Energy

Energy• Coal-remains of plants that have undergone carbonization• Occurs when partially decomposed plant material is

buried in swamp mud and becomes peat• Types of Coal-peat, lignite, bituminous, anthracite• Advantages

– Enormous reserves, cheap to mine, use as electricity • Disadvantages

– Recovery can be dangerous and hazardous-types of mining– Air pollution– Cannot be used for transport purposes– Non-renewable

• Interesting Facts– Accounts for 28% of nation’s

energy needs– Powered industrial revolution– Coal is crushed into powder

form and burnt

Oil and Natural Gas• Provides 40% of our nation’s energy use• Found in similar environments and typically occur together• Formation of petroleum and natural gas

– Microorganisms and plant remains in shallow pre-historic• Advantages

– Mobile (migrates toward surface), relatively low cost, plentiful for now, easily transported, electricity is proven reliable

• Disadvantages– Urban air pollution, acid rain, global warming, global tensions,

oil spills

Nuclear Energy• Energy released by reactions w/in atomic nuclei• Nuclear fission-nucleus of heavy atoms splits into 2 or more

fragments-process releases neutrons and energy• Nuclear fusion-nuclei of small atoms combine to form new,

massive nuclei-releases energy• Advantages

– Burn no fossil fuels, no air pollution, radioactive materials have long half live, cheap source, vast amount of energy in one atom

• Disadvantages– Separating the uranium isotopes is difficult, uranium is rare, cost

of building facility is pricey, radiation, accidents

• Interesting facts– Accounts for about 11% of

the worlds energy demands– Energy that reaches Earth

from sun-nuclear fusion– Fuel rods last several yrs

Geothermal

• Energy produced by heat w/in the Earth• Magma heats water-wells are drilled to reach hot water• Used as source of heat or sources of power to drive

turbines-generate electricity• Problems– Need large potent source of heat (magma) deep enough to

apply enough pressure and slow cooling– Steam and hot water lasts 10-15 hrs– Not expected to provide high % of worlds growing energy

needs

Hydroelectric and Tidal Power

• Electrical energy produced by flow of water, tides• Dams hold back water, control the flow, water

spins turbines which turn generators that produce electricity

• Contributes to 5% of country’s demands• Many occur in SE and Pacific NW of U.S.• Problems– Dams have finite lifetimes, rivers deposit sediment– Availability of sites

Wind• Wind is movement of air, results from air pressure differences

caused by sun’s uneven heating of Earth’s surface• Use movement of air to convert wind energy into mechanical

energy-generates electricity• Advantages

– Almost free, non polluting• Disadvantages

– Costs of large tracts of land in populated areas– No wind, no energy– Need better means of storage– Noise pollution