Solar Electric Systems Can Help During Power Outages
Richard Perez, ASRC; Steven Letendre, GMC; Christy Herig, NREL-NCPV


A recent report from the U.S. Department of Energy’s Power Outage Study Team, titled “Findings and Recommendations to Enhance Reliability from the Summer of 1999,” identified six major power outages. These outages occurred when high, heat wave-driven local demands causing stress on distribution systems, resulted in an inability to generate, purchase, and/or distribute enough electrical power.

An analysis of the solar resource during these outages, based upon satellite remote sensing data, shows that the output of local solar electricity systems would have been above 90% of ideal clear day output during five of the six outages and above 80% for the remaining one (as shown below). An analysis for a recent outage in San Francisco has also been included. All show that local availability of solar electricity can mitigate the conditions that lead to, and reliably prevent, this type of outage.

Factor in the results of commercial and residential customer-sited solar electric system economic analyses [1] showing cost-effective niches in Illinois, New York, and New Jersey (five of the six outages) and potential customer-oriented solutions emerge. In fact, the Solar Energy Industries Association identifies power quality and reliability as the major market drivers for the domestic solar electric market. Consumers already pay an average of 40¢/kWh for uninterruptible power supplies (UPS). A solar electric system integrated into the UPS for a relatively small incremental cost can extend the power outage back-up time, particularly during the worst outages as noted below. Contact: Christy Herig, NREL, 303-384-6546


[1]  “Residential Customer-Sited Photovoltaics Niche Markets 1999,” Herig et al., and “Mapping the Value of Commercial PV Applications in the US—Accounting for Externalities,” Perez et al., American Solar Energy Society Conference Proceedings, Portland, Maine, June 1999.