Maintenance of a Small-Scale Parabolic Trough Concentrating Solar Power Plant in Louisiana

Abstract

An accurate estimate of fixed operating costs is essential to determine the financial viability of any proposed project. Although other researchers have reported maintenance costs for large-scale concentrating solar power (CSP) plants in the United States [1 - 2], there is currently little information available specifically for small-scale CSP or solar Industrial Process Heat (IPH) plants. This paper discusses the maintenance of an operating small-scale CSP plant in Louisiana over a four year period. The results are also applicable to a small-scale IPH plant. Maintenance activities and costs are discussed for the collector field, the power block, and the cooling tower. For the collector field, a study of the degradation of mirror reflectance between washings was performed for three different types of reflective polymer thin films (3M 1100, 3M 2020, and Konica Minolta). Overall, the 3M 2020 film provided better reflectivity between washings than the other films. An optimized mirror washing schedule was determined. Optimal mirror washing schedules are very site-dependent, but for this humid subtropical location, the most economical washing schedule was found to be every 114 days, or approximately three times per year. A recommended maintenance plan for small-scale CSP and IPH plants is presented and actual maintenance costs over a four year period are provided. It was found that maintenance costs for small-scale plants are substantially larger than for large-scale plants, and that maintenance costs for small-scale IPH plants are much lower than for small-scale CSP plants, making IPH applications significantly more attractive. The average annual maintenance cost for a small-scale CSP plant was found to be approximately $457/kWe, or $0.27/kWhe. For a small-scale IPH plant the costs were $3.72/m2, $7.81/kWt, and $0.005/kWht.