TÜV Rheinland Photovoltaic Testing Laboratory (PTL) LLC is a world-renowned facility for photovoltaic (PV) technology testing located in Tempe, Arizona, USA. TÜV Rheinland PTL is a partnership between the TÜVRheinland, a $1.5 billion USD provider of independent testing, assessment, and certification services for industry; and Arizona State University (ASU), one of the leading research and educational institutions in the USA. Locally, the ASU’s photovoltaic have been providing testing services to the photovoltaic (solar) power marketplace since 1992. TÜV Rheinland PTL, is an ISO 17025-accredited facility by the American Association for Laboratory Accreditation (A2LA).