UL has created two new wind turbine certification product categories, Wind Turbine Drive-train Systems and Equipment (ZGDT) and Wind Turbine Tower Assemblies (ZGTA)
UL does certify PV module trackers under the product category Photovoltaic Solar Trackers (QIKA)
<a href="http://iaeimagazine.org/magazine/category/2012/may2012/">IAEI May-June 2012</a>