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