Hydro-battery Hybrids – A Case for Holistic Assessment of Hybrid Energy Systems

With the increasing deployment of renewable energy resources like solar and wind, the flexibility offered by hydropower generation will be instrumental in providing grid reliability. However, hydropower’s capabilities are often constrained to meet asset management targets and environmental flow requirements. To meet these requisites while utilizing hydropower’s full potential, hydro plus battery hybrids offer a logical solution. However, it is challenging to make the case for the economic feasibility of a hydro-battery hybrid given the required scale of battery storage to meet these requirements. To that end, this paper proposes a multi-objective analysis framework to maximize the advantages of hydro-battery hybrid systems from three different avenues: new market opportunities, environmental benefits and machine wear and fatigue. Using an illustrative case study of a hydropeaking plant, we simulate hydropower operations with and without 120 MWh of battery storage for four different simulated flow patterns ranging from hydropeaking operations to run-of-the-river operations and two intermediate flow patterns. The results demonstrate that hybridizing the hydropower plant can generate additional revenue while simultaneously enabling more environmental friendly operations and reducing the overall ramping mileage (sum of up and down ramping) of the turbines to approximately 1/5^th of the mileage from hydropeaking operations.