Page - 120 - in Water, Energy, and Environment - A Primer

generation, followed by the US, Brazil and Canada. Capacity growth has slowed in recent years, but cumulative capacity is still expected to increase bymore than 100GWby 2022, with hydropower remaining the world’s largest source of renewable electricity generation. Some studies of hydropower’s future development indicate the potential to reachmore than2000GW of installed capacity by2050. While it iswidely known that hydropower is a renewable and carbon-free generating source, what is less widely known is its value to the electric grid. It offers: load-following and flexible reserve, on time scales ranging from minutes to hours; smoothing of power demand–supply mismatches; spinning reserve that can respond quickly to outages and other system events; reactive power and voltage support; and black-start power – the capability to restart sections of the grid after a blackout. Figure 8.10 Schematic of high-head hydropower plant (Source: U.S DepartmentofEnergy). Water,Energy, andEnvironment–APrimer120