6.9 Hydroelectricity

how hydroelectricity produces energy

kinetic energy of moving water, spins a turbine (mechanical energy), turbine powers generator

largest renewable source of electricity globally

hydroelectricity

Biggest hydroelectricity producers

China, Brazil, US

water impoundments (dams)

dam built in a river creates a large artificial lake behind the dam (reservoir)

Drawbacks

reservoir floods habitats behind dam (forest/wetlands > gone; river becomes a lake), env. impacts = FF combustion during contruction, inc. evap, methane release due to anaerobic decomp. of org. matter in reservoir; econ. impacts = human homes and businesses relocated, sediment build up

fish ladders

cement “steps” or series of pools that migratory fish like salmon can use to continue migration upstream, around or over dams

benefits of hydrodams

no GHG emissions when producing electricity (initial construction does require cement and machines that emit GHGs), allows for control of downstream season flooding