Demand response (DR) programs are intended to reduce peak electrical demand on a utility system through the use of load control devices installed in residential or commercial buildings with customer permission. One method of DR is to use a device that controls loads such as air-conditioners or electric water heaters by cycling them on and off during peak load events, reducing instantaneous load on a utility’s system. Another method is to simply curtail service during peak events according to formal agreements between the utility and customer; in such cases, customers typically rely on backup generators to satisfy their power needs during a curtailment.
While the peak demand savings of DR programs are well understood, the energy savings of such programs are less understood. This is because of “snapback” effects, defined as the increase in energy or demand in the hours immediately following a DR event. Snapback results when controlled equipment is allowed to return to its operating set point following the event, and may offset all or part of the energy savings that were achieved when the equipment was cycled off or partially curtailed.