Techno-Economic Assessment of a 400 MWp Floating Photovoltaic System Integrated with Pumped Hydro Energy Storage (PHES) on Lake Toba

Abstract

Indonesia’s commitment to achieving Net Zero Emissions by 2060 has driven the exploration of large-scale renewable energy solutions, including the integration of  floating photovoltaic system and energy storage system. This study analyzes the techno-economic feasibility of a 400 MWp floating photovoltaic (FPV) system combined with Pumped Hydro Energy Storage (PHES) at Lake Toba, North Sumatra. This study presents a novel hybrid configuration not yet implemented in Indonesia. Multi-platform simulations were conducted using PVsyst for energy yield estimation and HOMER Pro for techno-economic optimization. The research provides new insights into the feasibility and optimal configuration of hybrid FPV-PHES systems to support Indonesia’s renewable energy transition.  The research employs PVsyst to evaluate the energy performance of the FPV system, while HOMER Pro was used for economic optimization across three scenarios: 400 MWp Floating PV only, Floating PV combined with 407 MWh PHES, and Floating PV combined with 511 MWh PHES. Simulation results from PVsyst showed an annual energy output of 5.72 GWh and a performance ratio of 80%, with relatively low temperature losses due to the water-based cooling effect. Among the scenarios, Scenario 2 (407 MWh PHES) offers the most favorable outcome with a Levelized Cost of Energy (LCOE) of Rp 1,298/kWh, ROI of 5%, IRR of 7.5%, and a payback period of 10.58 years. Grid simulations also confirm system stability under dynamic conditions. Environmentally, the hybrid system reduces greenhouse gas emissions by 8.87 million kg CO₂ annually. The results indicate that the FPV–PHES configuration is technically feasible, economically attractive, and environmentally beneficial, making it a strong candidate to support Indonesia’s energy transition goals.