Sensitivity Analysis of the Storage System Sizing for Solar Plants in Energy and Reserve Markets

A sensitivity analysis of Energy Storage System (ESS) sizing is proposed in this paper, in order to evaluate the influence of the ESS capacity in technical market requirements, market benefits and total profitability of the plant. With this objective, several market scenarios have been defined modifying ESS capacity, ESS costs, reserve band availability and energy imbalances prices. An increase in the ESS sizing allows a better real-time operation. On the other hand, the high ESS cost could results in a reduction of the plant profitability. Under current Iberian market conditions, a reduction of ESS costs is not sufficient to increase its profitability. However, under a scenario which penalizes more the energy imbalances, calculating the optimal ESS sizing will increase the overall plant profitability. For this purpose, the optimal ESS sizing should be found for each scenario, as well as optimizing the reserve band offers and applying an advanced energy management strategy in real-time.