Optical Durability of Candidate Solar Reflectors for Concentrating Solar Power

Concentrating solar power (CSP) technologies use large mirrors to collect sunlight to convert thermal energy to electricity. Commercialization of CSP technologies requires developing advanced reflector materials that are low cost and maintain high specular reflectance for lifetimes of 10 to 30 years under severe outdoor environments. This is accomplished through technology advances by moving from heavy glass mirror reflectors to lightweight reflectors such as thin-glass, polymer, and front-surface mirrors that include surface coatings to reduce soiling. Durability testing of a variety of candidate solar reflector materials at outdoor test sites and in laboratory accelerated-weathering chambers was performed at the National Renewable Energy Laboratory (NREL) in Golden, CO. The optical durability testing results for a large number of candidate solar reflector materials, including thin glass, thick glass, aluminum reflectors, and a silvered polymer laminate construction will be presented.