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.