Swift Current Energy, a Massachusetts-based independent power producer, has sued First Solar in the commercial division of the New York County Supreme Court. The complaint, filed in September and reported by PV Tech and pv magazine USA, concerns more than 2.4 million Series 6 Plus and Series 7 cadmium telluride (CdTe) thin-film modules, roughly 1.2 GW of capacity, bought between 2021 and 2024 for three US projects. Swift Current says it paid more than $360 million for the equipment. First Solar had not responded to PV Tech's request for comment at the time of publication, and none of the allegations has yet been tested in court.
The Illinois flagship
The largest site is the 800 MWdc Double Black Diamond project in central Illinois, which received its modules in 2023 and 2024. According to the complaint, the modules were "immediately plagued by performance issues", and contractors found output shortfalls during initial capacity testing. Swift Current says the shortfall leaves it unable to meet commitments to offtakers under power purchase agreements and has cut its income from capacity contracts at two of the projects.
Two manufacturing errors
The suit centres on two production problems. The first, known as edge grind, was disclosed by First Solar on its October 2024 earnings call, when the company said it was taking a $50 million warranty charge. Chief executive Mark Widmar explained at the time that ground-off edge material could "calcify" onto the glass. The second, which the complaint calls substrate defects, is said to stem from a 2021 process change affecting the absorber layer and, according to Swift Current, was never publicly acknowledged. The complaint says more than 1.6 million of the modules supplied to its projects were affected by the two errors.
Swift Current also cites a report by Leidos Engineering, commissioned by First Solar, which it says found an average power loss of about 8% after nearly a year in the field, with some modules down by more than 14%. First Solar's datasheets warrant linear degradation of 0.3% a year.
Metastability and preconditioning
Beyond the two defects, the developer argues that CdTe modules suffer metastability losses in cold, low-light conditions. It also claims that First Solar's pre-shipment "preconditioning", which measures output after at least eight hours of heat, voltage and irradiance, inflates nameplate ratings and departs from the international standards written into the supply contracts.
A stalled warranty claim
Swift Current filed a formal warranty claim on 23 December 2024. First Solar replied on 2 May 2025 that the defects had not been adequately evidenced and that system-level performance data is not a valid basis under the warranty terms. It proposed laboratory tests of individual modules instead. Swift Current calls that remedy "commercially impossible", since it would mean shipping more than 1.5 million modules back to the manufacturer. The developer is seeking damages, restitution and penalties under Massachusetts law. Both parties are due before Justice Andrew Borrok on 16 November 2026.
What it means for project owners
For developers and investors anywhere, the case is a reminder that a module warranty is only as strong as its testing clause. If a manufacturer can insist on lab measurement of individual modules, proving a fleet-wide shortfall becomes slow and expensive. Buyers negotiating supply contracts should check how degradation is measured, whether field data or sampled testing can trigger a claim, and how preconditioning before flash testing is defined. Lenders and independent engineers will also watch how a New York court treats system-level performance data as evidence of module underperformance.
Sources: PV Tech, pv magazine USA.
