World hydro capacity could increase to 5000 GW

At present hydro plants have a total capacity of 1150 GW and generate around 4000 TWh/year, adding to 18 000 TWh/year of thermal power production. By 2050, the author contends that hydro capacity could reach as much as 2000 to 2500 GW of capacity, and generate 7000 TWh/year, associated with some 40 000 TWh of variable wind or solar power. Increased storage of electricity by pumped-storage plants may be justified up to about 3000 GW of capacity, compared with 150 GW at present. The use of rivers and reservoirs will need to be optimized accordingly, between hydropower generation and storage, and this will be very different from present practice.