Conservation in California During the Summer of 2001

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The goal of this study is to approximately measure the total result of energy-conservation, energy-efficiency, and load-reduction measures in the California Independent System Operator (CAISO) region during the summer and the year of 2001. This is done by correcting for weather effects and matching loads across two years. The assumption is that any residual difference can be approximately assigned to the sum of the three effects listed, although there are other possible factors not considered here, such as changing levels of business activity. During the period leading up to summer 2001, California experienced power outages and unprecedented instability in electricity and natural gas markets. Expecting that hot 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 year 2001 relative to year 2000 and year 1999, and for the corresponding summers (June through September), 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. While other factors may certainly have had an effect on electricity load, e.g. the economic slowdown, these factors are not explored here. To determine the load reduction in California, hourly loads from 2000 were adjusted to simulate what load would have been under year 2001 weather conditions given the year 2000 electricity use patterns. 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 may have been affected by the energy crisis and the conservation programs put into place in response to it.

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