Examines the responses of time-of-use (TOU) electricity rates by large industrial and commercial customers in France, England, and Wales. The report analyzes quantitatively the daily and seasonal patterns of electricity use for a sample of customers who have faced TOU rates for 10 to 20 years. Some of the conclusions drawn are: TOU prices have an effect on customers' loads by almost any measure applied; industry-specific patterns of adjustment appear to be consistent with the industrial processes involved; and firms possessing self-generating capability make added adjustments in their daily loads by reducing peak and shoulder period use and increasing off-period electricity consumption. Two major policy implications for the United States are suggested: First, although on average there is clear evidence of response to TOU rates, considerable variability remains from firm to firm and from industry to industry. Second, offering optional rates allows a firm to select the most advantageous rate for the pattern of consumption the firm is willing to achieve.