Techno-Economic Feasibility of Floating Solar PV and BESS at Lake Toba

Abstract

This study evaluates the techno-economic feasibility of integrating a Floating Solar Photovoltaic (FPV) system with Battery Energy Storage System (BESS) at Lake Toba, North Sumatra. The simulation combines PVsyst for energy yield estimation and HOMER Pro for system optimization and financial modeling. Three system configurations were assessed: grid-only, FPV-only, and hybrid FPV-BESS. The hybrid configuration yields the highest performance, with an annual energy output of 1,343 kWh/kWp/year, a performance ratio of 82.9%, and minimal shading and thermal losses. The Levelized Cost of Electricity (LCOE) achieved in the hybrid system is 1,279.86 IDR/kWh—lower than the current Sumatra BPP—and offers the highest internal rate of return (27%) with the shortest payback period (4.1 years). BESS integration reduces curtailment by over 47 GWh/year and supports up to 12% of daily load during non-solar hours, demonstrating its critical role in improving energy utilization and dispatch flexibility. Cumulatively, the hybrid system delivers IDR 77 trillion higher profit over 27 years compared to the basecase, while reducing CO₂ emissions by 10%. These results support the replication of FPV-BESS integration as a strategic solution for achieving energy security, cost efficiency, and emissions reduction in Indonesia’s clean energy roadmap.