1. Environmental Science
Chapter 13:
Energy

2. Key Concepts Energy use in the U.S. and around world
Tradeoffs of different fossil fuels
Tradeoffs of nuclear energy
Improving energy efficiency
Energy saving options for cars

3. Commercial Energy for the World and US
Fig. 13-3, p. 287

4. Commercial Energy Use in US Since 1800
100
Wood
Coal 80
Natural gas 60
Contribution to total energy
consumption (percent)
Oil 40
Hydrogen
Solar 20
Nuclear
1800
1875
1950
2025
2100
Year
Fig. 13-4, p. 288

5. Net Energy Ratios Space Heating Passive solar 5.8 Natural gas 4.9 Oil
4.5
Active solar
1.9
Coal gasification
1.5
Electric resistance heating
(coal-fired plant)
0.4
Electric resistance heating (natural-gas -fired plant)
0.4
Electric resistance heating
(nuclear plant)
0.3
Fig. 13-5a, p. 289

6. Major Oil, Natural Gas, and Coal Deposits in North America
Fig. 13-7, p. 292

7. Tradeoffs of Conventional Oil Use
Advantages
Disadvantages
Ample supply for years
Low cost (with huge subsidies)
High net energy yield
Easily transported within
and between countries
Low land use
Technology is well
developed
Efficient distribution system
Need to find substitute within 50 years
Artifically low price encourages waste and discourages search for alternative
Air pollution when burned
Releases CO2 when burned
Moderate water pollution
Fig. 13-9, p. 293

8. Carbon Dioxide Emissions Per Unit Energy of Different Fuels
286%
Coal-fired
electricity
Synthetic oil and gas produced from coal
150%
100%
Coal
92%
Oil sand
86%
Oil
58%
Natural gas
17%
Nuclear power
Fig , p. 294

9. Tradeoffs of Natural Gas
Conventional Natural Gas
Advantages
Disadvantages
Ample supplies (125 years)
Nonrenewable resource
High net energy yield
Releases CO2 when burned
Low cost (with huge subsidies)
Methane (a greenhouse gas) can leak from pipelines
Less air pollution than other fossil fuels
Difficult to transfer from one country
to another
Lower CO2 emissions than
other fossil fuels
Shipped across ocean as highly
explosive LNG
Moderate environmental impact
Sometimes burned off and
wasted at wells because of low
price
Low land use
Easily transported by pipeline
Requires pipelines
Good fuel for fuel cells and gas turbines
Fig , p. 296

10. Increasing heat and carbon content Increasing moisture content
Coal
Increasing heat and carbon content
Increasing moisture content
Peat
(not a coal)
Lignite
(brown coal)
Bituminous Coal
(soft coal)
Anthracite
(hard coal)
Heat
Heat
Heat
Pressure
Pressure
Pressure
Partially decayed
plant matter in swamps
and bogs; low heat
content
Low heat content;
low sulfur content;
limited supplies in
most areas
Extensively used
as a fuel because
of its high heat content
and large supplies;
normally has a
high sulfur content
Highly desirable fuel
because of its high
heat content and
low sulfur content;
supplies are limited
in most areas
Fig , p. 296

11. Tradeoffs of Coal Fig. 13-15, p. 297 Trade-Offs Advantages
Disadvantages
Ample supplies
(225–900 years)
Very high environmental impact
Severe land disturbance, air
pollution, and water pollution
High net energy yield
Low cost (with
huge subsidies)
High land use (including mining)
Mining and combustion
technology well-developed
Severe threat to human health
High CO2 emissions when burned
Air pollution can be reduced with improved
technology (but adds
to cost)
Releases radioactive particles and
mercury into air
Fig , p. 297

12. Tradeoffs of Nuclear Power
Conventional Nuclear Fuel Cycle
Advantages
Disadvantages
Large fuel supply
High cost (even with large subsidies)
Low environmental
impact (without accidents)
Low net energy yield
High environmental impact (with major accidents)
Emits 1/6 as much CO2 as coal
Moderate land disruption and water pollution
(without accidents)
Catastrophic accidents can happen (Chernobyl)
No widely acceptable solution for
long-term storage of radioactive
wastes and decommissioning worn-out plants
Moderate land use
Low risk of accidents because
of multiple safety systems (except
in 35 poorly designed and run
reactors in former Soviet Union
and Eastern Europe)
Subject to terrorist attacks
Spreads knowledge and technology for building nuclear weapons
Fig , p. 301

13. Chernobyl fallout – April 26, 1986

14. Improving Energy Efficiency
Big four energy-wasting devices
Incandescent light bulb – wastes 95% of its energy input
Nuclear power plants – 86% wasted
Internal combustion engine (e.g., car) – 75-80% wasted
Coal-burning power plants – 67% wasted

15. Saving Energy: Cars
Fuel-efficient cars account for <1% of all car sales in U.S.
Relatively low cost of fuel
Preference of SUVs and trucks
Government’s failure to increase fuel economy standards

16. Hybrid Gas-Electric Car
Regulator
Fuel Tank
Trans- mission
Battery bank
Combustion
engine
Electric motor
Fuel
Electricity
Fig , p. 309

17. Hydrogen Fuel-Cell Car
Universal docking connection
Connects the chassis with the
Drive-by-wire system in the body
Body attachments
Mechanical locks
that secure the
body to the chassis
Rear crush zone
absorbs crash energy
Fuel-cell stack
Converts hydrogen
fuel into electricity
Air system
management
Drive-by-wire
system controls
Cabin heating unit
Side mounted radiators
Release heat generated
by the fuel cell, vehicle
electronics, and wheel
motors
Front crush zone
Absorbs crash energy
Hydrogen
fuel tanks
© 2006 Brooks/Cole - Thomson
Electric wheel motors
Provide four-wheel drive
Have built-in brakes
Fig a, p. 310

18. Hydrogen Fuel-Cell Car
Fig b, p. 310

19. What is E-85?
Flex-fuel vehicles can run on gas or any ethanol-gas mixture
Currently produced by Ford, Chrysler and GM
E-85
85% ethanol / 15% gasoline
Florida only has 2 stations and
neither are accessible to the
public

20. Other Alternative Fuels
Biodiesel
P-series
Compare different fuels
Find fueling stations
More information

21. Number of E85 stations

22. Any Questions?
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