PERESE: The new Hydro-Quebec optimization model for the long-term scheduling of reservoirs

A description of the PERESE model, that is presently developed at Hydro-Quebec to replace the EGERIE model built in the seventies, is given. The hierarchical model has four levels: At level 1, the optimal operating policy of the system, represented by a model in which all hydroelectric installations are aggregated together, is determined by stochastic dynamic programming on a semi-annual time basis. A level 2, the semi-annual results, for the period designated by the user, are splitted up between the months. Level $ dispatches the monthly hydroelectric production to the rivers, and level 4 distributes the production assigned to a river between its installations.