GEOG 102 – Population, Resources, and the Environment
Professor: Dr. Jean-Paul Rodrigue
Topic 7 – Energy Resources
A – Energy
B – Conventional Energy Resources
C – Alternative Energy Resources
A
Energy
■ 1. Sources of Energy
• What are the major sources of energy?
• How our usage of energy has changed in time?
■ 2. Energy Use
• To what purposes energy is used for?
■ 3. Challenges
• What major energy challenges are we facing?
1
Sources of Energy
■ Nature
• Energy is movement or the possibility of creating movement:
• Exists as potential (stored) and kinetic (used) forms.
• Conversion of potential to kinetic.
• Movement states:
• Ordered (mechanical energy) or disordered (thermal energy).
• Temperature can be perceived as a level of disordered energy.
• Major tendency is to move from order to disorder (entropy).
■ Importance
• Human activities are dependant on the usage of several forms
and sources of energy.
• Energy demands:
• Increased with economic development.
• The world’s power consumption is about 12 trillion watts a year, with 85%
of it from fossil fuels.
1
Sources of Energy
Chemical
Non-Renewable
• Fossil fuels (Combustion)
Nuclear
• Uranium (Fission of atoms)
Energy
Chemical
• Muscular (Oxidization)
Nuclear
• Geothermal (Conversion)
• Fusion (Fusion of hydrogen)
Renewable
Gravity
• Tidal, hydraulic (Kinetic)
Indirect Solar
• Biomass (Photosynthesis)
• Wind (Pressure differences)
Direct Solar
• Photovoltaic cell (Conversion)
1
Chemical Energy Content of some Fuels (in MJ/kg)
Wood
Coal
Crude Oil
Kerosene
Ethanol
Methanol
Methane
Natural Gas
Gasoline
Hydrogen
0
20
40
60
80
100
120
140
1
Sources of Energy
■ Energy transition
• Shift in the sources of energy that satisfy the needs of an
economy / society.
• Linked with economic and technological development.
• Linked with availability and/or remaining energy sources.
• From low efficiency to high efficiency.
• From solids, to liquids and then gazes:
• Wood, Coal.
• Oil.
• Natural gas and hydrogen.
1
Evolution of Energy Sources
Mid 21st
Century
Animal
Biomass
Coal
Oil
Natural Gas
Nuclear
Hydrogen
Late 20th
Century
Early 20th
Century
Mid 19th
Century
15th Century
0%
20%
40%
60%
80%
100%
1
Global Energy Systems Transition, (% of market)
100
Wood
Coal
80
Gases
Solids
60
Hydrogen
40
Liquids
20
Oil
Natural Gas
0
1850
1900
1950
2000
2050
2100
2150
8000
7000
Natural Gas
Oil
Coal
6000
5000
4000
3000
2000
1000
20
01
19
98
19
95
19
92
19
89
19
86
19
83
19
80
19
77
19
74
19
71
19
68
19
65
19
62
19
59
19
56
19
53
0
19
50
1
World Fossil Fuel Consumption per Source, 19502002 (in million of tons of equivalent oil)
Total World Electricity Generation by Type of Fuel,
2002
7%
2%
16%
40%
16%
19%
Coal
Natural Gas
Nuclear
Hydro
Oil
Other
1
Energy Sources
■ Hubbert’s peak
• Geologist who predicted in the 1950s that oil production in the
United States would peak in the early 1970s:
• US oil production peaked in 1973.
•
•
•
•
Assumption of finite resource.
Production starts at zero.
Production then rises to a peak which can never be surpassed.
Peak estimated around 2004-2008:
• One estimate places it symbolically at Thanksgiving 2005.
• Once the peak has been passed, production declines until the
resource is depleted.
30
25
Billions of barrels
1
World Annual Oil Production (1900-2004) and
Estimated Resources (1900-2100)
Actual
Predicted
20
15
10
5
0
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100
2
Energy Use
■ Energy and work
Energy
• Energy provides work.
• Technology enables to use energy
more efficiently and for more
purposes.
• Traditionally, most of the work was
performed by people:
Work
Modification
Appropriation &
Processing
Transfer
• Many efforts have been done to
alleviate work.
• Creating more work performed by
machines and the usage of even
more energy.
2
Energy Use
Modification of the
Environment
Appropriation and
Processing
Transfer
■Making space suitable for
human activities.
■Clearing land for
agriculture.
■Modifying the
hydrography (irrigation).
■Establishing distribution
infrastructures (roads).
■Constructing and
conditioning (temperature
and light) enclosed
structures.
■Extraction of resources
(agricultural products and
raw materials).
■Modifying resources
(manufacturing).
■Disposal of wastes
(Piling, decontaminating
and burning).
■Movements of freight,
people and information.
■Attenuate the spatial
inequities in the location of
resources by overcoming
distance.
■Growing share of
transportation in the total
energy spent
3
Challenges
■ Energy Supply
• Providing supply to sustain growth and requirements.
• A modern society depends on a stable and continuous flow of
energy.
■ Energy Demand
• Generate more efficient devices:
• Transportation.
• Industrial processes.
• Appliances.
■ Environment
• Provide environmentally safe sources of energy.
• Going through the energy transition (from solid to gazes).
B
Conventional Energy Resources
■ What sources of energy have filled our requirements so
far?
■ 1. Coal
■ 2. Petroleum
■ 3. Natural Gas
■ 4. Hydropower
■ 5. Nuclear Power
1
Coal
■ Nature
• Formed from decayed swamp plant matter that cannot
decompose in the low-oxygen underwater environment.
• Coal was the major fuel of the early Industrial Revolution.
• High correlation between the location of coal resources and early
industrial centers:
•
•
•
•
•
The Midlands of Britain.
Parts of Wales.
Pennsylvania.
Silesia (Poland).
German Ruhr Valley.
• Three grades of coal.
1
Coal
■ Anthracite
Carbon content (%)
0
20
40
60
80
100
Energy
Carbon
Lignite
• Highest grade; over 85% carbon.
• Most efficient to burn.
• Lowest sulfur content; the least
polluting.
• The most exploited and most
rapidly depleted.
■ Bituminous
• Medium grade coal, about 50-75%
carbon content.
• Higher sulfur content and is less
fuel-efficient.
• Most abundant coal in the USA.
Bituminous
Anthracite
■ Lignite
0
500
1000
1500
2000
Burned energy (1,000 calories per kg)
• Lowest grade of coal, with about
40% carbon content.
• Low energy content.
• Most sulfurous and most polluting.
1
Global Coal Production, 2002 (M short tons)
760
Production
Not significant
World Coal Production by Type, 2000
7%
18%
Anthracite
Bituminous
Lignite
75%
1
Coal
■ Coal use
• Thermal coal (about 90% use):
• Used mainly in power stations to produce high pressure steam, which
then drives turbines to generate electricity.
• Also used to fire cement and lime kilns.
• Until the middle of the 20th Century used in steam engines.
• Metallurgical coal:
• Used as a source of carbon, for converting a metal ore to metal.
• Removing the oxygen in the ore by forcing it to combine with the carbon in
the coal to form CO2.
• Coking coal:
• Specific type of metallurgical coal.
• Used for making iron in blast furnaces.
• New redevelopment of the coal industry:
• In view of rising energy prices.
Coal Consumption, 1950-1998 (in millions of tons)
4000
3500
3000
Rest of the world
India
U.S.
China
2500
2000
1500
1000
500
0
19
50
19
52
19
54
19
56
19
58
19
60
19
62
19
64
19
66
19
68
19
70
19
72
19
74
19
76
19
78
19
80
19
82
19
84
19
86
19
88
19
90
19
92
19
94
19
96
19
98
1
1
Coal as % of Energy Use and Electricity Generation,
1998
United States
Electricity (%)
Energy (%)
Germany
Denmark
Ukraine
South Korea
Australia
India
Poland
China
0
10
20
30
40
50
60
70
80
90
100
2
Petroleum
■ Nature
• Formation of oil deposits:
• Decay under pressure of billions of microscopic plants in sedimentary
rocks.
• “Oil window”; 7,000 to 15,000 feet.
• Created over the last 600 million years.
• Exploration of new sources of petroleum:
• Related to the geologic history of an area.
• Located in sedimentary basins.
• About 90% of all petroleum resources have been discovered.
• Production vs. consumption:
• Geographical differences.
• Contributed to the political problems linked with oil supply.
2
Petroleum
■ Use
• Transportation:
•
•
•
•
The share of transportation has increased in the total oil consumption.
Accounts for more the 55% of the oil used.
In the US, this share is 70%.
Limited possibility at substitution.
• Other uses (30%):
• Lubricant.
• Plastics.
• Fertilizers.
• Choice of an energy source:
• Depend on a number of utility factors.
• Favoring the usage of fossil fuels, notably petroleum.
Petroleum Production and Consumption, 2002 (M
barrels per day)
9,900
Production
Consumption
Not Included
2000
20.1
57.7
5.9
16.3
Industry
Transport
Non-energy
Other sectors
1973
26.2
0%
42.2
20%
40%
6.4
60%
25.2
80%
100%
2
Petroleum
■ Why an oil dependency?
• Favor the usage of petroleum as the main source of energy for
transport activities.
• The utility factors were so convenient that a dependency on
petroleum was created.
■ Taxes
• Should oil be taxed?
• Should the development of alternative sources of energy be
accelerated or enforced?
2
Factors of Oil Dependency
Occurrence
Localized large deposits (decades)
Transportability
Liquid that can be easily transported. Economies of scale
Energy content
High mass / energy released ratio
Reliability
Continuous supply; geopolitically unstable
Storability
Easily stored
Flexibility
Many uses (petrochemical industry; plastics)
Safety
Relatively safe; some risks (transport)
Environment
Little wastes, CO2 emissions
Price
Relatively low costs
Costs of Finding Oil, 1977-2000
18
70
Difference between oil costs and finding costs
16
60
Worldwide oil finding costs
14
10
40
8
30
6
20
4
10
2
19
99
19
97
19
95
19
93
19
91
19
89
19
87
19
85
19
83
19
81
0
19
79
0
Difference
50
12
19
77
Costs of finding oil ($ per barrel)
2
2
Petroleum
■ Oil reserves
• The world oil production is currently running at capacity:
• Limited opportunities to expand production.
• 20% of the world’s outcome comes from 14 fields.
• Ghawar:
•
•
•
•
•
The world’s largest oil field; been on production since 1951.
Produces approximately 4.5 million barrels of oil per day.
55 to 60% of Saudi Arabia’s production.
Expected to decline sharply (use of water injection).
Could be 90% depleted.
• OPEC countries may have overstated its reserves:
•
•
•
•
Production quotas are based upon estimated reserves.
The larger the reserves, the more an OPEC country can export.
In the 1980s, most OPEC reserves doubled “on paper”.
Extraction continues while reserves remain the same(?).
2
Major Crude Oil Reserves, 2003
0
Saudi Arabia
Iraq
Iran
Kuwait
United Arab Emirates
Russia
Venezuela
Nigeria
Libya
China
United States
Mexico
Algeria
Norway
Angola
50
100
Billions of barrels
150
200
250
300
2
Global Oil Reserves, 2003
Barrels (2003)
Less than 5 billion
5 to 25 billions
25 to 50 billions
50 to 150 billions
70%
More than 150 billions
Reserves
Production
60%
50%
40%
30%
20%
10%
0%
North Central & S. Western
America
America
Europe
Eastern Middle East
Europe &
FSU
Africa
Asia &
Oceania
2
Demand for Refined Petroleum Products by Sector in
the United States, 1960-2000 (in Quadrillion BTUs)
40
35
30
25
20
15
10
5
0
1960
1965
Transportation
1970
Industrial
1975
1980
1985
1990
Residential and commercial
1995
Electric utilities
2000
8
60
Production
Consumption
Imports
Real oil price
6
50
40
5
4
30
3
20
2
10
1
00
20
97
19
94
19
91
19
88
19
85
19
82
19
79
19
76
19
73
19
70
19
67
19
64
19
61
19
58
19
55
19
52
0
19
19
49
0
Dollars per barrel
7
Millions of barrels
2
Petroleum Production, Consumption and Imports,
United States, 1949-2002
2
Major Oil Flows and Chokepoints, 2003
Bosphorus
3.0 Hormuz
Suez
0.4
Panama
3.8
3.3
Bab el-Mandab
Million barrels
per day
15.3
Malacca
11.0
15
10
3
1
2
Petroleum
■ A perfect storm?
•
•
•
•
Booming oil prices after 2004.
Prior oil spikes linked with short lived geopolitical events.
The situation has changed at the beginning of the 21st century.
A production issue:
• Petroleum extraction appears to be running at capacity.
• Demand, especially new consumers (China), is going up.
• A distribution issue:
• Limited additional tanker and pipeline capacity.
• A refining issue:
• Limited additional refining capacity.
• No refineries were built in the US since 1974.
3
Natural Gas
■ Nature
• Formation:
• Thermogenic: converted organic material into natural gas due to high
pressure.
• Deeper window than oil.
• Biogenic: transformation by microorganisms.
• Composition:
• Composed primarily of methane and other light hydrocarbons.
• Mixture of 50 to 90% by volume of methane, propane and butane.
• “Dry” and “wet” (methane content); “sweet” and “sour” (sulfur content).
• Usually found in association with oil:
• Formation of oil is likely to have natural gas as a by-product.
• Often a layer over the petroleum.
3
Natural Gas
■ Reserves
• Substantial reserves likely to satisfy energy needs for the next
100 years.
• High level of concentration:
• 45% of the world’s reserves are in Russia and Iran.
• Regional concentration of gas resources is more diverse:
• As opposed to oil.
• Only 36% of the reserves are in the Middle East.
3
Natural Gas
■ Use
Mostly used for energy generation.
Previously, it was often wasted - burned off.
It is now more frequently conserved and used.
Considered the cleanest fossil fuel to use.
The major problem is transporting natural gas, which requires
pipelines.
• Gas turbine technology enables to use natural gas to produce
electricity more cheaply than using coal.
•
•
•
•
•
■ Liquefied natural gas (LNG)
• Liquid form of natural gas; easier to transport.
• Cryogenic process (-256oF): gas loses 610 times its volume.
• Value chain:
•
•
•
•
Extraction
Liquefaction
Shipping
Storage and re-gasification
3
Global Natural Gas Reserves, 2003
Trillion Cubic Feet (2003)
Less than 10 trillion
10 to 50 trillion
50 to 100 trillion
100 to 200 trillion
More than 200 trillion
40%
Reserves
Production
35%
30%
25%
20%
15%
10%
5%
0%
North Central & S. Western
America
America
Europe
Eastern Middle East
Europe &
FSU
Africa
Asia &
Oceania
4
Hydropower
■ Nature
• Generation of electricity using the flow of water as the energy
source.
• Gravity as source.
• Requires a large reservoir of water.
• Considered cleaner, less polluting than fossil fuels.
■ Tidal power
• Take advantage of the variations between high and low tides.
4
Hydropower
Sun
Evaporation
Water
Precipitation
Sufficient and regular
precipitations
Rivers
Flow
Reservoirs
Suitable local site
Accumulation
Dam
Gravity
Turbine
Electricity
Power loss due to
distance
4
Hydropower
■ Controversy
• Require the development of vast amounts of infrastructures:
•
•
•
•
Dams.
Reservoirs.
Power plants and power lines.
Very expensive and consume financial resources or aid resources that
could be utilized for other things.
• Environmental problems:
• The dams themselves often alter the environment in the areas where they
are located.
• Changing the nature of rivers, creating lakes that fill former valleys and
canyons, etc.
800,000
Brazil
Canada
United States
World
700,000
600,000
500,000
400,000
300,000
200,000
100,000
19
98
19
95
19
92
19
89
19
86
19
83
19
80
19
77
19
74
19
71
19
68
19
65
19
62
19
59
19
56
19
53
0
19
50
4
World Hydroelectric Generating Capacity, 1950-98
(in megawatts)
5
Nuclear Power
■ Nature
• Fission of uranium to produce energy.
• The fission of 1 kg (2.2 lb) of uranium-235 releases 18.7 million
kilowatt-hours as heat.
• Heat is used to boil water and activate steam turbines.
• Uranium is fairly abundant.
• Requires massive amounts of water for cooling the reactor.
5
Nuclear Power
Production and storage
Uranium
Suitable site (NIMBY)
Reactor
Fission
Waste storage and
disposal
Steam
Turbine
Electricity
Large quantities
Water
Nuclear Power Plants, 1960-2002 (in gigawatts)
400
35
350
30
300
250
20
200
15
150
10
100
50
5
0
0
Capacity
Decommissioned
Construction
Construction
25
19
60
19
62
19
64
19
66
19
68
19
70
19
72
19
74
19
76
19
78
19
80
19
82
19
84
19
86
19
88
19
90
19
92
19
94
19
96
19
98
20
00
20
02
Capacity
5
5
Nuclear Power
■ Nuclear power plants
• 430 operating nuclear power plants (civilian) worldwide.
• Very few new plants coming on line:
• Public resistance (NIMBY syndrome).
• High costs.
• Nuclear waste disposal.
• 30 countries generate nuclear electricity:
• About 17% of all electricity generated worldwide.
• United States:
•
•
•
•
109 licensed nuclear power plants; about 20% of the electricity.
Licenses are usually given for a 40 year period.
Many US plants will be coming up for license extensions by 2006.
No new nuclear power plant built since 1979 (Three Mile Island incident).
• China:
• Plans to had 2 new nuclear reactor per year until 2020.
5
Global Nuclear Energy Generation, 2003
Billion Kilowatthours (2003)
Less than 25.00
25 to 100
100 to 200
200 to 500
More than 500
5
Nuclear Power
■ Nuclear waste disposal
• Problem of nuclear waste disposal; radioactivity.
• Low level wastes:
• Material used to handle the highly radioactive parts of nuclear reactors .
• Water pipes and radiation suits.
• Lose their radioactivity after 10 to 50 years.
• High level wastes:
• Includes uranium, plutonium, and other highly radioactive elements made
during fission.
• Nuclear wastes have a half-life about of 10,000 to 20,000 years.
• Requirements of long-term storage in a geologically stable area.
• Long Term Geological Storage site at Yucca Mountain.
5
Nuclear Power
■ Reliance
• Some countries have progressed much further in their use of
nuclear power than the US.
• High reliance:
• France, Sweden, Belgium, and Russia have a high reliance on nuclear
energy.
• France has done this so as not to rely on foreign oil sources.
• It generates 75% of its electricity using nuclear energy.
• The need to import most fossil fuels provides an extra impetus to turn to
nuclear energy.
• Phasing out:
• Nuclear energy perceived as financially unsound and risky.
• No new nuclear power plant built in Europe since Chernobyl (1986).
• The German parliament decided in 2001 to phase out nuclear energy
altogether.
5
Nuclear Power as % of Electricity Generation, 1998
0
France
Belgium
Sweden
Slovakia
South Korea
Hungary
Switzerland
Finland
Japan
Germany
Spain
Britain
Czech Republic
United States
Canada
10
20
30
40
50
60
70
80
5
Nuclear Power
Pro Nuclear Side
Con Nuclear Side
■Reduced fossil fuels dependence ■Fear of accidents and sabotage
■Enhanced energy security
(terrorism)
■Environmental benefits
■Waste disposal
■High construction and
decommission costs
C
Alternative Energy Resources
■ What new sources of energy are likely to satisfy future
demands?
■ 1. Context
■ 2. Hydrogen and Fuel Cells
■ 3. Solar Energy
■ 4. Wind Energy
■ 5. Geothermal Energy
■ 6. Biomass Fuels
1
Context
■ Emergence
• Received increasing attention since the first oil crisis in 1973:
• Attention varies with fluctuations in the price of oil.
• Several alternate sources need further research before they can
become truly viable alternatives.
• Moving from carbon-based sources to non-carbon based:
• Europe: 22% of its energy to come from renewable sources by 2010.
■ Unsustainability of fossil fuels
• The resource itself is finite.
• Use contributes to the global warming problem.
• Some 35% of the carbon emissions in the USA is attributable to
electric power generation.
• Employing substitutes for fossil fuels in that area alone would
help alleviate our greenhouse gas problem.
1
Context
CO2 Emissions from Energy
Usage, United States 2001
10%
7%
54%
29%
Residential
Industrial
Commercial
Transportation
■ Fuel use efficiency
• Not an alternate energy source.
• Can have a great impact on
conservation.
• After 1973, many industries were
motivated to achieve greater
efficiency of energy use.
• Many appliances (including
home air conditioners) were
made more energy efficient.
• The USA continually ranks
behind Europe and Japan in
energy efficiency.
1
Average Gasoline Consumption for New Vehicles,
United States, 1972-2004 (in miles per gallon)
30
28
26
24
22
20
18
16
Cars
Light Trucks
Average
14
12
10
72
19
74
19
76
19
78
19
80
19
82
19
84
19
86
19
88
19
90
19
92
19
94
19
96
19
98
19
00
20
02
20
04
20
18000
16000
Trucks
Cars
14000
12000
10000
8000
6000
4000
2000
20
03
20
01
19
99
19
97
19
95
19
93
19
91
19
89
19
87
19
85
19
83
19
81
19
79
19
77
0
19
75
1
Light-Duty Vehicles Sales in the United States, 19752004 (in 1,000s)
1
Change in Average Vehicle Characteristics, 19812003 (in %)
Acceleration
Horsepower
Weight
Fuel Economy
0
20
40
60
80
100
1
Typical Energy Use for a Car
8%
12%
6%
13%
32%
29%
Momentum
Exhaust
Cylinder cooling
Engine friction
Transmission and axles
Braking
1
Context
■ Nuclear fusion
• Currently researched but without much success.
• It offers unlimited potential.
• Not realistically going to be a viable source of energy in the
foreseeable future.
2
Hydrogen and Fuel Cells
■ Hydrogen
Hydrogen
Oxygen
Fuel
Fuel Cell
Catalytic conversion
Water
Electricity
• Considered to be the cleanest fuel.
• Compose 90% of the matter of the
universe.
• Non polluting (emits only water and
heat).
• Highest level of energy content.
■ Fuel cells
• Convert fuel energy (such as hydrogen)
to electric energy.
• No combustion is involved.
• Composed of an anode and a cathode.
• Fuel is supplied to the anode.
• Oxygen is supplied to the cathode.
• Electrons are stripped from a reaction
at the anode and attracted to form
another reaction at the cathode.
2
Hydrogen and Fuel Cells
■ Fuel cell cars
•
•
•
•
Most likely replacement for the internal combustion engine.
Efficiency levels are between 55% and 65%.
May be introduced by 2004 (working prototypes).
Mass produced by 2010.
■ Storage issues
• Hydrogen is a highly combustive gas.
• Find a way to safely store it, especially in a vehicle.
■ Delivery issues
•
•
•
•
Distribution from producers to consumers.
Production and storage facilities.
Structures and methods for transporting hydrogen.
Fueling stations for hydrogen-powered applications.
2
Hydrogen and Fuel Cells
■ Hydrogen production
Fossil Fuels
Water
Biomass
Steam
Reforming
Electrolysis
Pyrolysis
• Not naturally occurring.
• Producing sufficient quantities to
satisfy the demand.
• Extraction from fossil fuels:
• From natural gas.
• Steam reforming.
• Electrolysis of water:
• Electricity from fossil fuels not a
environmentally sound alternative.
• Electricity from solar or wind energy
is a better alternative.
• Pyrolysis of the biomass:
• Decomposing by heat in an oxygenreduced atmosphere.
3
Solar Energy
■ Definition
• Radiant energy emitted by the sun (photons emitted by nuclear
fusion).
• Conversion of solar energy into electricity.
■ Photovoltaic systems
■ Solar thermal systems
3
Solar Energy
Level of insolation
(latitude & precipitation)
Solar cells
Sun
Mirrors
Concentration
Water
Evaporation
Conversion
Steam
Turbine
Electricity
3
Global Solar Energy Potential
3
Solar Energy
■ Photovoltaic systems
• Semiconductors to convert solar radiation into electricity.
• Better suited for limited uses such as pumping water that do not
require large amounts of electricity.
• Costs have declined substantially:
• 5 cents per kilowatt-hour.
• Compared to about 3 cents for coal fired electrical power.
• Economies of scale could then be realized in production of the
necessary equipment.
• Japan generates about 50% of the world’s solar energy.
450
90
Shipments
Prices
80
0
0
20
01
10
19
99
50
19
97
20
19
95
100
19
93
30
19
91
150
19
89
40
19
87
200
19
85
50
19
83
250
19
81
60
19
79
300
19
77
70
19
75
350
Dollars per watt
400
Megawatts
3
World Photovoltaic Annual Shipments and Price
1975-2001
3
Photovoltaic Production by Country or Region, 19942001
400
350
300
250
Rest of World
Europe
Japan
U.S.
200
150
100
50
0
1994
1995
1996
1997
1998
1999
2000
2001
3
Solar Energy
■ Solar thermal systems
• Employ parabolic reflectors to focus solar radiation onto water
pipes, generating steam that then power turbines.
• Costing about 5-10 cents per Kwh.
• Require ample, direct, bright sunlight.
• Drawback of the solar thermal systems is their dependence on
direct sunshine, unlike the photovoltaic cells.
■ Limitations
• Inability to utilize solar energy effectively.
• There is currently only about a 15% conversion rate of solar
energy into electricity.
• Low concentration of the resource.
• Need a very decentralized infrastructure to capture the resource.
4
Wind Power
Sun
Heat
Air
Pressure
differences
Wind
Major prevalent wind
systems
Wind mills
Site suitability
Fans
Turbine
Electricity
4
Wind Power
■ Potential use
• Growing efficiency of wind turbines.
• 75% of the world’s usage is in Western Europe:
• Provided electricity to some 28 million Europeans in 2002.
• Germany, Denmark (18%) and the Netherlands.
• New windfarms are located at sea along the coast:
• The wind blows harder and more steadily.
• Does not consume valuable land.
• No protests against wind parks marring the landscape.
• United States:
• The USA could generate 25% of its energy needs from wind power by
installing wind farms on just 1.5% of the land.
• North Dakota, Kansas, and Texas have enough harnessable wind energy
to meet electricity needs for the whole country.
4
Wind Power
• Farms are a good place to implement wind mills:
• A quarter of a acre can earn about $2,000 a year in royalties from wind
electricity generation.
• That same quarter of an acre can only generate $100 worth or corn.
• Farmland could simultaneously be used for agriculture and energy
generation.
• Wind energy could be used to produce hydrogen.
■ Limitations
• Extensive infrastructure and land requirements.
• 1980: 40 cents per kwh.
• 2001: 3-4 cents per kwh.
• Less reliable than other sources of energy.
• Inexhaustible energy source that can supply both electricity and
fuel.
35,000
30,000
Capacity
Addition
25,000
20,000
15,000
10,000
5,000
20
02
20
00
19
98
19
96
19
94
19
92
19
90
19
88
19
86
19
84
19
82
0
19
80
4
World Wind Energy Generating Capacity, 1980-2002
(in megawatts)
5
Geothermal Energy
■ Hydrogeothermal
• 2-4 miles below the earth's surface, rock temperature well above
boiling point.
• Closely associated with tectonic activity.
• Fracturing the rocks, introducing cold water, and recovering the
resulting hot water or steam which could power turbines and
produce electricity.
• Areas where the natural heat of the earth’s interior is much
closer to the surface and can be more readily tapped.
5
Geothermal Energy
Winter
■ Geothermal heat pumps
• Promising alternative to
heating/cooling systems.
• Ground below the frost line (about 5
feet) is kept around 55oF year-round.
• During winter:
House
5 feet
55o F
Summer
• The ground is warmer than the
outside.
• Heat can be pumped from the
ground to the house.
• During summer:
House
• The ground is cooler than the
outside.
• Heat can be pumped from the house
to the ground.
5 feet
55o F
World Geothermal Power, 1950-2000 (in megawatts)
9000
8000
7000
6000
5000
4000
3000
2000
1000
19
98
19
95
19
92
19
89
19
86
19
83
19
80
19
77
19
74
19
71
19
68
19
65
19
62
19
59
19
56
19
53
0
19
50
5
6
Biomass
■ Nature
• Biomass energy involves the growing of crops for fuel rather than
for food.
• Crops can be burned directly to release heat or be converted to
useable fuels such methane, ethanol, or hydrogen.
• Has been around for many millennia.
• Not been used as a large-scale energy source:
• 14% of all energy used comes from biomass fuels.
• 65% of all wood harvested is burned as a fuel.
• 2.4 billion people rely on primitive biomass for cooking and heating.
• Important only in developing countries.
• Asia and Africa: 75% of wood fuels use.
• US: 5% comes from biomass sources.
6
Energy Consumption, Solid biomass (includes
fuelwood)
Kenya
1990
2001
Tanzania
South Africa
Thailand
Congo, Dem Rep
Ethiopia
Viet Nam
Pakistan
Brazil
Indonesia
United States
Nigeria
India
China
0
50,000
100,000
150,000
Thousand metric tons oil equivalent
200,000
250,000
6
Biomass
■ Biofuels
• Fuel derived from organic matter.
• Development of biomass conversion technologies:
• Alcohols and methane the most useful.
• Plant materials like starch or sugar from cane.
• Waste materials like plant stalks composed of cellulose.
■ Potential and drawbacks
• Some 20% of our energy needs could be met by biofuels without
seriously compromising food supplies.
• Competing with other agricultural products for land.
6
Biomass
• Could contribute to reducing carbon emissions while providing a
cheap source of renewable energy:
• Burning biofuels does create carbon emissions.
• The burned biomass is that which removed carbon from the atmosphere
through photosynthesis.
• Does not represent a real increase in atmospheric carbon.
• Genetic engineering:
• Create plants that more efficiently capture solar energy.
• Increasing leaf size and altering leaf orientation with regard to the sun.
• Conversion technology research:
• Seeking to enhance the efficiency rate of converting biomass into energy.
• From the 20-25% range up to 35-45% range.
• Would render it more cost-competitive with traditional fuels.