Quality Assurance for Photovoltaic Systems

Publication Type

Case Study

Date Published




Ensuring that customer-sited photovoltaic (PV) systems perform adequately should be an important goal for clean energy fund managers. Performance issues are especially pertinent for state funds whose PV incentives are tied to installed capacity and not performance. This case summarizes the approaches that certain states have used to help ensure product quality and reliability. Innovative Features As discussed in this case, states have used a variety of approaches to attempt to ensure quality installation and reliability. These approaches can be segmented into:

  • system requirements (e.g., UL listing of modules and inverters),
  • installer requirements (e.g., installer certification and training),
  • installation requirements (e.g., to ensure proper orientation),
  • warranty requirements (e.g., on parts, labor, and installation),
  • performance incentives (e.g., apply incentives based on kWh rather than kW), and voluntary training and certification programs.


  • Performance and reliability issues with PV, especially for residential systems, clearly exist and are of concern to potential PV buyers.
  • This case study shows that states are taking very different approaches to provide quality assurance; some have taken minimal steps in this regard while others have aggressive warranty and installation requirements and/or use per-kWh payments rather than standard per-kW buy-downs. Installer training and certification requirements are also being considered in some states.
  • Unfortunately, no single "best practice" has emerged as offering the ideal balance between adequate levels of assurance and reasonable cost.

Secondary Title

Case Studies of State Support for Renewable Energy

Year of Publication






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