Abstract:In the context of the national “3060” dual carbon energy strategy, the South-to-North Water Diversion Project will bring opportunity to China’s western district. In the carbon limitation background, decarbonization methods should be valued to compensate the significant carbon emissions from the hydraulic engineering project. As the world biggest water transfer project, the South-to-North Water Division Project has completed the first phase of the Center Route and East Route, and its West Route is under plan discussion. In consideration of the carbon emissions from the hydraulic project, we introduced a new mode combining energy and hydraulic engineering for decarbonization, by installing the photovoltaic panels upon the water and protection zone, named as photovoltaic Tianhe. Based on the original length of 2300 km for the West Route, the length for photovoltaic panels of 1000 km, including the water and protection zone, and the total area of 120 km² were assumed. The whole photovoltaic volume would reach 14.4 GW, which will produce yearly 18.7 billion kW·h green electricity, save 2.3 million tons of the coal, and reduce 6.03 million tons of the CO₂ emission to help decarbonize the whole West Route project. Taking 1 MW as the baseline, the return on investment of the photovoltaic project is calculated as 14 years, which could be shortened by low-interest loan and new technology. According to the above research, we made two policy suggestions: firstly, the energy and hydraulic combination mode should be considered within the West Route’s planning phase, building photovoltaic Tianhe project upon the water panel; secondly, to establish several water-solar combined green energy bases along the West Route, composing of ground photovoltaic power station, water floating photovoltaic power station and pumped-storage hydroelectricity.