Survey of cost-effective photovoltaic applications at US electric utilities

A survey of 2909 electric utilities throughout the United States was conducted to determine the number of cost-effective photovoltaic (PV) systems currently owned and operated by electric utilities. In addition, information regarding the performance and reliability of these systems was collected and a list of utility contacts with PV experience was compiled. A total of 374 (13%) survey questionnaires were returned. The results revealed that over 1850 PV installations with an installed capacity of over 87 kW are owned and operated by 74 utilities across the country. Cost-effective PV systems are in use in virtually every state in the US and have been used by electric utilities since the late 1970's. The systems range in size from a few watts to 7.2 kW and typically service small, and frequently remote loads. Investor-owned utilities own over 1500 of the cost-effective PV systems in use, with an installed capacity of 56.5 kW; municipal utilities own over 170 systems, with an installed capacity of 7 kW; federally or state-owned agencies own over 100 systems, with an installed capacity of 8.7 kW; and rural electric cooperatives own over 80 systems, with an installed capacity of 14.8 kW. The devices were found to be highly reliable, with 97% of the utilities that operate PV reporting that they were either satisfied or very satisfied with the performance of their systems. Nearly 38% of these utilities reported that their PV devices required no preventive maintenance. 42.4% of the utilities with PV systems in use perform regularly scheduled maintenance; however, the level of maintenance required is minimal. The remainder of the utilities with PV devices perform unscheduled maintenance as required. Over 37% of the utilities operating cost-effective PV had experienced no downtime with their systems. Those that had experienced downtime cited component failure, vandalism, design problems, or improper installation as the cause