Floating photovoltaics (FPV) is fast becoming cost-competitive, but its social and environmental impacts are under debate. Meanwhile, developing economies anticipate hundreds of new dams over the next decade, with social and environmental implications for the next century. In this context, we estimate that FPV could produce 20–100% of the electricity expected from Africa’s planned hydropower depending on the scale of FPV deployment and its cost and efficiency relative to land-based photovoltaics. Here, at the system scale, we show that the same capital investment earmarked for planned dams in the Zambezi watercourse could be used more efficiently by building fewer reservoirs and substituting the energy supply with FPV. This approach yields an energy output 12% less variable and more robust to long-term hydrological changes. Our findings suggest that FPV’s potential to avoid the environmental, social and financial risks of hydro-dominated energy development may outweigh its potential impacts on existing reservoir uses.

浮动光伏发电（FPV）正在迅速变得具有成本竞争力，但其社会和环境影响仍存在争议。与此同时，发展中经济体预计未来十年将修建数百座新水坝，这将对下个世纪的社会和环境产生影响。在这种背景下，我们估计 FPV 可以产生非洲规划水电预期电力的 20-100%，具体取决于 FPV 部署规模及其相对于陆基光伏发电的成本和效率。在这里，在系统规模上，我们表明，通过建设更少的水库并用 FPV 替代能源供应，可以更有效地利用指定用于赞比西河道计划水坝的相同资本投资。这种方法产生的能量输出变量减少了 12%，并且对长期水文变化更加稳健。我们的研究结果表明，FPV 避免水力能源开发的环境、社会和财务风险的潜力可能超过其对现有水库利用的潜在影响。