Energy potential and environmental benefits of hybrid floating photovoltaic systems on dams in Thailand

Floating photovoltaic systems installed on hydropower reservoirs can expand renewable capacity without occupying land, yet country-specific, operationally calibrated assessments for Southeast Asia remain scarce. This study provides the first province-resolved techno-economic and environmental assessment of hybrid floating photovoltaic deployment on Thailand's hydropower dams, using a performance model calibrated against the operating Sirindhorn plant (measured specific yield 1289 kWh/kWp). Potential generation, levelized cost, net present value, evaporation savings and carbon abatement were quantified across 1%, 5% and 10% reservoir-coverage scenarios for the country's dam provinces, and a 10,000-run Monte Carlo simulation with Sobol variance decomposition was used to quantify uncertainty. At 10% coverage the dams could host about 83.8 GWp and generate roughly 103 TWh per year, equivalent to a large share of national demand, while reducing reservoir evaporation and avoiding carbon emissions. The national levelized cost of electricity is about 60 USD/MWh (10th to 90th percentile range 55 to 79), below Thailand's average retail tariff and competitive with regional utility-scale solar; the investment remains net-present-value-positive across the entire 10th to 90th percentile uncertainty range and improves further under carbon pricing. Cost is governed chiefly by capital expenditure and financing, and value by the electricity price. These results offer a locally grounded, uncertainty-quantified evidence base for integrating floating solar with existing hydropower in Thailand and comparable Southeast Asian settings.