Hydrokinetic resource assessment and techno-economic evaluation of energy recovery from the tailrace of Koyna Dam Powerhouse (KDPH), India

India’s existing hydropower infrastructure offers a potential opportunity to increase renewable energy generation with comparatively limited additional environmental disturbance relative to new infrastructure, though this has not been directly assessed in the present study. In this study, techno-economic evaluation of hydrokinetic (HK) energy recovery from the tailrace of Koyna Dam Powerhouse (KDPH) in the Koyna watershed, Maharashtra, India was conducted. Analysis of operational discharge data (from June 2024 to May 2025) from Maharashtra State Power Generation Company Ltd. (MAHAGENCO) was carried out along with velocity from Central Water and Power Research Station (CWPRS) test reports. A typical HK turbine (RivGen®-type) from representative of Ocean Renewable Power Company (ORPC) was chosen as the reference device. Based on the discharge conditions in the draft tube, velocities in the near field were calculated, showing a section-averaged exit velocity of about 1.26 m/s. The energy generation per device was estimated at ~5.31 MWh/year and the maximum extractable energy over the entire draft-tube area was ~90 MWh/year, a theoretical upper bound that is not practically recoverable in full. The levelized cost of energy (LCOE) varied from ₹11.17/kWh to ₹27.82/kWh (a partial, lower-bound figure) based on the capital expenditure (CAPEX); this range represents a minimum estimate since the installation, mooring and balance-of plant costs are not included. This multi-parameter sensitivity analysis shows that the energy yield and the economic feasibility are mainly affected by the flow velocity (cubically) and CAPEX. While the cost of current technology restricts grid-scale applications, HK can be technically integrated for modular, behind-the-meter applications, like auxiliary load support. The study provides a benchmark dataset and methodology for HK resource assessment in the Indian hydropower tailraces for the first time.