6.9- Hydroelectricity

How is hydroelectricity produced

By the kinetic energy of moving water through natural currents or tides, or by falling vertically through a channel

What are the top three countries that use hydroelectricity?

China, Brazil, US

Dams

Large walls built in rivers that create an artificial lake to produce hydroelectricity

Why are dams efficient?

Can control how much water is brought in to produce as much electricity as needed.

Pros of Dams

-Allows for downstream flow which prevents seasonal flooding

-Greate source of recreational money

Why are surrounding ecosystems less impacted by dams?

Dams prevent seasonal flooding which also prevents ecosystems from getting lots of nutrients to increase biodiv.

Why are dams not available all year round?

In warmer seasons river levels can be lower meaning less water can be used.

What is a drawback of tidal power?

Only available in coastal areas.

General consequences of hydrodams

-Floods habitats behind the dam which can cause rivers to turn into a lake

-Downstream wetlands suffer because nutrients don’t reach them

-Upstream becomes warmer and contains less O2

-Rocky steambed habitats covered in sediment

Environmental Impacts of hydrodams

-FF combustion during dam construction

-Increased evap. due to larger surface area

-Methane released from decomp. of organic matter

Economic Impacts of hydrodams

-Human homes and business need to be relocated from flooding

-Construction is very expensive

-Sediment buildup requires crane to remove

-Loss of ecosystem services from downstream wetlands cause loss of fishing revenue

Fish ladders

Cement steps/pools that fish can use to migrate around dams

Pros of Hydrodams

-No GHG emmissions or air pollutants when producing electricity

-Control of downstream seasonal flooding