Key technical components of a solar PV system go through the rigors of testing, evaluation, and certification — but what about when they're all assembled and running as a full PV plant? VDE and Fraunhofer ISE think they've found a new way to ensure the performance, reliability — and "technical bankability" — of solar PV plants with a new system-level certification spanning quality, safety, and performance of the plant as a whole and its components.

Plunging costs throughout the solar PV technology chain have helped to improve the cost profile of solar PV plants. But upstream upheaval also contributes to questions about supplier quality and viability, and adds uncertainty and risk for potential investors in a PV project. Standard certification of individual components by themselves is no longer sufficient to lower a plant's risk profile and make it more attractive to investors, according to the firms. What's needed is a higher level of certification that elevates the component-level view to system-wide performance and quality assurance. 

VDE is a well-known European standards body offering its stamp-of-approval brand for a wide range of components used in everything from household appliances to electric utility systems (including microinverters). Fraunhofer ISE, meanwhile, knows solar PV technology, and will offer yield reports, module characterization, system testing, and system monitoring. Together they offer a deep evaluation of the entire PV plant, as a third-party vs. an engineering firm that may be contracted, and compensated, by one of the project's stakeholders. "We provide an important service for reducing risk associated with financing," explained John Sedgwick, president of VDE America. Underwriters' Labs doesn't do this level of certification, while TUV does to some extent, he noted, but "the service we're contemplating is broader in range, and superior in the output it provides."

The new certification, VDE Quality Tested for PV Power Plants, applies 300 testing points spanning electrical and mechanical safety, system performance and energy yield verification, and proper system operation, with all elements checked against individual international standards and custom-developed system-level certifications.

Working with either the engineering firm or financing agency, VDE will do an independent review of the PV plant design, evaluating the PV array, verify all certification of the subcomponents, construction, and safety considerations. Once the plant is built, VDE sends teams out to the array to conduct a battery of tests to validate the quality of the array as it was constructed, gauging whether the modules as delivered do indeed provide yield as intended. Information about module performance is plugged into Fraunhofer's software model to compare how the system should perform going forward. Armed with that model, a plant can calculate performance starting from Day 1 to compare actual output vs. expectations on the DC or AC side, explained Sedgwick.

VDE has done a pilot project for its PV plant certification in Germany, Sedgwick, said, but it's set its sights on the fast-growing markets in North America — the U.S. (starting in California), Canada (Ontario), and Latin America (Mexico, Chile, Ecuador) — where larger-scale utility assets are being developed, many of which are still seeking funding, and some have been put on hold for that very reason. VDE is in talks now with potential customers and hopes to have a pilot customer identified in early 2Q13 on the 10-MW scale. The certification applies to "virtually any kind of solar PV technology," noted Sedgwick; "we are agnostic about it." (But solar thermal is not an area of focus, he added.)

VDE's testing and certification process. (Source: VDE)