News
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http://www.boston.com/news/world/australia/articles/2009/12/02/winds_
drive_icebergs_away_from_new_zealand/
http://www.boston.com/business/articles/2009/12/02/cape_wind_national
_grid_enter_pact/
http://www.boston.com/bostonglobe/editorial_opinion/editorials/articles/
2009/12/02/cape_wind_obstructionism___a_bad_legacy_for_kirk/
http://www.boston.com/bostonglobe/editorial_opinion/oped/articles/2009
/12/02/its_not_waste_its_energy/
http://www.boston.com/news/local/articles/2009/12/03/invasion_of_wint
er_moths_has_scientists_residents_looking_for_answers/
http://www.boston.com/news/world/europe/articles/2009/12/03/as_clim
ate_summit_nears_denmark_wearing_its_green_on_its_sleeve/
What is the most common source of
energy in the United States?
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A) Oil
B) Natural Gas
C) Coal
D) Nuclear
E) Hydroelectric
What is the most common source of
energy in the World?
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A) Oil
B) Natural Gas
C) Coal
D) Nuclear
E) Hydroelectric
Energy Sources
World:
United States:
Nonrenewable 82%
Nonrenewable 93%
Nuclear Power 6%
Nuclear Power 8%
Natural Gas 21%
Natural gas 23%
Coal 22%
Coal 23%
Oil 33%
Oil 39%
Renewable Energy 18%
Renewable Energy 8%
Biomass 11%
Biomass 4%
Hydropower Geothermal,
Hydropower Geothermal,
solar, wind 7%
solar, wind 3%
Powering the Planet
Nathan S. Lewis, California Institute of Technology
Power Units: The Terawatt Challenge
Power
1
1W
103
1 kW
106
1 MW
109
1 GW
1012
1 TW
Energy
1J=
1 W for 1 s
Global Energy Consumption, 2001
5
4.66
4
2.89
3
2.98
TW
2
1.24
1
0.285
0.92
0.286
0
Oil
Gas
Coal
Total: 13.2 TW
Hydro
Biomass
Renew
Nuclear
U.S.: 3.2 TW (96 Quads)
Global Energy Sources
Image courtesy of Ren21 under public domain
Today: Production Cost of Electricity
(in the U.S. in 2002)
25-50 ¢
25
20
15
Cost
10
5
1-4
¢
2.3-5.0 ¢ 6-8
¢
5-7
¢
6-7
¢
Wind
Nuclear
0
Coal
Gas
Oil
Solar
Energy Costs
$0.05/kW-hr
14
12
8
6
Brazil
$/GJ
Europe
10
4
2
0
Coal
Oil
Biomass
Elect
www.undp.org/seed/eap/activities/wea
How long will it be before all the
petroleum on earth is used up?
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A) 0-5 years
B) 5-20 years
C) 20-40 years
D) 40-100 years
E) more than 100 years
Petroleum
Trade-Offs
Conventional Oil
Image removed due to copyright restrictions.
US Reserves: 10-48
years
Global: 42-93 years
Advantages
Disadvantages
Ample supply for 42-93
years
Need to find substitute
within 50 years
Low cost (with huge
subsidies
Artificially low price
encourages waste and
discourages search for
alternatives
High net energy yield
Air pollution when burned
Easily transported within
and between countries
Releases CO2 when
burned
Low land use
Moderate water pollution
Technology is well
developed
Efficient distribution
system
Figure by UMB OpenCourseWare
Oil Resources
Figure by UMB OpenCourseWare
36 Estimates of the Time of the Peak of World Oil Production (There are More)
EIA’s short answer to “When will oil production peak?” is “Not soon, but within the
present century.” The most probable scenarios put the peak at about mid century.
Fossil Fuel Reserves-to-Production (R/P) Ratios at End 2004
YEARS
600
500
400
300
200
100
0
OECD
FSU
Emerging Market Economies,
excluding FSU
World
 The world’s R/P ratio for coal is almost five times that for oil and almost three times that for gas.
Coal’s dominance in R/P ratio is particularly pronounced in the OECD and the FSU.
 R/P ratios for oil and gas have been approximately constant or slightly increasing during the past 20
years. Both reserves and production have increased during this period. See next chart.
BP Statistical Review of World Energy 2005
Conclusions
•
•
Abundant, Inexpensive Resource Base of Fossil Fuels
Renewables will not play a large role in primary power generation
unless/until:
–technological/cost breakthroughs are achieved, or
–unpriced externalities are introduced (e.g., environmentally
-driven carbon taxes)
Projected World Energy Consumption in the Coming Century
1,286
Projections to 2025 are from the
Energy Information Administration,
International Energy Outlook, 2004.
World Primary Energy Consumption (Quads)
826
Projections for 2050 and 2100 are
based on a scenario from the
Intergovernmental Panel on Climate
Change (IPCC), an organization
jointly established in 1988 by the
World Meteorological Organization
and the United Nations Environment
Programme. The IPCC provides
comprehensive assessments of
information relevant to humaninduced climate change. The
scenario chosen is based on
“moderate” assumptions (Scenario
B2) for population and economic
growth and hence is neither overly
conservative nor overly aggressive.
Projected World Energy Consumption by Region
World Energy Consumption by Region (Quads)
World Regions
Overall, world energy consumption is predicted to increase faster than that of the U.S.
and other industrialized countries, because between 2000 and 2025 energy demand in the
developing countries nearly doubles.
Population Growth to
10 - 11 Billion People
in 2050
*Image removed due to copyright restrictions.
Per Capita GDP Growth
at 1.6% yr-1
Energy consumption per
Unit of GDP declines
at 1.0% yr -1
U.S. Energy Flow, 2003 (Quads)
Energy
Sources
Production
70.5
Consumption
98.2
Imports
31.0
Energy Consumption
Exports
4.0
Adjustments
0.7
 About 30% of primary energy is imported.
21
U.S. Energy Flow, 2003 (Quads)
 85% of primary energy is from fossil fuels; 8% is from nuclear; 6% is from renewables.
 Most imported energy is petroleum, which is used for transportation.
 The end-use sectors (residential, commercial, industrial, transportation) all use
comparable amounts of energy.
22
Alternative Energy Sources
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Name as many alternative energy sources as you
can think of…
What are the advantages and disadvantages of
each?
Resources
• http://www.youtube.com/watch?v=ztFDqcu8
oJ4
• http://web.mit.edu/newsoffice/2008/oxygen0731.html
Sources of Carbon-Free Power
• Nuclear (fission and fusion)
• 10 TW = 10,000 new 1 GW reactors
• i.e., a new reactor every other day for
the next 50 years
• 2.3 million tonnes proven reserves;
1 TW-hr requires 22 tonnes of U
• Hence at 10 TW provides 1 year of energy
• Terrestrial resource base provides 10 years of
energy
• Would need to mine U from seawater (700 x
terrestrial resource base; so needs 3000 Niagra
Falls or breeders)
• Carbon sequestration
• Renewables
Nuclear power
• 235U readily absorbs neutrons to become
236U
• 236U then decays into lighter fission
products
235U
+ neutron  fragments + 2.4 neutrons + 192.9 MeV
(remember 300K = 1/40 eV)
*Image removed due to copyright restrictions.
27
CO2 Burial: Saline Reservoirs
130 Gt total U.S. sequestration potential
Global emissions 6 Gt/yr in 2002 Test sequestration projects 2002-2004
Study Areas
• Near sources
(power plants,
refineries, coal
fields)
• Distribute only
H2 or electricity
• Must not leak
•At 2 Gt/yr
sequestration
rate, surface of
U.S. would rise
10 cm by 2100
One Formation
Studied
Two Formations
Studied
Power Plants (dot size proportional
to 1996 carbon emissions)
DOE Vision & Goal:
1 Gt storage by 2025, 4 Gt by 2050
What is the most promising form of
renewable energy?
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A) Wind
B) Solar
C) Geothermal
D) Biofuels
E) Tidal
Renewable Energy Consumption by Major Sources
Potential of Renewable Energy
• Hydroelectric
• Geothermal
• Ocean/Tides
• Wind
• Biomass
• Solar
Hydro-electric power
Image courtesy of U.S. Geological Survey
Gravity drives the whole process!
32
Hydroelectric Energy Potential
Globally
• Gross theoretical potential
4.6 TW
• Technically feasible potential 1.5 TW
• Economically feasible potential 0.9 TW
• Installed capacity in 1997
0.6 TW
• Production in 1997
0.3 TW
(can get to 80% capacity in some cases)
Source: WEA 2000
Three Gorges Dam
Yangtze River
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100 m high, 100 m thick
2.3 km long
22,000 MW
$32 Billion
10 Year payback
Image courtesy of roberthuffstutter, flikr under
Creative Common License
Geothermal Energy
*Image removed due to copyright restrictions.
1.3 GW capacity in 1985
Hydrothermal systems
Hot dry rock (igneous systems)
Normal geothermal heat (200 C at 10 km depth)
Geothermal Energy Potential
Geothermal Energy Potential
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Mean terrestrial geothermal flux at earth’s surface
Total continental geothermal energy potential
Oceanic geothermal energy potential
0.057 W/m2
11.6 TW
30 TW
Wells “run out of steam” in 5 years
Power from a good geothermal well (pair)
5 MW
Power from typical Saudi oil well
500 MW
Needs drilling technology breakthrough
(from exponential $/m to linear $/m) to become economical)
Wind Power
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http://www.capewind.org/
420 Megawatts of energy
75% of Cape and Islands
electricity needs
Equivalent to removing 162,000
cars
113 million gallons of oil
Birds, views, sealife, navigation,
noise
Image courtesy of EPA
Electric Potential of Wind
In 1999, U.S consumed
3.45 trillion kW-hr of
Electricity =
0.39 TW
Image courtesy of US Department of Energy
Global Potential of Terrestrial Wind
• Top-down:
Downward kinetic energy flux: 2 W/m2
Total land area: 1.5x1014 m2
Hence total available energy = 300 TW
Extract <10%, 30% of land, 30% generation efficiency:
2-4 TW electrical generation potential
• Bottom-Up:
Theoretical: 27% of earth’s land surface is class 3 (250-300
W/m2 at 50 m) or greater
If use entire area, electricity generation potential of 50 TW
Practical: 2 TW electrical generation potential (4% utilization
of ≥class 3 land area, IPCC 2001)
Off-shore potential is larger but must be close to grid to be
interesting; (no installation > 20 km offshore now)
Biomass Energy Potential
Global: Top Down
• Requires Large Areas Because Inefficient (0.3%)
• 3 TW requires ≈ 600 million hectares = 6x1012 m2
• 20 TW requires ≈ 4x1013 m2
• Total land area of earth: 1.3x1014 m2
• Hence requires 4/13 = 31% of total land area
Biomass Energy Potential
Global: Bottom Up
• Land with Crop Production Potential, 1990: 2.45x1013 m2
• Cultivated Land, 1990: 0.897 x1013 m2
• Additional Land needed to support 9 billion people in 2050:
0.416x1013 m2
•Perhaps 5-7 TW by 2050 through biomass (recall: $1.54/GJ)
• Possible/likely that this is water resource limited
Solar Energy Potential
• Theoretical: 1.2x105 TW solar energy potential
(1.76 x105 TW striking Earth; 0.30 Global mean albedo)
•Energy in 1 hr of sunlight  14 TW for a year
• Practical: ≈ 600 TW solar energy potential
(50 TW - 1500 TW depending on land fraction etc.; WEA
2000)
Onshore electricity generation potential of ≈60 TW (10%
conversion efficiency):
• Photosynthesis: 90 TW
Solar Thermal, 2001
• Roughly equal global energy use in each major sector:
transportation, residential, transformation, industrial
• World market: 1.6 TW space heating; 0.3 TW hot water; 1.3 TW
process heat (solar crop drying: ≈ 0.05 TW)
• Temporal mismatch between source and demand requires
storage
• (DS) yields high heat production costs: ($0.03-$0.20)/kW-hr
• High-T solar thermal: currently lowest cost solar electric source
($0.12-0.18/kW-hr); potential to be competitive with fossil energy
in long term, but needs large areas in sunbelt
• Solar-to-electric efficiency 18-20% (research in thermochemical
fuels: hydrogen, syn gas, metals)
Solar Land Area Requirements
6 Boxes at 3.3 TW Each
Solar Land Area Requirements
• U.S. Land Area: 9.1x1012 m2 (incl. Alaska)
• Average Insolation: 200 W/m2
• 2000 U.S. Primary Power Consumption: 99 Quads=3.3 TW
• 1999 U.S. Electricity Consumption = 0.4 TW
• Hence:
3.3x1012 W/(2x102 W/m2 x 10% Efficiency) = 1.6x1011 m2
Requires 1.6x1011 m2/ 9.1x1012 m2 = 1.7% of Land
Artificial Photosynthesis
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
http://web.mit.edu/new
soffice/2008/oxygen0731.html
Nathan Lewis (Cal
Tech)-creates electricity
from sunlight
Daniel Nocera (MIT)catalyst to split water
Fuel cell burns H2 + O2
*Image removed due to copyright restrictions.
The Need to Produce Fuel
“Power Park Concept”
Fuel Production
Distribution
Storage
Summary
• Need for Additional Primary Energy is Apparent
• Case for Significant (Daunting?) Carbon-Free Energy Seems
Plausible (Imperative?)
Scientific/Technological Challenges
• Energy efficiency: energy security and environmental security
• Coal/sequestration; nuclear/breeders; Cheap Solar Fuel
Inexpensive conversion systems, effective storage systems
Policy Challenges
• Is Failure an Option?
• Will there be the needed commitment? In the remaining time?
Energy Conversion Strategies
Fuel
Light
Electricity
Fuels
Electricity
SC
CO
2
e
Sugar
O
HO
H
2
2
sc
SC
2
O
2
Photosynthesis
H2O
Semiconductor/Liquid
Junctions
Photovoltaics
Fuel Cell vs Photoelectrolysis Cell
H2
A
e-
O2
Fuel Cell
MEA
H+
anode
membrane cathode
O2
H2
MSx
e-
Photoelectrolysis
Cell MEA
MOx
H+
cathode membrane
anode
Solar-Powered Catalysts for Fuel Formation
oxidation
2 H2O
reduction
4e-
chlamydomonas moewusii
Cat
Cat
O2
CO2
4H+
HCOOH
CH3OH
H2, CH4
10 µ
hydrogenase
2H+ + 2e-  H2
photosystem II
2 H2O  O2 + 4 e-+ 4H+
Photovoltaic + Electrolyzer System
Global Energy Consumption
Efficiency of Photovoltaic Devices
25
Efficiency (%)
20
15
10
crystalline Si
amorphous Si
nano TiO2
CIS/CIGS
CdTe
5
1950
1960
1980
1970
Year
1990
2000
US Energy Flow -1999
Net Primary Resource Consumption 102
Exajoules
Tropospheric Circulation Cross Section
Source: John Brandon www.auf.asn.au
Powering the Planet
Solar  Electric
GaInP2
h = 1.9eV
GaAs
h = 1.42eV
InGaAsP
h = 1.05eV
InGaAs
h = 0.72eV
Si Substrate
Chemical  Electric
Solar  Chemical
H3O+
CB
½H2 + H2O
e
__S*

Pt TiO2
h =
2.5 eV
S__
VB
H
__S+
½O2 +
H2O
OH
Photoelectrolysis: integrated
energy conversion and fuel
generation
S
O
Inorganic electrolytes:
bare proton transport
Extreme efficiency
at moderate cost
Solar paint: grain
boundary passivation
Catalysis:
ultra high
surface area,
nanoporous
materials
Bio-inspired
fuel generation
100 nm
Synergies: Catalysis, materials
discovery, materials processing
Hydrogen vs Hydrocarbons
• By essentially all measures, H2 is an inferior transportation
fuel relative to liquid hydrocarbons
•So, why?
• Local air quality: 90% of the benefits can be obtained from
clean diesel without a gross change in distribution and end-use
infrastructure; no compelling need for H2
• Large scale CO2 sequestration: Must distribute either electrons
or protons; compels H2 be the distributed fuel-based energy
carrier
• Renewable (sustainable) power: no compelling need for H2 to
end user, e.g.: CO2+ H2 CH3OH DME other liquids
Solar Land Area Requirements
• 1.2x105 TW of solar energy potential globally
• Generating 2x101 TW with 10% efficient solar farms requires
2x102/1.2x105 = 0.16% of Globe = 8x1011 m2 (i.e., 8.8 % of
U.S.A)
• Generating 1.2x101 TW (1998 Global Primary Power) requires
1.2x102/1.2x105= 0.10% of Globe = 5x1011 m2 (i.e., 5.5% of
U.S.A.)
Summary
• Need for Additional Primary Energy is Apparent
• Case for Significant (Daunting?) Carbon-Free Energy Seems
Plausible (Imperative?)
Scientific/Technological Challenges
• Coal/sequestration; nuclear/breeders; Cheap Solar Fuel
Inexpensive conversion systems, effective storage systems
Policy Challenges
• Energy Security, National Security, Environmental Security,
Economic Security
• Is Failure an Option? Will there be the needed commitment?