To maximize solar performance, start thinking long term

By Greg Shambo, VP of O&M Sales, Borrego

When solar operators open their proverbial pockets to contract with a long-term O&M firm, the opportunity to maximize solar plant performance is often doomed from the start. With a limited supply chain of critical replacement parts, a shrinking labor pool that drives up labor costs, and the looming awareness that financial models may be based on overly aggressive modelling, it’s easy to fall back on short-term solutions.

Borrego solar + storage facility in Assonet, Massachusetts. (Credit: Greg M. Cooper/Borrego)

The PV industry has been reported to operate with an average production deficit of 6%, and this type of single-digit deficit can have a dramatic 40% reduction in equity cash flow over a 10-year period. As explained in a recent webinar with Wood Mackenzie and kWh Analytics, many system owners have no choice but to limit the O&M scopes outsourced to third-party O&M service providers, choose to do some elements in-house, or let them all go together in hopes that everything will work out in the end.

These dynamics need to shift towards responsible long-term O&M planning to help system owners recover the most financial value from their solar energy. Here are some important considerations to think about the long-term performance of solar installations.

Preventive vs. corrective maintenance

Asset owners know that preventive maintenance for solar projects is critical to managing solar assets — ensuring the long-term health of the system, associated asset value, and ensuring that critical warranties on expensive equipment don’t expire. As the WoodMac webinar suggests, preventive maintenance alone is not enough to maximize the long-term performance of solar installations and extract the most value from an asset.

A Borrego project

Corrective maintenance issues are a regular occurrence, regardless of whether or not they affect availability. Borrego O&M, for example, operates more than 1,000 PV sites totaling 1.2 GW in the United States. With these project sites under its care, Borrego has so far successfully performed 2,100 corrective O&M services required by 2021. These reactive problems occurred in approximately 57% of the Borrego fleet. In other words, half of the project sites under Borrego care required 4.2 “unplanned” services by the end of Q3-2021.

Borrego’s experience is that when corrective maintenance is prioritized over preventive care, we see an overall raw availability increase of 2% in site performance.

There is a wide range of corrective O&M issues that we often see working on over 1.2 GW of large scale solar power plants. Most are caused by system failures, utilities, and non-utilities. Other common problems include failed termination, external damage, inverter failure requiring complete replacement, and faulty circuit breakers, fuses or other internal components. These common issues are some of the leading causes of reduced system throughput and are generally beyond the scope of most preventive maintenance packages.

In addition to maintenance-related issues

There are instances where an asset owner may require special O&M services depending on the complexity and skills required to resolve the instances that arise. These additional services may include performance engineering analysis, site surveys, upgrades and complex replacements. Some of these issues arise at specific times during the use of solar energy, such as inverter replacements and upgrades around 15 years and beyond. Other O&M issues can arise at any time during the asset’s life, such as weather-related damage. The diagram below illustrates the most common O&M issues and service needs over the life of the asset.

Here is a brief overview of the timing and typical scope of some of the most common O&M repair services required for solar power plants:

  • EPC stage and year 1
    • For asset owners who conduct O&M themselves, lenders may require or find it beneficial to have a third party perform a pre-commissioning inspection.
    • Within the first year, solar asset owners may require repair work on the EPC build. Borrego has seen failures due to improper circuit breaker tightening, loose bolts and poor underground cable installation.
  • Years 5-8 and beyond
    • For solar roof installations, it is not uncommon to see requests to remove systems, replace the roof and replace systems around the fifth year.
    • Also, around the fifth year, there is more demand for technical performance analysis. For example, Borrego conducted an independent technical analysis for SunRay, which was ultimately used to meet the lender’s requirements. Borrego looked at historical performance, predicted future performance and made recommendations to improve performance.
  • 15 years and beyond
    • After 15 years, repowering is one of the most common asset services, often accompanied by system upgrades for modules and inverters. It is often beneficial for asset owners to replace their central inverters with string inverters when powering up again.
    • In addition to repowering, other problems arise with aging systems, such as foundation crumbling, deterioration of electrical equipment, etc.
  • At any time
    • As part of preventive maintenance services, necessary repairs or replacements can be identified that are outside the scope of standard preventive maintenance. During preventive maintenance work, Borrego’s skilled technicians often identify problems and make recommendations to improve overall system health and performance.
    • In addition, regular performance anomalies or alerts occur as part of proactive system monitoring, allowing an O&M provider to initiate and perform corrective maintenance repairs.
    • Weather-related damage can occur at any point in the operation of a system and is generally beyond the serviceable scope. Examples of weather-related damage are water damage (eg water ingress and corrosion); misaligned and deteriorating equipment from erosional changes; broken and damaged panels due to lightning, hail and wind damage; and UV degradation such as corroded and exposed wiring.
    • With the increase in wildfires in recent years in the western United States, additional washing may be required to get the asset performance you want.

Maximizing the performance of solar energy

These examples illustrate how a long-term mindset is needed to improve performance and system health issues and ultimately increase the value of solar energy. Borrego operationalizes this long-term mindset with a team of technical subject matter experts who research, troubleshoot, repair and upgrade large-scale solar systems. They draw on extensive field experience and technical analysis on the more than 1.2 GW that Borrego manages.

Borrego offers a three-part approach to its O&M service offerings to support customers with the three core areas related to the performance of their system over the entire solar lifecycle:

  • Research and Performance Engineering Analysis
  • Replacement and upgrades
  • Proactive monitoring and preventive maintenance and repair


Greg Shambo has a background in sales and marketing and over 10 years of experience in renewable energy. Greg’s passion for improving the sustainability of the planet through renewable energy projects fuels his approach to building lasting relationships with customers and teams.

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