energy resources. energy resources: coal, petroleum, and natural gas considered fossil fuel because...
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Energy Resources
Energy resources: coal, petroleum, and natural gas
• Considered fossil fuel because derived from remains of plants and/or animals
• Composed mostly of carbon and hydrogen
• Energy derived from the stored energy of living organisms
• Energy released through combustion
• Combustion releases CO2 and pollutants to atmosphere
Coal
• Coal – organic sedimentary rock made from plant remains in a low-oxygen environment– Mainly used to in coal-fired electric
generating plants – Significant pollutants given off when burned– Reserves should last until ~2200 AD– Forming much slower than consumption rate
Fig. 5.17, p.108
Petroleum
• Petroleum – liquid hydrocarbon formed from organic residue of plants and animals.– Burial in mud, slow heating– Source rock – typically an organic shale– Oil traps – folds or other rock structures that
trap rising petroleum– Reservoir Rock – permeable rock (e.g.
sandstone, limestone) that holds oil in pores
Fig. 5.19a, p.109
Fig. 5.19b, p.109
Fig. 5.19c, p.109
Fig. 5.20, p.110
Extraction of Petroleum
• Extraction – companies drill wells into reservoir rock– Wells getting deeper– Much oil too viscous to pump
• Secondary recovery – injection of water• Tertiary recovery – use of superheated steam
and/or surfactants
– Found in hostile / sensitive places• Open sea floor, ANWR, Middle East
Natural Gas
• Natural gas – forms when source rock rises above 100°C– Often found with oil– Mainly methane, used as fuel without
processing– Coal bed methane – associated with coal
seams• Depletes water table• Is often saline and poses pollution hazard
Nuclear fuels and reactors
• Nuclear fuels – radioactive isotopes to generate electricity
• Fission reactors (branching chain reaction)– Fuel rod– Control rods– Heat exchangers– Powers steam turbine
Nuclear fuels and reactors
• Processing and using nuclear fuels creates radioactive wastes
• Used fuel could be recovered, but in the US it is not done.– Disposal of fuel rods
• Hazards: Three-mile Island & Chernobyl
Fig. 5.28, p.117