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How Degradation Analysis Can Change the Future of Solar

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Degradation is happening at faster rates than the previously accepted industry standards - here’s what owners and asset managers need to know. 

Photovoltaic (PV) installer employment alone is expected to grow 52% by 2030. While this is great news for the clean energy sector, the economy as a whole, and climate mitigation efforts, on-site solar jobs are among the riskiest in the industry. Aerial inspections with piloted aircraft help mitigate these risks and enhance safety throughout the life of a site. 

Occupational Risks 

People who install, inspect, and maintain large-scale solar sites face occupational hazards that can cause injury, illness, or fatalities. Site safety begins at the design phase and carries through construction and installation. Once a site is commissioned, the focus on safety shifts to ongoing maintenance. It’s paramount that owners, asset managers, and O&M take every precaution to protect workers across a full spectrum of risks. 

  • Electrical issues: Electrocution is one of the most prevalent risks on solar sites. Modules in short circuit or forward bias can pass current even when the combiner is offline. This current is not identifiable through remote monitoring systems and poses a serious risk for those conducting on-site tests. 

  • Rooftop installation risks: Performing work on rooftops and other heights compounds the risks of falls. DC issues can also cause fires, which are particularly risky in rooftop installations. 
  • Weather-related risks: Solar workers are exposed to weather elements year-round. Installations and inspections directly expose solar workers to the elements, often for prolonged periods of time, and can lead to heat-related illnesses, including heatstroke, exhaustion, and dehydration. 

  • Ground-related risks: On-the-ground risks can come with the territory - such as the risk of trip and fall from uneven terrain. Ground-related risks increase after extreme weather events. Sites can become obstacle courses with dangerous live wires, rattlesnakes on the ground, fire hazards from debris lodged under panels, and falling pieces of damaged equipment. Aerial inspections help eliminate the need for people to be physically on the ground and face these risks. 

On day one of a newly commissioned solar site, its array of panels are shiny, new, and operating at full capacity. Every year that follows, the panels begin to slowly degrade due to weather, debris, and natural wear and tear. While degradation expectations are built into financial modeling, manufacturer warranties, and performance estimates, Heliolytics’ findings show that commercial solar panels are degrading at a rate of 1% per year on average, double the previously accepted industry rate of 0.5%. Some sites show degradation levels as high as 2 to 3% per year. 

Why the discrepancy? The 0.5% rate was determined via an analytical review of smaller-scale sites, and that rate was then applied to utility-scale solar modeling. However, further testing indicated that the 0.5% rate was not as accurate for larger sites. Inaccurate degradation rates throw off energy production expectations and ROI estimates, which in turn can overinflate expected investor returns and stakeholder confidence. 


“Armed with true degradation rates, site performance details, and actionable data, owners and asset managers can make more informed decisions and optimize financial outcomes.”


How Heliolytics is Leading the Industry in Degradation Analysis 

Utilizing proprietary assessment methodology and aerial inspection expertise, we deliver comprehensive site degradation insights with a degree of specificity not available from standard degradation analysis alone. 

Heliolytics compares degradation analysis data to other available datasets, such as aerial inspection data, to estimate module degradation unobscured by DC health issues. They go beyond site level degradation analysis to compare all modules and inverters in a portfolio, in order to identify candidates for revamping or repowering endeavors. 

  • Using a proprietary process jointly created with NovaSource Power Services, Heliolytics assesses all data and then plots degradation. This process can filter through gigawatts of solar to determine whether or not a site is producing consistently or degrading over time.
  • Heliolytics conducts aerial scans to identify if a site performance concern stems from degradation or a DC health issue like a string outage. String outages are common, and an aerial inspection can identify and remove the noise of these outages from the degradation rate, revealing true module degradation.  
  • A sophisticated degradation analysis methodology measures a site from the system level to module level. This process determines the aggregate rate of degradation on site using daily inverter data, the distribution of degradation rates between inverters, and identification of anomalous inverters and their root causes.
  • Once the root causes are identified, Heliolytics produces an economic analysis forecasting Net Present Value of lost energy, and can provide guidance on actionable steps and/or remediation.

How Owners and Asset Managers Can Maximize the Benefits of Degradation Analysis

Degradation is a significant contributor to financial loss since higher rates of degradation translate directly into less power produced, which reduces future cash flows. Degradation analysis conducted in tandem with aerial inspections for DC health allow owners and asset managers to disentangle the degradation mechanisms, separating out degradation from DC health issues so each can be more accurately identified and rectified. Degradation analysis works best with historical data and images so issues can be plotted over time. This is another reason regular aerial scans and DC health data collection are important.

Armed with true degradation rates, site performance details, and actionable data, owners and asset managers can make more informed decisions and optimize financial outcomes. In addition to better overall ROI, degradation analysis helps identify photovoltaic system issues for warranty claims, providing the statistical evidence necessary for module replacement. For older sites, the analysis can identify potential repowering opportunities. 


Enhancing the Future of Solar

As solar energy expands its reach, accurate predictions and measures of power output become increasingly crucial. ROI estimates are dependent upon accurate data inputs, and true degradation rates produce more precise and reliable projections. The more accurate the financial model, the more investors will trust and gravitate toward solar investments. Ultimately, true degradation rates lead to better-performing sites with a greater impact on the transition to a clean energy future. 


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