Analysis of floating photovoltaics potential in Hong Kong: Green hydrogen production and energy application

Solar energy is now one of the most affordable and widely available energy sources. However, densely populated cities like Hong Kong often lack the land needed for large-scale solar deployment. Floating solar photovoltaics (FPV) offer a promising alternative by using water surfaces, such as reservoirs, while providing additional benefits over ground-mounted systems, including competition with urban development, such as housing and infrastructure. The advantage of this system has been explored in parts of the world, while Hong Kong is yet to fully exploit it despite the presence of pilot projects. This study uses PVsyst to evaluate FPV deployment across Hong Kong's reservoirs, estimating over 7 TWh of potential annual electricity generation. Even with 60 % surface coverage, generation reaches 4.6 TWh/year, with LCOE between $0.036–$0.038/kWh. In parallel, green hydrogen is explored as a clean energy storage solution and alternative transport fuel. By using electricity from FPV systems, hydrogen production via electrolysis is assessed through HOMER Pro. Results show annual hydrogen output ranging from 180,502 kg to 36,310,221 kg, depending on reservoir size, with associated LCOH between $10.2/kg and $19.4/kg. The hydrogen produced could support ongoing hydrogen bus projects and future expansion to other vehicle types as Hong Kong moves toward a hydrogen-based transport system. After coupling the FPV systems with hydrogen-generation units, the new LCOEs are found to be between $0.029–4.01/kWh. Thus, suggesting the feasibility of a hydrogen-integrated FPV system in Hong Kong.