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Case Studies

DEPCOM Power Repowers Inverters After Severe Fire

By September 15, 2022March 1st, 2023No Comments




When a catastrophic inverter fire took down all production at a five-megawatt PV plant in Durham, North Carolina, there was no way to know how or why the fire ignited. Although it was clear that the flames had started inside the inverter cabinets, damage to both power conversion stations was so severe that it was impossible to determine the root cause. Because the plant was commissioned in 2014, much of the original equipment is no longer made. The site was designed around now-obsolete 1000-volt DC inverters, while today’s plants are developed using 1500-volt DC systems.

Forced to work with a lump-sum payout from their insurers, the asset’s owners needed a plan — and fast. Under the power purchase agreement with the local utility, there was a limited grace period allowed before production had to be restored. If that deadline was missed, the PPA could be voided entirely.





Unlike other contractors that quote a price at the outset and then modify it with change orders as issues stack up, DEPCOM Power’s plant repowering expertise allows the EPC leader to cover the full scope of the project for a guaranteed price up front. As the project started, DEPCOM Power’s Repowering+ team determined that the four destroyed one-megawatt central inverters were no longer manufactured. Instead, they devised a plan to reuse the existing skid base and consolidate the four old units into two new inverters with a higher power density — reducing the project’s timeline and avoiding considerable construction costs.


DEPCOM Power’s strategy simplified the overall system design, minimizing the balance-of-system materials required and reducing the AC bus work and components needed, to create overall savings in installation costs. These savings offset the higher cost of manufacturing new 1000-volt inverters, which are now much more difficult to source and require components and materials no longer readily available.

Because the plant had to be partially redesigned, both local regulators and the contracting utility required that the facility meet all current standards and codes. This meant registering entirely new permits, updated testing, and a repeat approval process as if the plant were being commissioned for the first time.




DEPCOM Power brought in its repowering experts to mitigate the damage fast. Leveraging its EPC and O&M capabilities allowed DEPCOM Power to complete the permitting process efficiently, engineer and design the restoration rapidly, source new equipment, and remove damaged equipment. Timing was of the essence to complete the installation and fully test the new operation.

Ultimately, DEPCOM Power was able to bring the plant back online before the PPA grace period expired, preserving the contract. Because work was completed within the budget set by the insurance company, the asset owner had no out-of-pocket expense beyond paying the deductible.


DEPCOM Power’s ability to rapidly return the plant to production resulted in $400,000 to $700,000 more revenue than waiting for the delivery of new inverters. Combined with the $1.8 million savings from salvaging the flooded units, DEPCOM Power’s fast restoration plan resulted in total savings of more than $2.5 million for the asset owner.


Keeping everyone on the same page was critical. DEPCOM Power’s proactive communication between the owner, the insurance providers, and partners wove the team together for an efficient collaboration.