Assessing the dispatch flexibility of coordinated solar and hydro generation

Dispatch flexibility denotes the capability of electrical generation that can be dispatched to serve the load. Hydro power generation with water reservoir has favorable dispatch flexibility that can be used to mitigate the intermittency and uncertainty of photovoltaic. Hydropower and photovoltaic can be coordinated by storing water energy in the peak hours of solar and shifting it to off-peak periods. In this paper, a metric of dispatch flexibility is defined to evaluate to what extent the solar and hydro generation can be coordinated. The methodology for measuring the dispatch flexibility of solar-hydro coordination is proposed based on a multi-scenario dispatch model considering the uncertainty of water inflow and solar irradiation. Results are drawn with a study on the first and largest solar-hydro coordination project in China, the Longyang Gorge (LYG) project. The study quantifies the generation dispatch flexibility of LYG project and illustrates the potential impact of different factors on solar-hydro coordinated generation.