Observed Temperature Effects on Hourly Residential Electric Load Reduction in Response to an Experimental Critical Peak Pricing Tariff

The goal of this investigation was to characterize the manual and automated response of residential customers to high-price "critical" events dispatched under critical peak pricing tariffs tested in the 2003-2004 California Statewide Pricing Pilot. The 15-month experimental tariff gave customers a discounted two-price time-of-use rate on 430 days in exchange for 27 critical days, during which the peak period price (2 p.m. to 7 p.m.) was increased to about three times the normal time-of-use peak price. We calculated response by five-degree temperature bins as the difference between peak usage on normal and critical weekdays. Results indicated that manual response to critical periods reached -0.23 kW per home (-13%) in hot weather (95-104.9°F), -0.03 kW per home (-4%) in mild weather (60-94.9°F), and -0.07 kW per home (-9%) during cold weather (50-59.9°F). Separately, we analyzed response enhanced by programmable communicating thermostats in high-use homes with air-conditioning. Between 90°F and 94.9°F, the response of this group reached -0.56 kW per home (-25%) for five-hour critical periods and -0.89 kW/home (-41%) for two-hour critical periods.