Energy Resources. Energy resources: coal, petroleum, and natural gas Considered fossil fuel because...

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