holistic life cycle analysis: focus on cdte photovoltaics · expert peer reviews by: bnl, us-doe,...

1

Holistic Life Cycle Analysis: Focus on CdTe Photovoltaics

Vasilis Fthenakis

Center for Life Cycle Analysis, Columbia University

and

Photovoltaics Environmental Research Center, Brookhaven National Laboratory

Presentation at the SwissPhotonics Workshop,

Environmental and Economic Impact of PV Energy Production

EMPA, Zurich, 22 October 2013

2

CU-BNL: Outcomes from LCA research

• Original, data-based LCA on current & emerging PV technologies – CdTe PV

– High-efficiency mono-crystalline PV

– High Concentration PV (Si and III/V)

– GIGS PV

– Advanced c-Si PV

– Organic PV

• Corrected misrepresentations of PV environmental profiles – Emissions

– Energy Payback Times–Energy Return on Investment

– Land use

– Risks

• Addressing sustainability of large-scale deployment – Materials availability

– Recycling technologies

– PV variability –Grid integration

• Effective Dissemination of research results – Bibliography of 300 articles, ~60 on LCA

– www.bnl.gov/pv www.clca.columbia.edu

3

Large Scale PV –Sustainability Criteria

Low Cost

Resource Availability

Lowest Environmental Impact

Affordability in a

competitive world

Te in CdTe

In in CIGS

Ge in a-SiGe & III/V

Ag in c-Si

Lower than alternatives Life Cycle Impacts & Risks

Zweibel, Mason & Fthenakis, A Solar Grand Plan, Scientific American, 2008

Fthenakis, Mason & Zweibel, The technical, geographical and economic feasibility for solar energy in the US, Energy Policy, 2009

Fthenakis, The sustainability of thin-film PV, Renewable & Sustainable Energy Reviews, 2009

Fthenakis, Sustainability metrics for extending thin-film PV to terawatt levels. MRS Bulletin, 2012.

4

Large Scale PV –Sustainability Criteria: Focus on CdTe PV

Low Cost



Lowest

production cost

Concerns about Te

availability Concerns about Cd emissions

Zweibel, Mason & Fthenakis, A Solar Grand Plan, Scientific American, 2008

Fthenakis, Mason & Zweibel, The technical, geographical and economic feasibility for solar energy in the US, Energy Policy, 2009

Fthenakis, The sustainability of thin-film PV, Renewable & Sustainable Energy Reviews, 2009

Fthenakis, Sustainability metrics for extending thin-film PV to terawatt levels. MRS Bulletin, 2012.

5

A Solar Grand Plan

Energy Policy 37 (2009)

By 2050 solar power could provide 69% of electricity & 35% of total energy demand in the U.S. Sci. American, January 2008

.

6

Affordability: Projected PV Growth and Electricity Price Targets

Source: Solar Technologies Program, US-DOE, 25th EUPV, Valencia, Spain, Sept. 2010

Geographic Locations Phoenix, AZ

Kansas City, MO

New York, NY

Financing Conditions Low: 8.2%

High: 9.9%

7

Life Cycle Analysis

Raw Material

Acquisition

Material

Processing Manufacture Decommiss

-ioning

Treatment

Disposal Installation/

Operation

Recycling

M, Q

E

M, Q M, Q M, Q M, Q M, Q

E E E E E

M, Q: material and energy inputs

E: effluents (air, water, solid)

M, Q

E

Accidental

emissions

Separations,

Recovery

Experimental Research at BNL

8

Comparative Life-Cycle Analysis Metrics

Energy Payback Times (EPBT) and

Energy Return on Investment (EROI)

Greenhouse Gas Emissions

Toxic Emissions

Resource Use (materials, water, land)

EH&S Risks

Zero impact technology does not exist

Compare with other energy producing technologies as benchmarks

9

Energy Payback Times (EPBT)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

EP

BT

(Y

ears

)

Insolation: 1700 kWh/m2-yr (Southern Europe)

Multi-Si

13.2%

Mono-Si

14.0% CdTe

10.9%

BOS

Frame

Frameless

Module

1.8 1.9

0.8

- Fthenakis et al., EUPV, 2009 - deWild 2009, EUPV, 2009

- Alsema & de Wild, Material Research Society, Symposium, 895, 73, 2006

- deWild & Alsema, Material Research Society, Symposium, 895, 59, 2006

- Fthenakis & Kim, Material Research Society, Symposium, 895, 83, 2006

- Fthenakis & Alsema, Progress in Photovoltaics, 14, 275, 2006

Based on data from 13 US and European PV manufacturers

10

EPBT Historical Evolution

EPBT (years)

BNL-CU collaborative studies

Fthenakis, PV Energy ROI Tracks Efficiency Gains, Solar Today, 2012

Irradiation of 1700 and 2400 kWh/m2/yr

11

Greenhouse Gas (GHG) Emissions Insolation: 1700 kWh/m2-yr

0

10

20

30

40

50

Multi-Si 13.2%

Mono-Si 14%

CdTe

10.9%

CO

2-e

q (

g/k

Wh

)

BOS Frame Frameless

Module

Based on data from 13 US and European PV manufacturers - Fthenakis et al., EUPV, 2009 - deWild 2009, EUPV, 2009

-Fthenakis, Kim & Alsema, ES&T, 42, 2168, 2008

- Alsema & deWild, Material Research Society, Symposium, 895, 73, 2006

- deWild & Alsema, Material Research Society, Symposium, 895, 59, 2006

- Fthenakis & Kim, Material Research Society, Symposium, 895, 83, 2006

- Fthenakis & Alsema, Progress in Photovoltaics, 14, 275, 2006

12

0

200

400

600

800

1000

1200

1400

Coal (Kim and

Dale 2005)

Natural Gas

(Kim and Dale

2005)

Petroleum

(Kim and Dale

2005)

Nuclear

(Baseline -

Fthenakis and

Kim, 2007

PV, CdTe

(Fthenakis

et al, 2008)

PV, mc-Si,

(Fthenakis et al,

2008)

GH

G (

g C

O2

-eq

./k

Wh

)

Materials

Operation

Transportation

Fuel Production

GHG Emissions from Life Cycle of Electricity Production: Comparisons

24 18 30

Fthenakis, California Energy Commission, Nuclear Issues Workshop, June 2007

Fthenakis & Kim, Life Cycle Emissions…, Energy Policy, 35, 2549, 2007

Fthenakis & Kim, ES&T, 42, 2168, 2008

10.9% 13.2%

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Life-cycle Toxic Emissions

Fthenakis, Kim and Alsema, Environmental Science & Technology, 2008

Case 1- 2006 electricity mixture in Si production-Crystal Clear project;

Case 2- UCTE grid mixture & EcoInvent database;

Case 3- US grid mixture & Franklin database. Ground-mounted, Southern European insolation, 1700 kWh/m2/yr, performance ratio =0.8, lifetime=30 years

SOx

0

50

100

150

200

250

300

350

400

Case 1 Case 2 Case 3 Case 1 Case 2 Case 3 Case 1 Case 2 Case 3 Case 2 Case 3

Ribbon 11.5% Multi-Si 13.2% Mono-Si 14.0% CdTe 9%

mg

/kW

h

0

20

40

60

80

100

120

140

160

180

200

Case 1 Case 2 Case 3 Case 1 Case 2 Case 3 Case 1 Case 2 Case 3 Case 2 Case 3

Ribbon 11.5% Multi-Si 13.2% Mono-Si 14.0% CdTe 9%

mg/k

Wh

NOx

Case 1

As Cd Cr Pb Hg Ni

Em

issio

ns (

g/G

Wh

)

0

10

20

30

40

Ribbon-Si

Multi-Si

Mono-Si

CdTe

Case 2

As Cd Cr Pb Hg Ni

Em

issio

ns (

g/G

Wh

)

0

10

20

30

40

Case 3

As Cd Cr Pb Hg Ni

Em

issio

ns (

g/G

Wh

)

0

10

20

30

40

Case 4

As Cd Cr Pb Hg Ni

Em

issio

ns (

g/G

Wh

)

0

10

20

30

40

14

Life-Cycle Cd Atmospheric Emissions

0

10

20

30

40

50

0.4 0.7 0.6 0.2

g C

d/G

Wh

Fthenakis and Kim, Thin-Solid Films, 515(15), 5961, 2007

Fthenakis, Kim & Alsema, Environ. Sci. Technol, 42, 2168, 2008

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Life-Cycle Cd Atmospheric Emissions

3.7

0.3

44.3

0.9

0

10

20

30

40

50

0.4 0.7 0.6 0.2

g C

d/G

Wh

Fthenakis and Kim, Thin-Solid Films, 515(15), 5961, 2007

Fthenakis, Kim & Alsema, Environ. Sci. Technol, 42, 2168, 2008

0.02

0.23

0

0.05

0.1

0.15

0.2

0.25

Cd direct emissions Cd indirect emissions

g C

d/G

Wh

16

Simulations of Accidental Releases during Fires

Heat

Based on protocols by the ASTM and UL

Expert Peer Reviews by: BNL, US-DOE, 2004; EC-JRC, 2004

German Ministry of the Environment, (BMU), 2005

French Ministry of Ecology, Energy, 2009

• Weight Loss Measurements

• ICP Analysis of Cd & Te Emissions

• ICP Analysis of Cd & Te in Molten Glass

• X-ray Fluorescence Micro-Spectrometry of Cd in

Molten Glass

17

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 20000 40000 60000

Cd (counts)

positi

on (

mm

)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 50 100 150 200

Zr (counts)

positio

n (

mm

)

XRF-micro-probing -Cd & Zr distribution in PV sample

Unheated Sample -Vertical Cross Section

Fthenakis, Renewable and Sustainable Energy Reviews, 2004

Fthenakis, Fuhrmann, Heiser, Lanzirotti, Wang, Progress in Photovoltaics, 2005

18

XRF-micro-probe -Cd distribution in PV sample 760 °C, Section taken from middle of sample

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 20000 40000 60000

Cd (counts)

positi

on (

mm

)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 20000 40000

Cd (counts)

positi

on (

mm

)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 20000 40000

Cd (counts)

positi

on (

mm

)

Cd Loss = 0.6%

19

XRF-micro-probe -Cd distribution in PV sample

1000 °C, Section taken from middle of sample

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

0 10000 20000 30000

Cd (counts)

positio

n (

mm

)

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

0 10000 20000 30000 40000

Cd (counts)

positio

n (

mm

)-3

-2.5

-2

-1.5

-1

-0.5

0

0 2000 4000 6000 8000

Cd (counts)

pos

itio

n (m

m)

Cd Loss = 0.5%

20

XRF-micro-probing -Cd distribution in PV sample

1000 °C, Section taken from right side of sample

-4

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

0 10000 20000 30000

Cd (counts)

positio

n (

mm

)

-4.5

-4

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

0 10000 20000 30000

Cd (counts)

positio

n (

mm

)

-8

-7

-6

-5

-4

-3

-2

-1

0

0 5000 10000

Cd (counts)

positio

n (

mm

)

Cd Loss = 0.5%

21

XRF-micro-probing -Cd distribution in PV sample 1100 °C, Section taken from middle of sample

0

1

2

3

4

5

6

7

8

0 1000 2000 3000

Cd (counts)

po

sit

ion

(m

m)

0

1

2

3

4

5

6

7

8

9

10

0 2000 4000

Cd (counts)

positi

on (

mm

)-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

0 2000 4000 6000

Cd (counts)

positi

on (

mm

)

Cd Loss = 0.4%

22

Direct Atmospheric Cd Emissions from the Life-Cycle of CdTe PV Modules –Reference Case

Process (g Cd/ton Cd*) (% ) (mg Cd/GWh)

1. Mining of Zn ores 2.7 0.58 0.02

2. Zn Smelting/Refining 40 0.58 0.30

3. Cd purification 6 100 7.79

4. CdTe Production 6 100 7.79

5. CdTe PV Manufacturing 0.4* 100 0.52*

6. CdTe PV Operation 0.05 100 0.06

7. CdTe PV Recycling 0.1* 100 0.13*

TOTAL EMISSIONS 16.55

Fthenakis V. Renewable and Sustainable Energy Reviews, 8, 303-334, 2004

* 2009 updates

0.02

0.23

0

0.05

0.1

0.15

0.2

0.25

Cd direct emissions Cd indirect emissions

g C

d/G

Wh

23

Cd Use in CdTe PV Production

Cd is produced as a byproduct of Zn production and can either be put to beneficial uses or discharged

into the environment Above statement is supported by:

• US Bureau of Mines reports

• Rhine Basin study (the largest application of Systems Analysis on Industrial Metabolism)

Liewellyn T. Cadmium , Bureau of Mines Information Circular 1994, US Department of the Interior. Plachy J., U.S. Geological Survey Minerals Yearbook—2001, Cadmium—Chapter 17. Stigliani W, Anderberg S. Chapter 7. In: Ayres R, Simonis U, editors. Industrial metabolism. Tokyo, Japan: The United Nations University Press; 1994.

24

Cd Flow in the Rhine Basin

Source: Stigliani & Anderberg, Chapter 7, Industrial Metabolism, The UN University, 1994

25

Rhine Basin: Cd Banning Scenario

Source: Stigliani & Anderberg, Chapter 7, Industrial Metabolism, The UN University, 1994

26

Cd Use & Disposal in the Rhine Basin: The effect of banning Cd products

“ So, the ultimate effect of banning Cd products and recycling 50% of disposed consumer batteries may be to shift the pollution load from the product disposal phase to the Zn/Cd production phase. This … indicates that if such a ban were to be implemented, special provisions would have to be made for the safe handling of surplus Cd wastes generated at the Zn refineries!

One possible option would be to allow the production and use of Cd-containing products with inherently low availability for leaching.

The other option, depositing the Cd-containing wastes in safely contained landfills, has other risks ”

Source: Stigliani & Anderberg, Chapter 7, Industrial Metabolism, The United Nations University, 1994

27

Recycling of Spent Modules

Resolves environmental issues related to end-of-life

Provides a source of materials

Low Cost



Recycling

28

Recycling R&D at BNL: CdTe PV Modules

Filtration

Facility

Clean Glass

PV Module Fragments

Cd Electrowinning

Cell Cu Recovery

Column I

Cu

Column II

Cu

Column I

Cd, Fe

Column II

Cd, Fe

Leach

Device

Leachate Solution

(Te, Cd, Cu, Fe) CdSO4

Removal of Cu from Liquid

Using Resin A

Sp

en

t H

2S

O4

So

luti

on

Glass Slurry

H2SO4

H2O2

Cd Metal

Recycling of Spent Electrolyte

Selective Precipitation

Removal of Cd and Fe from Liquid

Using Resin B

Elution of Column

A

Elution of Column

B

Tellurium

Fthenakis V. and Wang W., Separating Te from Cd Waste Patent No 7,731,920, June 8, 2010

Wang W. and Fthenakis V.M. Kinetics Study on Separation of Cadmium from Tellurium in Acidic Solution Media Using Cation Exchange Resin,

Journal of Hazardous Materials, B125, 80-88, 2005

Fthenakis V.M and Wang W., Extraction and Separation of Cd and Te from Cadmium Telluride Photovoltaic Manufacturing Scrap, Progress in

Photovoltaics, 14:363-371, 2006.

29

Studies of Te Availability for CdTe PV Green M., Improved estimates of Te and Se availability from Cu anode slimes and recent price trends,

Progress in Photovoltaics, 14(8), 743-751, 2006.

Green M. , Estimates of Te and In prices from direct mining of known ores, Progress in Photovoltaics, 17(5), 347-359, 2009

Fthenakis V.M., Sustainability of photovoltaics: The case for thin-film solar cells, Renewable and Sustainable Energy Reviews, 13, 2746-2750, 2009.

Zweibel K., The impact of Te supply on CdTe PV, Science, 328, 699, 2010

Green M., PV Velocity Forum: Supply and Economics in Thin-film PV Materials, IEEE PVSC, Hawaii, June 23, 2010

Fthenakis V., PV Velocity Forum: Supply and Economics in Thin-film PV Materials, IEEE PVSC, Hawaii, June 23, 2010

Fthenakis V., Sustainability metrics for extending thin-film photovoltaics to terawatt levels. MRS Bulletin, 37(4), 425-430, 2012

Marwede M., Reller A., Future recycling flows of Te from CdTe Pv waste, Resources, Conservation and Recycling, 69, 35-49, 2012

Woodhouse M., et. al., Perspectives on the pathways for CdTe PV module manufacturers to address expected increase in the price of Te, IEEEPV Journal, 2012

Houari Y., Speirs J., Candelise C., Gross R., A system dynamic model of Te availability for CdTe PV, Progress in Photovoltaics, 2013.

30

Te from Copper Sulfide ores* Approximate Global Distribution in Copper Circuits

Refined copper

cathode

Anode Slimes

Cu Conc.

Lead Conc

Zinc Conc.

Precious

Metals Baghouse&

Scrubber Tellurium

To Sulfuric

Acid Plant

Tailings

Dust Treatment ?

Ore 180-260

135

35-120

5

Dump Slag 10 20

5

105

0 45

100

100

Tankhouse/Electro

Refining

Concentration

Smelting Furnace

Converter Furnace

Anode Refining

Furnace

Gas/dust Cleaning

Gas Cleaning

By-products Plant

Numbers refer to kg of Tellurium:

*Cu, Cu-Mo, Cu-Au & polymetallic ores, e.g., Pb-Cu-Zn-Ag ores

Ojebuoboh, Proceedings EMC, 2007; Nagaraj, 2010; Fthenakis update 2010

31

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

2010 2020 2030 2040 2050 2060 2070 2080 2090 2100

Te (

MT

/yr)

Tellurium for PV* from Copper Smelters

Tellurium Availability for PV* (MT/yr)

•Global Efficiency of Extracting Te from anode slimes increases to 80% by 2030 (low scenario);

90% by 2040 (high scenario)

* 322 MT/yr Te demand for other uses has been subtracted

All the future growth in Te production is allocated to PV

Low

High

32

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

2010 2020 2030 2040 2050 2060 2070 2080 2090 2100

Te

(M

T/y

r)

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

2010 2020 2030 2040 2050 2060 2070 2080 2090 2100

Te (

MT

/yr)

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

2010 2020 2030 2040 2050 2060 2070 2080 2090 2100

Te (

MT

/yr)

Te Availability for PV: Primary + Recycled

Tellurium Availability for PV (MT/yr)

Low

High

Recycling every 30-yrs 10% loss in collection 10% loss in recycling

Fthenakis V., Renewable & Sustainable Energy Reviews 13, 2746, 2009

Fthenakis V., MRS Bulletin, 37, 425, 2012

33

Te Utilization in thin-film PV

2010

PV

Metal Required

(MT/GW)

CdTe

Te 106

86.6 Material Utilization

-13.4 Total losses

-7 Loss in purification & CdTe synthesis

3.1 Collected for recycling

-3.5 Module scrap loss

24 Collected for recycling

-30 Deposition loss

(%) Material Losses & Utilization


34

Te Needs in CdTe PV

2010

Expected

2020

PV

Metal Required

(MT/GW)

Required

(MT/GW)

CdTe

Te 106 38-74



35

CdTe PV Production Constraints

Annual (GW/yr)

Most likely

Optimistic

Conservative

Most likely

Optimistic



Cumulative (TW)

Optimistic

Most likely

Conservative

Production can

increase with

direct mining

starting at ~2015

36

Major PV Sustainability metrics include cost, resource availability, and

environmental impacts.

These three aspects are closely related; recycling spent modules will

become increasingly important in resolving cost, resource, and

environmental constraints to large scales of sustainable growth.

Environmental sustainability should be examined in a holistic, life cycle,

comparative framework. Examples: Land use comparisons between coal and PV; Cd emission

comparisons between coal and various PV technologies; risk comparisons

among power life cycles

Every PV technology has some EHS issues, but the industry is proactive in

controlling them.

The environmental issues related to CdTe PV are outweighed by the

environmental benefits that PV displacement of fossil would generate.

email: [email protected]

www.clca.columbia.edu

www.pv.bnl.gov

Conclusion

37

CdTe PV Product Life –Accidental Releases

Leaching from shuttered modules • 10 mm fragments -Rain-worst-case scenario- “ leached Cd concentration in the

collected water is no higher than the German drinking water concentration.”

(Steinberger, Frauhoffer Institute Solid State Technology, Progress in Photovoltaics, 1998)

• < 4 mm fragments “Leached Cd exceeds the limits for disposal in inert landfill but

is lower than limits for ordinary landfills”

(Okkenhaug, Norgegian Geotechnical Institute, Report, 2010)

• < 2 mm fragments “CdTe PV sample failed California TTLC and STLC tests”

(Sierra Analytical Labs for the “Non-Toxic Solar Alliance”, 2010)

All PV modules would fail the California tests

c-Si for Ag, Pb, and Cu (ribbon),

CIGS for Se; a-Si marginally for Ag

Eberspacher & Fthenakis, 26th IEEEPVSC, 1997;

Eberspacher 1998

We advocate for all PV modules to be

recycled at the end of their life

38

Year Extraction Efficiency (%)

Tellurium Selenium Indium

2002 33 52 30

2006

40 80 70-80

2009 45 80 80

Main reason for lower Te than Se recovery rates

• Several refineries recover Se but not Te

Extraction Efficiencies from Slimes for Te, Se and In

Anderson 2002; USGS 2004, 2006; Ogebuoboh, 2007;

Fthenakis update 2010

39

Land Use in Energy Life Cycles

12000

13000

Fthenakis and Kim, Renewable and Sustainable Energy Reviews (2009);

Burkhardt et al (2011)

Rawl, WV Springerville, AZ

40

Corrected Misrepresentations of PV Environmental Profiles

0.03

0.34 0.17 0.45

0.33

ExternE: Environmental Damage Costs

Maximum fatalities/accident

1

10

100

1000

10000

100000

Lignite

Hard coal

Oil

Natural G

as

Nuclear

HydroW

ind PV

Hirschberg et al. 2004

Paul Sherrer Institute Report

PV Risks

Report to European Commission, 2004

41

Corrected Misrepresentations of PV Environmental Profiles

0.03

0.34 0.17 0.08

0.05

ExternE: Environmental Damage Costs PV Risks

Fthenakis V.M. and Alsema E., Photovoltaics Energy

Payback Times, Greenhouse Gas Emissions and External

Costs: 2004-early 2005 Status, Progress in Photovoltaics

Research and Applications, 14:275-280, 2006

2

Fthenakis V.M., Colli A., Arellano A., Kirchsteiger C., Ale B.

Evaluation of Photovoltaics in a Comparative Context,

Proceedings 21st European PV Solar Energy Conference,

Dresden, Germany, 4-8 September 2006

holistic life cycle analysis: focus on cdte photovoltaics · expert peer reviews by: bnl, us-doe,...

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