Abstract
This work is about different optimal solutions for the unit commitment problem in the Venezuelan hydrothermal power system, disregarding the transmission system. The centralized cost-based maximum net social benefit solution, the oligopoly solution and the unregulated monopoly solution are formulated and analyzed. The oligopoly is studied via Nash-Cournot equilibrium, obtained iteratively considering both price-maker and price-taker firms. The price-demand curves are created using a price-demand elasticity parameter. The hydro plants can be of the run-of-river type or can have a regulation period, like in the case of Guri. In latter case the future profit is represented by a fixed volume of water to be turbined in the day ahead. Since integer variable are necessary to simulate the shut-down, start-up process a mixed integer commercial programming application is employed.