Evaluating existing water supply reservoirs as small-scale pumped hydroelectric storage options – A case study in Connecticut

• Published in: Energy (Oxford) Vol. 226; p. 120354
• Main Authors: Emmanouil, Stergios, Nikolopoulos, Efthymios I., François, Baptiste, Brown, Casey, Anagnostou, Emmanouil N.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.07.2021; Elsevier BV
• Subjects: Alternative energy sources; Distributed energy storage; Electrical transmission; Energy output; Energy storage; Evaluation; Existing water infrastructure; Flexible storage solutions; Infrastructure; Optimization; Photovoltaic cells; Piezometric head; Reduction; Renewable energy; Renewable energy penetration; Reservoirs; Schedules; Seasonal variations; Small-scale pumped-hydroelectric storage; Solar energy; Solar power generation; Storage capacity; Substations; Water conveyance; Water levels; Water shortages; Water storage; Water supply; Water supply systems; United States > US; Connecticut; Renewable energy penetration; Small-scale pumped-hydroelectric storage; Existing water infrastructure; Flexible storage solutions; Distributed energy storage
• ISSN: 0360-5442; 1873-6785
• DOI: 10.1016/j.energy.2021.120354

Considering the reduction of steep power ramps caused by renewable energy penetration, the present study evaluates the potential of utilizing existing water supply infrastructure as small-scale pumped-hydroelectric storage (PHS) units. A novel methodology is developed that estimates the total storage capacity via the available space in five water supply systems in Connecticut (United States), by solely employing water level measurements and considering a water release schedule that favors power-demand peak reduction. The study culminates in the estimation of optimal areal requirements for hypothesized solar farms neighboring the studied systems, based on deficit minimization between storage capacity and energy generation over the study period. Analysis reveals that, in most cases, the seasonal pattern of the storage capacity is in accordance with the behavior of the corresponding hydraulic head timeseries, showing higher values in winter/autumn. Given certain assumptions regarding the infrastructure, a yearly average of approximately 95 MWh/day can be stored as an intersystem aggregate, illustrating that the amalgamation of existing water supply reservoirs could provide significant energy storage capacity to complement substation variability. Finally, the area covered by PV arrays increases proportionally with the storage capacity, while the calculated solar energy output demonstrates significant variability relative to the PHS storage potential. •Water supply infrastructure is evaluated as potential small-scale pumped-hydroelectric storage (PHS) units.•The storage capacity is estimated considering a water release pattern that favors power demand peak reduction.•Estimation of PHS potential is conducted via a novel methodology that depends solely on water level measurements.•The relation between storage potential and solar energy reveals the importance of complementary renewable energy sources.