Oil

1
All Possible Energy Sources

• Renewable
• solar energy
• hydropower
• wind
• biomass
• Nonrenewable
• coal
• oil
• natural gas

2
Development leads to greater energy use
Figure 19-3 Page 479
3
Where does our energy come from?

• 82 worldwide from nonrenewable sources
• - 76 fossil fuels
• - 6 nuclear power
• 93 U.S. energy from nonrenewable sources
• - 85 fossil fuels
• - 8 nuclear power
• U.S. uses 26 of worlds energy

4
Problems with using fossil fuels

• they will run out eventually
• air pollution caused by their burning
• NOx, SO2
• climate change due to CO2 from burning

Figure 19-7 Page 481
U.S. energy consumption
5
Net Energy Ratios

• ratio of useful energy produced
• useful energy used to produce it
• higher ratios greater net energy
• lower ratios much energy lost before use

6
Oil

• Petroleum / crude oil from fossilized organisms
• Extraction
• 35 from drilling
• heavy crude oil left behind (expensive)
• Environmental pros
• little environmental impact of wells
• Environmental cons
• possible spills at wells in transport

7
Oil

• where in the world? - most in Mid East
• where in the U.S.? - TX, LA, AK
• U.S. and oil
• uses 26 world oil
• has 2.9 world reserves
• U.S. dependence on foreign oil
• 1973 36 imported oil
• 2002 55 imported oil

Consumption
Domestic supply
Figure 19-12 Page 485
8
How long will oil supplies last?

• U.S. production peaked in 1975
• World peaks predicted 2010 2030
• How do they know how long oil will last?
• Identify reserves (R)
• Calculate present and predicted consumption
• Calculate production rates (P)
• R/P length of time reserves should last
  (years)
• World oil in 2001
• Proved reserves 1.05 trillion barrels
• Production 27 million barrels / yr.
• Consumption 27.6 million barrels / yr.
• R/P 38.9 yrs.

9
Source BP web site, www.bp.com
10
Long-term oil supplies

• Unidentified oil reserves?
• Increased prices in future?
• Consumption is expected to increase
• Population size will increase
• U.S. oil reserves (2001)
• 30 million barrels
• 2.9 of world reserves
• R/P 10.3 years supply

11
Extending our use of oil

• Discovering unidentified reserves
• Oil shale extract shale oil
• Currently not economically viable
• Still causes air pollution, adds CO2
• Tar sand (oil sand, or bitumen)
• Much is too deep underground
• Deposits wouldnt last the world long
• Still causes air pollution, adds CO2

12
Natural gas

• Methane (50 90 )
• Other hydrocarbons (CN)
• Ethane
• Propane
• Butane
• Hydrogen sulfide H2S)
• Formation fossil fuel
• Found underground, near crude oil or by itself
• Tapped, liquefied, transported

13
How long will natural gas supplies last?
Source BP web site, www.bp.com
14
Coal

• Solid fossil fuel
• Sulfur (SO2) released when burned
• Mined underground or at surface (strip mining)
• Electricity production in U.S. (51 )

15
Coal environmental impacts

• Highest environmental impact of any fossil fuel
• Land disturbance (mining)
• Air pollution
• CO2, mercury, radioactive particle emissions
• Water pollution (acid mine drainage)
• Human health effects
• Respiratory problems from coal burning
• Miners black lung disease, accidents, deaths

16
Nuclear energy

• Energy from nuclear fission of U235
• Enriched Uranium fuel
• Control rods (C) regulate reaction
• Coolant (water)

17
Nuclear energy environmental impacts

• Leakage of radioactive isotopes into environment
• Meltdown
• Disposal of wastes
• Low-level waste store for 100 500 yrs.
• High-level waste store for 10,000 240,000 yrs.
  
• Storage of high-level waste
• Geological repository (bury it deep)
• Yucca Mountain, Nevada
• May not be safe

• Decommissioning plants

18
Nuclear energy vs. coal

• Energy source
• Coal Nuclear
• Fuel needed 3 million tons 30 tons
• CO2 7 million tons 0
• SO2 300,000 tons 0
• Solid wastes 600,000 tons (ash) 250 tons
  (radioactive)
• enriched from 75,000 tons of ore. 235U must be
  at least 3
• (in natural ore, 99.3 238U / 0.7 235U)
• (note energy is needed to enrich)

19
Discuss with your group

• Which source of electricity do you think is
  better, from an environmental standpoint?
• Coal-burning
• Nuclear power
• What do you think will happen as we use up the
  remaining oil reserves?