The development of fishery-photovoltaic complementary industry and the studies on its environmental, ecological and economic effects in China: A review

The fishery-photovoltaic complementary industry is an emerging industrial model in China that integrates aquaculture with the solar industry. This innovative model involves conducting aquaculture activities while installing photovoltaic modules on the water surface to harness solar energy for electricity generation. However, despite its rapid growth in China, this model lacks substantial scientific data support across various domains. Therefore, based on an analysis of relevant research literature, this study reviews the current development status, environmental and economic effects, as well as challenges faced by the fishery-photovoltaic complementary industry in China. The aim is to provide scientific references for promoting sustainable development within this sector. The findings reveal that existing fishery-photovoltaic complementary industry projects are primarily concentrated in the middle and lower reaches of the Yangtze River and Pearl River Basin. The geographical distribution of these projects is predominantly influenced by local aquaculture areas and available solar energy resources, with a greater impact observed from the former rather than the latter. During summer months when water is shaded by photovoltaic panels, a slight decrease in the average water quality parameters across cases was observed, such as a decrease of 0.2 units in pH, a decrease of 1.06 °C in water temperature, a decrease in dissolved oxygen levels of 0.8 mg/L, inorganic nitrogen content and total phosphorus concentration dropped by 0.08 mg/L and 0.02 mg/L respectively. Conversely, there is a moderate increase noted in total nitrogen and ammonia nitrogen levels. The conclusion of the effect on phytoplankton biomass is not uniform, but it will certainly reduce zooplankton biomass. The impact on the species diversity of the zooplankton community was minimal, and its direction, whether positive or negative, varied depending on the specific aquatic ecosystem. A certain degree of shade is advantageous for the cultivation of shade-loving fish. Through the strategic deployment of photovoltaic panels and the implementation of scientific stocking practices, it is possible to achieve sustained levels of fisheries production. This model also can reduce an average of 978.6 tons of CO2 emissions per megawatt per year through energy production, thus achieving the combined goals of energy conservation and emissions reduction, and ensuring the profitability of power generation. Additionally, compared with the land utilization area of 3.66 hm2 per megawatt of traditional ground-mounted photovoltaics, fishery-photovoltaic complementary only requires 1.64 hm2, which can significantly save land resources by utilizing water surfaces, which mitigates the conflict between land use for agriculture and renewable energy installations. At the same time, research also pointed out that the existence of fishery-photovoltaic complementary will inevitably have some negative impacts on bird communities. Economic analyses indicate that while initial infrastructure costs and long payback periods pose challenges, the overall economic feasibility is promising, especially with governmental support and technological advancements. However, several challenges need to be addressed for further development: these include difficulties associated with infrastructure construction and initial costs, long payback periods; insufficient experience and technical support; as well as a lack of research on ecological and environmental impacts - particularly an urgent need for comprehensive life cycle assessments encompassing both environmental and economic aspects. Future research should focus on life cycle assessments, improved PV technology integration, and optimized aquaculture practices.