We examine electrical power price variability for 14 deregulated markets. Power price volatility is measured by price velocity, the daily average of the absolute Value of price change per hour. Deregulated markets show a wide variability in price velocity. Some price velocity is expected and arises from the daily diurnal price pattern, which differs significantly between markets. Even when the expected daily variability in price is removed, the residual unexpected variability differs between markets. Some deregulated markets, most notably Britain and Spain, show patterns that are predictable and consistent and have low values of unexpected price velocity. These markets create a climate conducive to Consumers facing the market through real time pricing and shaping consumption behaviors in response to price changes. Other markets, for example, South Australia and Alberta, have patterns that are inconsistent and irregular, and hence are hard for a customer to interpret; a customer in such a market will have a higher incentive to avoid demand side management and escape risk through hedging mechanisms. (C) 2003 Elsevier Ltd. All rights reserved.