水电是一种清洁、可再生,且对环境友好的能源。全球每年的水力发电量达到3930 TW·h,占全球总发电量的16%,同时占可再生能源发电量的78%(2015年)。水电和气候变化具有双重的关系。一方面,水电作为一种重要的可再生能源,对于避免温室气体排放和减缓全球变暖贡献显著;另一方面,气候变化会改变河道流量,进而影响水资源可用量和水力发电。水电对于减少温室气体排放和保障能源供应至关重要。与常规燃煤电厂相比,水电每年可避免3×109 t CO_2的排放,占全球年CO_2排放量的9%。除了对电力行业的贡献,水电项目还可作为多功能水库的融资工具,以及水资源应对气候变化影响的一项适应性措施,这是因为水库的蓄水可作为气候变化的缓冲器,有大水库调节的流域更能适应水资源变化,而不容易受到气候变化的影响。从全球层面来看,预期气候变化对现有全球水力发电的整体影响较小,甚至可能产生一些积极影响。然而,世界不同地区甚至各个国家内部可能存在巨大差异。总之,对水电的解读为:水电是一种廉价、成熟的技术,对减缓气候变化有重大贡献,且可以在水资源适应气候变化中发挥重要作用。有必要关注并减轻巨大的环境压力和社会成本,预计未来几十年内可新增水电装机容量1000 GW。 Hydropower is a clean, renewable and environmentally friendly energy source. The world’s annual hydroelectric power generation reached 3930 TW · h, accounting for 16% of the world’s total generating capacity, while accounting for 78% of renewable energy power generation (2015). Hydropower and climate change have a dual relationship. On the one hand, hydropower, as an important renewable energy source, contributes significantly to avoiding greenhouse gas emissions and mitigating global warming; on the other hand, climate change will change river flow, which in turn will affect the availability of water resources and hydropower generation. Hydropower is crucial to reducing greenhouse gas emissions and ensuring energy supply. Compared with conventional coal-fired power plants, hydropower can avoid emissions of 3 × 109 t CO 2 per year, accounting for 9% of annual global CO 2 emissions. In addition to its contribution to the power industry, hydropower projects can also serve as a financing tool for multi-purpose reservoirs and as an adaptive measure of water resources to address the effects of climate change because reservoirs can serve as buffers for climate change and have large Reservoir-adjusted basins are better adapted to changes in water resources and less susceptible to climate change. At a global level, the overall impact of climate change on existing global hydroelectric power is expected to be small and may even have some positive effects. However, there may be huge differences in different parts of the world and even in different countries. In summary, hydroelectricity is interpreted as: Hydropower is a cheap, mature technology that makes a significant contribution to climate change mitigation and can play an important role in adapting water resources to climate change. It is necessary to pay attention to and reduce the huge environmental pressure and social costs. It is estimated that the installed capacity of hydropower will be 1,000 GW in the next few decades.