Sammendrag
With an increasing amount of intermittent renewable energy sources, such as wind and solar energy, there will also be an increasing demand for balancing power. Hydropower, and pumped storage in particular, can be an efficient way of providing the needed flexibility. Hydropower scheduling, particularly for large power systems with large amounts of hydropower, is a very complex task. Therefore there are few models that really are capable of handling detailed analysis in large power systems like the Nordic or European. In this paper we present a simple test-case where two different models suitable for analysis of balancing power are compared. The first model, called ProdRisk, is based on state of the art SDDP-methodology and is used as the reference model. Calculation time, however, limits the number of reservoirs this model can handle satisfactorily. The second model, called ReOpt, is an improvement of an extensively used market power simulator capable of handling real size power markets. Both models are designed for detailed hydropower representation and are both capable of handling pumped storage, but the first model has a mathematically more correct representation of the stochastic optimization. The main idea of this paper is to illustrate the potential ReOpt has for analyzing the use of hydropower and pumped storage as balancing power in large power systems.