Solar Two Performance Evaluation Methodology

Solar Two is a 10-MWe prototype central-receiver plant east of Barstow, California. Solar Two, which is sponsored by a consortium of utilities and industry in partnership with the U.S. Department of Energy, began regular electricity production in February 1997. The objective of Solar Two's performance evaluation activity is to understand the plant's performance and to use the evaluationinformation for the following purposes: optimize plant performance, extrapolate Solar Two's performance to general performance of molten-salt central-receiver technology, and recommend revisions to predictive models and engineering design methods for Solar Two and future-generation molten-salt central-receiver technology. The primary aspect of the performance evaluation is the lost-electricityanalysis. This analysis compares the actual generation with the generation predicted by the Solar Two model. (SOLERGY, a computer program designed by Sandia National Laboratories to simulate the operation and power output of a solar central-receiver power plant is the code used to model Solar Two.) The difference between the predicted and the actual generation (i.e., the lost electricity) isbroken down into the different efficiency and availability categories responsible for the loss. Having the losses broken down by system and in terms of electricity is useful for understanding and improving plant performance; it provides a tool for determining the best operating procedures for plant performance and the allocation of operation and maintenance resources for the best performancepayback.