Impact of Materials Prices on Cost of PV Manufacture Part I - - PowerPoint PPT Presentation

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

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technology platforms

flat-plate

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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

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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

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0% 20% 40% 60% 80% 100% 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

market Share

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-Si 31% multi-Si 57% CdTe 6% CIS 2% TF-Si 3%

Output by Technology (2011)

c-Si PV value chain

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MG Si Polysilicon Crystal Wafer Cell Module

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Case Study 1 – Silicon

polysilicon production

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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

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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

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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 output

PV electronics

50 100 150 200

polysilicon price ($/kg)

Solar-grade silicon price trend

PV cost reduction

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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

Source: IRENA Renewable Energy Technologies: Cost Analysis, Solar PV 2012

*

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.

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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 silver cell

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

• ther

ethylene

• xide

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%
• f demand but increasing

with market growth

• No shortage of silver but

supply driven by mining and price

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• 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

sources: The Silver Institute PR 7 Apr 2011 and Photon International 8-2011

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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

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Ni plating of solar cells - US DoE/JPL funded work April 1980

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Ni/Cu/Sn plate v Ag print

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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

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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

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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

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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-12

module price ($/Wp)

Factory-gate c-Si module prices

Message Incumbent industries will find innovative ways to overcome material shortages or price escalation

Source: Photon Consulting