Last year's drought in China's Yunnan province slashed hydro power generation by nearly 30 per cent during the first five months of 2020, according to official data. Output this year remains curtailed by around 10 per cent. Yunnan usually accounts for roughly a quarter of China's total hydro generation, and the province is home to several aluminum smelting businesses that require vast quantities of power to operate. The province restricted metal producers' power use earlier this year, forcing some smelting capacity to be temporarily shut. More disruptions are expected. A recent study by researchers in Nanjing looked at the potential impact of climate change and rising temperatures on hydropower generation in Yunnan. Their models showed decreases in rain and snowfall during the October-April drought season and increases in the summer rainy season. To even out the variability, the researchers proposed more storage capacity - more dams and reservoirs. But the diversions ...