Design and cost optimization of utility-grade off-grid power systems

Electric utilities are beginning to provide off-grid electricity service to customers in lieu of extending uneconomic electric distribution lines. To a large extent, the success of an electric utility off-grid service program is dependent on the utility´s ability to provide power systems with excellent reliability and power quality at competitive prices. In December 1992, Pacific Gas and Electric Company (USA) tested the provision of off-grid service by procuring a first-generation PV power system which was installed at a customer´s residence in April 1993. This pilot was a technical success, demonstrating that an electric utility can provide reliable, high-quality off-grid power. The project did, however, highlight the need for large cost reductions necessary for significant market penetration. This paper presents a second generation design which attempts to address these issues