STATUS OF 2ND-GENERATION CENTRAL RECEIVER TECHNOLOGIES

Fifteen years of solar thermal technology development have produced a considerable amount of knowledge relating to the production of electricity from central receiver power plants. This body of knowledge is under examination by researchers from the United States of America and the Federal Republic of Germany for the purpose of defining the next generation of central receiver power plants. It is expected that this second generation represents a significant step toward commercialization of such systems. During the course of the study, specific activities needed to realize this next-step technology have been defined. The study is an international team effort. Under the International Energy Agency's "Small Solar Power Systems" project,-researchers from DLR, Interatom, Sandia National Laboratories, and Bechtel have designed a study in which technologies relating to existing systems are quantified, logical next-step systems are characterized, and future potential advances are identified. The receiver concepts under investigation are: (1) salt-in-tube, (2) volumetric air, and (3) direct absorption salt. Two plant power performance levels are examined: 30 and 100 MW(e). Each concept is applied with common capacity factors, and types and sizes of heliostats at each performance level. Reliability and uncertainty analyses are also performed. Annual energy production figures are calculated using the SOLERGY computer code. Economic methodologies are mutually agreed upon in order that levelized energy cost calculations will be consistent among the power plants. During the course of this effort, further potential advances in central receiver technology have continued to become apparent. These possible areas for improvement are described. Trends in cost-of-energy as functions of plant annual energy production and receiver type are presented. Similar trends involving trough-based technologies are also given.