Supply wind energy is also growing and is expected to

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Unformatted text preview: t reductions in river flow Q: why do you think that is?  ­glacier runoff is decreasing causing reduction in power plant production worldwide (Bolivia, Swiss., Peru, Ecuador) Nuclear Energy  ­occurs through nuclear fission in which the a neutron strikes a uranium nucleus and causes it to split into smaller parts producing free neutrons/photons and large amounts of energy  ­typically uranium is used (235U); ejected neutrons can also be used for new fission reactions and a continuous chain reaction occurs  ­LOTS of energy 1 gram of uranium produces the energy equivalent to 14 barrels of oil  ­8% of world energy use is nuclear  ­50% of France energy use is nuclear  ­increasing in use for many regions in particular Japan and Europe (where no native fossil fuels are found)  ­problems include security, since uranium is same ingredient used in nuclear weapons  ­power plant failure can create numerous, widespread environmental problems  ­need to dispose of nuclear waste materials  ­can be dangerous for 1000s of years Geothermal Energy  ­pull hot steam or water from deep, high pressure sources where the Earth’s internal heat is keeping temps of at least 180C or more  ­steam/water drives turbines which generates electricity  ­long term energy source because the Earth’s internal heat is going to remain high for quite some time  ­reserves are estimated at equivalent to 13 billion barrels of oil but efficiency of typical geothermal power plants is just 16%  ­problems: bring up also dissolved gases and toxic chemicals that need to be contained  ­also can cause subsidence locally  ­need to get through the Earth’s crust which is why many plants are in regions where crust is thin (Iceland, New Zealand) Winds/Tides/Solar  ­amount of energy reaching the Earth from the Sun is 10,000 x what we would need yearly  ­converting solar energy to electric energy is done with photovoltaic cells (solar panels) but efficiency remains quite low and costs high – so not many people are doing it  ­also solar energy is not produced at night and reduced production in winter when demand in the north is high  ­fastest growing energy supply  ­wind energy is also growing and is expected to be cost ­c...
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