VI. TYPICAL OPERATING SYSTEMS
Today, small PV systems number in the tens of thousands around the world. For example, in the United States, the Coast Guard has over 10 000 aids to navigation powered by PV and in California, over 8000 PV-powered roadside emergency call boxes are operating. Kilowatt-size systems in operation around the world number in the thousands. Starting in the late 1970's, intermediate- and large-scale systems began to be installed, mainly as part of utility- and government-supported programs in many nations around the world. A few hundred intermediate-scale systems are operating in Japan, the United States, many European countries, and in others. Large-scale systems are operating in only a few countries: among them are Japan, the United States, and Italy. This large number of operating PV systems provides an experience base which not only demonstrates technical feasibility of PV systems to supply power for a wide range of applications but also provides significant data on systems and component performance, reliability, equipment and component failures, and O&M costs. A brief description of a few of the larger and significant PV systems operating today is given in this section.