Impact of Materials prices on Cost of PV Manufacture SMEET 2... · coins & medals silverware...
Transcript of Impact of Materials prices on Cost of PV Manufacture SMEET 2... · coins & medals silverware...
Impact of Materials Prices on Cost of PV Manufacture – Part I (Crystalline Silicon)
Nigel Mason SMEET II Workshop, London 27 Feb 2013
content
Brief introduction to Solar PV Technologies
Part I - Crystalline Silicon Case Study 1 - Silicon Silicon production, consumption, price, cost reduction and impact Case Study 2 - Silver Usage in PV, silver demand & price, alternative technology Part 2 - Thin Film to be resented by Chiara Candelise Conclusions
2 Candelise & Mason / SMEET II 27Feb13
technology platforms
flat-plate
Candelise & Mason / SMEET II 27Feb13 3
sun-tracking concentrator
mono-crystalline
multi-crystalline
silicon ribbon
a-Si / c-Si
CdTe
CIGS
DSC
Polymer OPV
SM-OPV
Thin Film Emerging Crystalline Silicon
technology status
Candelise & Mason / SMEET II 27Feb13 4
Thin Film a-Si/ c-Si CdTe CIS/CIGS
Best lab cell efficiency 13% 19% 20%
Commercial module 7-10% 9-13% 10-14%
Emerging DSC Polymer SM-OPV
Best lab cell efficiency 12% 11% 12%
Today’s module eff. 3-5% 3-5% -
Wafer-Based Silicon Mono c-Si Multi c-Si
Best lab cell efficiency 25% 20%
Commercial module 15-20% 14-17%
market share & trend
Candelise & Mason / SMEET II 27Feb13 5
0%
20%
40%
60%
80%
100%
19
99
20
00
20
01
20
02
20
03
20
04
20
05
20
06
20
07
20
08
20
09
20
10
20
11
ma
rke
t S
ha
re
a-Si
CIS
CdTe
ribbon-Si
multi-Si
mono-Si
88% of PV production (2011) is wafer-based crystalline silicon technology (c-Si)
Market share of c-Si technology >80% for past 13 years
Source: Photon International
mono-Si31%
multi-Si57%
CdTe6%
CIS2%
TF-Si3%
Output byTechnology (2011)
c-Si PV value chain
6
MG Si Polysilicon Crystal Wafer Cell Module
Candelise & Mason / SMEET II 27Feb13
Case Study 1 – Silicon
polysilicon production
7
Carbo-thermic reduction of
quartz Si + HCl = SiHCl3
Fractional distillation SiHCl3
Reduction in H2 to Si
Metallurgical Grade Si
Siemens process for semiconductor grade Si (polysilicon)
cost ~$2/kg ~$20/kg
Candelise & Mason / SMEET II 27Feb13
300,000 MT/year
Pre-2005 PV industry used scrap Si from semiconductor industry at price ~$20/kg
Around 2005 PV consumption of polysilicon matched semiconductor industry where price ~$50/kg
Rapid growth in PV 2005-2008 exceeded supply and spot price increased to $500/kg at peak
Subsequent expansion in polysilicon production has resulted in excess supply and price fall to ~$20/kg
silicon price
Candelise & Mason / SMEET II 27Feb13 8
42%55% 58%
68%80%
88% 92% 94%
58%45% 42%
32%20%
12% 8% 6%
2005 2006 2007 2008 2009 2010 2011 2012
PV share of polysilicon outputPV electronics
0
50
100
150
200
po
lysi
lico
n p
rice
($/k
g)
Solar-grade silicon price trend
PV cost reduction
Candelise & Mason / SMEET II 27Feb13 9
The actions
Before the Si price spike the PV modules cost was ~$4/Wp of which ~$1/Wp was the silicon cost
The industry response was to reduce Si consumption from 15 g/Wp to 5 g/Wp by
• Thinner wafers • Reduced kerf loss • Higher yields • Increased recycling • Higher efficiency
At the same time the polysilicon industry significantly increased capacity (3-year lead-time)
Temporary increase in module price 2005-2010
Silicon cost in PV module reduced from $1.00 to $0.20/Wp
and c-Si remains cost-leading technology * Spot price for c-Si module in Germany week 8/2013 was €0.53/Wp ($0.70/Wp)
The outcome
Sou
rce:
IREN
A R
enew
ab
le E
ner
gy
Tech
no
log
ies:
Co
st A
na
lysi
s, S
ola
r P
V 2
01
2
*
Case Study 2 – Silver
used for electrodes (contacts)
Electrical contacts are made to the top and bottom surfaces of the silicon cell
These contacts are used to interconnect cells in a module and carry current to external circuit
Silver-loaded paste is screen printed on the silicon and heated to 780°C to form Ohmic contact to silicon
Silver is not detrimental to cell performance, is inert to firing temperature and produces a surface to which metal ribbon can be readily soldered.
Candelise & Mason / SMEET II 27Feb13 10
silver - cost challenge
Remarkable reductions in PV module cost have been achieved over recent years
but rising silver metal price has limited cost reduction in cell fabrication
Best-practice wafer-to-cell conversion cost <$0.20/Wp
Typical silver paste cost $0.09/Wp
11
module
silicon
wafer
process
silvercell
module cost breakdown
paste consumption ~300 mg/cell156mm
silver cost $ 1.10/g silver cost in wafer $ 0.33/cell ($0.09/Wp)
Candelise & Mason / SMEET II 27Feb13
-
5,000
10,000
15,000
20,000
2008 2009 2010 2011e 2012e 2013e 2014e 2015e
Industrial Demand for Silver other
ethylene oxide
solder & brazing
electrical & electronic
PV
MT
sliver demand
• Industrial demand for silver 55% of supply
• Prime industrial use is electrical & electronics
• PV consumes around 6% of demand but increasing with market growth
• No shortage of silver but supply driven by mining and price
12
-
5,000
10,000
15,000
20,000
25,000
30,000
coins & medals
silverware
jewelry
photography
industrial
demand (2010)
-
5,000
10,000
15,000
20,000
25,000
30,000 net gov. sales
recycle
mine production
supply (2010)
MT
sou
rces
: Th
e Si
lver
Inst
itu
te P
R 7
Ap
r 2
01
1 a
nd
Ph
oto
n In
tern
ati
on
al 8
-20
11
Candelise & Mason / SMEET II 27Feb13
base metal alternatives
Nickel plated contacts were used in PV cells in the early 80’s by Solarex and Motorola
Requires on-cell mask (e.g. photolith.) for electroless Ni deposition
Oxidation of nickel and copper limit their use in printed and fired pastes
Copper an ideal conductor (92% conductivity Ag) but a detrimental impurity in silicon
2-layer Ni/Cu offers an effective solution
13
Ni plating of solar cells - US DoE/JPL funded work April 1980
Candelise & Mason / SMEET II 27Feb13
Ni/Cu/Sn plate v Ag print
14
Attribute Ag Screen Print Ni/Cu/Sn Plating
Lower material cost Ag price $1200/kg Cu price $9/kg
Narrow line width 50-120 m 20-40 m
Lower Resistivity 3-10 Ω.cm 1.7 Ω.cm
Lower contact resistance sensitive to firing temp. <1 mΩ.cm2
Higher aspect ratio (h:w) Range 1:10 to 1:2 1:2 or better
Lower firing temperature 750-800 C 350-400 C
Candelise & Mason / SMEET II 27Feb13
Laser pattern SiN
Ni plate
350°C sinter Ni-Si
Cu plate + Sn cap
Screen Print Ag paste
780°C fire-through SiN
Copper - more complex process but lower cost and improved performance
early adopters (of Cu)
15
Source: Ji-sun Kim (Shinsung Solar) et al., PVSC 2011
In production today
Pilot production or R&D
Candelise & Mason / SMEET II 27Feb13
Pioneered by
summary (from case 1 & 2)
A 3-fold decrease in Si consumption
per Wp and a 2-fold decrease in Si
price has driven c-Si to a low price
High silver price is driving a range of
short-term silver paste-reduction
initiatives but copper-based
contacts provide a long-term
solution to sustainable cost
reduction
16 Candelise & Mason / SMEET II 27Feb13
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
Dec-08 Dec-09 Dec-10 Dec-11 Dec-12m
od
ule
pri
ce ($
/Wp
)
Factory-gate c-Si module prices
Message
Incumbent industries will find innovative ways to overcome
material shortages or price escalation
Source: Photon Consulting