Short-term Hydro Scheduling using Integer Programming: Management and Modelling Issues

The scheduling of hydro stations has stochastic, integer, non-linear, and continuous time aspects, with all the approaches described to date making some simplifying assumption about one or other of these aspects. The (integer) unit commitment decision has received relatively little attention, partly because the resulting problem was deemed intractable given the potential gains in efficiency. However, with the advent of deregulated energy markets, the implications of ignoring these integer effects may be costly, and so they must be considered in some way. We discuss some of the managerial and modelling issues relating to this problem and some ideas for heuristics that incorporate management priorities into an Integer Programming framework.