Pumped Hydro Energy Storage for Hybrid Systems - Chapter 2 - Need for pumped hydro energy storage systems

The integration of renewable energy-based sources is a growing phenomenon to limit dependence of fossil-based fuels in the power system to enhance energy security and reduce climate-related emissions. However, the increase in the share of intermittent renewable energy sources in the electric grid poses some system stability and security issues as it features variabilities and inflexibilities in demand and supply load curves. Energy storage systems provide the adjustability to match fluctuating energy demand. Pumped hydro energy storage (PHES) system is the most matured and utility-sized storage technology, which in time past was used to complement generation during peak times and also to act as back-up for nuclear power plants. Modern trends in electricity market developments and renewable energy integration have widened the focus on PHES to offer other services and benefits. This chapter provides information on the benefits of PHES within power network management including load balancing and peak shaving, and grid stabilization with emphasis on frequency and voltage regulation. Additionally, the chapter highlights some of the different PHES hybrid designs for both off-grid and grid-tied applications while the impact of climate change is discussed.