Finding Alternatives to Critical Materials In Photovoltaics and Catalysis

Jim Stevens and Harry A. Atwater

Corporate Fellow Howard Hughes Professor Core Research & Development Applied Physics The Dow Chemical Company Caltech

August 21, 2012

Part II: Industrial Perspective

Strategic Elements

Strategic material - properties are essential to nation, performs a unique function, and no viable alternative exists.

Critical material – Strategic material with significant risk of supply disruption.

Prediction of future demand is difficult - distribution of metal use changes with time as demands change. Digital photography - huge reduction in demand for

silver for film since 2000.

Silver for PV contacts and thin fibers in socks to counteract odors more than compensated Ag demand.

Slide 2

Criticality Depend on Timescale

Other sources include Pt-group (Pt,Pd, Rh, Ir, Ru, Os)

Slide 3

Source - DOE “Critical Materials Strategy” report, 2010.

Issues in Finding Alternatives to Critical Materials in Catalysis

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Context – Homogeneous / Heterogeneous Catalysts

Product/catalyst separation is easy

More stable / high reaction temp. possible.

Challenging to study. Poor degree of synthetic

control.

Opportunities Rational design of sophisticated

Het. cats. Emissions catalysis.

More selective / high reaction rates.

Can design complex structures for specific jobs.

Amenable to study and rational design.

Limited to lower reaction temperatures.

Opportunities New reaction mechanisms. High throughput techniques.

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Heterogeneous Homogeneous

Context – Catalysis in Chemical Industry

Catalysts produce many moles of product per mole of catalyst (productivity) ⇒ used in small amounts

Catalysts have very high rates of reaction (turn-over frequency) ⇒ used in small amounts.

>2,000,000 t/o; 600,000 h-1 tof1

Largest application of asymmetric catalysis ~10,000,000 Kg/y requires ~5 Kg Ir (assumes no recycle)2

(0.1% of 2010 Ir imports)

Slide 6 1 H.U. Blaser, et al., Chimia 53 (1999), 275. 2 Calculated from data in Blaser, Adv. Synth. Catal. 2002, 344, 17.

Ligand Cost Can Dominate Catalyst Cost

Enantioselective homogeneous hydrogenation catalyst.

Ir represents < 30% of catalyst cost.*

Generally metal can be recovered but ligands can not. Slide 7 * Calculated from data in Blaser, Adv. Synth. Catal. 2002, 344, 17 and spot market price of Ir on 9/15/2011

Ligand Cost Can Dominate Catalyst Cost

Ethylene copolymerization, EPDM catalyst

Ti ~ 0.05 – 0.5% of total catalyst cost1

Slide 8 1 Calculated from data in Metallocene Monitor and spot market metal price on 9/15/2011.

Isotactic polypropylene catalyst

Zr ~ 0.05 – 0.5% of total catalyst cost1

Enantioselective hydrogenation catalyst

Rh < 15% of total catalyst cost2

• Pt $57,544 • Pd $23,044 • Rh $59,707 • Ir $37,038

• Os $13,404 • Co $37 • Ni $22 • Ti $10

• Au $54,480 • Ag $1,280 • Zr $50 • Ru $5,997

2 P. Moran, Dow Chemical, personal communication.

Metal Spot Market $/Kg

Rhodium Historical Price (Spot market)

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$-

$50,000

$100,000

$150,000

$200,000

$250,000

$300,000

$350,000

Jan-00 May-01 Oct-02 Feb-04 Jun-05 Nov-06 Mar-08 Aug-09 Dec-10

Rhodium, $/Kg

Issues With Catalysts in Refineries

Refineries use enormous quantities of catalysts – millions of Kg. FCC units crack ~2x109 L/day of ~C14-C42

Reforming, isomerization reactions – Pt, Pd. PGM’s can be considered as working capital. Metals price can swing significantly, affecting

earnings. Limitations on supply of some particularly

rare elements for such large volume catalysts.

Potential opportunity for non-PGM catalysts. Slide 10

Hydrosilylation Catalysis

4-6 MT of Pt (as metal) per year is consumed in cured silicones and “lost” with the product*- $252M - $377M at 9/15/2011 price.

Additional 0.8 – 1.2 MT Pt used in silane / organofunctional silicone, high % recycled.*

Mechanism credit to T. Don Tilley, UC Berkeley * Richard Taylor, Dow Corning Corp., personal communication

Potential Opportunities in Hydrosilylation Catalysis

Desirable improvements: Lower cost catalysts ($ / Kg product), especially for

cured elastomers. Need to meet critical performance requirements to be

commercially viable (kinetics, “snap cure”, chemo- selectivity, environmentally benign, etc.).

Higher selectivity (regio-, chemo-, enantio-).

Potential approaches: Identify new silane, olefin activations Identify new mechanisms for hydrosilylation (e.g., mechanisms that

do not require a 2-electron redox process) High-throughput discovery

Slide 12

Pt $57,000 / Kg* Pd $23,000 / Kg Ni $22 / Kg

Slide prepared with T. Don Tilley, UC Berkeley * Spot price, 9/15/2011

Acetic Acid

5 million MT y-1 produced by catalytic carbonylation of methanol (2nd largest use of homogeneous catalysis).

1963 – BASF Co2(CO)8 catalyst 1970 – Monsanto [I2Rh(CO)2]- catalyst 1990’s – BP Cativa process [I2Ir(CO)2]- / Ru promoter -

~350 KTPa plant 2000’s – Celanese AO+ process – Rh / better I and

H2O management - ~800 – 1,200 KTPa plant, lower capital

Slide 13

Cativa Acetic Acid Process (BP)

Runs in same plant as Monsanto Rh-based process.

Lower H2O in process – lower capital from fewer drying columns

Higher selectivity Lower propionic acid Suppresses water-gas shift

reaction

Slide 14

Ir – a “non-critical” PGM? Acetic acid synthesis may not be a good opportunity for future research.

Monoliths AERIFY* Assemblies AERIFY*

Advantages of diesel • High performance & High torque • Durability & Reliability At least 500,000 miles life • Low maintenance • Fuel Economy 30% better than gasoline engine • Low gas emission (HC, CO, NOx) • Low CO2/mile (GHG)

Disadvantages • PM emission • Difficult to reduce NOx by existing catalyst

technology

• Emissions catalysis consumes 81% of PGM imports.

• CeO2 also used as oxygen buffer / NOx reduction.

• Some Pt can be substituted with Pd, Rh.

Slide 15 * Registered Trademark of The Dow Chemical Company

Opportunities for Emissions Catalysis

Non PGM catalysts Cannot form volatile compounds with CO (i.e.,

Ni) Need to meet critical performance

requirements / legislated standards. Cu cannot be used in N.A.

Better NOx catalysts, especially for diesel

particulate filters, new filter structures.

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Page 17

The LP OxoSM Process

World production levels - 2.5 million mt.p.a. of 2EH - 4.5 million mt.p.a. of butanols - 95% made by Rh catalysed hydroformylation Olefin hydroformylation is the largest volume homogeneous catalytic

reaction

• 1975 - UCC commercialised Rh-PPh3 catalyst - Low pressure (17 bar) and temperature (90oC) - 200 equivalents of PPh3 required - n:iso ratio = 10 • 1995 - UCC commercialised Rh-bisphosphite catalyst - 50 times more active than PPh3 system - Lower pressure (7 bar) and temperature (75oC) - n:iso ratio = 30

Potential Opportunities in Hydroformylation and Enantioselective Catalysis

Desirable improvements: Higher chemoselectivity and/or functional group tolerance Need to meet critical performance requirements to be

commercially viable (kinetics, overall catalyst cost including ligand, stability, sensitivity, safety, etc.).

Enantioselective catalysts with high rates and TON for addition reactions to C=O bonds Aldol reaction, Ene reaction, addition of MR to RCHO, Hetero Diels-

Alder, addition of CN- to C=O. Enantioselective catalysts with high rates and TON for cross-coupling

and metathesis reactions.

Potential approaches: Identify new mechanisms. High-throughput discovery methodologies New ligand families.

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Issues in Finding Alternatives to Critical Materials in Photovoltaics

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Why Does Chemical Industry Care About PV?

Chemical Industry is a large consumer of electricity/energy Dow Chemical uses as much electricity as Australia, and

~1x106 barrels of oil equivalent per day.

Huge addressable market. Worldwide electricity consumption: 20 PWh / $2 Trillion Low market penetration - Oct 2011 US PV electricity: 169

GWh from total of 309,279 GWh (0.05%) (US EIA)

Technological materials-based solution with rapidly changing & disruptive economics. At inflection point for economic viability

Plastic, adhesives, encapsulants, wafer processing chemicals, etc. supply.

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2010 - 2011 Solar Sector Dynamics

Enormous capacity build (2H 2010-1H 2011), especially in China.

2 Demand “shocks” from austerity measures and subsidy cuts Italy Q4 2010-Q3, 2011. Germany Q1-Q2 2011.

Inventories soared, prices collapsed >50%1

$0.80 - $1.00 per Wp module

Resulting shakeout of non-competitive technologies.

Spectacular and highly politicized solar module manufacturer bankruptcies. Solyndra, Evergreen Solar, SpectraWatt, Energy Conversion Devices,

Uni-Solar Ovonic, Q-Cells

Slide 21 1. Axiom Capital report, and A. Goodrich, Sr. Analyst NREL, personal communication.

Today

0.1

1

10

100

1980 2000 2020

Mod

ule

Sale

s Pr

ice,

$/W

Two Electricity Delivery Architectures

Centralized Grid-Tied Distributed

Generation cost + Connection fee = Cost to consumer

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Generation cost + Connection fee + Transmission cost + Utility profit + Taxes & fees

= Cost to Consumer

Your view of PV electricity depends on which side of the electric meter you are on (consumer vs. producer)

US Electricity Consumption Rises Steeply below $0.18/kWh

Slide 23

• PV electricity cost is a function of capital ($/W), lifetime, interest rate & average insolation.

• Average US insolation is 4.8kWh / m2 * day. (NREL).

• PV electricity value at $0.118 / kWh (US residential average) ranges from $0.06 / m2 * day (10% efficient) to $0.59 / m2 * day (100% efficient) at average US insolation.

• Current PV market penetration – 0.05% of total US electricity production. At $2/W total installed cost, >$1.5 trillion of

demand potentially economically served by residential PV.

$2/w $3/w $4/w

.Source - US EIA, Oct 2011

4 Key Obstacles to Widespread Residential Solar Adoption

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1. Installation complexity 2. Aesthetics 3. Price 4. Warranty concerns

The Opportunity: Dow set out to design a cost effective, easy to install, and aesthetically appealing roofing material that both generates electricity and withstands elements for 20+ years

Rooftop Area from Navigant Consulting

This would provide 7.0 EJ/yr with 20% modules (50% total US demand)

Total residential rooftop area available for PV systems in US: 6.4 billion m2

(total area of Delaware)

POWERHOUSE™ Photovoltaic Shingles

Core R&D/Energy/Dow Wire& Cable Thin film processing Mfg. process optimization Materials Science expertise Wire & Cable business

Dow Plastics /Specialty Films PV packaging Back sheet, low-cost injection molding

Dow Building Solutions BIPV commercial roofing BIPV residential roofing

Top layer

Encapsulant

Back sheet

Strategic / Critical Materials in PV

Slide 26

Steel

Barrier

Absorber

+

-

Emitter

Window

TCO

Price could be the limitation (Rare = expensive) Supply & demand are difficult to predict

$0 $50

$100 $150 $200 $250

1990 1995 2000 2005 2010 2015

Te, U

S$/K

g

Tellurium

0 200 400 600 800

1000 1200

1990 1995 2000 2005 2010 2015

In, U

S$/K

g

Indium

Indium (ITO)

Tellurium (CdTe), Indium (CIGS)

Silver (ECA)

Caltech/Dow Earth Abundant PV Project Combining the R&D strengths of Dow and Caltech to create a powerful alliance for innovation in the field of Photovoltaics

Focus on development and commercial implementation of PV materials that are inexpensive and earth abundant such as Zn3P2 and Cu2O

from P.H. Stauffer et al Rare Earth Elements – Critical Resources for High Technology, USGS (2002)

Summary

Most industrial chemical processes are very efficient users of PGM’s and other critical metals

Emissions catalysis is a significant opportunity & consumes significant amounts of PGM’s.

Hydrosilylation catalysis consumes ~2-4% of annual Pt imports (2010 basis).

Alternatives to critical materials must meet numerous critical performance requirements to avoid significant economic impact.

Extension of thin-film PV technology to the terawatt scale demands abundant materials and high efficiency.

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