The solar industry faced a notable increase in underperformance from faults and issues with photovoltaic (PV) equipment, rising to 4.47% in 2023 from 3.13% in 2022. This resulted in an annual revenue loss of up to $4.6 billion or $4,696 per MW.

Larger projects exceeding 100 MW experienced even higher average annual revenue losses, averaging around $5,000 per MW, according to Raptor Maps‘ Global Solar Report.

Source: Raptor Maps

The rise in power loss significantly challenges the solar industry’s ambitious growth goals. For instance, if power loss persists throughout a project’s lifecycle and is identified in the second year of operations, the Internal Rate of Return percentage of a 100 MW project can decrease by at least 190 basis points.

Larger solar project sites generally experience higher average power loss compared to smaller sites. For instance, sites ranging from 100 to 200 MW have an average power loss of 4.75%, while sites above 200 MW have an average power loss of 4.91%. This increased power loss at larger sites results in a substantial financial impact, with sites exceeding 100 MW averaging a yearly revenue loss of $5,000 per MW, surpassing the global average of $4,696 per MW.

Despite larger sites facing higher revenue loss per MW due to underperformance, power loss has risen across all site sizes over the past five years. Small sites with capacities of 50 MW or less also struggle with significant underperformance, with a power loss above 4% for all such sites in 2023.

Moreover, the most substantial increases in underperformance over the past year were observed at larger sites, with sites ranging from 100 to 200 MW and sites over 200 MW experiencing average year-over-year underperformance increases of 40% and 20%, respectively.

Reasons for faults

The report identified system-level faults as the leading causes of power loss. Inverter faults, string outages (including underperforming strings), and combiner faults are the most significant, impacting 1.91%, 0.90%, and 0.81% of total power inspected.

Furthermore, tracker issues have increased from 0.26% in 2022 to 0.46% in 2023, showing a wider range of challenges affecting system performance.

Faults at the module or submodule level usually result in less immediate power loss during inspections. Module-level issues causing power loss remained relatively stable year-over-year, decreasing by 12% to 0.21% of total power inspected.

However, module-level issues can have more significant repercussions, potentially affecting entire strings or inverter blocks. As climate change progresses, the frequency and intensity of extreme weather phenomena are expected to increase, leading to equipment issues such as module cracking or flooding on site. The median annual power loss attributed to weather events is approximately 1%, but there are instances where extreme weather conditions result in losses of up to 60%.

Operational inefficiencies, such as time wastage and inefficient resource allocation, are a concern across solar sites of all sizes. Preventative maintenance visual inspections and validating nuisance alarms were identified as significant sources of time wastage in a 2023 survey conducted by Raptor Maps.

Power loss by region

The report said adopting artificial intelligence and robotics for automation is crucial to address these challenges. This technology can streamline workforce development, reduce the need for manual labor, and empower operations teams to focus on more detailed tasks amidst growing operational difficulties.

Solar underperformance incurred the highest costs along the East Coast, with an average of $6,108 per MWdc in the Northeast and $5,784 in the Southeast. Regional differences likely contribute to these cost variations.

In areas like the Midwest and Plains Area, which often experience hail storms causing damage, power loss due to physical damage was higher compared to other regions. The storm-prone Southeast region also had significant power loss but trailed closely behind the Midwest and Plains Area regarding average losses.

Although there is a wide variance in underperformance by U.S. state, average solar equipment underperformance in the country is higher than the global average, and states with the largest solar farms and where solar is growing the fastest – including Texas, California, and Florida – are all seeing high rates of underperformance.

Source: Raptor Maps

Power loss by technology

When evaluating the health of PV systems based on module technology, those constructed with thin-film modules experienced lower power loss in 2023 than those using monocrystalline or polycrystalline modules — averaging under 4% for thin-film-based systems.

However, the type of PV module used does not always correspond directly with underperforming behavior. The differences observed are probably due to various factors, including the site’s age, operational approaches, region-specific obstacles, and other factors.

Source: Raptor Maps

When looking at defects affecting individual modules, thin-film modules had lower average power loss from such issues but showed a higher rate of physical damage. They experienced twice as much physical damage as polycrystalline modules and 3.5 times more than monocrystalline modules.

The higher occurrence of module-level problems in polycrystalline modules seems to be related to the average age of modules in the 2023 dataset. Thin-film farms averaged 1.5 years, monocrystalline averaged 1.6 years, and polycrystalline averaged 3.2 years. This suggests a possible connection between module age and defect occurrence.

Utility-scale solar is poised for robust growth in 2024, with a projected addition of 36.4 GW to the grid, according to the U.S. Energy Information Administration. This growth is nearly double the 18.4 GW increase seen in the previous year, which is a record for annual utility-scale solar installations in the U.S.