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 CO 2 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