The base-year technology (1997) is represented by the 25 kWe dish-Stirling system developed by McDonnell Douglas (MDA) in the mid 1980s. Similar cost estimates have been predicted for the Science Applications Internationa l Corporation (SAIC) system with the STM 4-120 Stirling engine . Southern California Edison Company operated a MDA system on a daily basis from 1986 through 1988. During its last year of operation, it achieved an annua l efficiency of 12% despite significant unavailability caused by spare part delivery delays. This annual efficiency i s better than what has been achieved by all other solar electric systems, including photovoltaics, solar thermal troughs, and power towers, operating anywhere in the world [13,21). The base-year peak and daily performance of near-ter m technology are assumed to be that of the MDA systems. System costs assume construction of eight units. Operatio n and maintenance (O&M) costs are of the prototype demonstration and accordingly reflect the problems experienced.