The GEF has identified solar thermal power technology (STP) as one of the renewable energy technologies it supports in its operational programs. Development of STP represents one of the most costefficient options for renewable bulk power production, and the most cost-effective way of producing electricity from solar radiation. Many GEF receipient countries, including India, Mexico, and those in the regions of Northern and Southern Africa and parts of Southern America, have high levels of solar radiation suitable for STP. The purpose of the review is to suggest, based upon project designs and preliminary implementation experience, whether GEF STP projects are contributing to technology cost reductions or other industry changes as envisioned under OP7. In the absence of substantial operating experience, the review provides updated perspectives on this question relative to when the projects were first proposed and early implementation experience.