This paper examines generators' incentives to exercise market power and the strategies they would follow if all electricity supplies were traded in an hourly-unregulated spot market. The industry is modelled as a Cournot duopoly with a competitive fringe; particular care is given to the hydro scheduling decision. Quantitative simulations of generators� strategic behaviour indicate that the largest (Endesa) would have the incentive and power to act unilaterally. It would schedule its hydro resources to take advantage of differences in price electricity: too little supply in high demand periods and too much in low demand periods. Two market power mitigation measures are analysed: requiring Endesa to divest some of its generating capacity, and fixed price forward contracts for dominant generators. Conditions for the development of a voluntary contract market are analysed, as it is not practical to rely