Operational design of off-river Pumped Hydro Energy Storage (PHES): An alternative to conventional river-based PHES

Conventional river-based PHES is a mature energy storage technology but frequently faces environmental and social issues due to its location near rivers. This study presents an hourly operational analysis of off-river PHES as an alternative to conventional PHES to support renewable electricity generation. A case study using Java-Bali data from Indonesia was conducted. It shows that the upper reservoir of the PHES system (5.1 TWh) at an elevation of 200 m between the reservoirs minimally requires an area of 6.64 × 10 8 m 2 and leads to a maximum water level rise in the upper reservoir of 14 m if all excess energy is stored. Optimization of hourly operation shows that typically, during a few hours in the afternoon, water needs to be pumped from the lower to the upper reservoir. Ultimately, this paper illustrates hourly operational design and optimization based on heads, weather, and energy demand-supply data for the PHES. • 5.1 TWh off-river Pumped Hydro Energy Storage (PHES) needs initial fill of 4.08 TL. • 5.1 TWh Java-Bali off-river PHES with a head of 200 m minimally needs 6.64 × 10 8 m 2. • 5.1 TWh off-river PHES fully supports renewable energy generation in Java and Bali. • Off-river PHES is an innovative design that is still rarely used. • Optimal sizing for 100 % off-river PHES scheduling matches existing PHES systems.