Unit 2: Lecture 11 - Alternative Energy Resources

nuclear energy

radioactive materials that release energy through the process of nuclear fission

nuclear fission

accomplished by bombarding the nuclear of heavy atoms (uranium-235) with neurons

this causes the uranium nuclei to split into smaller nuclei to emit neutrons and heat energy

the ejected neutrons bombard the nuclei of adjacent uranium atoms, creating a chain reaction

uranium-235

the only naturally occurring isotope that is readily fissionable, making it the primary fuel used in nuclear power plants

plant siting

close to urban areas = more people at risk in case of accident

far from population centers where energy is needed = more transmission loss of electricity

proximity to water is important for cooling purposes but makes water pollution more likely

hydroelectric power

generated by falling water and used to drive turbines that produce electricity

clean and non-polluting

renewable as long as streams have water flowing

damming reduces flooding dangers for farmer raising crops in floodplains

damming can also alter ecosystems upstream (flooding) and downstream (loss of sediment supply and flooding)

limitations on hydropower development

reservoirs tend to

• silt up

• increase surface area exposed to evaporation

• destroy habitats

• encourage earthquakes

reservoirs are stationary power sources— while there is plenty of hydroelectric potential in remote areas like Alaska, there is nowhere to transmit that power efficiently due to lack of nearby urban areas

geothermal energy

harnessed by tapping natural underground reservoirs of stream and hot water

used for heating and to generate electricity

these occur where subsurface temperatures are high due to relatively recent volcanic activity or nearby magma chambers

ex: 66% of Iceland’s energy use comes from geothermal as the country is a large volcanic island with current volcanic activity