A GIS-based techno-economic comparative assessment of offshore fixed and floating photovoltaic systems: A case study of Hainan

As solar photovoltaic (PV) systems are being gradually expanded into the ocean, there is an increasing need for rigorous techno-economic analysis to guide investment and deployment decisions across different PV technologies. At present, there is no clear division of locations for different offshore PV systems. This study presents a comparative analysis of two common offshore PV technologies—fixed and floating systems—through a geographic information system (GIS) approach. Using the proposed GIS model, power generation potential, costs, and economic feasibility under varying ocean conditions (e.g., water depth, offshore distance, and wind) are compared. Additionally, the geographic boundaries for each technology's applicability and the distribution of the levelized cost of energy (LCOE) are mapped for the first time. The methodology is applied to the coastal waters of Hainan Island, China, for a utility-scale offshore PV system. The research results indicate that the proposed fixed system has significant advantages when deployed at a water depth of 30 m offshore, with an LCOE significantly lower than that of floating systems, ranging from $81.2 ∼ $293/MWh. In contrast, the costs of floating systems are largely unaffected by environmental conditions, making them suitable for extensive deployment in offshore areas within 40 km with an LCOE ranging from $293 ∼ $442/MWh. This study introduces a fixed PV foundation structure designed for shallow water and validates its development potential through cost comparisons, addressing a critical gap in the offshore PV literature. Additionally, comprehensive cost models for both fixed and floating systems are presented, defining the optimal operational boundaries for each technology.