photovoltaics - markets and technologies 2010

Hansjörg GablerZentrum für Sonnenenergie- und Wasserstoff-Forschung (ZSW)

Baden-Württemberg, Stuttgart, Germany

DAAD Summer School 'Solar Shift'

ZEE – Zentrum für Erneuerbare EnergienAlbert-Ludwigs-Universität Freiburg, Germany

Freiburg, 31 May 2011

Electricity from the Sun -an Introduction

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PV-generator on farm-building roofs(Peiting-Hausen, 77 kWP, 2003)

Source: Sputnik Engineering AG / Photon 10/2003

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Photovoltaics: direct conversion of sunshine into electricity!

New installations¹ in year 2010, world: 15.4 GW

Cumulative installation until end of 2010: 37.4 GW Electricity produced² from PV in 2010, world: 44 000 GWh

Net electricity generation Germany in 2009: 617 000 GWh

Net electricity generation³ Bangladesh in 2008: 26 000 GWh

(1): Rated capacity, Photon 3/2011, p. 36, average from 10 independent estimates (2): very rough estimation: 'production' = 1200 kWh/a*kW(3): 'country Report', Hirak Al-Hammad PPRE, 2009 Oldenburg University, Oldenburg

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Source: EPIA: 'Global market outlook until 2013', www.epia.org

1250

7600

1100

600

350

350

900

900

400350

ROW 1250 MWGermany 7600 MWCzech Rep.1100 MWFrance 600 MWSpain 350 MWBelgium 350 MWUSA 900 MWJapan 900 MWChina P.R. 400 MWCanada 350 MW

PV Systems installed 2010: 15.4 GW

Source: Photon, 3/2011, p. 38, average of estimates, rounded

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Solar cells are electrically connected “in series” to achieve higher voltages

Source: Photon Special 2004

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Typical Structure:

• Glass• Transparent lamination foil

(Ethylen Vinyl Acetat: EVA)• Solar cells, electrically connected• back side protection

(Teflon foil or glass)

Packaging of solar cells into a solar “module” protects against destructive environment

Source: Photon Special 2004

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Module (Solar Panel):

Siemens SM55 monocrystalline Silicon

Source: Siemens Solar GmbH, Germany

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PV-generator on farm-building roofs(Peiting-Hausen, 77 kWP, 2003)

Source: Sputnik Engineering AG / Photon 10/2003

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Definitions

Solar cellthe solar cell is the basic unit which makes electricity from sunlight

Solar panel (or: solar module)the solar panel contains a number of cells and protects them

Solar arraythe solar array is the installaton of one (or many) solar modules

Solar system (or: solar generator)the solar system includes inverters or batteries (if needed) etc.

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Cost breakdown for a solar system based on Si-wafer PV cells, status 2006

Dates from J. Conkling, M. Rogol, The true cost of solar power, (Solarverlag, April 2007)

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Solar cell production 1999 to 2010

Quelle: PHOTON International 2011

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Shares per region for 2010 (2009)

Quelle: PHOTON International 2011

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PV industry turnover

PV systems installed in 2010: 15.4 GWprice of system installed: 3.0 €/W

→ turnover solar industry: 45 billion €

annual solar industry growth rates ˃ 50% over last 10 years

turnover semiconductor industry (components): 200 billion €annual long term growth rate 10%

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Price of PV-Systems and PV-Electric EnergyExpected development: SRA EU PV Platform (2007)

0.030.06(competitive

with wholesaleelectricity)

0.15(competitive

with retail electricity)

0.30>2Typical electricity generation costs, Southern Europe(2007 €/kWh)

0.512.55>30Typical turn-key system price(2007 €/Wp, excl. VAT)

Long term potential

20302015Today1980

Source: A strategic research agenda for Photovoltaic Solar Energy TechnologyPrepared by EU PV Technology Platform, Final Version June 2007

Assumptions: System yield at 1700 kWh/m²/yr: 1275 kWh/kWp/yr, O&M = 1 % of system price/yr, discount rate 4 %, depreciation time 25 years

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Why electric power from Photovoltaics?

four alternative motivations:

cost: PV may be the „least cost“ solution today

resources: PV is an alternative to the limited „classic“ energy sources, which will show in future high prices and limited accessibility

environment I: PV helps to avoid waste heat-, dust-, noise-, exhaust gas-, slag- and radionuclides emissions as well as risks

from the operation of nuclear power stations

environment II: PV helps to avoid the emission of „greenhouse gases“

Quelle: Photon 1/2001

International Space Station ISS,

1. Ausbaustufe: 62 kW (+ 16 kW)

Si-Zellen, = 14,5 %

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Rural Electrification: China

Suohourima township in November 2005, Qinghai Province

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Rural Electrification: China

System operator in front of 40 kW PV Generator, Suohourima

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Farmer with Solar Home Systems, June 2007, Kesheng, Qinghai Province

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Grameen Shakti, BangladeshSHS / PV: 40 – 120 Wpprice: 430 US$ for 50 W-system

microcredit:downpayment: e.g. 25%,loan@4%, payback over 2 years

60 000 SHS per annum (2008)110 000 SHS (2009)source: The Ashden Awards for Sustainable Energy(www.ashdenawards.org)and: www.gshakti.org

Bangladesh, end of 2009:SHS (total): 438 000 Installations in 2009:168 000source: Shahriar Ahmed ChowdhuryUnited International UniversityDhaka, Bangladesh,private communication.

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Why electric power from Photovoltaics?

four alternative motivations:

cost: PV may be the „least cost“ solution today

resources: PV is an alternative to the limited „classic“ energy sources, which will show in future high prices and limited accessibility

environment I: PV helps to avoid waste heat-, dust-, noise-, exhaust gas-, slag- and radionuclides emissions as well as risks

from the operation of nuclear power stations

environment II: PV helps to avoid the emission of „greenhouse gases“

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Navarra, Spain. Total power 1.2 MW, 280 tracker units with „BP-Saturn“ modules, 120 trackers with modules from other suppliers. Tracking along azimuth axis, module tilt 45°, commissioning 2003.

Source: EU PV Project Synopsis, 2003

Grid Connected PV Power:

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PV-generator on the roof of a family house (Sperberslohe-Wendelstein, 4.0 kWP, 2001)

Source: Photon 3/2005

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German 'Renewable energy law' (I) (renewable energy sources act, EEG)

Target: 30% of electricity delivered to customers shall be produced from renewable energies

(small hydro, land fill gas, biomass, geothermal, wind, photovoltaics) until year 2020

Electricity supplier must connect any producer of renewable electricity and must buy electricity for prices given by the law (feed in tariff)

Prices valid in year of installation are guaranteed (for PV) for 20 years

Prices for the kWh are reduced each year to force technical progress (degression)

Costs of the law are shared by (almost) all consumers of electricity via a supplement paid to each kWh (be it from coal, renewable or nuclear) which is consumed

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German 'Renewable energy law' (II) (renewable energy sources act, EEG)

Feed-in tariffs for electricity from PV:

01.01. - 30.06.10 Rooftop systems

<30 kW 39.14 c/kWh 30 – 100 kW 37.26 c/kWh100 – 1000 kW 35.23 c/kWh > 1000 kW 29.37 c/kWh

Ground based 1 28.43 c/kWh

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PV module prices 2009 to 2011

Jan.2009 Mar.2011 price fell to: €/Wp €/WpX-Si, EU: 3.19 1.61 50%

X-Si, China: 2.93 1.32 45%X-Si, Japan: 3.18 1.54 48%TF-CdTe: 2.09 1.09 52%TF-a-Si: 2.21 0.94 43%

international spotmarket net bid prices,source: www.pvXchange.com

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German 'Renewable energy law' (II) (renewable energy sources act, EEG)

Revision 12.08.2010

01.01. - 30.06.10 01.10. - 31.12.10 from 01.01.11 Rooftop systems

<30 kW 39.14 c/kWh 33.03 c/kWh 28.74 c/kWh 30 – 100 kW 37.26 c/kWh 31.42 c/kWh 27.34 c/kWh100 – 1000 kW 35.23 c/kWh 29.73 c/kWh 25.87 c/kWh > 1000 kW 29.37 c/kWh 24.79 c/kWh 21.57 c/kWh

Ground based 1 28.43 c/kWh 25.37 c/kWh 22.07 c/kWh

Additional regression of feed in tarifs by ca.16% in two steps (01.07.10 und 01.10.10)

Support of ground based systems severely restricted from 01.10.10

(1) auf 'Konversionsflächen'

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German 'Renewable energy law' (III) (renewable energy sources act, EEG)

Revision 12.08.2010

Annual degression: for roof top systems: ... < 100 kW: -9%

100 – 1000 kW: -10%

>1000 kW: -11%

This degression will be increased by up to 4% (2011) resp. 12.5% (2012) if the target for new installations (3500 MW) is surpassed.

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Notwithstanding severe price decreases,

PV electricity is not yet competitive to traditional forms of

electricity (coal, large hydro ...)

to reach market competitiveness for bulk electricity,

Photovoltaics still has a long way to go!

'We've come far, and we have far to go',

(Paula Mints, Navigant Consulting, Palo Alto, Calif.)

And there are good reasons to go ahead ...

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Technologies of todays Photovoltaic cells:

Form of semiconductor: Crystalline wafers (slices) or: thin films on substrates

Material:

Crystalline silicon or:other semiconductors

Solar cell: absorber crystalline silicon

Source: wikipedia.org/wiki/solar_cell

200 μm

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CIS Thin Film PV cell

SEM picture of cross section of PV cellPicture: ZSW

TCO/ZnO

Absorber/CIGS

Back contact/Mo

Substrate/glass

Buffer/CdS

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Technology options for major cost reductions:

Progress and innovation in crystalline (Wafer) Si-technology:

increase efficiency, reduce material costs, innovate cell and module design

increase productivity of investment

Progress and innovation in PV Thin Film technologies

Concentrating Photovoltaics (CPV)

Emerging and novel PV-technologies

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European Union: “Strategic Research Agenda for Photovoltaic Solar Energy Technology” (June 2007)

Status Target 2015

Turn key system price 5 €/Wp 2.5 €/Wp

Cost of PV-module 2.0-2.5 €/Wp 1.0 €/Wp

(Poly-) Silicon consumption 10 g/W 5 g/W(Wafer thickness reduced, Kerf losses reduced, high yield handling etc.)

Efficiency of module (Poly-Si) 13 % > 17 %

Specific manufacturing plant investment (long term target) 1 €/Wp < 0.5 €/Wp

Module manufacturing: roll-to-roll / automatic module assembly

Component standardisation to reduce installation and maintenance costs

Bild poly si

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Price of Polysilicon¹

year 2004: 32 $/kg 2005: 100 $/kg 2006: 175 $/kg 2007: 200 $/kgsept. 2008: 393 $/kgnov. 2009: 55 $/kgMay 2011. 60 $/kg

(1): Photon 5/2008 and Photon international 4/2009, www.pvinsight.com,

Prices are spot prices!

Dates from J. Conkling, M. Rogol, The true cost of solar power, (Solarverlag, April 2007)Polysilicon price at 60$/kg (?)

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Maximised efficiency and innovative cell structures for monocrystalline and multicrystallie Silicon cells

Metal contacts (laser fired back contacts, selective emitters)

Light trapping

Surface passivation

Quality of bulk material

Innovative structures: back contact cells have (+) and (-) busbars on their back side (rear emitters, metal

wrap through or emitter wrap through)

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Progress and innovation in crystalline (Wafer) Si-technology

Progress and innovation in PV Thin Film technologies.

increase efficiencies

innovative production technologies



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Why Thin-Film Photovoltaics?

“Thin” => thin active layers on a cheap substrate, => low material costs ( material needed for 1 kW PV: CIS = 0.2 kg / X-Si = 10 kg)

“Thin” => little energy needed for production

Commercial technologies from the “flat panel display” and the making of architectural glass may be adapted.

==>Thin Film PV has high cost reduction potential!

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Deposition equipment for “low emission glass”

Picture: Von Ardenne Anlagentechnik

Producing >10 km² of complex thin layers on glass per year(10 km² of PV-module have a nominal capacity of > 1 GW)

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Thin Film PV Production Line, FirstSolar in OhioLine capacity: 25 MW/yrFoto: FirstSolar

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Vertical Integration in Production

POLY Si Si wafer Si cell PVmodule

thin-film factoryglass,rawmaterials

modules

Crystalline silicon

Thin-film technology

all production steps in one line

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The three thin film technologiesin production or under construction today, a-Si, CdTe, CIS

2007

14 %9 -12 %

-

CIS process is complex

CIS

12 %8 -10 %

-production,

CdTe

10-11 %6 -7 %

-production

-

a-Si / µc-Si

2012

14 %9 -

-

12 % -

-

CdTe: fast process

6 -7 %

- industrial mass

-in the market

-µ

Moduleefficiency

-

State of Technology

450 MW

1450 MW

1350 MW

industrial mass

duction on the way,

turn-key solutions

industrial mass pro-

Moduleefficiency

Moduleproduction

2010

Source: estimate ZSW, cell/module production 2010: photon 4/2011

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Development of Thin-Film Solar Cells

1975 1980 1985 1990 1995 2000 2005 2010 2015468

1012141618202224

ZSWNREL

20.3 %

16.5 %

13 % (stabilized)

C IS CdTe a-S i "m ulti junction" a-S i "sing le junction"

Eff

icie

ncy

[%

]

Year

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The PV park Buttenwiesen came online in Sept. 2004. With 1 MW installed power using amorphous silicon modules from Mitsubishi Heavy Industries, it was at it’s time the world’s largest ground-mounted PV generator with Thin-Film modules.Source: Phönix SonnenStrom AG

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Repperndorf near Würzburg, First Solar, CdTe,80.000 Modules, 6.3 MW

Source: Fraunhofer ISE

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Flexible and light weight Thin Film Modules

For the power market: Low cost PV-modules through “roll to roll” productionPicture: Solar Integrated, www.solarintegrated.com

Portable power source (mobile communications), integration into flexible structures (tent roofs, air ships)

IPC Solar, www.IPC-Solar.com

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Lidl, Vars, southern France, 1 MW,Unisolar Modules, a-Si, flexible membranes, on roof


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Quelle: PHOTON Europe GmbH 2011

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Why Concentration Technologies?

The basic idea:

Use cheap optics for collection of the sunlight and reduce the expensive semiconductor material

Reduce cost of PV-generated kWh

solar radiation

lens F0

solar cell Fc

heat transport

High-concentration PV using III-V Solar Cells

USA:Emcore,NREL,Spectrolab

Japan:Sharp

Europe:Fraunhofer ISE,Azur Space

1982 1986 1990 1994 1998 2002 2006 201015

20

25

30

35

40

45

Year

Spectrolab 41.6 @~250xFhG-ISE 41.1 @ 454xNREL 40.8 @ 326x

III-V Multi-junction Cells Silicium Concentrator Cells Silicium One-sun Cells

Effi

cien

cy [%

]

Use high-efficient Cells: III-V Multi-junction Cells!

Si

GaInP GaInAs

Ge

Highest module efficiency with secondary optics


Module Development at ISEFLATCON® with Secondary Optics

0 20 40 60 80 100 120 140 1600

20

40

60

80

100

120

140

26. 04. 2008 Time: 14:39 ID 02389ISC

= 141 mA

VOC

= 138.3 V

FF = 82.5 %

DNI = 734 W/m2

TAmbient

= 23.0 °C

= 28.5 %

Aperture size: 768 cm²

Cu

rre

nt [

mA

]

Voltage [V]

b

Cool earth Solar

www.daido.co.jp/englishwww.daido.co.jp/english

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Cost break down for a solar system based on Si-wafer PV cells, status 2006

Dates from J. Conkling, M. Rogol, The true cost of solar power, (Solarverlag, April 2007)

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(organic solar cells,

'up/down conversion',

Thermo-Photovoltaics,

................................... )

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Roads to Cost Reduction (the medium and long term perspective):

• Novel Photovoltaic Technologies

Target 2020: Make PV cells with efficiency > 30 % by using largerparts of the sun’s spectrum than single layer cells

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Organic Solar cells (Polymer cells)

principle:

Replace the (anorganic) semiconductor silicon resp. CIS, CdTe etc. by a semiconducting polymer.These polymers are developed for LEDs (OLED). Very large research programmes in Europe and in the US focus on organic solar cells. Private companies are engaged (Konarca, …) in the field

Best cell efficiencies: 7.1%, (EUPVSEC Valencia, 2010)

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Organic solar module on polymer foil, prototype

photo: Fraunhofer press (www.young-germany.de)

Source: http://www.energystocksblog.com/2008/06/21/photovoltaic-summit-2008-dr-pv-mr-pv-and-the-terawatt-dilemma/

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Concluding remarks:

All solar panels in power applications must operate for more than 20 years, without larger power losses!

A number of 'classic' wafer silicon panels has successfully operated over that time. Each new technology has again to prove it's stability and durability, risk has to be compensated with price reductions.

The disscussion on the future of Photovoltaics is often focussed on solar cell development, 'Panel' technology and 'System' technology, which both have a high share of the total costs, are of equally high importance..

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The solar industry (PV) has grown big, however, the larger part of the market still needs heavy subsidies!

PV module prices will go down (down 50% in the last 15 months, expected 10% on average annually)

Wafer silicon, thin film technologies: steady progress in efficiencies and production experience

Concentrators: prototypes successfully in operation

Novel PV technologies: fast progress in laboratory

The future of Photovoltaics knows no:

either / orbut: coexistence of different technologies

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Thank you for your attention!

Thank you for your attention!