The Energy Balance of the Photovoltaic (PV) Industrygcep.stanford.edu/pdfs/symposium2012/MikDale_Symp2012... · 2012-10-31 · The Energy Balance of the Photovoltaic (PV) Industry:

The Energy Balance of the Photovoltaic (PV) Industry: Is the PV industry a net electricity producer?

Michael Dale

GCEP Symposium 2012

October 11th

Outline:

• Background

• Energy inputs to PV manufacturing

• Dynamic net energy analysis

• Results

• Conclusions

2

Outline:

• Background



• Results

• Conclusions

3

0

10

20

30

40

50

60

1999E 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011E

Glo

ba

l In

sta

lled

Ca

pa

city [

GW

]

Other

Ribbon

CIGS

CdTe

a-Si

mc-Si

sc-Si

Thin

Film

Wafer

PV industry is growing rapidly

4 DOE (2008), EPIA (2011), EIA (2012), UN (2012)

0

10

20

30

40

50

60

1999E 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011E

Glo

ba

l In

sta

lled

Ca

pa

city [

GW

]

Other

Ribbon

CIGS

CdTe

a-Si

mc-Si

sc-Si

Thin

Film

Wafer


5

Average growth

2000-2010

40% per year

DOE (2008), EPIA (2011), EIA (2012), UN (2012)

0

10

20

30

40

50

60

1999E 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011E

Glo

ba

l In

sta

lled

Ca

pa

city [

GW

]

Other

Ribbon

CIGS

CdTe

a-Si

mc-Si

sc-Si

Thin

Film

Wafer


6

Average growth

2000-2010

40% per year

DOE (2008), EPIA (2011), EIA (2012), UN (2012)

90%

crystalline

silicon

0

10

20

30

40

50

60

1999E 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011E

Glo

ba

l In

sta

lled

Ca

pa

city [

GW

]

Other

Ribbon

CIGS

CdTe

a-Si

mc-Si

sc-Si

Thin

Film

Wafer


7 DOE (2008), EPIA (2011), EIA (2012), UN (2012)

90%

crystalline

silicon

46%

manufactured

in China

Average growth

2000-2010

40% per year

0

10

20

30

40

50

60

1999E 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011E

Glo

ba

l In

sta

lled

Ca

pa

city [

GW

]

Other

Ribbon

CIGS

CdTe

a-Si

mc-Si

sc-Si

Thin

Film

Wafer


8 DOE (2008), EPIA (2011), EIA (2012), UN (2012)

90%

crystalline

silicon

75% installed

in EU

46%

manufactured

in China

Average growth

2000-2010

40% per year

Outline:

• Background



• Results

• Conclusions

9

Silicon production is very energy intensive…

10 Silicium Kazakhstan LLP – source: http://www.thyssenkrupp.com

…and that’s just the first step!

11

Poly-Si


12

Poly-Si Ingot


13

Poly-Si Ingot Wafer


14

Poly-Si Ingot Wafer Cell


15

Poly-Si Ingot Wafer Cell Module


16

Poly-Si Ingot Wafer Cell Module System


17

Financial costs ≠ energy costs

Polysilicon

12 %

Ingot

6 %

Wafer

9 %

Solar cell

14 %

Solar panel

25 %

System

34 %

Polysilicon

21 %

Ingot & Wafer

36 %

Solar cell

11 %

Solar panel

19 %

System

13 %

FINANCIAL COST

ENERGY COST

Poly-Si Ingot Wafer Cell Panel System

Swanson

(2011)


18

Financial costs ≠ energy costs

Polysilicon

12 %

Ingot

6 %

Wafer

9 %

Solar cell

14 %

Solar panel

25 %

System

34 %

Polysilicon

21 %

Ingot & Wafer

36 %

Solar cell

11 %

Solar panel

19 %

System

13 %

FINANCIAL COST

ENERGY COST

Poly-Si Ingot Wafer Cell Panel System

Swanson

(2011)

Alsema (2011)

Cumulative energy demand – meta-analysis

19

Kreith (1990)

Prakash (1995)

Kato (1997)

Keolian (1997)

Alsema (2000)

Frankl (2001)

Knapp (2001)

Mathur (2002)

GEMIS (2002)

Gürzenich (2004)

Krauter (2004)

Battisti (2005)

Fthenakis (2006)

Muneer (2006)

Mason (2006)

Kannan (2006)

Mohr (2007)

Pacca (2007)

Raugei (2007)

Ito (2008)

Stoppato (2008)

Roes (2009)

Fthenakis (2009)

Raugei (2009)

Zhai (2010)

Nishimura (2010)

Held (2011)

Laleman (2011)

0

2

4

6

8

10

12

14

16

All sc-Si mc-Si a-Si ribbon CdTe CIGS

(n = 57) (n = 10) (n = 21) (n = 10) (n = 3) (n = 9) (n = 4)

CE

D [kW

h(e

)/W

]

Lower value is better – less energy intensive

WAFER THIN FILM

Energy inputs to PV – energy learning curves

20

Learning is

reducing

energy cost of

PV systems

101100 103102 105104

101100 103102 105104

101100 103102 105104

101100 103102 105104

0.1

1

10

100

0.1

1

10

100

0.1

1

10

100

0.1

1

10

100

THIN FILM

sc-Si

mc-Si

a-Si

CdTe

Em

bo

die

d E

ne

rgy [kW

he/W

p]

Cumulative Production [MW]

WAFER

CE

D [kW

h(e

)/W

]

Outline:

• Background



• Results

• Conclusions

21

Energy flows: single plant

22

EPBT = 2 yrs

EROI = 12.5

Energy flows for PV industry – 100% growth rate

23

INP

UT

S

OU

TP

UT

S

t (yrs)

Net P

ow

er

[J/y

r]


24

INP

UT

S

OU

TP

UT

S

t (yrs)

Net P

ow

er

[J/y

r]


25

INP

UT

S

OU

TP

UT

S

t (yrs)

Net P

ow

er

[J/y

r]


26

INP

UT

S

OU

TP

UT

S

t (yrs)

Net P

ow

er

[J/y

r]


27

INP

UT

S

OU

TP

UT

S

t (yrs)

Net P

ow

er

[J/y

r]

Energy flows for growing industry

28

Energy

Subsidy

Energy

Payback

Payback

Year

Gross Output

Net Output

Net P

ow

er

[J/y

r]

INP

UT

S

OU

TP

UT

S

time

(decades)

Growing industry requires ‘start-up capital’

Breakeven

Year

1 10

10

100

1 10

Cumulative Electricity Demand [kWhe/Wp]

Gro

wth

Ra

te [

%/y

r]

EPBT [yrs] assuming 11.5% capacity factor

70 %

300 %

400 %

fractional re-investment 20 %

NEGATIVE NET ENERGY YIELD

80 %

90 %

100 %

250 %

30 %

40 %

50 %

POSITIVE NET ENERGY YIELD

500 %

700 %

60 %

125 %

20

40

60

80

2 8

150 %

175 %

200 %

4 5 3 9 7 6

2 84 5 3 9 7 6

30

50

Growing industry may be a net energy sink

29

ENERGY

DEFICIT

ENERGY

SURPLUS

Outline:

• Background



• Results

• Conclusions

30

Growth trajectory for sc-Si

31

1 10

10

100

1 10


Gro

wth

Ra

te [

%/y

r]


70 %



80 % 90 %

100 % 30 %

40 % 50 %


60 %

125 %

20

40

60

80

2 8

150 %

175 %

200 %

4 5 3 9 7 6

2 84 5 3 9 7 6

30

50

250 %

300 %

200

400 %

500 %

1000 %

750 %

2000

2002

2004

2006

2008

2010

1 10

10

100

1 10


Gro

wth

Ra

te [

%/y

r]


70 %



80 % 90 %

100 % 30 %

40 % 50 %


60 %

125 %

20

40

60

80

2 8

150 %

175 %

200 %

4 5 3 9 7 6

2 84 5 3 9 7 6

30

50

250 %

300 %

200

400 %

500 %

1000 %

750 %

mc-Si

Ribbon

sc-Si

CdTe

CIGS

a-Si

2000

2002

2004 2006

2008

2000 2000 2000

2000 2000

2010

2010

2010 2010

2010

Trajectories for all PV technologies

32

Growth trajectory for the PV industry

33

1 10

10

100

1 10


Gro

wth

Ra

te [

%/y

r]


70 %

300 %

400 %



80 %

90 %

100 %

250 %

30 %

40 %

50 %


500 %

700 %

60 %

125 %

20

40

60

80

2 8

150 %

175 %

200 %

4 5 3 9 7 6

2 84 5 3 9 7 6

30

50

2000

2010

Results:

34

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

-100

0

100

200

300

400

500

600

2000 2005 2010 2015

Perc

ent of 2010 E

lectr

icity P

roduction [

%]

Pow

er

Pro

duction [

TW

h/y

r]

PV industry breaks

even in period 2006-

2014

Outline:

• Background



• Results

• Conclusions

35

Conclusions

• The PV industry is now likely (>50%) to be a net

electricity provider.

• The PV industry almost certainly become a net power

provider by 2015.

• The industry will ‘pay back’ the electricity consumed in its

early growth between by 2018.

• Even in our ‘worst-case’ scenario, GHG emissions

breakeven lags electricity breakeven by 3 years.

36

Implications

• Not all financial cost reductions lead to reductions in

embodied energy

Economic analysis should be supplemented with energy

analysis

• PV systems with lower energy costs provide more net

energy

These systems will also cost less money

Have lower associated GHG emissions

37

Implications

• We must continue reducing embodied energy of PV

systems:

Currently the PV industry consumes around 90% of its own

production

IF current growth continues, by 2025 this would represent

consumption of 2900 TWh/yr

IF learning continues, this consumption would be greatly

reduced 300 TWh/yr or 8% of gross output.

• Reducing energy costs of PV system production should

be an explicit goal of technology development

38

Acknowledgements:

• Thanks to GCEP for funding this research;

• Thanks to Prof. Sally Benson, Dr. Richard Sassoon, Prof.

Adam Brandt and Dr. Charles Barnhart for very fruitful and

enlivening discussions;

• Thanks to Prof. Mike McGehee, Dr. Jenny Milne, Patricia

Carbajales, Leigh Johnson, Mark Golden and Maxine Lym

for very helpful comments;

• Thanks to you for listening…

… any questions?

39

References:

• EPIA, (2010) Solar Generation 6, European Photovoltaic

Industry Association

• Swanson, R. (2011) The Silicon Photovoltaic Roadmap

,Stanford Energy Seminar Nov 14, 2011,

http://energyseminar.stanford.edu/

• EIA, International Energy Statistics (2012).

• UN, UN Energy Statistics Database (2012).

40



41 41

INP

UT

S

OU

TP

UT

S

time

(yrs)

Net E

nerg

y F

low

[J/y

r]

EROI for PV – meta-analysis

42

0

5

10

15

20

25

30

35

40


(n = 57) (n = 10) (n = 21) (n = 10) (n = 3) (n = 9) (n = 4)

ER

OI

[kW

h(o

ut)

/kW

h(e

)]

Higher value is better – higher energy return

WAFER THIN FILM

Energy payback time (EPBT) PV – meta-analysis

43

0

2

4

6

8

10

12


(n = 57) (n = 10) (n = 21) (n = 10) (n = 3) (n = 9) (n = 4)

EP

BT

(yrs

) Lower value is better – faster energy return

WAFER THIN FILM

Equivalence of CED and EPBT

44

0

2

4

6

8

10

12


(n = 57) (n = 10) (n = 21) (n = 10) (n = 3) (n = 9) (n = 4)

EP

BT

(yrs

) CED = EPBT at capacity factor of 11.5%

CE

D [

kW

h(e

)/W

]

- 12

- 10

- 8

- 6

- 4

- 2

- 0

WAFER THIN FILM

0

10

20

30

40

50

60

8 10 12 14 16 18 20

Perc

ent

glo

ba

l in

sta

lled

ca

pa

city [

%]

Capacity Factor [%]

Mean = 12.8

Median = 12.5

UN

Mean = 12.2

Median = 11.5

EIA

Global PV capacity factor

45 UN (2011), EIA 2012

Documents

The Energy Balance of the Photovoltaic (PV) Industrygcep.stanford.edu/pdfs/symposium2012/MikDale_Symp2012... · 2012-10-31 · The Energy Balance of the Photovoltaic (PV) Industry: