Impact of pumped storage on power systems with increasing wind penetration

In this paper, the unit commitment and dispatch of a power system with and without a pumped storage unit is examined for increasing levels of installed wind power, from 17% of total energy to 80% of total energy generated by wind 3 (3GW to 15GW of installed wind on the Irish system in 2020). At high levels of installed wind, it is shown that storage reduces curtailment and increases the use the base loaded plant on the system. This reduces system costs. However, when the additional capital costs of storage are taken into account, it is shown that storage is not viable from a system perspective until extremely large levels of wind power are seen on the system. At these levels of installed wind, while the system can operate without storage, it is less costly to do so with storage. The capacity credit of the storage unit is also examined, using a simplified approach, and shown to decrease as larger amounts of intermittent wind power are added to the system.