Mid-Term Effects of Optimal Wind-Reversible Hydro Offering Strategies in Day-Ahead Electricity Markets

A coordinated strategy between wind and reversible hydro units for the mid-term that reduces the imbalance of wind power and improves system efficiency is proposed. A stochastic mixed integer linear model is used, which maximizes the joint profit of wind and hydro energies and Conditional Value at Risk (CVaR), where CVaR is the tool utilized to model risk. The offering strategies studied are: i) separate wind and hydro pumping offers, where the units work separately without a physical connection and ii) single wind and hydro pumping offer with a physical connection between them to store the wind energy for future use. The effects of a coordinated wind-hydro strategy for the mid-term are analyzed, considering CVaR and the future water value. The future water value in the reservoirs is analyzed for a period of two months, hour by hour, in a realistic case study.