NewsNews http://www.boston.com/news/world/australia/articles/http://www.boston.com/news/world/australia/articles/

2009/12/02/2009/12/02/winds_drive_icebergs_away_from_new_zealand/winds_drive_icebergs_away_from_new_zealand/

http://www.boston.com/business/articles/2009/12/02/http://www.boston.com/business/articles/2009/12/02/cape_wind_national_grid_enter_pact/cape_wind_national_grid_enter_pact/

http://www.boston.com/bostonglobe/editorial_opinion/http://www.boston.com/bostonglobe/editorial_opinion/editorials/articles/2009/12/02/editorials/articles/2009/12/02/cape_wind_obstructionism___a_bad_legacy_for_kirk/cape_wind_obstructionism___a_bad_legacy_for_kirk/

http://www.boston.com/bostonglobe/editorial_opinion/http://www.boston.com/bostonglobe/editorial_opinion/oped/articles/2009/12/02/its_not_waste_its_energy/oped/articles/2009/12/02/its_not_waste_its_energy/

http://www.boston.com/news/local/articles/2009/12/03/http://www.boston.com/news/local/articles/2009/12/03/invasion_of_winter_moths_has_scientists_residents_lookinginvasion_of_winter_moths_has_scientists_residents_looking_for_answers/_for_answers/

http://www.boston.com/news/world/europe/articles/http://www.boston.com/news/world/europe/articles/2009/12/03/2009/12/03/as_climate_summit_nears_denmark_wearing_its_green_on_as_climate_summit_nears_denmark_wearing_its_green_on_its_sleeve/its_sleeve/

What is the most common What is the most common source of energy in the source of energy in the

United States?United States? A) OilA) Oil B) Natural GasB) Natural Gas C) CoalC) Coal D) NuclearD) Nuclear E) HydroelectricE) Hydroelectric

What is the most common What is the most common source of energy in the source of energy in the

World?World? A) OilA) Oil B) Natural GasB) Natural Gas C) CoalC) Coal D) NuclearD) Nuclear E) HydroelectricE) Hydroelectric

Energy SourcesEnergy Sources

United States:Nonrenewable 93%

Nuclear Power 8%Natural gas 23%Coal 23%Oil 39%

Renewable Energy 8%Biomass 4%Hydropower Geothermal, solar, wind 3%

World:Nonrenewable 82%

Nuclear Power 6%Natural Gas 21%Coal 22%Oil 33%

Renewable Energy 18%Biomass 11%Hydropower Geothermal, solar, wind 7%

Powering the PlanetNathan S. Lewis, California Institute of Technology

Power Units: The Power Units: The Terawatt ChallengeTerawatt Challenge

Power1 103 106 109 1012

1 W 1 kW 1 MW 1 GW 1 TW

Energy1 J = 1 W for 1 s

Global Energy Global Energy Consumption, 2001Consumption, 2001

4.66

2.89 2.98

0.285

1.24

0.286

0.92

0

1

2

3

4

5

TW

Oil Coal Biomass NuclearGas Hydro Renew

Total: 13.2 TW U.S.: 3.2 TW (96 Quads)

Global Energy SourcesGlobal Energy Sources

Image courtesy of Ren21 under public domain

(in the U.S. in 2002)

1-4 ¢

2.3-5.0 ¢ 6-8 ¢

5-7 ¢

Today: Production Cost of Today: Production Cost of ElectricityElectricity

0

5

10

15

20

25

Coal Gas Oil Wind Nuclear Solar

Cost6-7 ¢

25-50 ¢

Cos

t , ¢

/kW

-hr

Energy Energy CostsCosts

0

2

4

6

8

10

12

14

$/GJ

Coal Oil Biomass ElectB

razi

l Eur

ope

$0.05/kW-hr

www.undp.org/seed/eap/activities/wea

How long will it be before How long will it be before all the petroleum on earth all the petroleum on earth

is used up?is used up? A) 0-5 yearsA) 0-5 years B) 5-20 yearsB) 5-20 years C) 20-40 yearsC) 20-40 years D) 40-100 yearsD) 40-100 years E) more than 100 yearsE) more than 100 years

PetroleumPetroleum

US Reserves: 10-48 yearsGlobal: 42-93 years

Trade-Offs

Conventional OilAdvantages Disadvantag

esAmple 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

Image removed due to copyright restrictions.

Oil Resources

Figure by UMB OpenCourseWare

36 Estimates of the Time of the Peak of World Oil Production (There are More)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

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.

600

500

400

300

200

100

0

YEARS

OECD FSU Emerging Market Economies, excluding FSU

World

BP Statistical Review of World Energy 2005

• 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)

ConclusionsConclusions

Projected World Energy Consumption in the Coming CenturyProjected World Energy Consumption in the Coming Century

World Primary Energy Consumption (Quads)826

1,286

2050

2100

Projections to 2025 are from the Energy Information Administration, International Energy Outlook, 2004.

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 human-induced 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 RegionProjected World Energy Consumption by Region

World Energy Consumption by Region (Quads)

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.

World Regions

Population Growth to 10 - 11 Billion People in 2050

Per Capita GDP Growthat 1.6% yr-1

Energy consumption perUnit of GDP declinesat 1.0% yr -1

*Image removed due to copyright restrictions.

U.S. Energy Flow, 2003 (Quads)U.S. Energy Flow, 2003 (Quads)

21

Production70.5

Imports31.0

Consumption98.2

Adjustments 0.7

Exports4.0

About 30% of primary energy is imported.

Energ

y

Sourc

es

Energ

y C

onsu

mp

tion

Sect

ors

U.S. Energy Flow, 2003 (Quads)U.S. Energy Flow, 2003 (Quads)

22

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.

Alternative Energy Alternative Energy SourcesSources

Name as many alternative energy Name as many alternative energy sources as you can think of…sources as you can think of…

What are the advantages and What are the advantages and disadvantages of each?disadvantages of each?

Resources

• http://www.youtube.com/watch?v=ztFDqcu8oJ4

• http://web.mit.edu/newsoffice/2008/oxygen-0731.html

• 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

Sources of Carbon-Free Power

Nuclear powerNuclear 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)

27

*Image removed due to copyright restrictions.

130 Gt total U.S. sequestration potentialGlobal emissions 6 Gt/yr in 2002 Test sequestration projects 2002-2004

CO2 Burial: Saline Reservoirs

Study Areas

One FormationStudied

Two FormationsStudied

Power Plants (dot size proportionalto 1996 carbon emissions)

DOE Vision & Goal:1 Gt storage by 2025, 4 Gt by 2050

• 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

What is the most promising What is the most promising form of renewable energy?form of renewable energy?

A) WindA) Wind B) SolarB) Solar C) GeothermalC) Geothermal

D) BiofuelsD) Biofuels E) TidalE) Tidal

Renewable Energy Consumption by Major SourcesRenewable Energy Consumption by Major Sources

• Hydroelectric

• Geothermal

• Ocean/Tides

• Wind

• Biomass

• Solar

Potential of Renewable Energy

Hydro-electric powerHydro-electric power

Gravity drives the whole process!

32

Image courtesy of U.S. Geological Survey

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

Hydroelectric Energy Potential

Three Gorges DamThree Gorges DamYangtze RiverYangtze River

100 m high, 100 m thick100 m high, 100 m thick 2.3 km long2.3 km long 22,000 MW22,000 MW $32 Billion$32 Billion 10 Year payback10 Year payback

Image courtesy of roberthuffstutter, flikr under Creative Common License

GeothermaGeothermal Energyl Energy

Hydrothermal systemsHot dry rock (igneous systems)Normal geothermal heat (200 C at 10 km depth)

1.3 GW capacity in 1985

*Image removed due to copyright restrictions.

Geothermal Energy Geothermal Energy PotentialPotential

Geothermal Energy Geothermal Energy PotentialPotential

Mean terrestrial geothermal flux at earth’s surface 0.057 Mean terrestrial geothermal flux at earth’s surface 0.057 W/mW/m22

Total continental geothermal energy potentialTotal continental geothermal energy potential 11.6 TW 11.6 TW Oceanic geothermal energy potentialOceanic geothermal energy potential 30 TW 30 TW

Wells “run out of steam” in 5 yearsWells “run out of steam” in 5 years Power from a good geothermal well (pair) Power from a good geothermal well (pair) 5 MW5 MW Power from typical Saudi oil wellPower from typical Saudi oil well 500 MW500 MW Needs drilling technology breakthrough Needs drilling technology breakthrough (from exponential $/m to linear $/m) to become economical)(from exponential $/m to linear $/m) to become economical)

Wind PowerWind Power

http://http://www.capewind.org/www.capewind.org/

420 Megawatts of energy420 Megawatts of energy 75% of Cape and Islands 75% of Cape and Islands

electricity needselectricity needs Equivalent to removing Equivalent to removing

162,000 cars 162,000 cars 113 million gallons of oil113 million gallons of oil Birds, views, sealife, Birds, views, sealife,

navigation, noisenavigation, noise Image courtesy of EPA

Electric Potential of Wind

Image courtesy of US Department of Energy

In 1999, U.S consumed3.45 trillion kW-hr ofElectricity =0.39 TW

• 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 greaterIf 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)

Global Potential of Terrestrial Wind

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

• 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: $1.5-4/GJ)• Possible/likely that this is water resource limited

Biomass Energy Potential

Global: Bottom Up

• 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 Energy Potential

• 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• (S) 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 Thermal, 2001

Solar Land Area Requirements

6 Boxes at 3.3 TW Each

• 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

Solar Land Area Requirements

Artificial PhotosynthesisArtificial Photosynthesis http://web.mit.edu/http://web.mit.edu/

newsoffice/2008/newsoffice/2008/oxygen-0731.htmloxygen-0731.html

Nathan Lewis (Cal Nathan Lewis (Cal Tech)-creates Tech)-creates electricity from electricity from sunlightsunlight

Daniel Nocera (MIT)-Daniel Nocera (MIT)-catalyst to split watercatalyst to split water

Fuel cell burns HFuel cell burns H22 + + OO22

*Image removed due to copyright restrictions.

H2 Purification, Storage,

Dispensing

H2 Production

Fuel

Cell

Stationary Generation

Fuel Processor

or Electrolyzer

Fuel Cell

H2

Reformate H2 /

The Need to The Need to Produce FuelProduce Fuel“Power Park Concept”

Fuel Production

Distribution

Storage

• 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?

Summary

LightFuel

Electricity

Photosynthesis

Fuels Electricity

Photovoltaics

sc

e

SC

CO

Sugar

H O

O

2

2

2

Energy Conversion Strategies

Semiconductor/LiquidJunctions

H2O

O H22

SC

O2AH2e-

cathodeanode

Fuel Cell vs Photoelectrolysis Cell

H2

anodecathode

O2

Fuel Cell MEA

PhotoelectrolysisCell MEA

membrane

membrane

MOxMSxe-

H+

H+

Solar-Powered Catalysts for Fuel FormationSolar-Powered Catalysts for Fuel Formation

hydrogenase

2H+ + 2e- H2

10 µ

chlamydomonas moewusii2 H2O

O2

4e-

4H+

CO2

HCOOHCH3OHH2, CH4

Cat Cat

oxidation reduction

photosystem II

2 H2O O2 + 4 e-+

4H+

Photovoltaic + Electrolyzer System

Global Energy Global Energy ConsumptionConsumption

1950 1960 1970 1980 1990 2000

5

10

15

20

25

Effi

cie

ncy

(%

)

Year

crystalline Si

amorphous Sinano TiO2

CIS/CIGSCdTe

Efficiency of Photovoltaic Efficiency of Photovoltaic DevicesDevices

US Energy Flow -1999US Energy Flow -1999Net Primary Resource Net Primary Resource

Consumption 102 ExajoulesConsumption 102 Exajoules

Tropospheric Circulation Cross Section

Source: John Brandon www.auf.asn.au

Powering the Powering the PlanetPlanet

Solar Electric

Extreme efficiency

at moderate cost

Solar paint: grain boundary passivation

Solar Chemical Chemical Electric

Inorganic electrolytes:bare proton transport

O

H

S

100 nm

Catalysis:ultra highsurface area,nanoporousmaterials

Photoelectrolysis: integrated energy conversion and fuel

generation

h = 2.5 eV

H3O+

½H2 + H2O

½O2 + H2O

OH

__S*

__S+

S__

TiO2

VB

CB

Pt

Bio-inspired fuel generation

e

GaAsh = 1.42eV

InGaAsPh = 1.05eV

InGaAsh = 0.72eV

Si Substrate

GaInP2

h = 1.9eV

GaAsh = 1.42eV

InGaAsPh = 1.05eV

InGaAsh = 0.72eV

Si Substrate

GaInP2

h = 1.9eV

Synergies: Catalysis, materials discovery, materials processing

• 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

Hydrogen vs Hydrocarbons

• 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.)

Solar Land Area Requirements

• 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?

Summary