PVI Lite Vol 05 2009 by Henley Media Group

New Products Kipp & Zonen's CMP series pyranometer I Hot melt sealing equipment by Komax I Satcon's inverter range for utility-scale installations

Photovoltaics International Volume 05 - 2009

lite

BP Solar unveils a new method for measuring EVA encapsulants

Yield for commercial-scale installations SunEdison surveys its project portfolio

The PV-Tech Blog: Clairvoyant and Oerlikon reinvent the Rust Belt at Ford's Wixom site

www.pv-tech.org

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Introduction Published by: Semiconductor Media Ltd. Trans-World House, 100 City Road London EC1Y 2BP, UK Tel: +44 (0) 207 871 0123 Fax: +44 (0) 207 871 0101 E-mail: info@pv-tech.org Web: www.pv-tech.org Publisher: David Owen Sub-Editor: Síle Mc Mahon Senior Contributing Editor: Tom Cheyney News Editor: Mark Osborne Editorial Manager: Emma Hughes Production Manager: Tina Davidian Design: Andy Crisp Commissioning Editor: Adam Morrison Account Managers: Adam Morrison, Graham Davie, Daniel Ryder and Gary Kakoullis While every effort has been made to ensure the accuracy of the contents of this supplement, the publisher will accept no responsibility for any errors, or opinion expressed, or omissions, or for any loss or damage, consequential or otherwise, suffered as a result of any material here published. Cover image: SunEdison’s 8.22MW PV installation in Alamosa, Colorado, USA. (Photo courtesy of SunEdison.) Printed by Manson Group Photovoltaics International Lite Volume 5, 2009 ISSN: 1757-1197 The entire contents of this publication are protected by copyright, full details of which are available from the publisher. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means – electronic, mechanical, photocopying, recording or otherwise – without the prior permission of the copyright owner.

As we enter the second decade of the 21st century, few solar markets have as much potential upside as the United States, both in terms of photovoltaic technology and manufacturing and the actual deployment of PV power plants. In a sense, this has always been the case. The U.S. was a leader in the early days of PV’s industrial development, but fell behind the Japanese and then the Germans as renewables were mostly neglected because of governmental indifference, low public awareness, and the country’s addiction to cheap oil and coal. But this time, it’s different. It’s no longer a case of “if” the solar revolution will come to pass, it’s “when.” The corner has been turned, and it’s becoming increasingly clear that the U.S. will be a central player in the planet’s momentous transition to clean energy. Talk about having one’s ducks in a row. The combination of factors aligning for a bright photovoltaic future in the U.S. is staggering. Industry leaders First Solar, SunPower, and ECD and friendly foreigners such as SolarWorld, as well as tool and materials suppliers like Applied Materials, Spire, DuPont, and Air Products make up a burgeoning domestic industry. Scores of venture-backed companies are in development mode or have started to come to market with advanced crystalline-silicon and especially thin-film technologies, while thirdgeneration nano-PV solutions move closer to commercialization. Gigawatts of PV queue in the utility project development pipeline, while commercial and residential markets prosper in California and other states. The most solar power-friendly administration ever in Washington has been doling out hundreds of millions of dollars in loans, grants, tax breaks, and other assistance across the PV value chain. The sobering recognition of the reality of climate change has led to a growing clamor for cleantech among consumers and recognition in the business community of what green can mean for the bottom line. Manufacturers continue to pound down their costs while balanceof-systems expenditures have also decreased (40% cheaper modules don’t hurt), so that pervasive, unsubsidized grid parity for solar versus other forms of energy appears to be only a few years away. As thousands of exhibitors and attendees convene for Solar Power International 2009, we offer this edition of PVI Lite, our show supplement which includes news, features, and extracts from the latest edition of Photovoltaics International, the tech resource for PV pros. We also encourage readers to join the more than 100,000 unique monthly visitors who regularly check out the solar industry’s leading online information source – www.pv-tech.org.

Tom Cheyney, U.S. Editor Photovoltaics International/ PV-Tech.org

Contents 2 News 14 Products – in brief 16 A new method for measuring cross-link density in EVA-based encapsulant BP Solar International, Inc. 20 Service & service architecture Sun Edison LLC

25 Installation Teams, Start-up Engineers and Field Service Engineers for PV and Semiconductor Production Lines Digitron Engineering Services

Spotlight on locations: Photo: Tom Cheyney

29 Buffalo Niagara Enterprise 30 Castilla-La Mancha

26 PV system optimization with distributed power optimizers: mitigating the PV system mismatches problem National Semiconductor 32 A look at solar efficiency issues and innovative output boosting technologies Tigo Energy

40 Solar Valley

Photovoltaics International Lite Solar Power International edition has been produced for exclusive distribution at Solar Power International providing access to a handful of technical papers, product reviews and opinion pieces, and serves as an introduction to the full subscription version, which features more than 20 technical papers from leading industry figures each and every quarter. Annual subscription available for US$199. For more information call Carlos at +44 (0) 207 871 0148 or email cnorthon@pv-tech.org

35 R&D process innovations and vertical integration at H.C. Starck H.C. Starck, Inc. Fabricated Products Group 36 ecoContact – fully automatic contacting system for the manufacture of thinfilm PV modules ACI-ecotec GmbH & Co. KG 38 Bürkle sets trends in solar module production Robert Bürkle GmbH 42 Cell Awards feature

44 Reinventing the Rust Belt: Clairvoyant, Oerlikon make plans for dormant Ford Wixom site Tom Cheyney

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News Suntech sets new 16.53% conversion efficiency record for multi-crystalline solar modules Suntech recently surpassed the previous conversion world record for multi-crystalline solar modules set 15 years ago by Sandia National Labs of 15.5%. The efficiency level of 15.6%, which was verified by the Fraunhofer ISE, has been topped by the company’s new world record conversion efficiency (aperture area only) of 16.53%, with an impressive claimed cell conversion efficiency of well over 17%. “The 16.53% conversion efficiency Suntech module has a clear margin over other multi-crystalline silicon photovoltaic technologies,” noted Dr. Martin Green, Research Director of the ARC Photovoltaics Centre of Excellence at the University of New South Wales, Australia. “It has set the new benchmark for the highest performance multi-crystalline module.” Suntech had said in August 2009 when it had originally announced breaking the long-standing Sandia National Labs record that its ‘Pluto’ cell technology currently being migrated across all cell production Suntech’s HiPerforma modules powered by Pluto cell l i n e s h a d b e e n a c h i e v e d o n technology. commercial-scale production lines. Suntech also said that it expects shipments of Pluto-powered modules to reach between 10MW to 15MW in 2009. However, in a statement issued by Suntech concerning the new world record no mention was made of production equipment being used to set the new module record, nor did the company unveil when these modules would enter production. This leap in conversion efficiencies from 15.6% to Suntech CEO 16.53% is a major achievement and is another confirmation that the race to higher efficiencies by Dr. Zhengrong Shi. the major PV manufacturers is continuing to gather significant pace.

PV Modules

Solon suffering from lack of sun The continued weak demand for both residential and commercial rooftop installations in conjunction with the lack of project finance available for utilityscale solar plants are forcing major module manufacturer Solon to undertake a further round of restructuring. Solon plans divestments, a reduction in its temporary workforce, and part-time work among other cost-saving measures. Solon also said it would review a potential spin-off of the Austrian production company, Solon Hilber Technologie. Key to the restructuring efforts will be a renewed focus on module sales in Germany, Italy and the U.S., deemphasizing sales efforts in other regions. A new business arm ‘Rooftops’ is to be established that will service both German and international demand for large-scale commercial rooftop installations.

Total module production reached 176MW in 2008, which could mean that without a significant increase in shipments in the second half of the year, production will be lower in 2009 and could fall back to levels set in 2006.

Emcore shifts terrestrial CPV business model The rapid decline of conventional crystalline based solar modules due to weak demand and massive over-capacity throughout the supply chain has forced CPV manufacturer, Emcore to take a long hard look at its terrestrial CPV business model. Company executives say that they will concentrate on solar cell receivers with 1,000 times concentrated reflected optics development and supply license and partners on complete systems. Previously, Emcore had followed the conventional model of manufacturing complete systems and being a solar project developer. The company acknowledged that in the current environment, financial institutions are extremely risk-averse, and new technologies are actually seen as a risk rather than an advantage.

DuPont increases capacity for Tedlar PVF product line Solon headquarters, Berlin Adlershof Technology Park. 2

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DuPont is providing further details of a multi-phase production expansion for its Tedlar polyvinyl fluoride (PVF) product line. This represents more than US$120

Tedlar polyvinyl fluoride.

million in investment, which increases the capacity of monomer and resin used in producing Tedlar films by over 50%. Site selections for the capacity expansion are complete, and construction has begun for new monomer and resin facilities at the DuPont Louisville, KY, and Fayetteville, N.C., sites, respectively. The facilities are scheduled to start up in mid-2010. The company expects that overall sales of its family of products into the PV industry will exceed US$1 billion by 2012. DuPont has already implemented capacity expansions this year for Tedlar PV2100 series film and is completing the engineering and design for a planned expansion of Tedlar PV2000 series film production, which together will more than double Tedlar film capacity for the photovoltaic industry. Tedlar films serve as the critical

backsheet component, providing longterm durability for photovoltaic modules in all-weather conditions.

Atlas develops new UV testing system Atlas has developed a new fluorescent, UV testing device for accelerated weathering. The device has been designed for economical weathering testing. In order to perform tests, the company uses artificial weathering, the objective of which is to reproduce real life product failures in a laboratory under accelerated and reproducible conditions. Fluorescent UV lamps are one light source used to simulate specific solar spectral power distributions. These sources are incorporated into fluorescent UV condensation devices like the new UVTest. The new UVTest will be available in early October 2009.

adjacent to Hemlock Semiconductor‘s polysilicon production facility, is expected to be completed in 2011. Monosilane is a key specialty material used in the production of certain thinfilm photovoltaic devices as well as liquid crystal displays. The company says the new facility represents an investment of hundreds of millions of dollars and will initially employ about 30 workers. Dow Corning also unveiled an installation of 136 PV panels at the Solar Discovery Center at its corporate headquarters in Midland, MI. In addition to providing 30kW-hours of clean energy to the electrical grid, the installation serves as a testing ground for the company’s silicone encapsulation solution. Half of the solar panels in the installation are encapsulated with its advanced silicone encapsulation solution to compare and test in real-life conditions, with the other half encapsulated using standard technology.

Fab & Facilities

Dow Corning to build PV monosilane gas manufacturing plant in Michigan Dow Corning has started construction of a high-purity monosilane gas m a n u f a c t u r i n g p l a n t i n Th o m a s Township, M I. The factory, located

centrotherm photovoltaics sees second turnkey polysilicon plant become operational Shaanxi Tianhong Silicon Industrial in Xian City, China, has successfully started polysilicon production at its 1,250MT plant, according to turnkey plant provider centrotherm photovoltaics.

centrotherm’s headquarters in Blaubeuren, Germany.

The plant was planned and developed by centrotherm SiTec, a subsidiary of centrotherm formed out of centrotherm’s acquisition of SolMic and from its former subsidiary centrotherm SiQ. This is the second turnkey plant the company has successfully completed. Shaanxi is targeting both semiconductor and solar markets with its polysilicon.

Centrosolar Group pulls out of solar cell manufacturing joint venture The joint venture between Centrosolar Group and Qimonda, known as Itarion Solar Lda, has announced that it has filed for insolvency. The negotiations for the Itarion Solar venture were cancelled following the insolvency of Qimonda in January 2009. Originally, a consortium of Portuguese industrial companies, banks and investment funds had been put together to take on Qimonda’s

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interest in the venture, yet Centrosolar came to the conclusion that the direction taken by the negotiations now ruled out the success of the project. The management resources required would therefore have represented a major distraction from the company’s own core business. Centrosolar says that it needs to write off its investment in Itarion with a current book value of ½10.1 million; further to this, Itarion carries net financial debt of approximately ½16.5 million, for which both Qimonda AG and Centrosolar are liable. An agreement has been reached with the lending banks to repay this amount in installments up until mid-2011; this arrangement will enable the company to continue expanding its core business. Materials

Timminco loses major UMG-Si customer One of the earliest customers to place a major long-term supply contract with Timminco’s subsidiary, Becancour Silicon for U M G- Si material has terminated the contract. The original five-year agreement for 13,100MT was signed in September 2007 with an unidentified supplier – Becancour’s third customer. In November 2008, the company had confirmed it had seven long-term contracts including Q-Cells, CaliSolar, Canadian Solar and Solar Power Industries. Owing to its lack of capital, Timminco has issued approximately 3.4 million common shares to the customer in replacement of a payment of an original outstanding deposit of US$3.9 million.

The acquisition of the Themis sawing technology also means that Kuka is now able to supply customers with almost the full range of equipment from start to finish for the automated production of crystalline PV modules.

SiXtron scores order with top-tier solar-cell manufacturer to evaluate silane-free gas delivery tool SiXtron Advanced Materials has secured an evaluation purchase order from a top 10 Asian solar-cell manufacturer for its SunBox gas system, which delivers the company’s silane-free antireflective coatings. The Montreal-based firm said that its application specialists will support the production evaluation of the plug-andplay tool with the new customer to achieve system optimization and ensure seamless integration into existing and new manufacturing lines. SiXtron’s SunBox system gasifies a harmless solid polymer precursor to produce gas with equivalent, and even improved, results as compared to a silane system, according to the supplier. The company said in March that leading PECVD equipment providers are working to integrate the SunBox into their turnkey offerings to cell manufacturers.

Kuka Systems joins US$1 billion wafering equipment market with technology acquisition With the explosive growth in crystalline silicon production capacity over the last few years, the wafering equipment market exceeded US$1 billion in sales in 2008, according to data from VLSI Research. This had attracted major equipment suppliers such as Applied Materials, Komatsu and now Kuka, via its Kuka Systems Division, to acquire established players in this expanding market. Kuka Systems recently acquired the ‘Slicing Technology’ of Czech-based mechanical engineering company Themis a.s. for an undisclosed sum. Key technology purchased included IP, experienced workforce as well as process equipment for sawing and shaping ingots and wafers. Like its new rivals, the company is planning to leverage its expertise in robotics and manufacturing automation to further develop the equipment portfolio to compete in the market. 4

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PV Crystalox silicon wafers.

million), on wafer shipments of 100MW, down slightly from 110MW in the same period a year ago. The company guided shipments of between 210MW and 230MW for the year, down from last year’s guidance of 275MW. PV Crystalox was able to maintain wafer ASPs despite the global collapse in polysilicon prices and the knockon affect on wafer prices due to its customer base (85%), which is focused on major PV manufacturers in Japan, Germany and China. The company also saw an increase in multi-crystalline ingot production capacity to 350MW, which came on-stream in the first-half of the year. However, the key defensive move would seem to be coming from its polysilicon production plant in Bitterfeld, Germany. The company said that polysilicon production commenced in July 2009 with an output of 2MT in the same month. PV Crystalox expects to ramp up production to 200MT this year and continues to guide for 1800MT in 2011.

SiXtron’s SunBox.

The company, which has raised more than US$12 million since its inception, secured over US$3 million in grants, and recently won a Cell Award at Intersolar Munich and has worked closely throughout its product development with leading research organizations such as the NREL and the University Center of Excellence for Photovoltaic Research and Education in Atlanta.

PV Crystalox escapes pricing problems for now Business conditions at U K-based integrated solar wafer producer, PV Crystalox Solar look reasonably good after reporting first-half sales of ½121.6 million (H1 2008: ½126.3

Key technology purchased included IP, experienced workforce as well as process equipment for sawing and shaping ingots and wafers. Kuka, like its new rivals is planning to leverage its expertise in robotics and manufacturing automation to further develop the equipment portfolio to compete in the market. The acquisition of the Themis sawing technology also means that Kuka is now able to supply customers with almost the full range of equipment from start to finish that is required for the automated production of crystalline PV modules.

Plextronics closes US$14 million funding round led by Solvay Plextronics has closed a US$14 million Series B-1 financing round, which was led by Solvay North American Investments (a member of the Solvay Group). This marks Solvay’s second investment in Plextronics in three years, raising the Belgian chemical firm’s stake to US$12 million and making it the largest minority shareholder in the printed electronics materials development company. Leopold Demiddeleer, GM of Solvay’s future businesses competence center, said that his company “has identified organic electronics and sustainable energy as platforms for future growth based on radical innovation.” The

group believes that the new materials and technologies, which it is currently developing through its own R&D efforts and a number of partnerships with technological leaders, convey potential solutions to some of our contemporary societies’ most acute issues, such as the cost-effective implementation of renewable energy sources and energyefficient devices.

Atlas Material Testing gets in on the ACT Atlas Material Testing Technology has formed a partnership with ACT Test Panels to distribute within the European market. Now the two companies have joined forces, ACT will produce the panels and Atlas will sell them, throughout Europe. Atlas will begin by stocking TRU panels for immediate delivery and later sell ACT’s entire range of panels. The TR U panels assure accurate spray out, flow, color match, and coverage evaluations and are available prepackaged with VCI paper. They are also formulated for longer shelf life and batch-to-batch consistency. Cell Processing

Motech pushes cell efficiencies over 17.5% Motech Industries has developed a new cell structure code named X- C E LL, which have an average

Motech’s X-CELL.

conversion efficiency of more than 17.5% for mono-crystalline solar cells. Performance was boosted with a unique texturing process which enhances light trapping. Motech also said that breakage rates of finished cells have been significantly reduced compared to conventionally textured cells. The benefit for customers is thus twofold. X-CELL technology is already available with 5” mono-crystalline cells. Motech plans to introduce X-CELL technology on 6” mono-crystalline cells in the third quarter of 2009.

E-Ton mulling cell capacity expansion Although the current weakness in demand has seen E-Ton unprofitable

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in the first-half of 2009, the solar cell manufacturer is said to be mulling plans for capacity expansions as demand from customers, notably in China and other parts of Asia has been improving. E-Ton shipped 30MW in Q109 and 50MW of solar cells in 2Q09, however the company is expecting shipments to increase to approximately 60MW in 3Q09. E-Ton is reported to have a current capacity of 320MW, predominantly multi-crystalline based. The company could look at expanding production to over 400MW in 2010 and beyond in tandem with a focus on cell efficiencies of over 16% for multi-crystalline and 18% for moNo. E-Ton is also focusing on 6” cells with improved efficiencies and higher production output.

Applied Materials to use Baccini Esatto technology for back-end processing systems Applied Materials’ Baccini Esatto technology will be used for the company’s Baccini back-end solar cell processing systems. The Esatto technology, featuring proprietary hardware and software innovations, is designed to increase the efficiency of c-Si solar cells by enabling the fabrication of advanced contact structures. Applied's Baccini Esatto technology, a high-precision, multi-step screen printing capability, will be used initially for double-printed metal line deposition where it has apparently raised absolute cell efficiency by as much as 0.5%. This will allow manufacturers to print taller, narrower grid lines, reducing the shadowing effect caused by wider grid lines and improving electrical conductivity. Results from the production environment show that Esatto technology allowed the replacement of

High-resolution cameras form part of Applied Materials’ Esatto technology kit. 6

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single 120μm-wide lines with two-layer, double-height lines less than 80μm wide on the finished cell. This will be the first of many applications for the technology. Th e E s a t t o t e ch n o l o g y a l l o w s multiple layers of different materials to be overlaid with better than ±15μm repeatability. It was designed to enable advanced contact formation techniques such as double-printed front-side metal lines and the multiple process flows required to create selective emitter structures.

Q-Cells to roll out polycrystalline cells with 17% conversion efficiency in 2010 As part of its new strategy to focus greater effort and resources on technological advancements of its solar cells, Q-Cells will be launching a polycrystalline cell with a conversion efficiency of 17% in 2010, using existing production lines. The cells were developed at Q-Cells’ new €50 million ‘Technikum’ pilot line in Thalheim, Germany. Q - Cells claimed this was a new efficiency record for polycrystalline cells. The Fraunhofer Institute for Solar Energy Systems (ISE) has tested and certified that modules using the highperformance cells achieved efficiency of 15.9% and an output of 249W. The company also said that when the development phase has been finished further increases in the efficiency rating are expected when volume production is started. “The efficiencies already achieved are only the beginning,” noted Anton Milner, Chairman of the Executive Board at Q-Cells. “We are of course delighted with this achievement, which is after all a world record.”

Researchers at UNSW claim record 43% conversion efficiency Solar cell researchers at the University of New South Wales (UNSW) in Sydney, Australia, claim the highest efficiency for solar power ever recorded, announcing a new world record of 43% of sunlight converted into electricity at the research stage. This research expands on earlier work, which produced results of 42.7%. This new ‘composite’ experimental efficiency of 43% will be the highest reported to date for any combination of photovoltaic devices. The UNSW team, led by Professor Martin Green, Research Director of the UNSW ARC Photovoltaics Centre of Excellence combined with two US groups to demonstrate a multi-cell combination that has apparently set a new standard for converting sunlight into electricity. Speaking with Prof. Green, Photovoltaics International found that

Diagram showing UNSW researchers’ 43% efficiency cell composition.

these cells were being developed for use in CPV (concentrated photovoltaics). The diagram shows the five-cell stack, composed of NREL and Emcore independently developed cells and UNSW’s cell. The UNSW PERL cells ZT-1-4E were tested with 4.2 suns concentration, while the others at 20-40 suns concentration. All of these cells have been independently tested by Sandia National Laboratories.

Suntech grabs multicrystalline module efficiency world record Independently tested by the Fraunhofer Institute for Solar Energy Systems (ISE), Suntech’s ‘Pluto’ cell technology has been used in multi-crystalline silicon PV modules to set a new world record in this classification of 15.6% conversion efficiency. The previous record (15.5%) had been set 15 years ago by Sandia National Labs. Suntech’s Pluto cells have a conversion efficiency exceeding 17%. The company also noted that the new world record was set using the framed area, without which Suntech believes it would achieve a conversion efficiency of well over 16%. “Improving the conversion efficiency of multi-crystalline silicon modules has proven particularly challenging and this is a very impressive achievement for such a large module from a commercial supplier,” noted Professor Martin Green, Research Director of the ARC Photovoltaics Centre of Excellence at the University of New South Wales, “I can confirm that the 15.6% multi-

Suntech’s Pluto cell technology.

crystalline module result is the highest known conversion efficiency measured by a PIP-recognized test centre.” Suntech has had close association with the Australian research centre for many years. The world record has been accepted by the scientific journal Progress in Photovoltaics (PIP). Suntech also said that it expects shipments of Pluto powered modules to reach between 10MW to 15MW in 2009.

Trina Solar sees revenues rise, profits return, PV module shipments increase during quarter Trina Solar saw its second-quarter revenues increase over the previous quarter although sales numbers were down from the same period in 2008, while net income went back into the black compared to the first quarter. The Chinese integrated photovoltaics manufacturer shipped nearly 31% more modules in the quarter versus the preceding three months. Trina’s net revenues in the second quarter were US$150.0 million, an increase of 13.5% sequentially and a decrease of 26.5% year-over-year, due to a decline in module average selling price. Total shipments were 63.9MW, compared to 48.8MW in 1Q09 and 47.6 MW in 2Q08. Gross profit in the quarter was US$41.2 million, compared

to US$22.7 million in 1Q09 and US$47.4 million in 2Q08. Trina estimates it will ship between 90 and 110MW of PV modules in the third quarter and 350-400MW for the year, which would represent an increase of 74% to 99% from last year. The company also expects to add approximately 150MW of additional capacity as part of its new East Campus capacity expansion, reaching a total cell and module nameplate annual capacity of 600MW by year’s end.

Suniva hits production cell efficiencies of over 18%, opens second production line Suniva has achieved record conversion efficiencies on its monocrystallinesilicon solar cells and started production on its second manufacturing line. The Norcross, GA-based company said that its ARTisun cells are achieving efficiencies of better than 18%, which the firm claims is a record for screenprinted cells in full-scale production. Its newly commissioned manufacturing line will add 64MWp of cell-making capacity to the existing 32MWp line opened in October 2008, pushing the firm’s total production capability threefold to nearly 100MW. Through optimized metallization and other proprietary processes initiated by Suniva founder/CTO Ajeet Rohatgi

at Georgia Tech’s University Center of Excellence for Photovoltaic Research and further developed in its R&D department, the company has achieved NREL-certified lab efficiencies of more than 20% on screen-printed cells. The company said it plans to steadily raise its commercial efficiencies above 20% through a series of incremental design and processing innovations. Suniva also recently completed a US$75 million Series C financing round led by Warburg Pincus, bringing its total fundraising round to US$125 million since February 2008. Thin Film

NREL verifies 15.45% total area efficiencies on Global Solar production-level flex CIGS cells The U.S. National Renewable Energy Laboratory has verified that productionlevel copper indium gallium (di) selenide solar cells from Global Solar Energy have achieved 15.45% total area conversion efficiencies. The thinfilm CIGS photovoltaics manufacturer says that it has also reached record peak efficiencies of 11.7% on flexible stainless-steel cell strings manufactured on its roll-to-roll lines at its full-scale production facilities in Arizona and Germany. “The material came directly off our

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new record for single-junction cells and was achieved with the use of its proprietary TCO front- and backcontact technology. Oerlikon Solar said that they expect to have customers in commercial production with this technology by the end of 2010 and to achieve module conversion efficiencies of 10% or more.

First Solar U.S. project pipeline tops 1GW, as thinfilm PV company signs 550MW deals with SCE Global Solar’s flexible solar cell.

production line,” explained company CTO Jeff Britt during an interview with PV-Tech. “With the experiments at NREL, we compared various stages of our process with their standard process. These are results that popped out during the course of the tests. There were many devices over 15% that were measured, but the 15.45% was the highest efficiency of the group.” Noting that the results were for fullarea devices, Britt said that if one were to compare this result to the ‘active area efficiency’ calculation that some CIGS companies “back out” of similar testing, Global’s efficiencies “would be somewhere around 16.6%.”

Oerlikon Solar uses TCO contacts to reach 10% efficiencies with singlejunction a-Si cell Recently verified by the U.S. National Renewable Energy Laboratory (NREL), Oerlikon Solar has repeatedly reproduced amorphous silicon (a-Si) single-junction PV cells with stabilized conversion efficiencies of over 10%. The company said that this was a

First Solar’s U.S. project pipeline now tops the 1GW mark, after the thinfilm photovoltaics company and utility Southern California Edison signed deals that will lead to the construction of two large-scale solar power projects in Southern California. The installations in Riverside and San Bernardino counties will have a combined generation capacity of 550MW (AC) of solar electricity, or about 1.2 billion kWh, enough to provide power to approximately 170,000 homes, according to SCE. First Solar will engineer, procure and construct the two solar facilities, the 250MW Desert Sunlight site near Desert Center (to begin in 2012) and the 300MW Stateline project in northeastern San Bernardino county (to begin in 2013), it will also equip the power plants with its cadmium-telluride modules. The projects will create hundreds of construction jobs. The agreements must be approved by the California Public Utilities Commission; once network upgrades are done and applicable governmental permits are received, both projects are expected to be finished by 2015.

Shell to exit solar PV, sell share of CIS venture Avancis to Saint-Gobain Shell plans to focus on biofuels and exit the solar photovoltaics business, selling its 50% share of thin-film PV company Avancis to joint venture partner, Saint-Gobain. The German firm produces copper-indium-selenide (CIS) modules at its 20MW plant, which came online last year. Saint- Gobain said that it will “accelerate the industrial development of Avancis.” Two additional production lines are being ramped up at the manufacturing site in Torgau, Saxony.

CIGS thin-film firm DayStar Technologies running out of money, could file for bankruptcy soon Oerlikon Solar’s amorph highperformance thin-film silicon PV modules. 8

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DayStar Technologies, a copperindium-gallium-(di)selenide thin-film PV developer based in Santa Clara, CA, is running out of money. Although the company posted a smaller net loss in its

just-announced second-quarter results than it experienced in the first quarter and the value of its net property and equipment has risen to US$50 million because of increased investment during the period, its cash and cash equivalents have dwindled to US$1.3 million. As a result of its financial woes, DayStar says it will need “substantial funds in the near term” to continue operations, ramp its first production line, and begin shipping products, and a failure to raise such monies may result in the company declaring bankruptcy and possibly shutting down part or all of its operations. DayStar has a proprietary onestep sputter process that it says can continuously deposit high-efficiency CIGS films over large-area glass substrates. The company claims the approach can meet the sub-US$1-perwatt manufacturing cost threshold at a capacity scale of 100MW or more, including the achievement of commercial module efficiencies better than 13%.

Centrotherm claims 12% efficiencies for turnkey CIGS production line The CIGS company has begun building out its first 25MW module production line and has a contract with solar PV integrator Blitzstrom to buy at least half of its production run through 2011, as long as the modules meet the proper performance criteria. centrotherm established a R&D centre in Blaubeuren, Germany at the beginning of 2008 for CIGS development. Based on results from its own pilot line, centrotherm photovoltaics has said that it has achieved CIGS (copper indium gallium diselenide) thin-film module (0.1m 2 size) efficiencies of 13% and expects its first customer for its turnkey system to achieve 12% efficiencies with 1.5m2 sized thin-film modules in 2009.

Flexible CdTe thin-film cells reach 12.4% efficiency R e s e a r c h e r s f r o m E M PA h a v e improved the efficiency of flexible CdTe thin-film solar cells to 12.4% v a l u e . Th e l a b o r a t o r y f o r Th i n Films and Photovoltaics of E M PA, Switzerland has developed highest efficiency flexible CdTe thin-film solar cells on a lightweight polymer (polyimide) film by using a low temperature, below 450°C, vacuum evaporation process to grow CdS/ C d Te l a y e r s a n d a s u b s e q u e n t annealing step in air. This 12.4% device structure is the use of ZnO:Al as a transparent electrical contact instead of the expensive ITO (indium tin oxide) layer the company used earlier in 11.4% efficiency solar cells. Substitution of ITO with a bi-layer of ZnO/ ZnO:Al also improved

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process yield and reproducibility of high efficiency solar cells. The photovoltaic parameters of the 12.4% efficiency solar cell measured under standard AM1.5 illumination condition are Voc = 823mV, Jsc = 19.6mA/cm-2, FF = 76.5%. The research group has been involved in the development of CdTe solar cells on glass and polymer substrates for several years, developing low temperature and compatible processes and combating the reduction of optical and electronic losses limiting the cell performance. All the process steps of the flexible solar cells are compatible with continuous in-line processing and can be transferred to roll-to-roll manufacturing of large area solar modules with high deposition speed. Such high efficiency flexible CdTe solar cells could become a low cost option for cost effective solar electricity generation in the near future, meaning another potential increase for the sector market. Power Generation

DelSolar to boost capacity to 360MW Having raised new finance earlier in the year, DelSolar will use the mid-term working capital to build a new solar cell plant in Wujiang, China and equip eight solar cell production lines. The expansion will take DelSolar’s capacity to 360MW. The company also stated that it was now shifting to production to cells with conversion efficiencies of 18.3% for monocrystalline wafers and 16.6% for multi-crystalline wafers. This follows news in March, 2009 from Gintech Energy that said it was shipping multi-crystalline wafers with conversion efficiencies of 16.6%. The company will aim for an average conversion efficiency of 17.5% in 2010.

Neo Solar returns to full capacity Neo Solar Power reported first half of 2009 sales totalled NT$3.818 billion, representing a 13.9% decline year-on-year, while total sales volume was up by 38%. However, Neo Solar saw July 2009 sales return to NT$1 billion and utilization was back to over 100%. Quarter-over quarter growth is forecasted at 40-50% for the third quarter of 2009 and expects to return to profitability in the second half of 2009.

Zebasolar wins concession to build 10MW solar PV power station in Gujarat, India A bidding team led by Zebasolar’s Indian unit has won the concession to build a 10MW solar photovoltaic power station in Gujarat. The award comes as part of a government plan for 743MW of solar farms to be developed in the Indian state and is the company’s first in the country. Featuring a ½35 million investment on the part of Zebasolar Pvt. India (an 85% subsidiary of Zebasolar Inc. USA), the Gujarat PV project will produce 16.37 million kWh per year and have a franchised operation term of 25 years. Majid Khan, director of Zebasolar India, said that “the project is expected to start construction within five months and has to be completed within the six following months,” adding that the plant, which will feature a ground-mounted PV tracker system, will come online in mid-2010. The company said it is in the process of setting up the Gujarat joint venture company and confirming the EPC (engineering, procurement, and construction) contract.

SMA sees global growth for solar market in 2009 In giving a positive full-year financial guidance of solar inverter sales potentially up by 7%, SMA Solar Technology (SMA) expects the global solar market to see positive growth in 2009. Although the company did not give any further details, SMA said in a statement that the market should exceed the record levels set in 2008 of 5.7GW installed, despite the current economic and PV related market conditions. 10

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Do you want to join a leading research institute? Do you want to be part of its photovoltaic ambition? Then IMEC is the place for you! We offer you a position in our strongest growing program.

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Your proﬁle If you are interested in stepping into this challenge and joining IMEC in its growing PV program, this is your opportunity. We are currently looking for enthusiastic colleagues at different levels of expertise and responsibility: senior candidates for management positions as well as experts for functions with focus on research, engineering, …. Experience in an industrial context is an asset. We are also open to receive applications from candidates with a ﬁrst experience in photovoltaics.

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SolarWorld reports 25% recruitment increase SolarWorld has reported a recession busting increase in employment for the first half of 2009, contradicting many others who are having to stick at existing levels and in many cases reduce the amount of employees during these tough economic times. In the first six months of this year, SolarWorld had 2,500 people working for the company worldwide, this is a 25% increase in comparison to the same period of 2008. SolarWorld pursues a sustainable development strategy, also for its employees whereby every new position is adjusted to the growth of the company in order to be able to offer all employees a long-term perspective.

First Solar and juwi Group plant is world’s second biggest First Solar and juwi group say that the Lieberose solar farm under construction in Brandenburg has reached status as the second biggest solar power plant in the world and the biggest in Germany. This news came after the 560,000th solar panel in the project was put in place by German Infrastructure Minister, Wolfgang Tiefensee and Brandenburg Minister President Matthias Platzeck. At present there is a total investment volume of more than ½160 million. Once complete the plant will have an output of approximately 53MW and will be bigger than 210 football fields. The project is being developed on the largest former military training site of the Soviet army in Germany.

Lieberose is scheduled to be fully operational by the end of 2009; upon completion, about 700,000 thin-film modules, predominantly from First Solar’s nearby Frankfurt/Oder factory, will produce enough climate-friendly electricity to cover the equivalent electricity needs of about 15,000 households. In addition to producing the solar panels, First Solar helped finance the project.

Canadian Solar obtains rights for 500MW plant in Mongolia Pending a feasibility study and government approvals, Canadian Solar will obtain rights to design, install, operate, and maintain a 500MW solar power plant system. According to the letter of intent with the Administration Committee of Baotou National Rare Earth Hi-Tech Industrial Development Zone (‘CPT’) in Baotou, Inner Mongolia, the solar power plant will be located in CPT. The plan is set out in three phases: the first is expected to run from September 2009 to December 2011 and calls for the installation of a 100MW PV system, while the second and third phases each call for the installation of 200MW PV systems. There are no binding commitments until the feasibility study is completed and approvals are obtained. Market Watch

First Solar’s market share set to soar Setting the lowest cost-per-watt production figures in the photovoltaics industry while ramping production past the 1GW level in 2009, First Solar has become the largest solar cell producer in 2009, leapfrogging Q-Cells and Sharp for the first time. According to market research firm iSuppli Corp., First Solar is set to produce more than double the 503MW it made in 2008 and increase its market share, claiming responsibility for nearly a third of global installations this year.

First Solar and juwi plant in Brandenburg, Germany. 12

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Source: Photovoltaics International

SMA said that it had seen growth in countries outside Germany with strong demand for inverters in the USA, Australia, Belgium, France and Italy. Product mix in the first quarter was primarily the Sunny Boy product group with low power classes, while Sunny Mini Central product group sales dictating in the second quarter due to increased activity in the large-scale solar project market. Total sales in the first half-year equate to sold inverter power of 792MW.

iSuppli: Top 10 solar cell producers’ output and market share (forecast September 2009).

Totting up first-half-year figures and taking into account third-quarter company projections, iSuppli has projected that First Solar is set to produce 1,100MW worth of solar cells in 2009 and actually have the majority of this record production level installed rather than a given percentage stuck in inventory. The company will also be the first among the ‘Top 4’ (Suntech, Sharp & Q-Cells) solar cell suppliers able to gain market share in 2009, according to iSuppli. Its global share is expected to rise to nearly 13% (12.8), up from 7.5% in 2008. More impressively, iSuppli predicts that First Solar’s cells will account for as much as 28% of the estimated 3.92GW total installed base for 2009, closing in on a third of the expected market demand for the year. Because of its cost advantage, thin-film technology overall will grow to account for 34.5% of worldwide solar production in terms of MW in 2013, up from 14.2% in 2008.

Semiconductor foundry UMC to invest $45 million in solar, LED development efforts The board of semiconductor foundry United Microelectronics Corp. has approved the establishment of a new business development centre and a 100% owned subsidiary, UMC New Business Investment Corp., which will focus on solar energy and LED projects. About NT$1.5 billion (US$45 million) will be invested in the new effort, and Wen Yang Chen, senior VP of UMC, will run the centre. UMC believes that its knowledge and technologies are highly applicable to the fundamentals of these two industries; in the short-to-mid term, the Taiwanese company plans to complete the development of related technologies and establish a preliminary scale of operations. For the long term, as key proficiencies mature and resource integration is complete, the company said it expects the new energy business to become another UMC core business with high competitive advantages.

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MAKE LIGHT | MANAGE LIGHT | MEASURE LIGHT

Products – in brief RENA’s InCellPlate inline single-side plating tool offers low CoO Ag plating on Ag-paste Applications: Light-induced plating of Ag on printed Ag Platform: The InCellPlate machine platform allows the combination of different etching, cleaning, plating and rinsing modules, with drying performed using the cost effective ‘AirChannelDryer’ technology. Availability: Currently available.

RENA’s InCellPlate tool can achieve a throughput of 2400 cells per hour.

RENA has introduced a high-volume inline plating tool, the InCellPlate, that employs a single side wetting/plating principle, where only the lower side of the cells is in contact with the plating chemistry. This setup reduces the drag out of silver-plating chemicals – an important cost-reducing effect. The cells are contacted on the dry upper side by special conductive brushes that are located above dry drain areas to avoid the wetting the brushes when not in use. Used in combination with RENA’s 50μm fine line print screens, efficiency increases of up to 0.5% were achieved compared to cells with standard printed contacts.

Bekaert’s one-piece AZO rotatable target delivers superior TCO layers Applications: TCOs in thin-film PV cells. Platform: All conventional types of target fixations are supported. Available in lengths up to 152 inches, in several thicknesses and in standard or ‘dog bone’ shapes. Availability: Currently available.

Bekaert Advanced Coatings’ one-piece AZO rotatable target for thin-film PV applications is used for the deposition of TCO layers and back contacts. Directly applying the AZO material to the backing tube during production eliminates the need for bonding material that has a low melting point, allowing better cooling through optimized thermal conductivity and the ability to use higher sputter power densities. The new onepiece AZO rotatable target ensures high quality TCO layers, superior deposition rates and accuracy leading to lower cost of ownership, and a firm stability over the lifetime of the solar cells.

Bekaert’s one-piece AZO rotatable target.

Kipp & Zonen instruments provide reliable and accurate solar radiation monitoring Applications: Good quality solar

Kipp & Zonen’s CMP series pyranometer.

radiation data is essential to improve solar energy technology, find optimal locations, monitor performance and efficiency, schedule maintenance and maximize the return on investment. Platform: CMP series pyranometers accurately measure the total solar energy available. The CHP 1 pyrheliometer mounted on a SOLYS 2 automatic sun tracker measures the ‘direct’ radiation from the sun. A complete research-grade solar monitoring station can be built up. Availability: Currently available. Kipp & Zonen’s CMP and CHP radiometers use thermopile type detectors

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with a flat spectral response. The types of instruments, performance specifications, and calibration methods are defined by the World Meteorological Organisation (WMO) and International Standards Organisation (ISO). Data can be compared with measurements from meteorological networks and satellites, across the globe and for different types of solar energy systems. CMP pyranometers can be mounted horizontally for the ‘global’ radiation, or tilted on solar panels. Adding a shading assembly and another pyranometer to the SOLYS 2 provides ‘diffuse’ sky radiation measurements. The SP Lite2 silicon pyranometer uses a photo-diode detector and has spectral response similar to solar cells. It is widely used for field testing and monitoring applications.

Products – in brief New hot melt sealing equipment by Komax enables precise and continuous butyl application Applications: Thin-film photovoltaic modules (substrates as well as superstrates). Platform: The sealing equipment is part of the Komax thin-film prelamination line and can also be integrated into existing lines. Availability: Currently available.

A new sealing equipment for thin-film modules from Komax enables continuous and precise hot melt dispensing of high-viscous butyl. Butyl improves the adhesion and protection of the module against humidity, and its application as a hot melt butyl allows more precision and a simpler system for the EVA or PVB cutting and marriage. The equipment avoids the need for exchanging reels of tape, eliminating a process step and reducing material costs. The high-viscous butyl is pumped from a barrel to a dispensing head that allows for alteration of shape. While a butyl reel lasts only for about one hour, a 200kg barrel will last approximately two days.

Sealed thin-film module from Komax.

Satcon offers PowerGate Plus, Prism, Spectrum and Solstice inverters for utilityscale installations Applications: Commercial rooftop and utility-scale solar PV installations. Platform: All 11 available power ratings are UL and CE certified. The inverters feature an outdoor-rated enclosure and a wide operating range, and are applicable to most PV module types and technologies. Maximum power point tracking is provided by Satcon’s Edge solution. Availability: Currently available.

‘Rugged and reliable’ inverters from Satcon’s range are applicable to all utilityscale solar power installations and backed by world-class warranty and support programs. With over 340MW of total units installed globally, over 170MW of which is the PowerGate 500kW unit, Satcon is planning the launch of a first-of-its-kind two-stage architecture, Satcon Solstice, in the third quarter of 2009. The inverters offer stable and reliable performance with advanced grid interconnection capabilities and can increase total system energy harvest by 4-12%.

Satcon’s 1MW PowerGate Plus inverter.

ecoContact from ACI-ecotec enables speedy thin-film module contacting Applications: Thin-film adhesive dispensing. Platform: ecoContact comprises standard components for applying conductive adhesives, longitudinal and lateral contacting and soldering bus bars for the manufacture of all common thin-film module sizes. Availability: Currently available.

ACI-ecotec has introduced ‘ecoContact’, a fully automatic contacting system for the application of small pieces of adhesive tape in attaching bus bars to thin-film modules. In conventional contacting, adhesive tape is applied along the entire length of the bus bar – an expensive method. This innovative solution automatically cuts small pieces of tape from the adhesive roll, removes them from their backing and sticks them onto the bus bar at predefined points. In the dispensing module of ‘ecoContact’, the conductive adhesive is applied using two dispensing heads at speeds of between 40 and 70mm per second, using approximately one gram of adhesive for a 1300 to 1400mm-long substrate.

ACI-ecotec’s fully automatic contacting system.

Phot ov olt aic s I nt ernat ional

A new method for measuring cross-link density in ethylene vinyl acetate-based encapsulant

Zhiyong Xia, Daniel W. Cunningham & John H. Wohlgemuth, BP Solar International, Inc., Frederick, Maryland, USA

This is part one of a technical article that appeared in Photovoltaics International’s fifth edition. To access the rest of this article, please visit our online journal archive. ABSTRACT

Among the different packaging materials used in photovoltaic solar modules, ethylene vinyl acetate-based (EVA) encapsulants play an important role during the lifespan of the module assembly. Prior to lamination, EVA is a thermoplastics polymer containing a number of additives. During the lamination process, EVA cross-links into a three-dimensional network structure, i.e., a thermoset, which provides protection for solar cells against detrimental environmental conditions. Since EVA has a very low glass transition temperature and melting points, proper cross-link density has to be achieved through the lamination process to prevent the EVA from cold flowing in the field. As a result, module manufacturers constantly monitor the cross-link density or gel content of EVA after lamination. This paper proposes a new method of measuring the EVA cross-link density value while avoiding many of the pitfalls associated with conventional cross-link density test method.

Introduction Many of today’s commercial photovoltaic solar modules carry a 25-year warranty. Significant efforts have been dedicated to understanding and improving the reliability and durability of the whole module assembly [1], the majority of these modules use ethylene vinyl acetate (EVA) as an encapsulation material. Evidence suggests that among the different module components, the encapsulant plays a critical role in ensuring the lifetime performance of the solar module [2-3]. The EVA encapsulant serves several key functions including: 1) holding/ bonding the module components together; 2) optically coupling the glass and the solar cell; 3) providing the required barrier between the solar cells and the environment; and 4) maintaining electrical isolation. The most commonly used EVA encapsulant for PV modules is a block copolymer of ethylene and vinyl acetate (VA) with a VA content of about 33% by weight. The high VA content guarantees a greater than 90% light transmission onto the solar cells. Fig. 1 is the chemical structure of an EVA block copolymer. Uncured EVA is a thermoplastics polymer that has a low glass transition temperature and low melting points. In order to be suited to PV module applications, EVA must be cross-linked (or cured) into a three-dimensional network structure such as a thermoset polymer. The curing is typically achieved through the application of cross-link agents activated during the module lamination process. Cross-link agents that are generally used to cure EVA are 16

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peroxides, such as 2,5-dimethyl-2,5-ditert-butylperoxy hexane (Lupersol 101) and tert-butyl 2-ethylhexyl percarbonate (TBEC) [4].

During the standard module lamination process, the peroxide will decompose homolytically to generate a pair of oxy radicals. Each of these radicals can abstract a hydrogen atom from the EVA molecule and initiate the crosslinking in EVA. During the standard module lamination process, the peroxide will

decompose homolytically to generate a pair of oxy radicals. Each of these radicals can abstract a hydrogen atom from the EVA molecule and initiate the cross-linking in EVA. Research carried out at Jet Propulsion Lab [5] showed that the presence of VA functional groups is critical to the cross-linking of EVA, and that polyethylene without VA groups could not be cured at all with these peroxides under normal lamination conditions. Since EVA is an elastomer, achieving a proper cross-link density in EVA is essential to overcome the ‘cold flow’ of EVA and thus make the module durable for field applications. As a result, module manufacturers should constantly check the crosslink density of cured EVA. The most widely accepted way of measuring the EVA cross-link density is through solvent extraction [5], which must be operated at elevated temperatures for better solubility of EVA in the solvent. Some common solvents that have been used to extract EVA include toluene, tetrahydrofuran and xylene.

Figure 1. Chemical structure of an EVA block copolymer.

During the extraction process, the uncured EVA will be dissolved in the hot solvent, while the cured EVA will remain solid. The samples are weighed before and after the extraction with the ratio between the two weights representing the gel content. However, this solvent extraction method poses several drawbacks including health, safety and environment issues resulting from dealing with chemicals, long turnaround time, high test variability, and the potential for built-in inaccuracies as will be discussed later in this paper. Thus it is of great interest to the PV industry to develop an alternative method for measuring the cross-link density in cured EVA that can overcome the aforementioned shortcomings associated with the solvent extraction method. In this work, the feasibility of using differential scanning calorimetry (DSC) as an alternative method of measuring EVA cross-link density was evaluated. Compared with the solvent extraction method, DSC is a thermophysical method, and can also provide structural information about the EVA formulation.

Experimental The EVA used in this study was a standard fast cure EVA with 33 wt% vinyl acetate. The EVA was laminated under different conditions, after which process all samples were conditioned at approximately 23ºC and 50% relative humidity for 48 hours prior to the DSC or solvent extraction test. DSC tests were performed on a Q2000 modulated DSC equipped with an auto-sampler and Tzero aluminum sample pans with standard lids. During the DSC scan, an N2 purge at 50ml/min was used to protect the sample from oxidation. The temperature range for

the test was from -60ºC to 300ºC, with a heating rate of 10ºC/min, which was chosen because the heating rate of EVA during lamination in this study was also around that range. The integration range for measuring the curing enthalpy was from 100ºC to 200ºC, and the samples weighed approximately 5mg. Toluene solvent extractions were performed on the same set of samples that were analyzed by D S C. The extractions were carried out at 60ºC for 24 hours. Samples were weighed before and after the extraction. The gel content was then calculated using the following formula:

gel content =

final weight initial weight

Key assumptions involved in this method are that uncured EVA dissolves 100% in hot toluene, and anything that is not soluble after the extraction will be counted as gel content. As will be shown in the results and discussion section, this method poses some key drawbacks, including over-predicting the EVA gel level if the solvent extraction is performed at temperatures lower than the high end of the EVA melting range.

Results and discussion As discussed earlier, cross-linking of EVA is through the reaction between peroxide and EVA. However, under normal module lamination conditions, not all of the peroxide will be consumed in cross-linking EVA due to a number of factors including limitations in EVA-curing kinetics, the presence of antioxidants in the formulation, absorbed oxygen, ethylene chain branching, and un-saturation of the

polyethylene backbone [6]. According to the research carried out by Ezrin et al. [7], there remains about 30% unused peroxide in a typical EVA module immediately after lamination. These residual peroxides will either further react with EVA in the field and/ or decompose into by-products as a result of outdoor aging [7]. Differential scanning calorimetry technique The residual peroxide within the partially cured EVA can be further reacted in a controlled manner using a continuous temperature scan. DSC is an ideal technique for this application. In a standard DSC set-up, there are two heating stages inside a furnace. During the test, two aluminium pans are placed on the two heating stages. One pan holds the test sample, while the other is empty and used as a reference. Th e f u r n a c e i s h e a t e d a n d t h e temperature of each pan is monitored. If the test sample undergoes a thermal transition, a difference in temperature between the two pans will ensue. The DSC instrument converts the temperature difference into exothermic or endothermic heat flow data. Since the curing reaction of EVA gives off heat, when there is residual peroxide, an exothermic peak will appear in the DSC trace. By comparing the size of the exothermic peak in the uncured and the partially cured EVA, the relative amount of residual peroxide in the partially cured EVA can be quantified. In other words, the larger the exothermic peak, the more residual peroxide is left in the partially cured EVA, meaning less peroxide was used in cross-linking the EVA. Using the same rationale, one can also monitor the shape and position of the exothermic peak. The latter

Figure 2. DSC trace of a partially cured EVA heated from -60ºC to 300ºC at 10°C/min.

Phot ov olt aic s I nt ernat ional

Figure 3. DSC traces of both uncured EVA (blue) and a partially cured EVA (red).

is especially useful to differentiate specific EVA curing packages. Fig. 2 shows a DSC temperature scan for a partially cured EVA. As the sample was heated from -60 º C to 300ºC, a series of thermal transitions w e r e o b s e r v e d . Th e t w o m a j o r endothermic peaks at 43 º C and 59 º C are related to the two crystal morphologies in EVA. The peak at 43 º C is due to the melting of less perfect crystals, while the peak at 59ºC corresponds to the crystalline phase of the better packed polyethylene chains. This complex crystallographic structure of EVA comes from the presence of VA functional groups [8], which in turn disrupt the regularity of the polyethylene chain, which leads to poor chain packing or poor crystal structure. The melting process continues until 75 º C. It is worth noting that these melting points – which have also been reported in other studies [9] – overlap with the glass transition temperature of EVA. As the temperature of EVA increases to greater than 100 º C, a major exothermic peak becomes visible – a result of the reaction between EVA and peroxide during the DSC heating process. The peak temperature centres around 167ºC, and continues to about 190ºC. Integration of this peak shows that the amount of curing enthalpy is 8.433J/g for this sample. In order to further understand t h e ch a n g e i n c u r i n g e n t h a l p y during lamination, an as-received EVA sample (uncured EVA) was analyzed using the DSC method, the results of which analysis are depicted in Fig. 3. For comparison purposes, the partially cured sample 18

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in Fig. 2 is also plotted in Fig. 3. To determine the extent of cure, the total energy released under the curve is determined as J /g. In the case illustrated, the uncured EVA has a total curing enthalpy of 17.93J/g versus 8.433J/g for the partially cured sample. Based on these data, about 50% of the original peroxide still remains in the partially cured EVA, while the other 50% of the peroxide has been consumed in cross-linking EVA during lamination.

Summary DSC has been proved to be a fast and reliable method of measuring the cross-link density of EVA. Given the nature of the analysis, no chemicals are involved in the process. DSC takes a much shorter time than t h e s o l v e n t ex t r a c t i o n m e t h o d . Furthermore, with a well-controlled lamination process, it is actually a more accurate way of measuring EVA cross-link density. Compared with solvent extraction, DSC is not only able to predict cross-link density, but also is capable of determining the curing kinetics of different peroxides.

Want to read more? Download part two of this article at the Photovoltaics International journal archive online at http:// www.pv-tech.org/journal_archive

About the Authors Dr. Zhiyong Xia received his Ph.D. from Texas A&M University in materials science and currently works at BP Solar as a materials scientist. His major research area is encapsulation and packaging of solar cells. A member of ACS, SPE and IEEE, Dr. Xia holds three US patents, 18 US patent filings and has contributed to more than 30 technical publications in peer reviewed journals and conference proceedings. Dr. Daniel Cunningham is Module Technology Manager at BP Solar. His responsibilities include product design, reliability and certification, and in the past he has served as Director of Technology for the company’s CdTe activity where his R&D team produced a record module efficiency of 11%. He has extensive experience in silicon solar cell processing and crystal growth in which he has numerous publications. Dr. Cunningham graduated from Southampton University, UK with a Ph.D. in physical chemistry. Dr. John Wohlgemuth earned a Ph.D. in solid-state physics from Rensselaer Po l y t e c h n i c I n s t i t u t e and has been working at Solarex/BP Solar for more than 30 years. His PV experience includes cell processing and modelling, Si casting, module materials and reliability, PV performance and standards. Dr. Wohlgemuth is the convener of WG2, the module working group of TC-82, the IEC Technical Committee on PV.

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Service & service architecture â&#x20AC;&#x201C; yield monitoring, optimization and reporting for commercial-scale solar utility installations

Steve Voss Dr. Tassos Golnas Steve Hester & Mark Culpepper Sun Edison LLC, Beltsville Maryland, USA

This is part one of a technical article that appeared in Photovoltaics Internationalâ&#x20AC;&#x2122;s fifth edition. To access the rest of this article, please visit our online journal archive. ABSTRACT

Over the past five years the primary metric for the PV industry has evolved from watts to kilowatt-hours. This transition has emphasized the importance of PV asset monitoring, operation and maintenance. The need to maximize system economics, by increasing uptime and decreasing service costs, requires a complex set of high quality data to drive decision making and continuous improvement efforts and is driving a rapid maturation of the PV industry, as discussed in this paper.

Introduction Incentive structures based on kWh production, such as feed-in-tariffs, performance-based incentives and renewable energy credits, have become the norm in the PV industry. Additionally, many companies are now applying the structures and principles of project finance to PV projects. The purpose of project finance is to create a business structure which brings together multiple entities, aligns their interests, and allocates the projectâ&#x20AC;&#x2122;s inputs and outputs

(i.e. risks and rewards) in such a way that the overall benefits derived from the project are maximized. In the simplest possible scenario, this has meant a transition from a simple cash transaction between integrator and host to a more complex transaction involving a third-party financing partner. Historically, under the cash sale model, photovoltaic systems were built by integrators who purchased equipment through distributors and maintained minimal responsibility for the long-term

Figure 1. ECO infrastructure example for a net-metered rooftop system.

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operation of the systems. This created a disconnected supply chain with little or no accountability for the ultimate operation and productivity of the system beyond the initial transaction. Even today, it is difficult for many OEM suppliers to account for the ultimate destination and performance of their products. This disconnect has been made possible in part by the inherent reliability of photovoltaic systems which operate without moving parts. However, no system

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s ROC (Renewable Operations Center) – the facility where company staff monitor power plants, detect and diagnose issues, process service tickets and dispatch service crews. s C l i e n t C o n n e c t – t h e o n l i n e monitoring portal that the company’s customers use to access solar energy production, environmental attributes, energy costs, and SunEdison bills.

Figure 2. Example of possible impact of O&M expenditure on a 1MW portfolio of PV assets with a fixed uptime of 98.5%. The make-up of the outages – in terms of frequency and average cost to repair – has a significant impact on realized cash from operations.

is failsafe and as a result many assets underperformed or were inadequately monitored to ensure proper operation. This mode of operation is unsustainable since it ignores the ultimate purpose of a photovoltaic system: the reliable delivery of power (capacity) and energy. The introduction of power purchase agreements (PPAs) to the solar industry goes a long way towards rectifying this disconnect, enabling the host to avoid the high capital investment and only pay for kilowatt-hours delivered or peak energy savings. However, to focus on the PPA exclusively is to oversimplify the symbiotic relationships created through project finance. When properly applied to the photovoltaics industry, project finance will align the interests of all parties involved in the finance, construction and operation of a power plant, including host, integrator, project investor, utility, subsidizing agency and OEM provider alike. This is accomplished by creating a project entity whose economic engine is driven by the value creation of the asset throughout its operational life. This entity is the Solar Energy Services Provider (SESP). Initially, the SESP is responsible for managing the complex contractual relationships required. Project finance is built on a series of contracts which define the roles, responsibilities and obligations of the various parties involved. With regards to power production, project finance typically involves four primary contracts: 1) a construction and equipment contract; 2) a long-term fuel contract; 3) a long-term power purchase agreement; and 4) an operating and maintenance contract [1]. For solar projects the fuel contract is obviously eliminated; however, it is frequently replaced by a contract for the environmental attributes of the system, which under some incentive structures can represent a significant portion of project revenues. 22

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Th i s d e a l s t r u c t u r e h a s m o s t frequently been applied to extremely large projects which can justify relatively high transactional costs. PV projects – particularly on the commercial scale – are small in comparison. The successful SESP must therefore focus on efficiency, strong relationships, repeatability and risk mitigation. From an operational perspective, this requires a complete auditable trail of system components, generation data and system performance metrics which provide accountability and transparency to project performance and value delivered to the various stakeholders. In other words, in order for this business model to be sustainable, all parties must be able to validate that all covenants, contracts and commitments are being honoured. The ECO architecture ECO (Energy Costs Optimization) is the services architecture developed by SunEdison for monitoring and operating a portfolio of solar PV power plants. ECO increases solar savings for host customers and reduces investment risks for financiers by providing information necessary for effective decision making. ECO includes the following components: s S E E D S ( S u n E d i s o n E n e r g y & Environmental Data System) – the equipment and software platform for remote monitoring and control of solar PV power plants. s SOIL (Site Objects & Information Ledger) – the asset management system, data repository, and analytics engine for site and monitoring information, storing data in 1-min or 15-min intervals, and providing a comprehensive listing of site components. s TREES (Tariff and Rate Engine for Energy Systems) – the billing and monetization engine that enables the company to automate energy billing and to calculate customers’ energy costs and savings.

All the components of the ECO architecture are necessary to efficiently operate and service a portfolio of photovoltaic power plants. By combining information on operation and economics, disseminating the information and enabling efficient response to the information, this toolset serves two fundamental needs. The first is the transparency and accountability required to operate effectively under the project finance model, while the second is the provision of actionable information required to maximize the economic value of the assets monitored. From the standpoint of the PV power plant, energy yield (or kilowatt hours produced) is the key metric driving economic value. The ability to rapidly detect, respond to and restore underperforming systems is essential to maximizing that energy yield. However, over time, it is also important to minimize the cost of achieving high uptimes, especially when dealing with a portfolio of distributed assets where the fixed costs of a ‘truck roll’ or service deployment are relatively high. The calculus used to evaluate system uptime must include: the economic value of the energy (opportunity cost), the cost to repair the system and the frequency and duration of outages. Consider a 1MW portfolio of PV assets deployed in S outhern California. Assuming a performancebased incentive of US$0.34/ kWh, a PPA rate of US$0.11/kWh, maximum production of 1500kWh/ kW and an uptime of 98.5%, this portfolio would produce cash flows of US$675,000 per year. Taking the definition of uptime as set out in Equation 1 in the following section, a 1% decrease in uptime translates directly to a 1% reduction in cash from operations. However, Number of systems

198

Average size (kWp)

259

Minimum size (kWp)

Maximum size (kWp)

1727

Average age (months)

11.9

Minimum age (months)

0.3

Maximum age (months)

44.6

Table 1. SunEdison’s systems’ statistics.

the cost to achieve that uptime is determined by the number of outage events and the average cost to repair. Fig. 2 illustrates the impact on total cash flows from the portfolio when the number of outages ranges from five to 25 events and the average cost to repair ranges from US$5001000 per event. If the events are too frequent and/or too costly to repair, then the advantages of high uptime are soon lost. At the risk of stating the obvious, the Solar Energy Services Provider must strive to maximize uptime by minimizing the duration and frequency of outage events, while simultaneously minimizing the average cost to repair systems. This can only be accomplished by a thorough understanding of the failure modes and mechanisms. ECO has enabled SunEdison to undertake a rigorous, data-driven approach to identifying, eliminating and reducing the cost impact of system outages and maximizing the financial return of our portfolio of systems. In the future, as power (as opposed to energy) becomes an increasingly important part of the value equation, availability or firmness will become increasingly important as well. This in turn will reinforce the necessity of maintaining the full suite of tools provided by the ECO architecture. The effort to eliminate and/or reduce the cost impact of various outage causes is an iterative process that requires defining, measuring, analyzing and controlling key parameters. It is a long-term endeavour aimed at continuous improvement and is of value to all the stakeholders involved in the project

finance model. The remainder of this article will be an exploration of some of the operational data derived from ECO and which is being used to drive SunEdison’s continuous improvement efforts.

Want to read more? Download part two of this article at the Photovoltaics International journal archive online at http://www. pv-tech.org/journal_archive

Review of the SunEdison solar fleet As of June 2009, SunEdison m a n a g e s m o r e t h a n 70 M Wp o f PV systems in North America and Europe, the vast majority of which are deployed in Distributed Generation sites. Data regarding the reliability of PV systems worldwide are relatively s c a r c e , a s r e s e a r ch i n s t i t u t i o n s generally manage a small number of small sites. On the other hand, commercial operators are usually very protective of their performance data in the same way as semiconductor device manufacturers tend to be protective of their yield data. We have decided to publish detailed information at this time based on the belief that transparency is of greater value than any potential intellectual advantage. The systems included in this survey account for 77% of SunEdison’s managed fleet in terms of installed MWp and 78% in terms of number of systems under management as of June 2009 (see Table 1). Cumulative operation time of the systems at the end of the survey period was 196 system years. The subset of SunEdison systems surveyed was selected exclusively on the basis of the project’s financing scheme, and covers a wide variety of geographic and environmental conditions as shown in Fig. 3.

About the Authors Steve Voss is the Director of Applied Engineering and Development for SunEdison, where he oversees technology evaluation and development. Before joining SunEdison in 2006, he held engineering roles at the National Renewable Energy Laboratory (NREL), Applied Materials and at Siemens Solar (later Shell Solar). He holds a B.Sc. in physics from the University of Colorado at Boulder, an M.Sc. in materials science and engineering from Stanford University, and an M.B.A. from the University of Wisconsin, Madison. Dr. Tassos Golnas is SunEdison’s S o l a r Te c h n o l o g y A n a l y s t . H i s responsibilities include managing relations with emerging technology vendors and contributing to the definition of the company’s technology roadmap. He spent seven years in R&D and technical management positions at companies such as Advantest, NeoPhotonics and Applied Materials. He received his B.Sc. in physics from Aristotle University of Thessaloniki, Greece, and his M.Sc. and Ph.D. in materials science and engineering from Stanford University. Steve Hester is a Senior Electrical Engineer at SunEdison, in which role he provides technical oversight, performance analysis, and operational evaluations of SunEdison’s various PV systems. With over 31 years of gridconnected PV experience, he worked at Pacific Gas and Electric’s R&D group for over 20 years and performed a variety of roles including PV Program Manager, PV Group Leader and PVUSA Project Manager. Steve holds a B.Sc. in electrical engineering from the University of Colorado at Boulder.

Figure 3. Geographical distribution of surveyed systems. The size of the slices represents the number of systems in each U.S. state.

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Mark Culpepper is responsible for shaping SunEdison’s service-oriented architecture for data acquisition and power plant control, creating the connection between solar energy data and customers’ immediate financial and energy savings. With over 18 years in the telecommunications and IT security industries, his mission is to simplify solar energy services, providing government, commercial and utility customers the real-time data and analytics needed to optimize solar production and asset performance.

Installation Teams, Start-up Engineers and Field Service Engineers for Photovoltaic and Semiconductor Production Lines In today’s marketplace customer service has become a strategic success factor and competition is just as often about the quality of that service – than the actual product itself. All of this is further complicated by the way that equipment and systems installations take place globally, sometimes in remote locations.

Introduction Introducing Digitron Engineering Services GmbH, an independent German consultancy and outsourcing partner. Their business field is the Nanotech, Semiconductor and Photovoltaic Industry. The solutions or “products” they deliver are “Human Capital” in the form of highly qualified engineers and technicians who are experienced in customer service. These personnel are available through loan, outsource or rental packages to OEMs who wish to supplement their internal field service teams. Digitron's staff has solid background and experience with installation, periodic maintenance, repair and field service of high technology manufacturing equipment used in the production of semiconductors, photovoltaics and solar cell modules. The client destinations these service personnel are sent to include semiconductor production facilities, photovoltaic device fabrication lines or direct placement at service sites and installations around the world.

Technical expertise Digitron specializes in servicing and supporting high technology manufacturing, automation, materials handling, processing, etching, contact printing, scribing plus the test and inspection equipment associated with these production methods. As a dedicated service provider they offer manpower for technical and field support, especially with respect to equipment suppliers, machine manufacturers and vendors. Their clients rely on them to help them balance out the “ups and downs” of the market while managing their human capital more efficiently. Digitron is a multinational and multicultural group with subsidiaries in Munich and Dresden/Germany; Zelenograd/ Russia; Singapore and San Jose, California. Digitron's customers can count upon having a competent and flexible outsourcing partner with outstanding industry references. OEM clients benefit by releasing their high-value, seasoned support and application engineers from mundane or repetitive service and support tasks. Even labor intensive but otherwise routine fab line installations can be delegated so that key employees remain dedicated to the more profitable activities of in-house machine builds and tool qualification testing. This redistribution of effort allows OEMs to maintain peak internal productivity while remaining competitive in the strenuous arena of after warranty service and customer support. Services available include machine installations and warranty repairs, On-site service and preventive maintenance, modification, calibration, updates and retrofits, tool disconnection, relocation and reinstallation of equipment, production line installations and startups and spare parts logistics and local storage.

Digitron’s business plan The German company is also a valuable resource for helping to cover temporary staff shortages; business peaks, hiring freezes and vacations or other unexpected absences. Their available staff includes some forty English-speaking engineers and other electronic or mechanical technicians. Each comes with a solid background in electronics, mechanics or industrial chemistry and a minimum of three years experience in repairing and maintaining microelectronic, nanotechnology or photovoltaic equipment. Digitron Engineering Services can be your contract service and support provider, offering you substantial savings in labor, travel and time. They offer project-related contracts ranging from weeks to years that are tailored to your individual requirements. Digitron also has the unique ability to time-share staff between a cluster of regional clients for even greater savings. All of their engineers are fully employed or exclusively contracted. Digitron is an award winning internationally recognized service organization and recipient of the coveted 2007 & 2008 EuroAsia IC-Industry Awards for “Maintenance Outsourcing Services”. For more information or to contact Digitron directly, please visit their web site at www.digitron.de. Call Digitron Engineering Services today and find out how your organization can enhance productivity and profitability without compromising responsiveness or customer support. Corporated Headquarter: An der Moosach 7 - 85376 Neufahrn/Massenhausen, Munich, Germany Tel: +49 8165-99959-0 Email: sales@digitron.de

Phot ov olt aic s I nt ernat ional

PV system optimization with distributed power optimizers: mitigating the PV system mismatches problem An analysis and comparison of centralized versus distributed MPPT By Ralf J. Muenster & Aaron R. Thurlow, National Semiconductor Introduction Installing a solar electricity, or photovoltaic, system requires a significant upfront investment in both time and money, but the returns promised can be phenomenal compared to other low-risk investments, including a reduced electricity bill and a favorable ROI. Once a solar installation is up and running, advertising suggests the PV system owner can sit back and relax for the next 25 years. But is this really the case? Unfortunately, many solar system owners are unaware of how their new PV systems operate and to what degree their solar systems may be under-performing. In fact, many do not know about the problem of panel or system mismatches and may have little or no knowledge about the potentially devastating impact of shading from trees and chimneys on the power output of a system. PV system mismatches occur when voltage and current combinations do not match up, and can be caused by a number of culprits, such as partial shade, moving clouds, reflections from nearby objects, varying tilt angles and orientations, soiling, and temperature variations across a solar array. In fact, shading that covers just a few percent of a solar array can result in a power loss in the range of 25 to 50%.

Problem: panel mismatch In estimating the performance of a PV system, it is common practice to assume typical conditions of irradiance, temperature, and module parameters, and that these conditions are uniform across all cells and modules in a PV array. However, there are many situations such as partial shading of the array and different module tilts that cause significant variations of these factors within an array or a single string of PV panels. The result is panel mismatch and lowered system performance; in short, actual performance will deviate significantly from what would be expected. From testing and field trial results collected at National Semiconductor Labs (Fig. 1) and referencing other studies, panel mismatches resulting from shade or other factors can result in disproportionate power loss in solar panels, whereby just a few percent of shading can lead to significant energy loss. Additionally, Chaintreuil et al. [1] note that for crystalline silicon PV arrays, depending on the array connection, as little as 2.6% shading could lead to a total energy loss of 16.7% (Fig. 2). Photon International found that shade from a dormer window covering about 20% of an array can reduce the output power of a PV system by a massive 81%, making the system unviable (Fig. 3) [2]. Unidentified mismatch issues at the time of installation cause many PV installations to fail to meet their full energy harvest potential, leaving the system owner with a less than 26

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Figure 1. Panel mismatches resulting from shade or other factors can result in disproportionate power loss in solar panels (source: National Semiconductor Labs).

Figure 2. Difference in performance of arrays in shaded conditions [1].

Figure 3. Shade from a dormer window covering about 20% of an array can reduce the output power of a PV system by a massive 81% [2]. ideal investment. Additionally, known mismatch issues may cause projects to be abandoned entirely due to less-thanideal energy harvest projections. These mismatch cases lead to an under-delivery of energy from PV systems and an under-utilization of available space for solar deployments. Many of todayâ&#x20AC;&#x2122;s rooftop commercial installations could be 10 to 20% larger if they could utilize space with partial shading such as around parapet walls and mechanical equipment. Some residential customers are simply â&#x20AC;&#x2DC;shaded outâ&#x20AC;&#x2122; either from trees that cannot be cut or from adjacent buildings and one can only hazard a guess as to the amount

39/LWH $GYHUWRULDO B

because of non-uniform parameters. With a centralized MPPT, this can lead to additional disproportionate losses for two reasons. Firstly, the centralized MPPT becomes confused, stopping on a local maximum point and settling in a sub-optimal point of the voltage to power configuration. Secondly, the voltage point of the MPP can be very diverse due to irregular conditions, going beyond the scope and voltage range of the centralized MPPT. Because the variations between panels are significant, it is in these cases that the ability of power optimizers in distributed MPPTs can enhance the performance of panels independently and boost performance.

Source: National Semiconductor Corporation.

Source: California Public Utility Commission ‘Itron SGIP Impact Evaluation’

of solar energy that could be generated from these sites. From a survey conducted by Greenberg Quinlan Rosner Research of 150 installers in the US in January 2009, installers acknowledged the problem as endemic, with as many as 54% stating that any shade on installations was unacceptable. Installers instead choose to “design around the problem,” leading to an average cost increase of 19% [3]. Moreover, according to a study published by the California Public Utility Commission in June 2009, the average annual production of metered sites under the CSI program consistently underperformed PV Watts expectations (Fig. 4) [4].

Figure 4. Average annual production of metered sites under the CSI program consistently underperformed PV Watts expectations. To explain the phenomenon of panel mismatch and why small variations in cell parameters can affect the systemlevel performance of the PV array, we need look at the way PV systems are commonly being architected today.

Figure 5. Grid-tied PV system with centralized MPPT

Source: National Semiconductor Corporation.

PV arrays for residential, commercial, or utility installations are typically configured as shown in Fig. 5. In this setup, multiple strings of PV panels are connected in parallel and they feed the input of a grid-tied inverter. Panels themselves consist of a series configuration of cells. A centralized inverter not only converts DC to AC power as a primary function, but also contains an MPPT (maximum power point tracker) controller which seeks to maximize the energy harvest through an MPPT algorithm from the PV array at all times by regulating its input impedance.

Solution: distributed power optimization Power generated by a solar module is calculated by multiplying current (I) by voltage (V). At any given time under any given conditions, there exists one optimal point – the maximum power point (MPP) – at which location a module is generating the most power possible for those conditions. In other words, the single MPP of a PV module is a function of an exponential relationship between current and voltage. MPPT is an electronic form of tracking that utilizes algorithms and control circuits to search for this maximum energy point and thus allow a converter circuit to harvest the maximum power available from a PV module. In cases where irradiation, temperature, and other cell parameters are uniform, there would be no difference between the performance of distributed MPPT and centralized MPPT besides conversion efficiency differences. However, where partial shading is present, the panel mismatch problem is at its greatest. Partial shading will result in an array having multiple MPPs from different panels

Figure 6. Grid-tied inverter with Power Optimizer distributed MPPT. In a PV array with power optimizer technology and distributed MPPT (Fig. 6), a power optimizer unit is attached at each panel. Power optimizers have a dual tracking system: on the one hand, they track the best localized MPP, and on the other hand, they translate the input voltage/current to a different output voltage/current to maximize the energy transport in the system. The power optimizers communicate with each other in an indirect manner. They are cognitive and self-organizing – they sense their I & V environment and adjust themselves until a total string optimum is achieved, while simultaneously arriving at a local optimization point at the panel level. At present, only SolarMagic™ power optimizers are capable of this. Power optimizers keep the time-proven seriesparallel panel arrangement and improve it by distributing only the DC/DC and MPPT function to the panels. Phot ov olt aic s I nt ernat ional

Meanwhile, the power optimizer architecture is perfectly compatible with existing multi-stage inverters and will actually allow them to run more efficiently because the bus voltage can be kept higher and more constant. Power optimizers are much more than just boosting DC/DC converters, as they deal with both extra energy and reduced energy. This means additional irradiance from reflection, the opposite mismatch to shadowing, can be captured as additional energy harvest. Likewise, it means that power optimizers are capable of power changes caused by adding panels to a string (making that string generate more energy) or subtracting a panel or two from a string (thus reducing energy). This enables greater flexibility for arrays as installers can design systems with different string lengths. Additional flexibility added by power optimizers includes allowing different types of modules to be mixed on a single string as well as installing modules in different orientations on the same string. Power optimizer architecture enables solar electricity systems to harvest the most energy available.

Power optimizers have the added benefit of providing protection against falling PV system performance over time from a variety of problems such as wiring and module degradation, ensuring that the system owner achieves the full potential of their investment. In another case, Photon International recently tested SolarMagic power optimizers and found that it could recoup up to 71% of the lost energy due to shade mismatches making the solar installation with dormer windows viable (Fig. 3) [2].

A recent case study performed by National Semiconductor on a 30kW solar array owned by solar visionary Jigar Shah showed intriguing gains. Prior to the installation of power optimizers, the installation was performing well below expectations with a performance ratio of only 67%. After the installation of the power optimizers on about one-third of the 204-panel system, the overall power output was boosted by 22.6%, even with the presence of shading, panel and wiring imbalances, and the performance ratio of the system reached unseen heights of 82%, a number above PV Watts expectations.

[1] N. Chaintreuil, F. Barruel, X. Le Pivert, H. Buttin, J. Merten. “Effects of shadow on a grid connected PV System” INES R.D.I., Laboratory for Solar Systems (L2S). [2] H. Neuenstein, C. Podewils “Rare Magic,” Photon International, September 2009. [3] Installer Survey by Greenberg Quinlan Rosner Research, January 2009. [4] Sachu Constantine, California Public Utilities Commission, SolarTech Performance Symposium, July 13, 2009.

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Power optimizers will not only increase the output of current rooftop installations, but will also allow installers to design systems that maximize roof space, while helping customers achieve quicker returns on their investments. Along with the much-anticipated renewable energy-friendly policies of the new administration, the introduction of the power optimizer technology marks a major step towards lowering the cost of solar energy.

References

Buffalo Niagara sees a bright future in solar By David Griggs, Director of Business Development, Buffalo Niagara Enterprise The Buffalo Niagara region has been relying on Niagara Falls to power its electricity needs since the first street lamps were turned on. So it's only natural that, with the growing need to develop new sources of renewable energy, a light bulb went off: Buffalo Niagara is well poised to serve as a hub of solar manufacturing in the United States. The same strengths that led to Buffalo Niagara’s original rise in the early part of the 19th century can and should be utilized to lead the region into a new era. These strengths include access to water and low-cost hydroelectric power, a strong supply chain, a skilled and diversified workforce and the availability of shovel-ready, affordable sites.

Low-cost Hydropower When the Niagara Power Project produced its first power in 1961, it was the largest hydropower facility in the western world at the time. Today, Niagara is the biggest electricity producer in New York State, generating 2.4 million kilowatts. This low-cost electricity saves the state's residents and businesses hundreds of millions of dollars every year. Low-cost hydropower has been reserved by New York State law for companies planning to build or expand in the Buffalo Niagara region. The program offers hydroelectric power at an extremely affordable rate.

Our region also has a strong metal manufacturing base and major companies producing solar energy components including glass, solar cells and other manufactured components.

Workforce/Workforce Development Buffalo Niagara can also keep renewable energy companies supplied with human resources. We have a highly skilled, highly motivated, highly productive workforce; led by graduates of the University of Buffalo's outstanding engineering school, our region produces over 400 engineers each year, as well as a ready supply of scientists. Buffalo Niagara labor costs are lower than those of other northeastern and Great Lakes region metropolitan areas of comparable or greater size, such as Cleveland, Ohio, Philadelphia, Pennsylvania and Boston, Massachusetts. Buffalo Niagara has a strong base of universities and colleges, many of which are involved in research and development and have training programs related to renewable energies. The University of Buffalo, along with Erie Community College, has developed workforce training programs specifically designed to meet the needs of the solar industry.

Supply Chain

Availability of Sites

Due to the availability of low-cost power and water supply from the Niagara River, Buffalo Niagara has a number of large chemical manufacturers that all form a part of the supply chain for the solar industry. In Buffalo Niagara, renewable energy companies are surrounded by manufacturers producing the materials they require in order to do business. Manufacturers include: Globe Metallurgical, one of the world's largest producers of silicon metal; Dupont, leading materials supplier to the PV industry; Praxair, supplier of atmospheric, process and specialty gases; Linde Gas, which manufactures industrial gases or products required by some technologies; and Occidental Chemical, a leading producer of potassium hydroxide products, chlorinated isocyanurate products, and sodium silicates.

New York State has been a pioneer in establishing the concept of certified ‘shovel-ready’ sites and Buffalo Niagara is a leader in New York State in developing these sites. Buffalo Niagara offers a variety of certified shovelready sites as well as brownfield sites that are uniquely qualified for the solar industry’s needs. With united and coordinated action, Buffalo Niagara has an unlimited potential to show the world how a declining manufacturing city can transform itself into a focal point within a new growth economy. For more information, please visit www.buffaloniagara.org/photovoltaic

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Location – in brief Location: Castilla-La Mancha is located in the center of the Iberian Peninsula. It occupies a surface area of approximately 80,000km², with a population of almost two million people. Its strategic location, bordering Madrid, and excellent communications allow for rapid access to the rest of Europe and North Africa. Introduction: Castilla-La Mancha has grown to currently become the leader in renewable energy production in Spain, particularly in the areas of wind and solar PV energy. In May 2009, energy consumption from renewable sources reached 70% in Castilla-La Mancha, where the objective is to reach 100% by 2012. At the beginning of the year, Castilla-La Mancha had 800MW installed capacity in PV, 25% of the total installed power in Spain. From Castilla-La Mancha you get a direct access to the most important solar markets in Spain. Regarding solar photovoltaic energy, key factors contributing to the enormous development experienced during the last two years include excellent radiation, available surface area, access to the grid and a supportive administration. The entire value chain of the PV industry is present in the region, from raw material transformation to BOS components. In addition, you will find very well trained human resources and solid cooperation with training centers and Universities in our region. Infrastructures: Castilla-La Mancha is centrally located in Spain, forming a strategic communications node and crossroads between northern Europe and Africa, including the harbors of Valencia and Lisbon. Roads – Castilla-La Mancha has more kilometers of roads and highways than any other Region in Spain: 2,790 km representing 20% of all highways in Spain. Railways – Castilla-La Mancha is the best connected Region in Spain, with 1,000 km of High Speed Trains. A irports and Ports – Close to both the Valencia Sea port and Madrid Barajas International Airport, it’s wellcommunicated by road. In Castilla-La Mancha, Ciudad

Real Airport offers cargo facilities and commercial flights to the rest of Europe. Energy infrastructures – Castilla-La Mancha has become the leading region in Spain, among other reasons, due to its infrastructure for the transportation and distribution of electricity. Key features/incentives: Castilla-La Mancha is an EU “Convergence” area. These EU funds are focused on improving infrastructures and training, as well as encouraging business investment to increase regional economic progress. The region possesses financial instruments to support the establishment of foreign companies, such as soft loans and holding company equity. Grants for employment and training subsidies are available to companies willing to set up in Castilla-La Mancha. Industrial land and labor force costs are significantly lower compared to the rest of Spain, resulting in a harmonious area for employment and social discourse. R+D Centers: International R&D Centers: I SFOC ( Instituto de Sistemas Fotovoltaicos de Concentración) is a worldwide reference for promoting the development of Concentration Photovoltaic Systems (CPV). In order to generate key knowledge within this technology, ISFOC is operating several power plants (up to 3MW in total), incorporating different concentrator technologies that will soon be brought to market. National Institute for Hydrogen Fuel Cell. The objective is to lead the national strategy on hydrogen and fuel cell technologies, as well as to coordinate R&D activities in order to benefit the industrial sectors involved. There are also Science & Technology Parks in Albacete and Guadalajara, as well as an Institute for Renewable Energy in Albacete. University of Castilla-La Mancha (UCLM), a modern and innovative university with several R+D Centers related to solar PV such as Renewable Energy Investigation Institute , Nanotechnology and Nano-sciences Institute , Environmental and Chemical Technology Institute , Industrial Applications and Energy Investigations Institute… Key organisations in renewable energies: Iberdrola, Acciona, General Electric, Vestas, Rewair, Titan Tracker, Eiffage, Silicio Solar, Siliken, Solaria, Soldaduras Avanzadas, Ingeteam… Contact: Elena Laburu BestinCLM – Investment Agency for Castilla-La Mancha Centro de Empresas nº 1 C/ Valdemarías, s/n 45007 TOLEDO – España Tel: +34 925 33 41 41 Fax: +34 925 33 37 19 Email: elaburu#jccm.es Website: www.investincastillalamancha.com

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Castilla-La Mancha: leading the way with 100% renewables by 2012 Interview with Paula Fernández Pareja, Regional Ministry for Industry, Energy and Environment, Regional Government of Castilla-La Mancha (Spain) – Interview by Mark Osborne, News Editor for Photovoltaics International 1. Why has the region been so successful in the past in attracting the PV industry?

It’s not chance, but to a well-planned and executed strategy. Castilla-La Mancha was one of the first regions in Spain of having its own legislative framework in the field of renewable for the Promotion of Renewable Energies and Incentives for Energy Efficiency and Conservation. We’ve managed to position ourselves as leaders in solar photovoltaic energy generation accompanied by an enormous rise of industry components manufacturers in our region. 2. What progressive incentive schemes does the region have to offer and are they competitive with established schemes in Germany and now in the U.S.?

There currently exists a feed-intariff system in Spain for photovoltaic facilities connected to the grid, very similar to that of Germany; as well as a subsidy policy for off-grid systems. Solar photovoltaic installed power has been much higher as first expected. Such rapid development has resulted in numerous industrial investments related to solar photovoltaic technology, so that the entire value chain can be found in Castilla-La Mancha. 3. What effective transport systems are provided by Castilla-La-Mancha, considering its central location?

Castilla-La Mancha has known how to take advantage of its geographic location in the center of the Iberian Peninsula, becoming a strategic area in terms of transport infrastructures, combining a

(ISFOC), located in Puertollano which, along with the National Center for Experimentation in Hydrogen and Fuel Cell Technologies, located in the same city, puts Castilla-La Mancha in a privileged situation when it comes to researching new energies.

dense high-capacity road network, highspeed train, two airports in Ciudad Real and Albacete (with direct access to Madrid Barajas international airport). 4. What is offered and what is planned in the region to enable sustained growth for a PV manufacturer?

6. What strategies, incentive schemes etc. are in place and/or planned to assist manufacturers’ expansion plans?

Existing projects involving power generation, industry and research are backed by a capable workforce. Moreover, the University of Castilla-La Mancha offers postgraduate degrees and other courses related to renewables and solar photovoltaic energy. All in all, we can safely say that Castilla-La Mancha possesses the talent and the required training to continue enjoying sustained growth in the industry.

We possess a useful and efficient tool: the Castilla-La Mancha Strategic Framework for Energy Development, one of whose main objectives is “to meet the entire electricity demand with renewable energies and satisfy primary energy consumption with renewable energies.” We intend, with this measure, to reduce our CO 2 emissions, thereby fighting against the effects of climate change. Initiatives associated with these objectives include significantly increasing installed capacity of renewable energies. The required investment for reaching the growth objective for renewable energy facilities totals approximately 6 billion euros in the period covering 2008-2012. Anticipated investment for setting up electricity production facilities, based on solar energy for all modules, totals 4 billion euros; in other words, 68% of the total forecasted investment for renewable energy facilities and 53% of that forecasted for electricity production facilities. This corresponds to 38% of investment in solar photovoltaic facilities and the rest in thermoelectric solar facilities.

5. What is offered and what is planned in the region to enable sustained growth for a PV R&D capabilities?

Our Regional Government is convinced that Castilla-La Mancha must base its economic growth on providing technology and know-how. We are supporting innovation and providing incentives to companies through the Innoempresa program, for example, aimed at assisting innovation projects developed by our SMEs. Since the program began in 2007, we’ve provided grants to 343 business projects, with a total investment of more than 15.3 million euros. We are also very aware of the key factor of combining research with the University. Therefore our region has committed to housing the Institute for Concentrating Photovoltaic Systems

BURGOS-BILBAO-FRANCE ZARAGOZA-BARCELONA-FRANCE

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MADRID

CUENCA

GUADALAJARA

SALAMANCA

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MADRID AVILA

CUENCA TARANCON

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CIUDAD REAL

ALICANTE

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PUERTOLLANO

BADAJOZ MURCIA

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HIGH SPEED TRAINS IN SERVICE HIGH SPEED TRAINS UNDER CONSTRUCTION HIGH SPEED TRAINS IN PLANNING STAGE

JAEN CORDOBA

MOTORWAYS AND HIGHWAYS IN SERVICE

SEVILLE-CADIZ ALGECIRAS

MOTORWAYS AND HIGHWAYS UNDER CONSTRUCTION MOTORWAYS AND HIGHWAYS IN PLANNING STAGE

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A look at solar efficiency issues and innovative output boosting technologies By Sam Arditi & Jeff Krisa Today’s PV systems are typically comprised of solar modules (panels) serially connected to one another in strings until the voltage maximum is met (600V or 1kV as restricted by the US and Europe respectively). For larger installations, several of these strings are connected in parallel to form an array. With serial string design, the power output of each module in the array will be affected by the weakest modules. Therefore it is important for the array to be comprised of PV modules that perform identically. Significant effort is expended by the value chain to match the modules (in type, power rating and manufacturer), orient them in the same direction, and ensure co-planarity thus minimizing output variability at installation. This increases the cost of module production and installation while greatly reducing the options for rooftop hosts of solar systems. Furthermore, environmental effects such as uneven soiling, temperature variations, settling or other slight differences in orientation, and property migration of silicon become evident within weeks leading to significant losses due to increasing mismatch. These effects compound over time through the life of the project (20-25 years).

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Central or string inverters perform the DC to AC conversion necessary to deposit energy production onto the grid. The inverter also attempts to keep the array (or string) at the highest power output possible. To find the point at which the entire system can produce the maximum power at the current solar irradiance point, the inverter usually applies a sophisticated ‘trial & error’ algorithm, which adjusts its current draw on the system. By measuring the new DC power input, the inverter will determine whether to continue the adjustment in the same direction or reverse course. There are many variants of the algorithm but with input data limited to array DC voltage and current, it is unlikely that any individual module is performing at its peak output. The task becomes significantly more complex during times of changing irradiance (e.g. cloud cover, shading), as each module’s maximum power point moves dynamically. System stabilization may take several minutes after a cloud has passed leading to high losses. Each module has a series of by-pass diodes, so a module that is significantly under-performing due to extra soiling or some of the other environmental effects will be ‘turned off’ when the current drawn from the inverter exceeds its ability to provide power.

Perhaps the most promising technology that directly addresses these production losses due to module performance mismatch has been developed by Los Gatos-based solar efficiency pioneer, Tigo Energy. The company adds a small electronics footprint on each module that maximizes power output on every module, offers unprecedented system visibility for performance monitoring, maintenance, and debugging, and brings new levels of safety for rooftop and building-integrated applications.

MORE ENERGY The Tigo Energy™ Maximizer Solution (pictured on previous page) instruments module and environmental characteristics, calculates maximum power point and ensures each module provides the most power output possible. The system can react instantaneously to irradiance changes as each module adjusts quickly and independently to maintain maximum contribution. In well-designed commercial systems, the Tigo Energy™ Maximizer Solution will typically return 4 to 8% incremental power output throughout the life of the system. More distressed projects that contain shading can return up to a 20% increase in energy production. Projects that were previously not viable with traditional design constraints can now be placed in profitable operation.

MORE VISIBILITY Tigo Energy’s Module Maximizer communicates module characteristics to the Tigo Energy Management Unit,

which computes the operating point of each module using both module and array data. This data is also provided to a database (the Management Unit additionally provides a ‘gateway’ function) that feeds the Tigo Energy MaxiManager application suite (see screenshot overleaf). Application modules analyze long-term array performance, flag underperforming or broken modules, and provide reports for targeted maintenance actions in near real-time. This allows project owners to lower O&M costs, exercise warranty replacements and keep the system running at peak efficiency throughout the life of the project. System operators and owners gain an understanding of not only how, but also why the system is performing at its current output. The granularity of project visibility has never before been available in such a cost-effective implementation. The Tigo Energy™ MaxiManager software can also create customized reports for historical data to enable the system owner to see trends in energy generation during different times of the year and varying weather conditions. The data can be accessed through a secure web-enabled computer so that even when the system owner is not in the office, the status of the panels can be instantly viewed.

MORE SAFETY In California and regions with large amounts of PV installed such as Germany, emergency services personnel have raised concerns that today’s solar rooftop installations present a danger when extinguishing a structural fire. This hazard extends to homeowners

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or maintenance professionals who choose to service an installation. Even after the DC disconnect is activated, the modules continue to generate power as long as there is sufficient irradiance. Due to the serial connectivity of the string, each module and cable can carry a lethal level of voltage (well in excess of 400V). The potential for arcing and electrocution from applying water or cutting through a module is an impediment to addressing a burning structure. This is significantly different from residential or commercial facilities without a solar installation in which disconnecting the facility from the grid normally makes it safe for firefighters. To avoid such a scenario with solar installed facilities, local building authorities are slowing approvals and requiring expensive ‘quick-release’ racking systems which further burden the cost of solar installations. The Tigo Energy Maximizer System includes Tigo Energy™ PV-Safe circuitry, which is able to ‘disconnect’ each module from the interconnecting cabling, deactivating the array and limiting exposure to high voltages. When not connected to the Management Unit, the electronics default to the ‘off’ state, also creating a safe environment during installation. When the system is functional, the array may be deactivated by the PV-Safe button on the Management Unit or remotely through the web-based management console.

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Tigo Energy’s system provides an innovative solution to maximizing power output in today’s PV systems. The revolutionary technology provides up to 20% improvement from the same PV array by implementing a combination of innovative technologies that provide more energy production, increased visibility into the individual system components, and additional safety in array deactivation. With systems installed around the world and operational for over 12 months, Tigo Energy has gathered significant data on reliability, stability and up-time in real-world conditions for improved energy harvest and is rapidly expanding. Tigo Energy was founded in early 2007 and has numerous patent submissions; strong financial backing from leaders in the venture capital community (including Matrix, OVP, and ICV); and is led by an experienced team of Silicon Valley and international technology executives. The company which now has offices in the United States, Japan, Germany and Israel, has successfully deployed numerous installations in cooperation with several of the most prominent solar industry leaders and is rapidly expanding. Additional information on improving solar panel efficiency and Tigo Energy is available at: www.tigoenergy.com

R&D process innovations and vertical integration at H.C. Starck: sputtering target manufacturer for thin-film photovoltaics H.C. Starck’s Fabricated Products Group is responding to the demand to lower the cost per watt in the rapidly growing photovoltaic industry by actively promoting its planar and rotary sputtering targets for thin-film PV (TFPV) energy applications. Particular emphasis is being given to molybdenum and nickel-based monolithic rotary targets for CIGS, CdTe and a-Si (amorphous silicon) technologies.

offering improved sputtering target quality by careful microstructural control and increased homogeneity.

A highly qualified team of Ph.D. engineers and trained R&D professionals works closely with customers to optimize and develop new products and technologies. Committed to the research and development of thin films, they invested in stateof-the-art laboratories for material processing Qualified at major CIGS and CdTe module manufacturers and thin films. Their facilities include a Thin Film worldwide, H.C. Starck’s molybdenum targets are Materials Lab equipped with sputtering tools designed to help cut costs by offering reduced arcing, plus the supporting equipment for testing film increased power density and high material utilization. characteristics. Customers benefit from in-house Constant development and years of production experience prototyping, modeling and analytical capabilities. with refractory metals has resulted in targets with extremely low oxygen levels, full density and refined Finite Element Modeling is integral to microstructure optimized for improved sputtering. process development, ensuring uniformity of microstructure and maximum yield. The employment of advanced analytical tools such as electron backscattering diffraction analysis (EBSD) confirms optimum crystallographic EBSD analysis revealing a sputtering target’s texture, glow discharge mass spectroscopy Monolithic Rotary homogeneous microstructure, with fine equiaxed (GDMS) measures every metallic impurity down Sputtering Targets. crystallographic grains. to 1 part per million by weight, and ultrasonic scanning results in elimination of banding in the microstructure, consistent chemical composition Safety of supply from mine to market – and effective non-destructive inspection.

global supply chain

Active in more than 30 countries, H.C. Starck stays close to its customers by delivering hundreds of tons of sputtering target materials yearly direct to market. One of the world’s largest producers of molybdenum powders, as well as tungsten and tantalum, H.C. Starck is vertically integrated with expertise in reducing, pressing and sintering these high performance materials and finishing them for market. To produce planar and rotary targets, technical-grade molybdenum oxide (MoO3) powders are reduced to metal and processed for either rolling or extrusion then finished to customer specifications.

Production capabilities As a vertically integrated supplier, H.C. Starck has production capabilities that surpass most of its competitors. Utilizing its world-class extrusion facilities with its 5,000 metric ton direct extrusion press, H.C. Starck can produce molybdenum rotary targets with inside diameters of 125mm (monolithic) and 135mm (bonded) applications in molybdenum up through the current largest large area coating rotary target requirement. Tantalum, niobium, nickel-vanadium and other materials can also be produced by H.C. Starck in planar or rotary form. Targets in lengths of 4m (or more) can be produced as per customer specification.

H.C. Starck is one of the few companies in the world capable of in-house conversion of raw materials into finished, high-purity sputtering targets offering unmatched quality control and excellence in execution. Controlling the process of material production from the start helps control the physical properties of the materials produced and yields a far superior final product. H.C. Starck Inc., Fabricated Products Group 45 Industrial Place, Newton, MA 02461 USA Cristian Cretu Tel: +1 216.692.6985 Fax: +1 216.692.0031 Email: info#hcstarck.com Web: www.hcstarck.com Close attention to the action in the sputtering chamber of H.C. Starck’s lab tool pays dividends.

Technical expertise and R&D H.C. Starck is benefiting greatly from experience accumulated during years of supplying sputtering target materials to main manufacturers in the flat panel display (FPD) and semiconductor markets. This resulted in Phot ov olt aic s I nt ernat ional

ecoContact â&#x20AC;&#x201C; the worldâ&#x20AC;&#x2122;s fastest fully automatic contacting system for the manufacture of thin-film photovoltaic modules More efficient contacting of thin-film modules Developed by ACI-ecotec, ecoContact requires less than 30 seconds to manufacture a thin-film PV module, completely automatically. As well as offering outstanding speed and high contact quality, the system is highly flexible and extremely economical with materials. This state-of-the-art solution can be used to apply small pieces of adhesive tape for attaching bus bars â&#x20AC;&#x201C; helping save up to 100,000 euros a year in adhesive materials alone, compared to other systems. Because of the large capital expenditure involved, production systems for thin-film photovoltaic modules must operate as efficiently as possible. And that is where ecoContact comes in. This innovative and fully automatic contacting system was developed by St. Georgen-based automation specialist ACIecotec GmbH & CO. KG. It comprises standard components for applying conductive adhesives, longitudinal and crosscontacting and soldering bus bars in accordance with the given production technology. These components can be combined in a flexible way to manufacture all common thin-film module sizes. The substrates are transported and precisely positioned using a multi-lane conveyor belt. The patented ecoContact system is already being used in many production facilities for thin-film PV modules worldwide.

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The ecoContact provides complete flexibility in offering various layouts, various module sizes and a recipe driven control system.

In the dispensing module of ecoContact, conductive adhesive is applied using two dispensing heads at speeds of between 50 and 70 mm per second with continuous monitoring of the needles.

Application of conductive adhesives using two autonomous dispensing heads The conductive adhesive is applied via two dispensing heads at speeds of between 50 and 70 mm per second, with ongoing monitoring of the needles any bumps or irregularities in the surface of the glass plate are automatically levelled out. Thanks to the controlled, high-precision application, less than 0.3 grams of adhesive is required for a substrate that is 1300 to 1400 mm long. Because the CNC heads operate autonomously, the position, length and distance between the adhesive strips can be programmed flexibly. This enables the application of more than two adhesive strips without modifications.

High-precision contacting with huge cost savings in materials Following the application of conductive adhesive, the substrate is automatically indexed and aligned for longitudinal contacting. The tin-plated bus bar is applied using reels up to up to 380mm diameter, minimising downtime due to changeovers. To maintain the required tension between the continuously spinning reel and the cyclical application of the bus bar, the system has an integrated mechanical control bobbin. This detects if there is insufficient bus bar left on the reel and stops the machine automatically, minimising substrate waste. To prevent the bus bar from breaking loose before the adhesive has cured in the laminator, it is fixed with specially designed adhesive tape. In conventional contacting, this tape is applied along the entire length of the bus bar. However, ACI-ecotec deploys an innovative solution that automatically cuts small pieces of tape from the roll, removes them from their backing and sticks them onto the bus bar at predefined points. This economic use of the adhesive tape enables annual cost savings of up to 100,000 euros a year, as well as also significantly increasing system availability. For cross-

The bus bars are connected via an automatic soldering process, and their ends turned upwards or downward in accordance with the customerâ&#x20AC;&#x2122;s specifications. contacting, exactly the same technology is used. Subsequently, at a different workstation, the bus bar contacts are soldered together and their ends turned upwards or downwards in accordance with the customerâ&#x20AC;&#x2122;s specifications. Optionally, the glass cover can also be applied automatically.

Greater productivity and flexibility Like the adhesive dispensing station, the standard components for longitudinal and cross-contacting are fitted with two autonomous CNC units for attaching the bus bar. With ecoContact, ACI-ecotec aims for manufacturing times of less than 30 seconds for a complete thin-film PV module. Furthermore, the redundant solution, which has programmable axes, allows production to continue while maintenance work is being performed on one of the dispensing heads or application components.

Robust design with integrated switchgear cabinet Each ecoContact module is based on a stable steel structure with an integrated switchgear cabinet. As well as saving space, this design enables rapid implementation of the contacting system. More information: ACI-ecotec GmbH & Co. KG Bahnhofstrasse 10 78112 St. Georgen Germany Tel: +49 (0)7724 934-0 Website: www.aci-ecotec.com

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Bürkle sets trends in the solar module production The Ypsator is considered the first and largest multi-opening laminator worldwide. With the “Ypsator” Robert Bürkle GmbH has succeeded in making the breakthrough in the solar module production at its first go. The German plant manufacturer is considered a pioneer of the multi-opening lamination. By using this technology 20 solar modules can be produced at the same time on the (up to) ten openings of the Ypsator respectively 150 solar modules per hour.

Introduction This module production rate “is a world record”, says Ralf Spindler, the managing director. Spindler explains that Bürkle has supplied and commissioned more than ten multi-opening laminators since the market launch at the end of 2007. “No manufacturer has supplied more”, says the 45-year-old manager (responsible for sales and marketing). All in all this corresponds to the capacity of more than 50 traditional singleopening laminators. Last year Bürkle also sold 13 units of the same. In 2008 the machine manufacturer gained ½31 million in the new photovoltaic sector straightaway and thus raised the turnover to ½115 million. Also in the year 2009 the laminator business for the photovoltaic industry proved a success. “Five further units of the Ypsator brand have been ordered and will be supplied by the end of the year”, explains Spindler. The Bürkle lines for pressing glass, foil and solar cells to crystalline or thinfilm modules are located in Germany, Europe, America and Asia.

Ypsator’s Success It is not surprising that Bürkle, although a newcomer, has found success in this area. Bürkle is regarded as an expert in the lamination and pressing sector since it has built up a technological know-how in the wood and electronics segment for many decades. “We have got prepared ourselves intensely for the entry into the solar market”, highlights Spindler. Awards show that the Ypsator is not only on a technologically high level, but also in regard to its design: iF Award, red-dot Award as well as the American Good Design award. The strategy of manufacturing solar modules on several openings has proven: “The Ypsator sells so well as hall space is very expensive and it nearly fits every works structure”, declares the sales manager. Producers such as Scheuten

Bürkle Back-end lines for the production of thin film modules.

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Solar and Day4Energy rely on Bürkle technology that can even be integrated in existing lines without any problems. The Fraunhofer Institute for Solar Energy Systems ISE in Freiburg also uses a laminator from Freudenstadt for its research.

Research and Development Due to the tight coupling to research and to the proven technology of laminating on steel heating platens heated with thermal oil, the plant manufacturer secures competitive advantages. This is added to the fact that Bürkle sets trends with the development of the three-step lamination of glassglass modules. The repartition of the process in pre-lamination (under a vacuum), final lamination and cooling increases the capacity of the line and the quality of the produced modules. For enlarging their competence, the Black Forest company invested ½5.5 million in new machines and buildings at the locations in Freudenstadt, Rietberg-Mastholte and Shanghai last year. The highlight is the innovation center with 1000m2 in Freudenstadt, which is visited daily by customers since the inauguration last November. “Here we analyse what our customers need and which line concepts and processes match the solar module producers”, defines Spindler. For this reason he knows that – besides the actual laminators – more and more turnkey solutions are demanded on the market. It is for these reasons that Bürkle has enlarged the production portfolio by transport and handling equipment as well as storage units. Moreover the manufacturer offers complete lines for the so-called back-end of the module production for the thin-film technology. This comprises crucial components from their own development and production such as foil uncoiling and foil lay-up, cover glass lay-up and automatic setting of junction boxes – just to name a few components. Remote service systems are also demanded. BY doing this, you can externally intervene into lines via the internet for finding and remedying possible failures promptly. Bürkle’s targets in the photovoltaic sector are ambitious: By the end of 2011 the company wishes to gain half of the turnover in the PV industry. Currently around 100 staff members (of the 480 staff members in Freudenstadt and Mastholte) plus 20 service technicians are working worldwide for the solar sector.

Location – in brief Solar Valley – a sustainable region in the heart of Germany

Location: Located in the south of the centrally situated state of Saxony-Anhalt, the Solar Valley is perfectly placed for access to major markets in Germany, Spain, Italy and the rest of the EU (operating in EU economic zone). The location also won the Cell Award for “Best Region for Manufacturing Solar Technology”. Introduction: Saxony-Anhalt is one of the leading solar regions in the world, responsible for the production of 80% of German solar cells. The Solar Valley Centre for Silicon Photovoltaics has the highest density of companies involved in the PV industry. In order to initiate private investments in solar electricity systems, the town of Bitterfeld-Wolfen and the district of Anhalt-Bitterfeld have launched an initiative – the “1000-Dächer-Programm (1000 Roofs Programme)”. The project is aimed at all citizens in the region who want to make an active contribution to protecting the environment by installing a PV system on their roof and at the same time achieve secure returns over a period of 20 years. As for the industry, solar cell manufacturers Q-Cells and the module manufacturer Sovello AG from Thalheim are also signed up. Sovello is providing a quota of solar modules with special conditions for the first 1000 roof projects and is offering local installation companies special training courses. For financing a rooftop solar electricity system without capital, the local savings bank will provide support as a partner. Infrastructure: s The 1000 roofs project will bring in 3,600 jobs. s The solar industry in Saxony-Anhalt can benefit from the expertise and knowledge of the universities and research institutes in the country. s Equipment and material supply companies have operated in the region for over 30 years supplying the semiconductor and automotive industries. Key features/incentives: With the “1000-DächerProgramm”, Solar Valley in Saxony-Anhalt is once again emphasising its special position in photovoltaics and at the same time presenting itself as a modern and environmentallyfriendly place to live and work. Around 3,600 jobs in the solar

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industry attest to its economic strength and companies such as Q-Cells, Sovello, Calyxo, Solibro, Sontor and Malibu support it. At the 24th European Photovoltaics Conference and Exhibition from 21st to 24th September, Solar Valley will also wave its flags and dedicate itself to sustainable topics. At the community stand organised by the Investment and Marketing Corporation of Saxony-Anhalt, the Institute for Plastics Technology and Recycling, the Central German Technology Park and SRU Solar AG will present technology, solutions and infrastructure for the energy of the future. Exhibitors will also include Vetro Solar, which has announced the construction of a new solar glass factory in Halle (Saale) and the Fraunhofer Center for Silicon Photovoltaics CSP. Scientists from Halle (Saale) will present the most recent developments in various areas of research such as silicon crystallisation, thin-layer technology and material development, the production and assessment of modules as well as electrical, optical and microstructural material and component characterisation. In addition to this, Fraunhofer scientists will, amongst other things, bring along a crystal weighing approx. 50 kg as well as a test arrangement of fluorescent mono-crystals. Key tenants: Q-Cells, ersol, Sovello, Calyxo, Solibro, Sontor, PV Crytalox and Malibu.

Recognising TECHNOLOGICAL EXCELLENCE International Solar Technology Awards 2009 There are many awards programs in the industry that focus on academic or ďŹ nancial merit. The launch of the Cell Award marks an ambitious goal to create an award ceremony that is judged by the persons and companies using current solar technology. During Intersolar in Munich, the PV manufacturing industry gathered together to honour technological achievement in the progression of solar technologies. The International Solar Technology Awards, dubbed the Cell Awards, were created to provide an independently judged platform upon which the most successful and esteemed

www.cellaward.com

technologies and potentials in the solar industry can be recognised. The International Solar Technology Awards are organised by a group of leading solar media, research organisations and industry associations. The award winners determined by the combination of scores from an expert judging panel and a popular vote from PV professionals. The judging committee for Cell Award 2009 included senior technical experts from the Fraunhofer ISE, Moser Baer, SolarWorld, Q-Cells, Suntech, and China Sunergy. The awards are designed to acknowledge and recognise achievements in the production of

solar technology. Emphasis is placed h l d on real-world technical expertise required throughout the supply chain to push solar power toward grid parity without government subsidies. The seven Cell Awards were presented by leading industry representatives, including Nick Sarno, Senior Vice President of Manufacturing at LDK Solar; Holger von Hebel, President of ersol; Dr UroĹĄ Merc, CEO of Bisol; Eleni Despotou, Policy Director and Deputy Secretary General of EPIA; and Jerry Stokes, President of Suntech Europe. Within the seven categories, the organisers came up with a shortlist of two or three entries per category.

currently in production and the extent of its service network for product support. The sub-categories included the ‘Best Technical Product for Module Assembly’, ‘Best Process Technology c-Si Cell Manufacturing Lines’, ‘Best Technical Product for Thin-Film Module Manufacturing’ and ‘Best Technology for Silicon Feedstock and Wafer Processes’. The shortlist for the best technical product for module assembly included EFD – PV cell ribbon and bus bar methodology; Cookson – Alpha PV-Ready Ribbon and Komax – Xcell 3400 Stringer. EFD came out as overall winner, and the award was presented by Dr. Uroš Merc, CEO Bisol Solar to EFD’s Peter Lambert (pictured).

Kicking off the ceremony was the award for the ‘Best Region for Manufacturing Solar Technologies’, which saw The State of Oregon, IMG Saxony - Solar Valley and The Silicon Border, Mexicali go head to head. The winner of this category was The Solar Valley. The award was presented to Senior Manager of IMG Saxony, Dorrit Koebke-Friedrich by Nick Sarno, Senior Vice President of manufacturing for LDK Solar. Next up was the ‘Manufacturing Equipment and Services Awards for the Solar Industry’ category which was open to suppliers of services, materials, and equipment to cell and thin-film manufacturers and module assemblers. The category was split into four sub-categories, each of which had a shortlist as well as an overall winner. There was a specific judging criterion for this category, focusing on the success of this technology, product or process in increasing overall efficiency of modules

Those shortlisted for the ‘Best Process Technology for c-Si Cell Manufacturing Lines’ award included Advent Solar – Ventura Technology; SiXtron – SunBox silane-free coating system and BTU International – Meridian in-line Diffusion System. It was SiXtron’s SunBox that came out on top, the award being presented by ersol president, Holger van Hebel to SiXtron’s VP of sales and marketing, Bates Marshall. The winner of the ‘Best Technical Product for Thin-Film Module Manufacturing’ award was Oerlikon Solar with its KAI 1200 PECVD system, just beating Applied Materials – SunFab Line and Veeco – PV-Series Thermal Deposition Sources. The award was presented to Oerlikon Solar’s Head of Marketing Communications, Jürg Steinmann by Dr. Uroš Merc, CEO of Bisol Solar. The ﬁnal award in the manufacturing equipment and services awards for the solar industry category, the ‘Best Technology for Silicon Feedstock and Wafer Processes’, had just two companies in the shortlist: Solaicx, with its Czochralski (CZ) manufacturing process and Tec5 VINSPEC SP In-Line process control. The award went to Tec5; Jerry Stokes, president of Suntech Europe, presented the award to the company’s Steffen Piecha.

EFD, Inc.’s Peter Lamb

ert (right) receives the award from Dr. Uroš Merc , CEO, Bisol Solar the Cell Award 2009 even t in Munich.

Nextt up was the ‘Green Solar Manufacturing Award.’ Those shortlisted for this prize included Edwards with its Spectra Z 3000 and Linde Electronics’ Onsite Fluorine Generator. Linde walked away with the award, which was presented to the company’s General Manager, Ian Travis by Eleni Despotou, policy director and deputy secretary general of EPIA. All of the entrants from the 2009 Cell Awards were automatically entered into the ‘Industry Choice Award’ category, with SiXtron’s SunBox, BTU International’s Meridian in-line diffusion system and IMG’s Solar Valley making it onto the shortlist. The winner of this award was BTU International, presented to the company’s sales director for France, Oliver Wehner by LDK Solar’s senior vice president of Manufacturing, Nick Sarno (pictured).

LDK Solar’s Senior Vice President of Manufactur ing Nick Sarno (left) prese nting the Industry Choic e Award to BTU International’s Olive r Wehner (right), Sales Director for BTU France.

In his closing address to the audience at the ceremony, David Owen, publisher of Photovoltaics International, encouraged the industry in these difﬁcult times to reﬂect on current technologies that will help PV manufacturers achieve cost and yield goals: “It is vital that we continue to recognise and acknowledge new technical innovation in PV manufacturing now and in the future to encourage further technical developments.” Entries for the 2010 Cell Awards opened on September 28th 2009; further details will be available on www.cellaward.com. Emma Hughes, www.cellaward.com

www.cellaward.com

The PV-Tech Blog By Tom Cheyney

Reinventing the Rust Belt: Clairvoyant, Oerlikon make plans for dormant Ford Wixom site

All photos courtesy of Ford Motor Company.

Ford’s Wixom plant northwest of Detroit has sat idle since 2007, a testament to the drastic changes in the automotive manufacturing business in the United States. But the 4.7 million square-foot factory space where millions of Lincoln Continentals and other cars once rolled off its lines and generations of workers earned a good living now has a legitimate shot at becoming a world-class showcase for renewable energy technologies — offering a chance to reinvent a relic of the Rust Belt and turn it into an iconic symbol of the Greentech Revolution. With the help of generous tax incentives from the state of Michigan and expected U.S. Federal government loans and credits, Ford’s active role, and the visionary participation of energy-storage innovator Xtreme Power and Clairvoyant Energy (and turnkey partner Oerlikon) on the solar side, the nowdormant assembly line may soon provide thousands of jobs as it reverberates with the sounds of advanced energy-storage, thinfilm PV, and other cleantech production lines within a few years. The Wixom site would represent the first installation of Oerlikon’s turnkey micromorph production line in the United States. If all the government assistance comes through as planned and the additional financing is lined up, the first silicon thin-film modules would be produced in 2011, with a ramp to full production in early 2012.

The first line would have a nominal capacity of 90MW, both parties confirmed, with as many as three additional lines added in the future — depending on market conditions and future incentives. (Factory floorspace is not an issue, according to Clairvoyant CEO David Hardee, since “there’s certainly enough room for four lines.” ) Although Oerlikon’s current line capacity is 75MW (up from 60MW), Oerlikon’s Chris O’Brien said the company expects that rating to rise to 90MW, once the Clairvoyant factory is ready for installation and commissioning of the equipment. Hardee said his company chose Oerlikon’s micromorph-silicon thin-film PV technology because it wanted to make sure the technology was “state of the art, proven, capable, where you get economies of scale, and in our mind we could see the next generation. We like the Oerlikon people; they understand our culture and what we’re trying to do in Michigan. It’s a world-class company. We’re going to have a much deeper relationship with them, rather than [them] just being a vendor.” “What Clairvoyant is betting on,” explained O’Brien, “is that by investing in Oerlikon’s micromorph line, they can leapfrog to a more competitive cost position, one that’s more competitive

w ww. pv - t e ch . o r g

even with the continuing decreases in crystalline module prices.” Before any tools come in, the Wixom site will have to be renovated and refurbished for its new tenants’ operations. Hardee said that there will be environmental remediation since it’s a brown-field site. “Ford will have the building cleaned out and ready to occupy. It’s a fair amount of work but it’s not nearly the kind of work we’d need for a green-field development. “We’ve got 50MW of power going directly into the factory — the largest single site in the state of Michigan for power,” he continued. There’s interstate highway access nearby and rail lines running directly to the plant. Hardee broke out his company’s expected portion of the $725 million total price tag announced for the project. “Clairvoyant’s part will be about $250 million of that, with the rest coming from Xtreme. That’s just for phase one. For phases two, three, and four, we estimate another $200 million per line.” While the government incentives take shape, Hardee explained that “on a parallel track, we’re pursuing private equity sources. We’ve got a number of very interested parties.” The move by Clairvoyant into manufacturing represents a vertical extension of its business model, which until now has focused on utility-scale solar project development in the U.S. and Europe. Why the change? Based on the company’s experiences as developers, Hardee said they started to see “holes in the supply chain that we were unable to work around. We started thinking that controlling our manufacturing process and being vertically integrated has a lot of merit to it.” The company, which is actively continuing its project development efforts, “anticipates the original solar panels manufactured in Michigan being placed in Southern California and Arizona as part of our whole process. We’re negotiating large utility-scale power projects in the Southwest.” Although Clairvoyant will partner with Oerlikon initially, Hardee explained that “in the longer term, we’re tech agnostic. It may be crystalline, it may be CIGS, it could be next-generation Oerlikon. Who knows where all this technology is going? It’s hard to predict.” What isn’t hard to predict is a continuation of the growing trend to build more solar production in the States, to serve what most observers believe will be a booming market. In a new report on PV manufacturing in the U.S., Greentech Media forecasts that U.S. cell and module capacity will “grow at an annualized rate of 50% and 45%, respectively, from 2008 to 2012." This is good news for those who believe that a strong PV manufacturing infrastructure is critical not just for the U.S.’s quest for a renewable-energy future but for the nation’s economic well-being and national security as well.

This is an edited version of a blog that originally appeared on PV-Tech.org.

Tom Cheyney is Senior Contributing Editor (U.S.) for the Photovoltaics International journal and writes blogs for PV-Tech.org.

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