Evaluating the potential benefits of float solar photovoltaics through the water footprint recovery period

In the context of higher demands on the development of clean energy technologies due to the issue of water shortage in China and the implementation of the 2060 carbon-neutral objective, floating photovoltaic (FPV) systems present novel opportunities for transforming the energy structure through land conservation and enhancement of power generation efficiency compared to conventional solar systems. However, there is currently a lack of comprehensive analysis on the potential benefits of FPV. Utilizing reservoir databases and employing a professional FPV system design, a methodology for determining the water footprint recovery period was introduced, which enables the assessment of potential FPV benefits. The water footprint recovery period for constructing FPV on 909 reservoirs in China was found that ranges from 1.86 yr to 10.48 yr. It is found that reservoir evaporation, latitude, and climate are closely related to the water footprint recovery period of FPV. Furthermore, by implementing FPV panels with an optimal tilt angle, covering 30% of the area in each reservoir, the annual electricity generation can amount to 1429.19 TWh, leading to savings of 5.76 billion m³ of water. This achievement corresponds to 19.41% of the national electricity consumption and a 6.86% reduction in the national residential water consumption in 2020. The overall economic benefit is 5.61 myriads RMB, equivalent to 5.76% of the national GDP. These benefits are unevenly distributed and mainly concentrated in areas with more reservoirs. The anticipated enhancement of FPV system benefits is foreseen with the ongoing development and implementation of future reservoir power infrastructure and energy storage technology. These results demonstrate the significant potential of installing FPV systems on the reservoirs in China. This study proposes a method to comprehensively evaluate the comprehensive benefits of constructing FPV in China and conduct a thorough analysis of the feasibility of FPV, which could provide reference for the development of regional industries and the achievement of sustainable development goals (SDGs).