Compatibility Evaluation of Photovoltaic and Hydroelectric Power Generation Potential in the Beijiang River Basin Based on Climate Resources

With the continuous expansion of green energy development, multi-energy coupled power generation systems have effectively improved resource utilization, but still face challenges related to instability and unpredictability of grid-connected power generation. In order to achieve optimal utilization of a multi-energy coupled power generation system, it is crucial to understand the capacity of climate resources and their alignment with the power production sources. Taking Beijiang in Guangdong as an example, meteorological data from 1984 to 2023, runoff data from 2003 to 2017, as well as data such as elevation, land use and soil types, combined with photovoltaic, hydrological, and hydroelectric power generation potential models are used to calculate the normalized hydroelectric and photovoltaic potential power generation. From perspectives of spatial and temporal dimensions, and considering imbalances, fluctuations, differences, synergies, and complementarity of water-solar coupling power generation, various indices are constructed. Additionally, the self-organizing map (SOM) clustering method is employed. The evaluation of climate resources, matching analysis, and zoning assessment for the potential for water-solar power generation are conducted in the Beijiang River Basin. Results indicate that, spatially, total solar radiation and runoff display a distribution pattern characterized by high in the middle and low on both sides and low in the north and high in the south, respectively. The normalized power generation potential spatial occupancy and imbalance variation trends identified by the imbalance index are categorized into 4 scenarios that are photovoltaic greater than hydroelectric with an increasing trend, photovoltaic greater than hydroelectric with a decreasing trend, photovoltaic less than hydroelectric with an increasing trend, and photovoltaic less than hydroelectric with a decreasing trend, are concentrated in the eastern and western parts of the Basin, as well as in the downstream and middle reaches of Beijiang. In terms of time, climate resources display a unimodal distribution, following the seasonal order of summer, spring, autumn, winter. The potential power generation of water-light coupling exhibits complementary characteristics throughout the year, exhibiting significantly lower volatility and variation compared to independent systems. The distribution trend of the synergy index is consistent with the complementarity index, while exhibiting an inverse trend to that of the volatility index. The region with abundant resources and moderate matching property is concentrated in the central part of the Basin, and the coupled potential power generation has a good trend of one fading away and the other grow and stability improvement effect, making it suitable for planning and developing coupled system. The region characterized by abundant resources and low matching is concentrated in the southeastern part of the Basin, where coupled power generation exhibited instability and the highest volatility. The trend of synergy and stability improvement is not significant; therefore, it is a key focus area that needs insurance products to transfer risks.