This paper presents the introduction of an open electricity market in Victoria, Australia, and the analysis of spot prices from July 1994 till January 1998. A new structure of a competitive market where independent energy suppliers and users create electricity prices in a bidding system is discussed. Electricity trading takes three major forms: vesting contracts, hedge contracts and the spot market. Although less than 10% of electrical energy is purchased in the spot market, spot prices strongly affect contract prices and the behaviour of pool participants. The statistical analysis of spot prices shows a continuing trend towards very low spot prices. However, network limitations and the coincidence of scheduling line maintenance with hot weather leads to extremely high prices. The anatomy of the Black Week in November 1997 is discussed in detail.