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Overview of Renewable Energy Sources

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					A. Shakouri 3/25/2009

Overview of Renewable Energy Sources
Ali Shakouri
Baskin School of Engineering University of California Santa Cruz
http://quantum.soe.ucsc.edu/

Philips Research Lab, Eindhoven, Netherlands; 25 March 2009 1

World Marketed Energy Use by Fuel Type 1980-2030
13TW

A. Shakouri 3/25/2009

2050: 25-30TW

34% 28% 24% 26%
Share of World Total

38%

23%
8% 7% 6% 6%

US Department of Energy; Energy Information Administration (2007)
2

US Energy Consumption

A. Shakouri 3/25/2009

DOE Energy Information Administration (2007)
3

A. Shakouri 3/25/2009

Martin Green, UNSW
4

Cost of Renewable Energy
Levelized cents/kWh in constant $2000
40 COE cents/kWh 100 COE cents/kWh

A. Shakouri 3/25/2009

Wind
30 20 10 0 1980 1990 2000 2010 2020

80 60 40 20 0 1980

PV

1990

2000

2010

2020

10 COE cents/kWh 8 6 4 2

0 1980

1990

70 Geothermal 60 50 40 30 20 10 0 2000 2010 2020 1980 COE cents/kWh

COE cents/kWh

Solar thermal

15 12 9 6 3 0 1980 1990 2000

Biomass

1990

2000

2010

2020

2010

2020

Source: NREL Energy Analysis Office These graphs are reflections of historical cost trends NOT precise annual historical data. Updated: October 2002

Keith Wipke, NREL
5

Microprocessor Evolution
1,000,000 100,000 10,000 1,000 100 10 1 ’75 ’80 ’85 ’90 ’95 ’00 ’05 ’10 ’15

A. Shakouri 3/25/2009

K

1 Billion Transistors
Pentium® 4 Pentium® III Pentium® II Pentium® i486 i386 80286 8086

6

Airplane Speed/Efficiency Evolution
Airplane Speed

A. Shakouri 3/25/2009

US Energy Intensity (MJ) per available seat km
@ 160kg payload/seat

McMasters & Cummings, Journal of Aircraft, Jan-Feb 2002

NLR-CR-2005-669;Peeters P.M., Middel J., Hoolhorst A.
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A. Shakouri 3/25/2009

Felix‟s forecasts of US energy consumption in year 2000 (early 1970‟s)

Nuclear Natural gas Oil Coal
Vaclav Smil, Energy at the Crossroads, 2005
8

Electric Potential of Wind
• Significant potential in US Great Plains, inner Mongolia and northwest China

A. Shakouri 3/25/2009

• U.S.: Use 6% of land suitable for wind energy development; practical electrical generation potential of ≈0.5 TW • Globally: Theoretical: 27% of earth’s land is class >3 => 50 TW Practical: 2 TW potential (4% utilization) Off-shore potential is larger but must be close to grid to be interesting; (no installation > 20 km offshore now)
Nate Lewis, Caltech
9

Turbine Sizes

A. Shakouri 3/25/2009

Trend toward bigger turbine sizes
Helge Aagaard Madsen, DTU Riso10

A. Shakouri 3/25/2009

http://www.eere.energy.gov/

11

Offshore Wind Farm
Nysted, Denmark

A. Shakouri 11/25/2008 A. Shakouri 3/25/2009

EE 181 Renewable Energies in Practice CA-Denmark Summer Program 2008

12

Geothermal Energy Potential
• Mean terrestrial geothermal flux at earth‟s surface • Total continental geothermal energy potential • Oceanic geothermal energy potential

A. Shakouri 3/25/2009

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)
Nate Lewis, Caltech
13

Energy from the Oceans?

A. Shakouri 3/25/2009

Currents

Thermal Differences

Tides
Ken Pedrotti, UCSC

Waves
14

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

A. Shakouri 3/25/2009

Nate Lewis, Caltech

15

A. Shakouri 3/25/2009

Amount of land needed for 20 TW at 1% efficiency: 9% of land

Chris Somerville, UC Berkeley

16

Corn Ethanol Greenhouse Gas Emission

A. Shakouri 3/25/2009

Farrell et al. (Science 311, 2006)

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A. Shakouri 3/25/2009

Steve Koonin, BP

18

Biofuels

A. Shakouri 3/25/2009

Dan Kammen, Berkeley

19

A. Shakouri 3/25/2009

Bioenergy and Sustainable Development, Ambuj D. Sagar, Sivan Kartha Annual Review of Environment and Resources, Vol. 32: 131-167 (November 2007)

20

Solar Energy Potential
• Theoretical: 1.2x105 TW solar energy potential • Practical: ≈ 600 TW solar energy potential • Onshore electricity generation potential of ≈60 TW (10% conversion efficiency): • Photosynthesis: 90 TW • Generating 12 TW (1998 Global Primary Power) requires 0.1% of Globe = 5x1011 m2 (i.e., 5.5% of U.S.A.)

A. Shakouri 3/25/2009

Nate Lewis, Caltech

21

World Insolation

A. Shakouri 3/25/2009

12 TW
2.0-2.9 4.0-4.9 6.0-6.9

22

A. Shakouri 3/25/2009

Boyle Renewable Energy Sources

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Potential of Carbon Free Energy Sources
A. Shakouri 11/25/2008 A. Shakouri 3/25/2009

From: Basic Research Needs for Solar Energy Utilization, DOE 2005

Chris Somerville, UC Berkeley

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A. Shakouri 3/25/2009

Vaclav Smil Energy at the Crossroads
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Energy Storage Options

A. Shakouri 3/25/2009

Specific Power (W/kg)

Combustion Engine

Specific Energy (Wh/kg)
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Power ~3.3TW
A. Shakouri 11/25/2008 A. Shakouri 3/25/2009

1.3TW

Rejected Energy 61%

Lawrence Livermore National Lab., http://eed.llnl.gov/flow 27

India‟s Energy Consumption 2005
A. Shakouri 3/25/2009

Waste Energy Biomass

Coal

Petroleum

28

Direct Conversion of Heat into Electricity
A. Shakouri 3/25/2009

Seebeck coefficient DV S  (1821) DT

Hot
Electrical Conductor

Cold

DV~ S DT
Efficiency function of thermoelectric figure-of-merit (Z)
Z  S 
2

I

Rload = RTE internal
2

k Z  ( Seebeck ) ( electrical ( thermal conductivi ty )

conductivi ty )

29

Power Generation Efficiencies of Different Technologies
0.8

A. Shakouri 3/25/2009

Conversion Efficiency Energy Optimal efficiency

0.7 0.6 0.5 0.4 0.3 0.2 0.1 0

ZTm=0.5 ZTm=1 ZTm=2 ZTm=3 Carnot limit

Carnot

ZTavg=20
Coal/ Rankine

Solar/ Stirling Solar/ Rankine Cement/ Org. Rankine

3 2 1 0.5

Geothermal/ Organic Rankine

400

600

800 T (K)
hot

1000

1200
C. Vining 2008
30

Radioisotope Thermoelectric Generators (Voyager, Galileo, Cassini, …)

A. Shakouri 3/25/2009

• 55 kg, 300 We, „only‟ 7 % conversion efficiency • But > 1,000,000,000,000 device hours without a single failure
Hot Shoe (Mo-Si)

B-doped Si0.78Ge0.22 B-doped Si0.63Ge0.36 p-type leg

P-doped Si0.78Ge0.22 P-doped Si0.63Ge0.36 n-type leg Cold Shoe

SiGe unicouple
Cronin Vining, ZT Services
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Which Materials To Choose for TE Modules?
A. Shakouri 3/25/2009

Seebeck

S


S2

Electrical Conductivity

ZT= S2T/k

Free carrier concentration Thermal Conductivity
Electronic contribution

k
Insulator Semiconductor Metal

Lattice contribution

For almost all materials, if doping is increased, electrical conductivity increases but Seebeck coefficient is reduced. Similarly  ↔ k

32

Microrefrigerators on a chip
• Monolithic integration on silicon • DTmax~4C at room temp. (7C at 100C)
UCSC, UCSB, HRL Labs

A. Shakouri 3/25/2009

Hot Electron

Cold Electron

Relative Temp. (C)

50mm
1 µm
J. Christofferson
Nanoscale heat transport and microrefrigerators on a chip; A. Shakouri, Proceedings of IEEE, July 2006
Featured in Nature Science Update, Physics Today, AIP April 2001
33

Hot Electron Filters in Metal/Semiconductor Nanocomposites

A. Shakouri 3/25/2009

Even with only modestly low lattice thermal conductivity and electron mobility of typical metals, ZT > 5 is theoretically possible
Assume: klattice=1W/mK, mobility ~10 cm2/Vs
8 7 6 5

Metal/Semiconductor N o n-c o n s er ved Nanostructure

4

(E

D. Vashaee, A. Shakouri;

5

3

b a rrie r

ZT

-E ) / k T

Physical Review Letters, 2004

4 3 2 1 0 0 2 4 6 8 10 12 14

2

• Need lattice-compatible 1 composites with appropriate barrier heights
B

f

PlanarnBarrier C o se rv e d

0

-1

FermiFenergy E n e rgfree electron e rm i eV (↔ y (eV ) concentration)
34

ErAs Semi-metal Nanoparticles imbedded in InGaAs Semiconductor Matrix

A. Shakouri 3/25/2009

 ErAs dots are lattice-matched and incorporate without any visible defects in InGaAs despite different crystal structures (Cubic vs. Zinc-blende)

As In,Ga
Er
1nm

• “Random” ErAs particles ~ 2-3 nm • Size is invariant to growth conditions

J. Zide et al. UCSB/UCSC

35

Beating the Alloy Limit in Thermal Conductivity
ErAs:In0.53Ga0.47As
A. Shakouri 3/25/2009

Phonon scattering by ErAs nanoparticles  3-fold reduction in thermal conductivity beyond the alloy limit
T h e rm a l C o n d u ctivity [W /m -K ]

InGaAs
6

0.3% ErAs:InGaAs
3

3% ErAs:InGaAs 6% ErAs:InGaAs

Nanoparticle

0 0 200 400 600 800
36

T e m p e ra tu re [K ]

W. Kim et al. UCB/UCSB/UCSC

Module Power generation results
400 elements (10-20 microns ErAs:InGaAlAs thin films, 120x120mm2)
3

A. Shakouri 3/25/2009

Output Power (W/cm )

2.5 2 1.5 1 0.5 0

20 mm module 10 mm module

2

0

20

40

60

80

100

120

140

DT (K)

140 mm/140 mm AlN

G. Zeng, J. Bowers, et al. (UCSB, UCSC) Appl. Physics Letters 2006 37

Summary

A. Shakouri 3/25/2009

• Significant amount of energy produced in the world is wasted in the form of heat (61% is US) • Thermoelectric effects can be engineered via nanomaterials
– Modify the average energy of moving electrons – Selective scattering of phonons w.r.t electrons

• Micro refrigerators on a chip (silicon based)
• Localized cooling, Cooling power density > 500 W/cm2

• Metal semiconductor nanocomposites for direct conversion of heat into electricity
• Potential to reach 20-30% conversion efficiencies

38

A. Shakouri 11/25/2008 A. Shakouri 3/25/2009

Nate Lewis, Caltech

39

Plan B for Energy
• WAVES AND TIDES (Reality factor 5) • HIGH-ALTITUDE WIND (Reality factor 4) • NANOTECH SOLAR CELLS (Reality factor 4) • DESIGNER MICROBES (Reality factor 4) • NUCLEAR FUSION (Reality factor 3) • SPACE-BASED SOLAR (Reality factor 3) • A GLOBAL SUPERGRID (Reality factor 2) • SCI-FI SOLUTIONS (Reality factor 1)
– Cold Fusion and Bubble Fusion – Matter-Antimatter Reactors

A. Shakouri 3/25/2009

September 2006; Scientific American; W. Wayt Gibbs

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A. Shakouri 3/25/2009

41

Can Renewables Save the World?

A. Shakouri 3/25/2009

• Fossil fuels have excellent energy characteristics. • Wind/ geothermal are among the cheapest of renewables. There is potential for significant growth but they can not solve our energy problem. • Solar energy has the potential to provide all our energy needs.
– Currently expensive; it is intermittent.

• Currently no clear options for large scale energy storage • Biomass has the potential to provide part of transportation energy needs
– Cellulosic biofuels and algaes are interesting but they have not demonstrated large scale/long term potential. One has to consider the full ecosystem impact (water, food, etc.).
42

A. Shakouri 3/25/2009

World Average

John Bowers, UCSB

43

Can Renewables Save the World?
A. Shakouri 3/25/2009

• If our goal is to have a planet where everybody has a level of life similar to developed countries, energy need is enormous and it is not clear if we can do this by working on the supply side alone. • Energy efficiency is important but it is not enough. • We need to consider changes in lifestyle, city planning and social structure (transportation, lodging, grid).

44

Oil Resources

A. Shakouri 3/25/2009

S. Koonin, Chief Scientist BP nrg.caltech.edu

45

A. Shakouri 3/25/2009

400,000 years of greenhouse-gas & temperature history based on bubbles trapped in Antarctic ice

Last time CO2 >300 ppm was 25 million years ago.
Source: Hansen, Clim. Change, 68, 269, 2005.

John P. Holdren, 2006

46

EE80J Renewable Energy Sources
Spring 2009, Also Summer 2009
• • • • • • • Energy, power and thermodynamics Home energy audit Power plants, nuclear power Solar energy Wind energy, hydropower, geothermal Biomass, hydrogen, fuel cells Economics, Environmental and Societal Impacts
A. Shakouri 3/25/2009

EE181J Renewable Energies in Practice (July-August 2009)
CA/Denmark summer school (UCSC, UC Davis, UC Merced, Techn. Univ. Denmark, Roskilde) –Extensive field trips
UCSC Courses
47


				
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