infrastructure. We provide safe, professional, and reliable operations and maintenance services enabling the growth of C&I (Commercial and Industrial) and Residential renewable energy sectors. Website


PowerFactors: Power Factors develops software that accelerates the global energy transition by empowering all renewable energy stakeholders to collaborate, automate critical workflows, and make the best decisions. Power Factors fights climate change with code. Power Factors has incorporated its three flagship solutions Drive, Greenbyte, and BluePoint to build an integrated suite of open and smart apps.

These apps are purpose-built for asset management, field service optimization, and performance optimization. Leveraging the domain expertise and machine learning-based advanced analytics within these apps, customers can maximize the value of their renewable assets in order to stay competitive. Power Factors' renewable energy software platform is the most extensive and widely deployed solution in the market with more than 50GW of wind, solar, hydro, and energy storage assets managed worldwide.


PV Evolution Labs: PV Evolution Labs (PVEL) is the leading independent lab for the downstream solar and energy storage industry and a member of the Kiwa Group. As a bankability testing pioneer, PVEL has accumulated more than a decade of measured reliability and performance data for PV and storage equipment. Today, PVEL provides developers, investors and asset owners with a suite of technical

services for mitigating risk, optimizing financing and improving system performance throughout the project lifecycle. Website


Raptor Maps: Raptor Maps offers advanced analytics, insights and productivity software for the entire solar lifecycle. The Raptor Solar software platform features a digital twin of your solar sites, aerial thermal inspections, data standardization and normalization, serial number mapping, warranty claim features, equipment records, mobile tools and more - all powered by their industry-leading data model. Website


SolarGIS: Solargis is a data and software architect for bankable solar investments. Solargis works with solar stakeholders throughout the lifetime of their projects and portfolios, reducing risk and creating transparency with the most accurate and reliable solar data on the market. Solargis data and software platform helps the industry to simplify the process of an energy assessment, maximize asset performance, and forecast long and short-term production and returns. Solargis data have helped develop several GW of assets worldwide and are also used for monitoring and forecasting solar power plants. Website


Solar Support: Solar Support is the single-source engineering services company that delivers peak performance. Through expert equipment knowledge and plant reliability solutions, Solar Support helps boost uptime, cut costs, and maximize production. With over 50 years of combined industry experience, we fuse operations and maintenance expertise with deep inverter knowledge and project management acumen to resolve complex performance issues. Website


STS: Founded in 2010 French solar veterans, STS is an independent ISO17020-accredited Inspection Body specialized in the photovoltaics and energy storage industry. The company supports solar and storage developers' procurement efforts through supplier evaluation, manufacturing site audit, inspection and quality control, and technical due-diligence services. STS is the global market leader for PV modules Pre-Shipment Inspection services. Present in 9 different countries globally with operational focus in Asia, STS enjoys the largest inspector fleet in the industry and conducts more than 200 quality assessment projects per year for clients in more than 30 countries including leading EPCs, developers, independent power producers and utility companies. Website


 VDE Americas: VDE Americas is a wholly-owned subsidiary of VDE. Our goal is to advance the deployment of clean energy projects that are bankable, investable and insurable. We support this goal by offering technical due diligence and engineering advisory services in addition to providing neutral 3rd- party product certification and testing. We provide value for our customers by maximizing quality and reducing technical risks at both the system and equipment level. Website


 Wood Mackenzie Power & Renewables: Wood Mackenzie Power & Renewables delivers actionable insight into the state and the future of the global electricity sector, from wind and solar to power markets and grid edge technology. Wood Mackenzie research is backed by exclusive relationships with industry partners, proprietary models, and an ever-expanding executive network. Website

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