Deriving Optimal End of Day Storage for Pumped-Storage Power Plants in the Joint Energy and Reserve Day-Ahead Scheduling

Abstract

This paper presents a new methodology to maximise the income and derive the optimal end of day storage of closed-loop and daily-cycle pumped-storage hydropower plants. The plants participate in the day-ahead energy market as a price-taker and in the secondary regulation reserve market as a price-maker, in the context of the Iberian electricity system. The real-time use of the committed reserves is considered in the model formulation. The operation of the plants with the proposed methodology is compared to the ones that use an end of day storage of an empty reservoir or half of the storage capacity. Results show that the proposed methodology increases the maximum theoretical income in all the plants analysed both if they only participate in the day-ahead energy market and if they also participate in the secondary regulation service. It is also shown that the increase in the maximum theoretical income strongly depends on the size of the plant. In addition, it is proven that the end of day storages change notably in the new reserve-driven strategies of pumped-storage hydropower plants and that the proposed methodology is even more recommended if the secondary regulation service is considered.

A Review of Pumped Hydro Storage Systems

“…Daily pumped hydro storage (DPHS) systems are typically suitable for managing the daily fluctuations in electricity demand (day-night energy arbitrage). Although they are the most common PHS application today [8,37,38], the reduction in the cost of batteries and the decentralization of power generation might reduce the importance of this type of PHS plant in the future. Typically, these plants have reservoirs in the order of 10 6 to 10 9 m 3 .…”

“…This introduces the need for innovative strategies and technological advancements to construct effective bid and offer curves, enabling PHS to participate successfully in the day-ahead electricity market. Encouragingly, the existing literature [38,59,63] has begun to explore predictive approaches for balancing PHS supply and demand, which points towards a promising trajectory for further innovation in this sector.…”

Flexibility-Based Reserve Scheduling of Pumped Hydroelectric Energy Storage in Korea

“…Two approaches are used for efficiently operating a PHES in a power system: energy and reserve scheduling [14,15]. For reference, some research has addressed these two types of scheduling together using co-optimizing techniques [20,25].…”