Conservation in California During the Summer of 2001

The goal of this study is to measure the results of energy-conservation, energy-efficiency, and load-reduction measures in the California Independent System Operator (CAISO) region during the summer of 2001.

During the period leading up to summer 2001, California experienced power outages and unprecedented instability in electricity and natural gas markets. Expecting that warm summer temperatures would exacerbate the already unstable energy market, state agencies and utilities created conservation and load-reduction programs that included advertisements and publicity, bill discounts for decreased customer electricity use, and financial payments for real-time load interruptions. Because the state avoided major electricity grid disturbances during the summer, few of the load-reduction programs were tested; however, the conservation and energy-efficiency programs appear to have been quite effective.

The purpose of this study is to determine the extent to which electricity loads decreased in summer 2001 relative to summer 2000 and summer 1999, independent of differences in weather patterns. Our assumption is that the portion of load reduction that is not attributable to weather can be attributed to energy-efficiency and conservation measures.

To determine the load reduction, we adjusted year 1999 and year 2000 hourly loads to simulate what load would have been under year 2001 weather conditions given the use patterns of years 1999 and 2000. The resulting load growth profile for 2001 was then compared with the load growth between 1999 and 2000 to determine how the pattern of load growth was affected by the energy crisis and the conservation programs put into place in response to it.