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chapter notes

Environmental Science
Course Code
Carl Mitchell

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Chapter 16
- 81% of world’s energy comes from oil, coal, and natural gas
- Powers 2/3 of world’s electricity generation
- conventional alternatives to fossil fuels Æ less environmental impact
- Fuel and biomass = 10.0% of world’s energy; nuclear power = 6.3%; hydropower = 2.2%
- Nuclear & hydropower each accounts for 1/6 of world’s electricity generation
Hydropower: uses the kinetic energy of moving water to turn turbines and generate electricity
- Storage: keeping immense amounts of water stored behind the dam
- Reservoir water passes through a dam Æ turns blades of turbines Æ generator generates
electricity Æ transmitted to electric grid by transmission lines
- Run-of-river: generates electricity without disrupting the flow of river water
- sacrifices the reliability of water flow across seasons minimizes the impacts of large dams
- divert a portion of a rivers flow through a pipe/channel Æ powerhouse Æ back to river
- 2.2% of world’s energy supply, 16.0% of the world’s electricity production
- For flood control and irrigation
- Renewable as long as precipitation falls from the sky and fills rivers/reservoirs
- Cleanliness no carbon compounds are burned in the production of hydropower no CO2 or
other pollutants are emitted into the atmosphere
- Fossil fuels are used in constructing and maintaining dams
- EROI = ~10:1
Negative impacts
- Destroys habitat for wildlife, natural flooding cycles of rivers are disrupted, sediments become
trapped behind dams
- thermal pollution (water downstream may become unusually warm if water levels are kept
unnaturally shallow Æ period flushes of cold water)
- Æ thermal shocks + habitat alteration = diminished or eliminated native fish populations
- blocks passage of fish/other aquatic creatures fragmenting the river and reducing biodiversity
- weight of water in a large reservoir Æ geological impacts e.g. earthquakes
- dam collapses result of earthquakes/landslides/degradation of construction materials
not much room for expansion
- not many more rivers to dam
- more awareness about ecological impacts of dams
- regional residents are resisting dam construction
- International Energy Agency (IEA) hydropowers ability to generate will decline, other
renewable energy sources will triple 2% Æ 6%
Nuclear power: usable energy extracted from the force that binds atomic nuclei together
- Free of air pollution
- Nuclear energy: the energy that holds together protons and neutrons within the nucleus of an
- Æ thermal energy Æ generate electricity
- Nuclear fission: splitting apart an atomic nuclei
- Neutrons are slowed down in order to break apart
- Each split nucleus emits heat/radiation/multiple neutrons
- Can become positive feedback that release enormous amounts of energy (nuclear bomb)
- Nuclear reactors: facilities contained within nuclear power plants
- uranium ore is finite
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