The objective of this report is to identify potential off-river reservoirs suitable for a pumped storage hydropower (PSH) system in the Kalvarayan Hills. PSH is crucial in the evolving energy landscape, characterized by the increasing presence of variable and intermittent renewable energy sources like solar and wind. These renewables pose significant challenges to grid stability, making integrating storage and ancillary services imperative. Among various storage technologies, PSH stands out as a clean, domestically available, and internationally accepted solution that has proven effective over time.
The global status of PSH highlights its importance, with substantial renewable capacity added in recent years. Countries like China, Japan, and the United States lead in PSH technology, facilitating the integration of fast-growing renewables into the grid. In India, the potential for PSH is notable, with several projects in various stages of development.
PSH operates by pumping water from a lower reservoir to an upper reservoir during periods of surplus electricity, storing energy for later use. When demand is high, water flows back down through turbines, generating power. This process allows PSH plants to balance electricity supply and demand efficiently, providing a reliable power source. PSH presents numerous benefits, including sustainable storage of surplus electricity generated during peak hours of solar and wind utilization. It promotes local development, offers extended discharge durations, and ensures high reliability.
Closed-loop or off-river PSH systems have fewer environmental impacts compared to open-loop systems. By not maintaining continuous connections to flowing bodies, they reduce surface water disturbances, benefiting aquatic ecosystems. The scope of this report is to identify reservoirs suitable for developing PSH in the Kalvarayan Hills area of Kallakurichi District and assess the extent to which these sites overlap with unused lands.
The site suitability assessment involves a two-step filtration process to identify reservoirs that consecutively meet technical and highest potential criteria. The report identifies 311 reservoir pairings meeting the technical criteria, collectively representing a PSH capacity of 14,159 GWh. These reservoirs span various capacity ranges, revealing significant technical potential for developing off-river PSH in the Kalvarayan Hills.
The evaluation indicates a promising future for PSH in Tamil Nadu. Developing PSH on sites with a high share of unused land ensures minimal impact on land cover. PSH’s flexibility and suitability for extended operation make it a dominant player in the global energy storage landscape. The next part of the analysis can include a cost model and grid modelling to fully understand PSH’s role in India’s energy mix.
