Hybrid generation of renewables increases the energy system's robustness in a changing climate

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Hybrid generation of renewables (e.g., hydro, solar, and wind energy sources) is an increasingly important technology to improve energy use efficiency and reliability. However, renewables are usually influenced by climate factors. In a changing climate, it is essential to know whether the integration of renewables enhances or weakens the robustness of the energy system, which is defined as “the insensitivity of the system's operational performances to climate change”. To answer this question, we first modeled the long-term operation of several hybrid renewable energy systems (HRESs) (i.e., hydro–solar–wind, hydro–wind, and hydro–solar systems) and a hydropower energy system using historical hydro-meteorological data and stochastic dynamic programming. Then, we constructed uncertain climatic conditions using a multi-variable stochastic simulation technique, which considered spatial-temporal correlations between inflow, solar, and wind power output. Finally, we compared the robustness of the operating rules under the simulated climatic conditions. A hypothetical case study based on China's Longyangxia hydro–photovoltaic (PV) power plant showed that: (1) the integration of PV and/or wind power significantly improved the system's robustness compared to only hydropower sources under uncertain climatic conditions; (2) the hydro–solar–wind HRES was the most robust system, meeting the energy demand more than 90% of the climatic conditions; (3) the hydro–solar–wind HRES was most sensitive to inflow change, followed by changes to wind and PV power. These findings hightlight the importance to implement hybrid generation of hydro, solar, and wind energy sources in a changing climate.