1-in-10 standard

While it’s theoretically possible to keep the lights on with a much smaller reserve than the U.S. utility industry historically has maintained, the costs of doing so might be higher than some analyses suggest. As demand response plays a growing role on the grid—and as system planners reconsider reserve margins and reliability standards—quantitative risk analysis will guide resource adequacy decisions.

The one-day-in-10-years criterion might have lost its usefulness in today’s energy markets. The criterion is highly conservative when used in calculating reserve margins for reliability. Can the industry continue justifying the high cost of overbuilding?