Recovery of 4.2 MWh Through Proactive Detection of Thermal Derating

Industry problem: Inverter INV07 was consistently generating less energy than similar units because of thermal derating (power limitation due to overheating), creating hidden production losses and safety risk.

Delfos solution: The Delfos Platform remotely identified this underperformance pattern and linked it to repeated “Overtemperature” alarms. This allowed the O&M team to inspect the inverter, find non-functioning cooling fans, replace them, and recover 4.2 MWh while reducing the risk of fire and total inverter loss.

Industry problem: Thermal derating occurs when an inverter automatically limits its power output to protect internal components from overheating. This protects the hardware, but silently reduces generation and revenue if not detected quickly.

Delfos solution: Delfos continuously analyzes inverter time-series data and generation curves to flag patterns consistent with thermal derating. By surfacing these events in advance, the platform helps asset owners intervene before small thermal issues turn into long-term energy loss or equipment damage.

Industry problem: Plants without SCADA lack centralized visibility, making it hard to spot subtle anomalies like one inverter underperforming compared to others with the same rated power.

Delfos solution: In this case, Delfos acted as the client’s primary diagnostic and monitoring tool, replacing the role of SCADA. The platform compared INV07 with nearby inverters, highlighted its lower production during high irradiance, and correlated this with overtemperature alarms, enabling the owner to detect thermal derating remotely and act with confidence.

Industry problem: Traditional monitoring often misses performance drifts, such as one inverter consistently limiting output while others operate normally, resulting in long periods of unnoticed energy loss.

Delfos solution: Delfos combines comparative analytics and alarm intelligence to pinpoint the root cause:

In the reported case, this data-driven workflow led directly to identifying failed cooling fans and restoring the inverter’s expected power curve.

Industry problem: Non-functioning fans cause the inverter to overheat, forcing it to limit output throughout the day. In extreme cases, overheating can escalate to fire and total loss of the equipment, posing both safety and financial risks.

Delfos solution: The Delfos Platform quickly identified abnormal thermal behavior and repeated “Overtemperature” alarms. This early warning allowed the O&M team to replace two failed fans before any catastrophic event occurred, turning a high-risk situation into a simple maintenance task.

Industry problem: Undetected thermal derating can accumulate over months, eroding plant performance and revenue, with no clear visibility of the real impact.

Delfos solution: In this project, Delfos enabled the client to:

• Recover 4.2 MWh of energy that would otherwise be lost.
• Address around 6 months of accumulated losses linked to the issue.
• Eliminate the risk of potential fire and total inverter loss related to overheating.
• Confirm through the platform that the inverter’s power curve and generation returned to expected levels after fan replacement.

This closed loop—from detection to validation—shows how Delfos converts data into tangible financial and operational gains.

Industry problem: O&M teams often receive generic alarms without context, spending time on broad inspections instead of targeted, high-impact actions.

Delfos solution: Delfos’ Performance Engineering team used the platform to summarize the issue—thermal derating due to suspected cooling problems—and shared it during a performance review meeting with the client. With this clear guidance, the O&M team performed a focused field inspection, quickly identified two non-operational fans, implemented a straightforward replacement, and restored normal operation with minimal downtime.

Industry problem: Plants without SCADA or advanced on-site systems have blind spots in real-time performance monitoring, making it harder to justify and prioritize maintenance actions.

Delfos solution: Delfos becomes the central visibility and analytics layer for these assets. In the reported case, the platform replaced a missing SCADA solution by aggregating data, detecting abnormal behavior in INV07, and providing actionable insights that led to immediate corrective maintenance. This makes Delfos especially valuable for portfolios where on-site infrastructure is limited but reliability and performance expectations remain high.

Industry problem: After maintenance, many operators rely on spot checks instead of continuous analytics to confirm that the issue is fully resolved, leaving room for residual underperformance.

Delfos solution: Once the faulty fans were replaced, the Delfos Platform tracked the inverter’s power curve and energy generation in real time. The data confirmed that the inverter was no longer limiting output during high irradiance and that its production aligned again with similar units. This evidence-based validation closes the loop, proving that the intervention effectively removed the thermal derating and recovered the expected energy yield.

Industry problem: Overheating issues may start as minor alarms but can escalate into severe incidents, including potential fire and complete inverter loss if they aren’t addressed quickly.

Delfos solution: By correlating overtemperature alarms with limited power output and historical patterns, Delfos identified the thermal derating early and quantified its impact. This prompted timely maintenance, removing the cause—failed cooling fans—before the equipment reached a critical state. As a result, the client not only recovered energy but also avoided a high-risk operational incident.

Industry problem: Many solar portfolios suffer from unnoticed inverter issues—such as thermal derating, ventilation failures, and chronic underperformance—that gradually reduce returns and increase operational risk.

Delfos solution: By connecting your inverters to the Delfos Platform, you gain remote visibility, automated detection of abnormal behavior, expert performance engineering support, and post-maintenance validation. This combination helps you transform scattered data into clear actions that recover energy, extend equipment life, and protect your assets.

To explore how Delfos can be applied to your plants, you can request a tailored demo focused on your portfolio’s challenges.