When performance drops without a clear cause, the issue is usually deeper than it appears

 

In many PV projects, underperformance doesn’t begin with a visible failure.

There are no obvious defects or a single component that is clearly responsible. Systems pass initial checks, meet specifications, and appear to perform as expected. Then, gradually, performance begins to drift.

Certain strings fall below expectations and output can vary across a site. In some cases, entire sections underperform without a clear pattern. In others, issues appear long after installation risks are assumed to no longer be a concern.

These are not random issues, they are symptoms. Understanding them requires root cause analysis (RCA), even though it is often only applied after the problem has already escalated.

 

The problem is rarely what it looks like

What appears as inconsistent performance is often the result of something that happened much earlier.

Small variations during manufacturing. Stress during transport. Installation practices that introduce uneven mechanical load. Configuration decisions that only show their impact under real operating conditions.

Individually, these factors may seem minor. But combined, they can create performance issues that are difficult to detect and even harder to trace, especially without a structured way to connect what is happening in the field back to its origin.

 

Why standard checks don’t catch it

On paper, most systems look correct.

Components meet specifications, certifications are in place and testing has been completed under standardized conditions. But these checks don’t fully reflect how systems behave in the field.

They don’t capture variability across production batches or account for the impact of transportation and installation. And they don’t show how small deviations interact over time.

This creates a gap between expected performance and actual performance, one that root cause analysis is designed to uncover.

 

Why the same problems keep coming back

When the underlying cause of underperformance isn’t clearly identified, corrective actions tend to focus on what is visible.

Modules are replaced, settings are adjusted and monitoring is increased. In some cases, performance improves temporarily.

Because the source of the issue hasn’t been addressed, the same problems can reappear. Over time, what started as a localized issue can spread, increasing energy losses and complicating recovery.

 

What root cause analysis actually does

Root cause analysis is not just about identifying what failed, it is about understanding why and where the issue originated. It also helps support claims needed to recover economic losses.

In practice, it connects field observations with performance data and traces issues back through earlier stages of the project, including manufacturing, transport, and installation. It isolates the mechanisms driving underperformance and clarifies how far they extend across the system.

When done correctly, it creates a clear link between what is observed on site and what caused it so corrective actions solve the problem at its source, rather than managing its impact.

The difference between managing and resolving

Projects that respond to underperformance without fully understanding the cause often remain in a cycle of reactive fixes.

Projects that apply this type of structured analysis are able to break that cycle. They can determine whether an issue is systemic or localized, understand how far it extends, and implement corrective actions that fully resolve it.

 

Understanding the cause changes the outcome

Underperformance rarely comes with a clear explanation. It builds over time, behaves inconsistently, and often points in multiple directions.

The difference is not whether issues occur, but whether the cause is identified early enough to act on it.

 

How STS Can Help

STS provides independent root cause analysis to identify the underlying drivers of PV underperformance. By connecting field observations with performance data and tracing issues back through manufacturing, transport, and installation, STS helps ensure corrective actions address the source of the problem, not just the symptoms.

Learn more about Root Cause Analysis