Photovoltaics; Opportunities and Challenges Photovoltaics; Opportunities and Challenges Harnessing...

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Transcript of Photovoltaics; Opportunities and Challenges Photovoltaics; Opportunities and Challenges Harnessing...

  • Emanuel
Sachs
 Fred
Fort
Flowers
and
Daniel
Fort
Flowers


    Professor
of
Mechanical
Engineering
 MIT



    Photovoltaics; Opportunities and Challenges

  • Harnessing solar energy is critical

    •  Covering
0.2%
of
the
land
area
of
the
US
with
20%
 efficient
PV
systems
would
generate
all
the
electricity
 that
the
US
consumes


  • History and Status of Silicon PV

    *LCOE calculated assuming 5.75kWh/m2/day (17% capacity factor), a 7% discount rate, and a 30-year project life.

  • Solar at the cost of coal

  • Wafers; Sawn ingots vs. Kerfless Current Silicon-Wafer Process

    Cast Ingot Cut Brick

    5


    Saw Wafers Clean & Damage Etch Wafers

    2X of Everything for

    1 Wafer

    Silicon to Wafer in 1 Machine

    Mold
 Wafer


    Pure Silicon

    50% contaminated

    waste

    Pure Silicon

    1366 Direct Wafer (DW)

  • Direct Wafer: Timeline

    1/09 Dec Conception

    First Tin Wafers

    First Silicon Wafers

    Win $500k NREL

    Win $4M

    ARPA-E

    First cells

    1/10 6” furnace design and build

    Scale to 3” wafers

    12.5% cells

    15-16% on 6”

    wafers

  • String Ribbon silicon Issues:
 1.  Break
quality
/


    throughput
tradeoff


    2.  Reduce
capital
costs


    3.  Produce
standard‐size
 wafer


  • Vertical ribbon growth Increasing Growth rate → Low Lifetime

    → high dislocation density → low lifetime (after Bentzen, J. Appl Phys. 99)

    Maximize
growth
rate


→


high
temperature
gradient
&
curvature

 → high stress

    Te m pe

    ra tu re

    Height

  • Self-Aligned Cell

    Self‐Aligned
 MetallizaUon


    30µm fingers Texture and grooves in 1 step

    Light-trapping texture guides precision metallization

    9


  • Isotexture Issues •  Light
trapping
 •  CosmeUc
uniformity
and
 consistency


    •  Saw
damage
sensiUvity
 •  Wafer
quality
sensiUvity


    –  ShunUng
at
dislocaUons
 •  Inconsistent
with
future
PV
 direcUons
 –  Rear
dielectrics
 –  Kerfless
wafers


  • 1366 Texture Solution •  Elegant,
low‐cost,
texturing
 technology
to
simultaneously:


    1.  Form
honeycomb
front
 texture
 o  Best
proven
texture
for


    mulU


    2.  Polish
the
back
 3.  Form
front
grooves
if


    desired
 o  High
performance


    metallizaUon


  • 1366 Metallization Solution

    •  Self
aligned
deposiUon
of
Ag
paste
into
grooves
 •  Plated
fingers


  • China Leading Global Race to Make Clean Energy Jan 30, 2010

    •  Largest
Manuf
of
Wind
 Turbines


    •  Largest
Manuf
of
solar
 panels


    •  2%
loans
to
build
 factories


  • PV in China

    •  Cost
of
capital
 •  Labor
rate
 •  Cost
of
raw
materials
 •  Permicng
and
Environmental


    Total
cost
advantage
with
idenUcal
 technology
~30%


  • Basic Science; US Dominates

    Balance of Trade??

  • Can Silicon PV be Manufactured in US Silicon is >80% of PV market,

    but US trails Asia/Europe

    Source: Photon International

  • 1366 Strategy in Cell Making

    •  Sell
Equipment
 •  Partnered
with
RENA,
global
leader
in
wet
 processing
for
PV,
based
in
Germany


    •  First
product
launch
scheduled
for
Sept
2010


  • U.S. In Manufacturing: The Bigger Picture

    Restoring American Competitiveness Gary Pisano and Willy Shih Harvard Business Review, July-Aug 2009.

    •  Decades of outsourcing manufacturing has left U.S. industry without the means to invent the next generation of high-tech products that are key to rebuilding its economy”

    •  Industrial Commons: the collective R&D, engineering, and manufacturing capabilities that sustain innovation

  • Summary

    •  Lots
of
US
innovaUon
in
PV
 •  US
may
be
able
to
secure
a
posiUon
in
PV
 manufacturing
equipment


    •  In
current
environment,
Asia
will
dominate
 manufacturing
of
PV
products.


    •  Economists
need
to
take
into
account
collateral
 damage
of
moving
manufacturing
offshore.


    •  Loss
of
supply
chain
jobs.
 •  Loss
of
industrial
commons.