PV Expo Tokyo 26 02 2014 Sinke

www.ecn.nl

Silicon photovoltaics: prepared for terawatts Wim Sinke

ECN Solar Energy

PV EXPO 2014

Tokyo, Japan

26 February 2014

Contents

• Silicon photovoltaics: mature, yet young – half a century of development and much more to come

• Entering the terawatt regime within a decade – opportunities and challenges

• Shaping the future – technology contributions from ECN and its partners

• Outlook – a bird’s eye view

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Contents





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First Solar HyET Solar Würth Solar / Manz

Cell & module technologies

Commercial

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Flat plate: wafer-based silicon (90%) - monocrystalline - multicrystalline & quasi mono

Module efficiencies 14 22%

Toyota City of the Sun (NL)

Concentrator (<1%) - multi-junction III-V semiconductors - silicon


Abengoa/Concentrix FhG-ISE

Flat plate: thin films (10%) - cadmium telluride (CdTe) - copper-indium/gallium-diselenide/sulphide (CIGSS) - silicon


Concepts & technologies: lab and

pilot production (incl. “nanotechnology at km2 scale“)

• super-high-efficiency concepts (incl. combinations of existing technologies)

– more complete use of solar spectrum (optimize cell or modify spectrum)

– advanced light management (incl. macro- and micro-concentration)

• super-low-cost concepts (& technologies for new applications)

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Example: spectrum conversion using

quantum dots (Univ. of Amsterdam)

Example: polymer solar cell (Solliance)

Commercial module efficiencies (selection)

History + short-term projections (announced)

wafer Si IBC

wafer Si IBC

wafer Si mono wafer Si HIT

wafer Si multi CdTe

CIGS

tf a/µcSi

tf aSi

wafer Si IBC

M.J. de Wild-Scholten SmartGreenScans

(June 2013)



wafer Si IBC

wafer Si IBC


wafer Si multi CdTe

CIGS

tf a/µcSi

tf aSi

wafer Si IBC


(June 2013)



wafer Si IBC

wafer Si IBC


wafer Si multi CdTe

CIGS

tf a/µcSi

tf aSi

wafer Si IBC


(June 2013)

25% at low cost in 2020?

Commercial module efficiencies History + long-term projections (simplified estimates)

Wafer-based silicon technologies:

a variety of options (selection)

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Conductivity type

Crystal type Contact geometry

Junction geometry

Junction type

Light collection

Identity

P-type N-type

Multi Quasi-mono Mono

Front & rear Front Homo Front Today’s workhorse: monofacial

Front & rear Today’s workhorse: bifacial version

Hetero Front HJT / HIT (today’s high end)

Front & rear

Rear -

Rear Front Homo Front Metal Wrap-Through (MWT) (emerging) Front & rear

Hetero Front HJ-MWT (novel)

Front & rear

Rear Homo Front Interdigitated Back Contact (IBC) (today’s high end)

Front & rear

Hetero Front HJ-IBC (novel)

Front & rear -

Technology evolution in

wafer silicon based PV

front junction, front & rear

contacts

front-to-rear tabbing

typical module

efficiency range & TRL

cells

modules

17-21% 20-23% 22-25% 25-30% 30-35+% TRL 7-9 TRL 5-8 TRL 4-5 TRL 2-3 TRL 1-2

front junction, rear contacts

MWT

foil-based inter-

connection

rear junction, rear contacts

IBC

foil-based inter-

connection

IBC + thin-film 4-terminal

tandem

hybrid inter-connection

wafer-silicon + thin-film 2-terminal

tandem

t.b.d.

Technology evolution in

wafer silicon based PV

front junction, front & rear

contacts

front-to-rear tabbing

cells

modules

front junction, rear contacts

MWT

foil-based inter-

connection

rear junction, rear contacts

IBC

foil-based inter-

connection

IBC + thin-film 4-terminal

tandem

hybrid inter-connection

wafer-silicon + thin-film 2-terminal

tandem

t.b.d.

alternatives: bifacial,

heterojunction

alternative: bifacial

alternatives: bifacial, ultra-thin,

heterojunction

alternatives: ultra-thin,

heterojunction, spectrum converters

alternatives: bifacial, printed interconnection

alternatives: printed

interconnection

alternatives: ultra-thin,

spectrum converters

alternatives: bifacial

heterojunction

alternatives: bifacial

Towards and beyond 25% 1-sun

module efficiency at competitive cost

• Bring wafer-silicon technology to perfection (to 25%) – ST/MT – reduce process complexity and cost of current high-end technologies

– combine key features of current high-end technologies (e.g. rear hetero-junction, rear contact)

– use ultra-thin wafers + advanced light management

• Combine the best of two worlds (beyond 25%) - MT – high-efficiency wafer-silicon + wide-gap thin-film technology (2- or 4-terminal one-

sun tandem)

• Novel routes (to and beyond 25%) - MT/LT – high-efficiency wafer-silicon + spectrum converters

– other multi-gap approaches (bulk, quantum dots, nanowires, etc.)

– other high-efficiency approaches ( multi carrier, hot carrier, intermediate band, etc.)

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Challenge: combine the best of two

worlds for a record efficiency

14 (Dec. 2013)

Advanced light management for high

efficiency silicon cells

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Advanced light management for

ultra-thin solar cells (1)

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Advanced light management for

ultra-thin solar cells (2)

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sun tandem)




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Silicon wafer based tandems

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Challenges:

• Tandem module needs to be more efficient than silicon module

(higher energy output) – high quality, wide-gap top cell needed

• Tandem needs to be cost competitive – cost increase should be compensated by efficiency gain (at system level)

• Tandem module needs to meet high standards of existing silicon modules (lifetime and stability) – severe demands on top cell

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sun tandem)




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Nanotechnology for high-efficiency PV:

finding the way in a jungle of options

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Example: spectrum shaping to boost

efficiency (“add-on” to solar cells)

26 Courtesy: Tom Gregorkiewicz (Univ. of Amsterdam)


Contents





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Multi-terawatt use

Challenges and opportunities

• Competitive generation costs – typically 0.05 0.10 €/kWh (or below)

<0.51 €/Wp turn-key system price including sustainable margins

0.20.5 €/Wp module price

• High efficiency – cost reduction lever at all levels

– facilitates large-scale use

• From renewable to fully sustainable – Materials & processes

– Design for sustainability

• Total quality

Sustainability

Materials

Introduction of new materials driven by (potential) scarcity, by high prices or by price risks, e.g.: silver copper

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x7 in 7 years

Total quality

• All levels and aspects: components, systems, installers, production processes, etc.

• Need for coordination, information and communication

• High priority in R&D and industry

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Contents





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Selected innovations from the Netherlands

• Integrated cell & module design: Metal Wrap-Through (MWT) back-contact technology (ECN, Eurotron, a.o.)

• n-type silicon for high-efficiency, cost-competive cells and modules, mono- and bifacial (ECN, Tempress, a.o.) e.g. Yingli Panda module series

• Advanced light management using nanopatterns (AMOLF, ECN, a.o.)

• More on the way

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Integrated cell and module

architecture: MWT cell

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Base: p Base: p n+

Base: p n+

Base: p n+ n+

emitter

rear Al

ARC

MWT Ag

Front Rear

Integrated cell and module

architecture: MWT module

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4*4 via designInterdigitated Cu foilCA interconnection

Compatible with ultra-thin cells Low cell-to-module losses

Fast single-shot manufacturing

Ongoing MWT innovations

• Replace copper by aluminum in conductive foil

• Reduce encapsulant thickness and consumption of conductive adhesives

• Increase number of vias to further reduce losses and silver consumption

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Excellent aesthetics and many front

pattern design options

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ECN’s Black Beauty

technology only

technology ánd design

Contents





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The future of PV at a glance (rounded figures)

Current 2020

Long-term

potential

Commercial module efficiency flat

plate/concentrator (%) 722 / 2533 1025 / 3038 2050

Turn-key system price

(€/Wp)

13 (upper values for

specials)

()0.81.5 (with sustainable

margins)

0.51

Typical cost of electricity

(LCoE, €/kWh)

0.050.30 (range related to

investment and

insolation)

0.040.15 0.030.10

Energy pay-back time (yrs) 0.52 0.251 0.250.5

Installed capacity (TWp) 0.1 0.5 10++

The future of PV at a glance (rounded figures)

Current 2020

Long-term

potential

Commercial module efficiency flat

plate/concentrator (%) 722 / 2533 1025 / 3038 2050

Turn-key system price

(€/Wp)

13 (upper values for

specials)

()0.81.5 (with sustainable

margins)

0.51

Typical cost of electricity

(LCoE, €/kWh)

0.050.30 (range related to

investment and

insolation)

0.040.15 0.030.10

Energy pay-back time (yrs) 0.52 0.251 0.250.5

Installed capacity (TWp) 0.1 0.5 10++

x 23

x ½⅓

x 100++

Acknowledgements

Thank you:

• colleagues at ECN Solar Energy, AMOLF and University of Amsterdam;

• industry and research partners in the Netherlands and throughout the world;

• members of the European Photovoltaic Technology Platform;

for excellent work, vision and fruitful discussions.

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42 City of the Sun, Municipality Heerhugowaard, NL (photo Kuiper Compagnons)