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Photovoltaics International Volume 07 - 2010

What’s going on in the U.S. market? REC Solar cuts costs Pre-construction and engineering approaches for residential installations

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The PV-Tech Blog visits Heliene's manufacturing facility

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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 Managing Editor: Síle Mc Mahon Senior Editor, North America: Tom Cheyney Senior News Editor: Mark Osborne News & Features Editor: Emma Hughes Production Manager: Tina Davidian Design: Daniel Brown Commissioning Editor: Adam Morrison Sales Manager: Neill Wightman Account Managers: Adam Morrison, Graham Davie, Daniel Ryder, Gary Kakoullis, David Evans, Nick Richardson & James Park Marketing Manager: Joy-Fleur Brettschneider 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 shows a PV system at the Aspen Mountain Ski Resort. Image courtesy of NREL. Credit: Aspen Skiing Company. Printed by Quentin Press Photovoltaics International Lite Volume 7, 2010 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.

Thousands of solar panels help energize the Los Angeles Convention Center, one of the first exhibition hall complexes to put photovoltaic power to work in a meaningful way. Two arrays totaling a combined 392kW were installed by the Los Angeles Department of Water and Power in 2000–2002 – 144kW on the canopy of the center’s south hall and 248kW integrated as car shades on top of the Cherry Street parking garage. Once completed, the system was hailed as a “major” installation, and its collection of 65W and 75W AstroPower monocrystalline modules regarded as some of the best on the market. Flash forward less than a decade to the site, which hosts this year’s Solar Power International conference and exhibition. Although a nearly 400kW PV system remains worthy of mention, the industry – which has grown from hundreds of megawatts worldwide when the LACC system was activated to double-digit gigawatt levels – has seen hundreds of projects attain multimegawatt scale. As the show begins, North America temporarily lays claim to the largest solar electric power plant operating on the planet – the 80MW Sarnia field in Ontario – which was officially activated in early October. The tens of thousands of modules deployed at the site are made by First Solar, a U.S. company that was struggling to get to market in the early 2000s with a technology – cadmium telluride thin film – that was untested commercially and viewed suspiciously by many photovoltaic experts. Today, you can’t discuss the industry’s prodigious growth without mentioning First Solar’s amazing run to the top. And what of AstroPower? The one-time top 10 solar manufacturer and technology leader has vanished from the scene, even if its legacy modules continue to turn photons into electrons on homes and businesses in various parts of the globe. After being delisted by NASDAQ and going bankrupt in 2004, the company’s assets were bought for a relative pittance by GE. Then last year, the former AstroPower/GE module plant in Delaware was saved from oblivion by Taiwanese cellmaker Motech, which purchased the facility to gain a foothold in the North American market. Where will the photovoltaic revolution be in another 10 years? In the United States, as the team at Renewable Analytics point out in their article beginning on page 46, much of the answer to that question rides on whether progressive public policy gains continue to be implemented and the jumble of local, state, and federal permitting and regulations smooth out into some semblance of a sane process flow. Of course, the future can also be seen in the innovation overflowing among the 1000-plus Solar Power International exhibitors taking up residency in the PV-powered halls – even if for every First Solar wannabe on the showfloor, there lurks another potential AstroPower-like cautionary tale. But this much we can be sure of: the best days of the solar PV industry lie ahead, and it’s gonna be one hell of a ride! Tom Cheyney Senior Editor, North America Photovoltaics International/PV-Tech.org

Contents

20 Large-scale PV power plants – new markets and challenges PV Resources 27 DERlab round-robin testing of photovoltaic single-phase inverters ERSE & IWES 33 Pre-construction, engineering and design costs of large-scale residential installations – part 1 REC Solar

Image courtesy of Sputnik Engineering /SolarMax

2 News 14 Products

Photovoltaics International Lite SPI edition has been produced for exclusive distribution at Solar Power International in California, 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 Nick at +44 (0) 207 871 0123 or email nrichardson@pv-tech.org

36 Atmospheric deposition techniques for photovoltaics National Renewable Energy Laboratory 42 Expectations for the UK solar market Photovoltaics International 46 U.S. solar PV market – an overview Renewable Analytics 48 The PV-Tech Blog: Heliene’s moduling operations in Ontario Tom Cheyney

Photovoltaics Inter national

News World first: SoloPower is awarded UL certification for flexible CIGS modules In a breakthrough achievement in flexible solar photovoltaics technology, SoloPower has received Underwriters Laboratory (UL) certification for its lightweight flexible CIGS modules, a first-ever accomplishment in the thin-film industry. This is the first UL-certified product in a range of high-power flexible modules being introduced initially to the European and North American markets. The UL certification was granted following rigorous testing at an independent laboratory where the flexible thin-film modules were tested to UL 1703, the standard for safety for PV module manufacturing. SoloPower also claims to have conducted extensive internal testing exceeding the safety, quality, and reliability standards established by these tests. “The certification of SoloPower’s flexible CIGS module is an important step toward the realization of lightweight, high-power, flexible solar modules with potential to expand the roof-top solar market and reduce balance of system costs. It is an important milestone for the industry. I feel very gratified to see, after a 30-year career in Thin Film CIGS PV at NREL, the technology become mature,” said Dr. Rommel Noufi, principal scientist of the NREL. SoloPower’s range of flexible photovoltaic module products include the SFX1 module (80Wp, 0.3m x 2.9m, 2.3kg/5lbs.), the SFX2 module (170Wp, 0.3m x 5.8m, 3.6kg/8 lbs.), and the SFX3 module (260Wp, 0.9m x 2.9m, 6kg/13lbs.).

Thin-Film News

DuPont’s PV8600 series to be used for Sharp’s solar cell modules DuPont Photovoltaic Solutions has disclosed that its new ionomer encapsulant sheet, known as Himilan ES in Japan and PV 8600 series elsewhere, will be used by Sharp in its thin-film solar cell modules. The encapsulant was made for amorphous silicon and other thin-film module technologies and has recently entered the commercial market. “ I o n o m e r- b a s e d s h e e t s a r e f u n d a m e n t a l l y m o re re s i s t a n t t o moisture intrusion, current leakage and discoloring,” said Steve Cluff, global business director for DuPont Encapsulants. “Their use in glass-glass module designs is well-established, but adhesion to polymer-based backsheets, such as DuPont Tedlar and PET, required

modifications that we’ve introduced in the new DuPont PV8600 Series sheets.” DuPont advised that with the exception of Japan, the encapsulant will be available for customer evaluation later this year.

Masdar gains second contract for PV modules in India In an effort to develop a more sustainable community for families in India, Masdar PV has partnered with IG Solar PVT and signed a contract, wherein Masdar will provide 1.5MWp of their silicon-based thin-film PV modules. The modules will be mounted on the rooftop of buildings in India under MAG’s current project, which is developing housing that uses renewable energy resources. Ten projects will be put into action over the next year. MAG’s aim is to build cost efficient private houses, which have renewable energy sources. Three thousand people are said to be able to live in each village with part of the electricity supply being provided with Masdar’s PV solar modules on the rooftops. This is the second project in two months that Masdar has committed to that is located in India.

Sunvalley Solar to use a-Si thin-film modules from TianWei SolarFilms

Sharp’s solar modules use DuPont Photovoltaic Solutions’ PV 8600 ionomer encapsulant sheet.

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Installation of SoloPower’s lightweight flexible CIGS modules.

U.S.-based PV installer Sunvalley S o l a r h a s a d d e d m o d u l e s f ro m TianWei SolarFilms to its list of product offerings. Sunvalley Solar has supply agreements for Canadian Solar’s poly and mono crystalline panels as well as for CEEG. TianWei SolarFilms will supply an unspecified amount of a-Si

TianWei SolarFilms’ CTO Mai Yaohua presents the company’s production process to a guest. thin-film modules to Sunvalley Solar, which are now CEC (California Energy Commission) certified.

TSMC to sell own-branded CIGS thin-film modules as first 200MW fab starts construction Moving away from its ‘pure-play’ foundry business model to which it has vehemently adhered in the s e m i c o n d u c t o r i n d u s t r y, Ta i w a n Semiconductor Manufacturing Company (TSMC) will directly sell copper-indiumgallium (di)selenide thin-film modules to the global market from its first 200MW plant, which broke ground recently. An initial US$258 million is being invested to build a Thin Film Solar R&D Center and production plant, using technology from Stion. The thin-film start-up is partnering with TSMC, which will be its manufacturing and technology development partner.

designed for large commercial and solar farm installations. The inverter will be distributed in Europe initially through OEM partner One Network Energies in France, according to Direct Grid, with additional partner agreements near finalization and set to be announced in the near future.

TSMC’s headquarters. TSMC also announced plans to add a second phase to the facility and expand CIGS production to more than 700MW, employing around 2,000 staff at the facility in Taichung’s Central Taiwan Science Park, home to its leading-edge semiconductor and newly-announced foray into the LED market. First-phase equipment move-in was said to be planned for the second quarter of 2011, with plans to achieve initial volume production of 200MW per year in 2012. No timelines were given for the larger, second-phase capacity expansion. The first CIGS facility was said to be 110,000m 2 in size with a production area of 78,000m2.

Power Generation News

Power-One to build 1GW inverter production plant in Phoenix Inverter company Power-One has chosen Phoenix, AZ, as the site for its new manufacturing facility. The plant will produce the company’s PV and wind inverters, including single- (2-6kW) and three-phase string inverters, as well as NEMA 3R 250kW, 300kW, and 400kW central inverters. The estimated cost of the new plant was not disclosed. Manufacturing at the Arizona facility will begin in October and annual inverter production capacity at the site is expected to reach 1GW by mid-2011. Power-One has recently expanded its worldwide production capacity with the initiation of Canadian manufacturing and the expansion of its European plant, which will result in more than 4GW of inverter capacity coming online by year’s end.

SunEdison signs MOU with Korean province to develop 400MW of solar PV power plants In a potential deal that would dwarf the scale of the company’s previous development projects, MEMC subsidiary SunEdison has signed a memorandum of understanding with the Gyeongsangnam-do provincial government for the establishment of 400MW of PV power plants in the southeastern Korean province. The nonbinding MOU, which is subject to negotiation and completion of definitive agreements, could lead to the utilization of public land and building rooftops to develop and install the PV systems. The provincial government said it will support SunEdison in securing the proper land or building areas and in completing the authorization and permission processes. The projects will be completed by the end of 2013. No financial details of the proposed deal were disclosed.

Direct Grid gets CE, VDE certification for utility-grade solar PV microinverter Direct Grid Technologies has received CE and VDE0126-1-1 certification for its DGM-S460 Series utility-grade grid-tie photovoltaic microinverter 4

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Power-One’s Aurora inverter system.

SunEdison wins contract for 14.5MW plant on DavisMonthan Air Force Base, Arizona Adding to the company’s ever-expanding portfolio of large-scale installations, SunEdison has won the contract to provide a 14.5MW ground-mounted solar power installation at the DavisMonthan Air Force Base (DMAFB) in Tucson, Arizona. The agreement will see SunEdison look after the financing, design, construction, operation and maintenance of the ~130 acre site, which, upon completion, will provide as much as 35% of DMAFB’s energy needs. SunEdison has also entered into a long-term ground lease agreement with DMAFB for the use of their land, and in return, will provide the DMAFB with electricity supply at a fixed rate.

Air show at Davis-Monthan Air Force Base.

Gigawatt scale: CEC approves Solar Millennium’s planned 1GW Blythe CSP power plant

The California Energy Commission has given its unanimous approval to Solar Millennium to build and operate the Blythe Solar Power Project in Riverside County, a planned 1GW concentrated solar power (CSP) plant that would be the largest solar generating station in the world. Construction on the first pair of four planned 250MW parabolic-trough CSP sections is scheduled to begin by the end of the year. Although the CEC approval was critical, the company must still secure a “Record of Decision” approving the project’s “Right of Way Grant” from the Federal Bureau of Land Management, which is expected to occur this fall. The Solar Trust of America project development subsidiary said it is also actively pursuing completion of financing with the U.S. Department of Energy Loan Guarantee Program for the initial 500MW phase of the project. The project will generate approximately 2500 jobs during the construction period and create more than 200 permanent jobs once the 1GW facility is fully operational, according to the company. Once completed, the dry-cooled CSP plant will produce enough energy annually to supply more than 300,000 homes. Solar Trust says it has nine utilityscale solar thermal projects in advanced stages of development in California and Nevada. The Blythe plant is the third major CSP farm to gain CEC approval recently, following the recent go-aheads given to NextEra Energy’s proposed 250MW B e a c o n p ro j e c t a n d t h e 2 5 0 M W

Solar Millennium’s Andasol 1, the first parabolic trough power plant in Europe.

Abengoa Mojave Solar Project. The commission is expected to rule on several other CSP projects before the end of the year.

iSuppli: massive solar inverter shipments projected by 2014 Global solar inverter shipments are expected to surpass 23.3 million units by 2014, up by a factor of nine from 2.6 million in 2010, according to a new report from iSuppli Corp. Revenue will subsequently increase to US$8.9 billion in 2014, up from US$5.3 billion in 2010. This would result in solar inverters sales becoming one of the highestvolume ruggedized electronic systems sold, according to report author Greg Sheppard. Despite such soaring demand, the average price per watt for inverters worldwide will decline by 13.5% this year. In particular, Asian suppliers are trying to drive prices down with lower costs, Sheppard noted, even though they have been challenged to deliver bankability. Insulated Gate Bipolar Transistor (IGBT) modules are now experiencing rising sales in a number of hot applications, including automotive electronics as well as PV and wind inverters. Combined with conservative investments in new IGBT capacity, the strong demand has spurred a supply crunch. Despite such soaring demand, the average price per watt for inverters worldwide will decline 13.5% this year. In particular, Asian suppliers are trying to drive prices down with lower costs, Sheppard noted, even though they have been challenged to deliver bankability – i.e., the capability to provide a lower Total Cost of Ownership (TCO). Interestingly, iSuppli believes that price declines are being impacted by the increasing market share of larger inverters, which boast a lower price per watt.

PV Modules News

CNPV to supply 20MW of modules for China-based projects Module manufacturer CNPV is providing Linyi Juhuang New Energy Technology Development Company with 20MW of PV modules through 2012 for a series of 1MW projects in Shandong Province, China. Initially, 1MW will be supplied in October 2010 and the remaining 19MW during 2011 and 2012. “The first grid connected system is on target for connection using our premium solar module range,” said B. Veerraju Chaudary, CNPV’s COO, CTO, and member of the board. “This bespoke system will add a further 25% yield 6

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CNPV’s 72-cell standard monocrystalline PV module. increase on our premium range’s market leading capability.”

ECN receives IEC 61215 certification for MWT module ECN has achieved the IEC 61215 industry standard certification for its metal wrap through (MWT) module technology. The certification was awarded in collaboration with an undisclosed solar photovoltaics company as part of a joint research framework agreement. Paul Wyers, manager of ECN Solar Energy said, “”After years of development we were not only confident about the performance, but also about the robustness of our back-contact modules. The back-contact module production method is beyond state-ofthe-art. We use materials that are new for crystalline silicon modules, such as conductive adhesives and conductive back-sheets. We are very happy that our MWT module technology has been awarded the certificate by TÜV-SÜD and we are confident that modules with this technology will be sold in the near future.” IEC 61215 is a recognized industry standard that verifies that the modules have passed the required series of tests and are suitable for long-term operation in a range of climates.

TÜV Rheinland opens solar testing laboratory in Bangalore TÜV Rheinland has now officially opened its seventh solar modules and systems testing laboratory, based in Electronics City in the Indian city of Bangalore. TÜV invested €2 million in the new solar test centre, which will offer services to India’s burgeoning solar industry.

TÜV Rheinland India’s Bangalore headquarters.

The test centre includes 2,000m 2 of space, including an outside test field of 500m 2 , with equipment such as five climate chambers and two sun simulators. This makes it one of the most advanced PV testing laboratories in the entire South Asian economic area. “All our laboratories are working closely together and contribute to our global PV business. We are delighted about the opening of the new Indian facility which will enable us to cover the expanding demand and expected growth in the Asian region and continue to offer tailor made solutions that suit the needs of our customers,” says Stefan Kiehn, head of the PV testing facilities at TÜV Rheinland Japan.

Roth & Rau enters EVA backsheet production market with plant in Italy Roth & Rau has adopted a new business strategy with its move into EVA (ethylvinyl-acetate) backsheet material production at a new plant in Monza, Italy. Claiming a high market share already for EVA foil in the Italian market, Roth & Rau said the €2.5 million plant investment will enable a faster response to customer requirements and would assist in expanding sales in southern Europe. The new EVA production plant is claimed to be one of the most modern across the whole of Europe and has an annual production capacity of 5 million square metres, operating on a three-shift cycle.

Yingli to supply 7.9MW of modules for groundmounted systems in southwest France Yingli Green Energy has signed a 7.9MW photovoltaics module sales agreement with system integrator Cegelec, one of the largest PV installers in France. The modules supplied under the agreement are expected to be utilized in groundmounted systems located in the southwest of France. This agreement is the largest between the two companies to date. Yingli Green Energy recently set up an office in Lyon, France to aid in European business development.

JinkoSolar secures CEC approval for trio of PV modules Chinese PV manufacturer JinkoSolar said that three of its modules have met the requirements of the California Energy Commission (CEC). As a result, one of the company’s 175-185W models and two of its 220-240W models will also be added to the list of Senate Bill 1 guidelines-compliant photovoltaic modules eligible for finance and project incentives in the state of California,

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Jinko Solar’s 220-255W monocrystalline module. Hawaii, and some other U.S. states. The CEC, which specifies criteria for SB1 guidelines-compliant PV modules, conducts stringent PV module tests on module power, voltage, current, irradiance, and operating temperature. The CEC’s PV module requirements are standard practice for solar companies in California and recognized as one of the highest PV module standards.

Fab and Facilities News

Solarwatt doubles module capacity to 400MW; new line produces module every 28 seconds Touted as the ‘world’s most modern module manufacturing facility,’ Dresdenbased Solarwatt has officially opened its new production lines that double capacity to 400MW and produce a solar module every 28 seconds, according to the company. A new 13,000m2 logistics centre has also been built, which includes a 260kWp solar power plant. The total investment was €35 million. As is the norm for many Westernbased manufacturers, the key to module manufacturing competitiveness is to have highly automated plants. According to Solarwatt, the new line employs 29 industrial robots from Kuka Systems, which include its Robo Frame, Robo Trimm, and Robo Load solutions.

150MW c-Si module assembly plant in Glava, Sweden, REC will wind down and close its operations at REC ScanModule by the end of 2010. Åsmund Fodstad, Senior Vice President Sales & Marketing at REC Solar, told PV-Tech that the plant had been running at close to full capacity but due to its isolated position from other facilities within the group, it had struggled to be profitable. The approximately 300 employees will be supported by the company in seeking employment elsewhere. REC expects to recognize restructuring costs of approximately SEK 104 million in the third quarter 2010, including termination of employment agreements and other contracts. With the ramp of its new integrated module assembly plant in Singapore underway, REC noted that module supply would be unaffected by the closure of the plant in Sweden. The company will be using outsourced, contract manufacturing for some of its module production requirements as well.

Danfoss announces expansion plans for its Nordborg headquarters As a result of what Danfoss Solar is calling a period of very strong sales, the company has announced plans to expand its production and logistics capacities by moving to larger facilities at the company’s Nordborg, Denmark headquarters. Danfoss states that it has outgrown its supply chain facilities in Gråsten and Sønderborg, Denmark and with this move will be able to not only increase their 2011 capacity to 3.5GW, but have the ability to double the assembly size in a few months. Production at the new location is expected to start in the first quarter of 2011, with the move finalized by the end of next year. In addition, Danfoss will be expanding its China and US facilities to facilitate the demand for solar inverters.

with the rules as they see the local market highly attractive. EU laws do not allow such ‘local content’ rules; now that Japan is raising the issue of the pricing guarantees offered by Ontario’s FiT system actually constitute subsidies that are not allowed under international trade law.

SMA Solar raises revenue guidance a second time: expects PV market to top 17GW in 2010 The global PV market is set to soar higher than previously expected, according to solar inverter market leader, SMA Solar Technology. As a result, the company has raised its revenue guidance for the year, the second time it has done so in 2010. SMA Solar now expects the global photovoltaics market to reach approximately 17GW of new installations in 2010 and with more than 40% of the inverter market, is guiding revenue of between €1.7 and €1.9 billion. Previously, SMA Solar had forecasted the PV market would reach 14GW and company revenue of €1.5 to €1.8 billion. SMA Solar said that Germany would remain the largest single PV-market with new installations reaching 8GW. South European markets and the U.S are also fuelling growth. However, forecasting growth for 2011 is proving more difficult, according to the company. On the one hand, it expects PV global growth of 20% in 2011 but uncertainties surrounding various FiT changes and possible negative impacts on the market could in another scenario see the PV market decline 10% next year. Key countries that could dictate growth levels for 2011 were identified as the U.S. and Italy, which could become very important growth markets next year.

Market Watch News

Japan protests to WTO about Ontario’s locally produced product quotas for FiT

Dr. Ulrich Link, COO of Solarwatt AG, presents the company’s new production line to Stanislav Tillich, Premier of Saxony.

REC set to close 150MW solar module plant in Sweden Despite recent efforts to improve the cost competitiveness of a fully-automated 8

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Ontario’s locally produced product quotas that are required to benefit from its lucrative Feed-in tariff have upset the Japanese, according to Reuters, which has led to an official complaint to the World Trade Organisation (WTO). The two sides are set to meet but the likely outcome is to move proceedings to a WTO panel that would make a judgement about the legality of Ontario’s FiT requirements. There have been numerous announcements from PV manufacturers throughout the supply chain that are setting up facilities in Ontario to comply

SMA Solar Technology’s Sunny Boy inverter.

California to drive midsized solar projects with new incentive program The California Public Utilities Commission (CPUC) has issued a proposed decision to launch a new renewable incentive program with the aim of driving the uptake of mid-sized renewable energy development. This next-generation feed-

Location Briefing SOLAR VALLEY, Germany

SOLAR VALLEY Saxony-Anhalt – a sustainable region in the heart of Germany Location: The SOLAR VALLEY SaxonyAnhalt, located in the centrally suited state of Saxony-Anhalt bordering the states of Saxony and Thuringia, is one of the leading Solar regions in the world and is comprised of a network of 29 international operating firms, nine leading research institutes, and four universities. The SOLAR VALLEY Centre for Silicon Photovoltaics has the highest density of companies involved in the photovoltaics industry.

Introduction: The SOLAR VALLEY also lives up to its superior production of photovoltaics and uses its own products. In order to initiate private investments in solar electricity systems, the town of Bitterfeld-Wolfen and the district of Anhalt-Bitterfeld launched the “1000 Roofs Programme” initiative. Manufacturers like Q-Cells and Sovello have signed up for the project, providing a quota of solar modules with special conditions for the first 1000 roof projects and is offering local installation companies special training courses. As for the financing part, the local savings bank will provide support as a partner. The project is aimed at all citizens in the region who are willing to contribute actively to the protection of the environment by installing a PV system on their roof and at the same time want to achieve secure returns over a period of 20 years. A new trend within the project is the idea to even put up solar modules on the roofs of churches and historical buildings of Saxony-Anhalt.

yy Around 3,500 jobs in the solar industry attest to the area’s economic strength yy Generous investment incentives cover a high percentage of capex yy Fast-track project realization, due to the close proximity of the world’s leading PV equipment suppliers and superior engineering as well as local authority services and support yy Leading glass producers and glass suppliers located in Saxony-Anhalt offer best siting conditions yy C l o s e R & D c o o p e r a t i o n w i t h Germany’s leading PV research institutes and four universities yy Shorter time to markets, via state-ofthe-art infrastructure for lower rate of long-term transport inventories yy Skilled and flexible workforces, low labour costs yy Nearby international schools to join the solar family life yy A modern and environmentally friendly place to live and work

Key features/incentives: yy Cell Award Winner for “Best Region for Manufacturing Solar Technology” in 2009

Q-Cells, Sovello, PV-Crystalox, Solibro and Malibu

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65,920 projects in Saxony-Anhalt have been co-financed till 2009. Nearly 24,000 jobs were created in the process and an additional 78.400 jobs have been secured. From 2007 – 2013 the EU will provide € 3.39 billion in subsidies for Saxony-Anhalt. Already 5,931 economic projects have been initiated and more than 50,000 Sachsen-Anhalter have been qualified for the modern labour market.

In Saxony-Anhalt, investors receive the offer of a business location in just 24 hours. Feel free to contact me

Dorrit Koebcke-Friedrich Investment and Marketing Corporation Saxony-Anhalt Am Alten Theater 6 39104 Magdeburg Germany E-Mail: Dorrit.Koebcke-Friedrich@img-sachsen-anhalt.de Phone: +49 (0)391 568 99 27 Fax: +49 (0)391 568 99 50 Mobile: +49 (0)1515 262 64 64 www.invest-in-saxony-anhalt.com

European Commission European Regional Development Fund INVESTING IN YOUR FUTURE

in tariff program will require investorowned California utilities to purchase electricity from renewable energy systems between one and 20MW in size. “California has robust policies for developing large, utility-scale solar power plants and for putting smaller systems on homes and businesses, but there is a clear gap in the middle. The CPUC proposal is designed to unlock that missing piece, providing an additional opportunity for solar market and job growth and for quickly bringing massive new amounts of clean energy to the state,” said Adam Browning, executive director of Vote Solar, who will work with CPUC to implement these changes. The CPUC proposal establishes a 1GW pilot program for power from eligible mid-sized renewable energy systems. The program requires California’s three largest investor-owned utilities to hold biannual competitive auctions into which renewable developers can bid. Utilities must award contracts starting with the lowest cost viable project and moving up in price until the MW requirement is reached for that round.

Cell Processing News

JA Solar nabs supply agreements for 500MW throughout 2011 JA Solar Holdings has secured multiple s u p p l y a g re e m e n t s w i t h s e v e r a l undisclosed customers, which will see the company delivering over 500MW of mono-crystalline and multi-crystalline solar cells throughout 2011. The signed contracts will see deliveries begin in January 2011, continue through December 2011 and have prepayments for next year’s committed solar cell deliveries. In addition, JA Solar released that its year-end capacity for 2010 will be 1.8GW with actual productive capacity at 1.4GW for the end of the second quarter.

Comtec Solar to deliver over 600MW monocrystalline solar wafers in 2011 Comtec Solar Systems, together with its subsidiaries, has signed new wafer supply framework agreements, with price subject to negotiation, to provide major customers Gintech Energy, Jetion Solar, CHINT Group and Neosolar Power with a total of approximately 200MW in monocrystalline solar wafers. These orders are thus added to the existing agreements between Comtec and China Sunergy, JA Solar, Suntech and Canadian Solar. Under the terms of the contracts, Comtec will supply each of the companies with approximately 50MW of monocrystalline wafers from January 10

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Materials News

Company: China Sunergy JA Solar Holdings Suntech Power Holdings Canadian Solar Gintech Energy Jetion Solar Holdings CHINT Group Neosolar Power

100MW 150MW 150MW 50MW 50MW 50MW 50MW 50MW

Total:

650MW

Comtec’s wafer supply deals for 2011. 2011 to December 2011 (see table for breakdown).

Singulus Technologies to deliver Singular inline coating systems to China Singulus Technologies has received further orders for its Singular inline coating systems from several unnamed customers in China. The company was planning on shipping one of these Singular machines, which are used both for processes in the manufacturing of silicon solar cells and for refining new solar concepts, by the end of September 2010. Singulus has already successfully installed its first inline coating system for the application of anti-reflective coatings to silicon solar cells, thus taking an important step towards substantially strengthening its market position for production systems for solar cells.

Silicon Genesis introduces PolyMax system for production of solar wafers Silicon Genesis (SiGen) has made a move towards what it deems as a replacement of the wire saw process with the production of solar wafers using its PolyMax system. SiGen has produced 85μm-thick, 156mm2 kerf-free monocrystalline silicon wafers. Kerf is a material that is translated into saw dust and used in the sawing process. “We believe the benefit of using kerffree wafers will allow the PV industry to reach unsubsidized grid parity. The start up of our high volume manufacturing system is a key step towards achieving this goal,” said Francois Henley, CEO of SiGen.

Yingli Solar signs fiveyear polysilicon supply agreement with OCI Chemical Yingli Solar has signed a five-year polysilicon supply agreement with OCI Chemical, the leading chemicals producer in Korea. Under the terms of the agreement, OCI has agreed to supply polysilicon with a total value of approximately US$442 million to Yingli Green Energy from 2011 to 2015. Yingli recently posted strong revenue, gross margin, and net income numbers in the second quarter of 2010, with sequential increases shown across the board. The vertically integrated Chinese solar manufacturer said it experienced a substantial increase in PV module shipments during the period ended June 30 and still expects to hit between 950MW and 1GW in total panel shipments for 2010.

CRS executes long-term contract with Nexolon Company C R S R e p ro c e s s i n g S e r v i c e s a n d Nexolon Company have endorsed a Singulus’s Singular inline coating system.

LDK Solar completes first production line of solar cells at Xinyu City facility LDK Solar has successfully completed the installation and trial runs of the first production line of solar cells in its newly installed manufacturing facility in Xinyu City. The solar cell manufacturing line has a present annualized capacity of 60MW; however this figure is expected to reach 120MW by the end of the third quarter of 2010.

CRS Reprocessing Services’ slurry recycling system.

multi-year contract in which CRS will supply on-site reprocessing services at its production facilities. Nexolon is continuing towards its goal to reach a 1.5GW capacity by the end of next year. The plant is located in Iksan, South Korea, and will use CRS’s turnkey solution for reprocessing slurry from the production of solar wafers. The signed contract has an agreed term of five years with a four-phase build out. It is predicted that at the plant’s peak production, the slurry yield will be up to 36,000MT per year.

Tokuyama’s planned polysilicon plant in Samalaju Industrial Park, Malaysia gets go-ahead Although site selection had been undertaken back in November, 2008, Tokuyama has now approved the construction of a 6,000MT polysilicon plant in the heavy industry based Samalaju Industrial Park in Malaysia. The plant will commence construction in early 2011 and start operations in the spring of 2013, according to the company. Plant costs were said to be ¥65 billion and utility costs of ¥15 billion. The polysilicon plant will be dedicated to supply the solar industry. Previously, Tokuyama planned to start operations in 2012 and have a plant with 3,000MT capacity to supply both solar and semiconductor industries.

LDK Solar teams with NREL on silicon research activities LDK Solar has signed an MOU with the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) that will see the two embark on research and development activities. The companies will work closely on topics such as silicon feedstockrelated issues, development of standards and evaluation methods for solar-grade silicon, and research on crystallization technologies and their commercial implementation.

Polysilicon production at LDK Solar’s new plant in Xinyu City, China.

Air Liquide signs major long-term gas supply contract with 3Sun Air Liquide has signed a major long-term contract with 3Sun – the newly formed manufacturing venture between Enel Green Power, Sharp and STMicroelectronics – to become the sole supplier of gases and services to the company. The Catania, Italybased factory will start operations in 2011 and is expected to be the second largest Si thin-film solar factory in the world behind Sharp’s facility in Japan. 3Sun’s 160MWp per year output will be used by ENEL Green Power and Sharp to serve a large market that extends to Europe, Middle East and Africa. This agreement covers the supply of very large volumes of specialty gases, the pipeline supply of carrier gases and the provision of all related services. Air Liquide will build the entire gas distribution and gas abatement networks on a turnkey basis. In order to meet these needs, Air Liquide will invest in additional hydrogen production capabilities in Sicily and also in the specialty gases supply chain.

AC Modules and Solar Power Electronics Patrick Chapman, Ph.D. CTO & Greg Madianos, Product Line Director, SolarBridge Technologies Introduction Ever since solar microinverters were first conceived of 30 years ago, the development of solar modules that directly produce grid-compatible AC power has been a long-sought goal of the PV industry. As a step in that direction, module-level microinverters were first introduced to the PV market in the 1990s. Only recently, however, have they progressed to the point where they provide a compelling alternative to the central inverters most commonly used today in PV systems. Additional forms of module-level electronics promising gains in energy harvest among other benefits have also emerged recently, and many industry analysts expect that within a few years most PV modules will feature some form of module-level power electronics. This article summarizes the various forms of power electronics available today for PV modules, ranging from central inverters used in traditional DC-based systems to newly-developed AC modules (see Fig. 1). The primary characteristics examined lie in the areas of energy harvest, installation costs, communications, and ongoing service requirements over the operational life of a PV system, typically 25 years.

Figure 2. - Central inverter with multiple strings. Central inverters also necessitate additional installation and system design costs, and a failure of the inverter results in a complete loss of production from the entire array. As most central inverters carry 5- or 10-year warranties, such a systemlevel outage can occur several times over the operating life of a PV system, and leads to the costly purchase and installation of a replacement inverter each time. Finally, central inverters limit the design and site selection of PV systems, particularly in residential applications. They require co-planar module layouts and a lack of partial shading from chimneys, trees, vent pipes, etc. PV installers may opt out of half or more of potential sites due to these restrictions.

DC-DC Optimizers Figure 1. - Solar power electronics categories.

Central inverters

Central inverters are the most common form of power electronics used in PV systems today. In this model shown in Fig. 2, a single, large inverter is connected to many PV modules wired in series to form strings with up to 600V of open-circuit voltage (1,000V in Europe). Multiple strings within the array may also be wired together in parallel before converging at the inverter, yielding some added flexibility in system design and performance. Capitalizing on many years of development, the DC-to-AC conversion efficiency of many central inverters is 95% or higher, and they feature a relatively low unit cost per watt. However, central inver ters have multiple drawbacks. They perform maximum power point tracking (MPPT) on the combined DC voltage and current produced by the seriesconnected modules, resulting in lost energy harvest due to module mismatch and varying shading conditions across the array. The use of high-voltage DC wiring raises some safety concerns, including a higher risk of arc faults, a primary cause of PV-related fires. Central inverters cannot monitor the performance of individual PV modules, so damaged or otherwise compromised modules often go undetected.

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DC-DC optimizers supplement a central inverter with individual DC-DC converters installed for each PV module (Fig. 3). There are several types of DC-DC optimizers â&#x20AC;&#x201C; some are wired serially in strings, while others produce high voltage and are wired in parallel. Some step each moduleâ&#x20AC;&#x2122;s DC output voltage either up or down, while others can do both.

Figure 3. - Central inverter with one DC-DC optimizer per module.

The central inverter still converts the combined DC output from across the array to grid-compatible AC power, but the DC-DC optimizers perform MPPT at the module level. This allows each module to produce its full output without being held back by any under-performing modules in the array. DC-DC optimizers also permit module-level communications and performance monitoring. However, DC-DC optimizers retain a key disadvantage of central inverters – a failure of the central inverter still results in a complete loss of system output. Furthermore, some DC-DC optimizer systems also require a separate command-and-control device to operate, creating one more point of potential system failure in addition to the central inverter. With additional equipment to purchase and install, DC-DC optimizers add to the initial cost of a PV system. The added module-level hardware also imposes a penalty on overall systemlevel efficiency by introducing an additional stage of costly power conversion.

compatible AC power (Fig. 5). AC modules attain all of the energy harvest and other advantages of detached microinverters, but since they ship as factory-tested power generators that satisfy a stringent set of requirements around coupling and integration, they eliminate the need for the additional installation steps required by detached microinverters.

Detached microinverters

Detached microinverters are installed on the racking system beneath each PV module (see Fig. 4). By performing MPPT at the module level, detached microinverters offer enhanced energy harvest relative to central inverters, and have developed to the point where some achieve power conversion efficiencies close to those of central inverters. Module-level communication and monitoring is possible, typically via power line communications, and system design is simplified by eliminating the need to account for varying levels of performance across modules in the array.

Figure 5. - AC modules with integral microinverters. AC modules simplify system design, allowing any number and combination of modules to connect directly to the grid, and provide enhanced safety by eliminating all exposed DC wiring from the system altogether. To capture the full advantage of AC modules, however, the integrated microinverter must achieve a high level of reliability and longevity, enabling it to support a module-compatible 25-year warranty and obviating the need for the system owner to buy and install multiple replacement inverters. For example, SolarBridge Pantheon™ microinverters feature an advanced design that eliminates failure-prone components such as electrolytic capacitors and opto-isolators, replacing them with highly-ruggedized components with no near-term wear-out mechanisms.

Conclusion Figure 4. - Detached microinverters. However, the additional labour required to install detached microinverters adds substantially to the initial cost of a PV system. Furthermore, as most detached microinverters offer only five- to 15-year warranties, it is almost certainly necessary to replace all of them – at varying times – during the operational life of a PV system, which requires the costly de-installation and re-installation of one or more modules each time. As such, ongoing operating costs for detached microinverter systems can be significant.

AC modules with integrated microinverters

The National Electric Code defines AC modules as: “A complete, environmentally protected unit consisting of solar cells, optics, inverter, and other components, designed to generate AC power when exposed to sunlight.” In an AC module, a microinverter is directly integrated with a PV panel, yielding a module that natively generates grid-

This article summarizes solar power electronics architectures, including several that have emerged in recent years as alternatives to traditional PV systems in which series-wired DC modules are connected as a group to a central inverter. Of these architectures, AC modules with integrated, long-life microinverters such as the SolarBridge Pantheon™ achieve the dual advantages of both enhanced energy harvest and significantly reduced installation and operating costs, yielding the lowest levelized cost of energy and hastening the arrival of grid parity for solar energy.

SolarBridge Technologies 9229 Waterford Centre Blvd., Suite 110 Austin, TX 78758 Email: info@solarbridgetech.com Toll-free: 877-848-0708

www.solarbridgetech.com

Photovoltaics Inter national

Products Solland Solar’s new Sunweb modules use MWT cells for 10% higher yields Applications: Sunweb modules are especially designed for the European residential rooftop and BIPV markets, covering also middle-sized commercial rooftop projects. Platform: High efficient, silicon based MWT back-contact cells with narrow spacing, low serial resistance and low surface shadowing due to the optimized metallization pattern. Availability: Early 2011.

Solland Solar’s Sunweb modules are claimed to yield 10% higher power output than its competitors per m 2 on the module level. The modules are designed using the company’s backcontact Sunweb cells, and use Solland’s patented In-Laminated Soldering technology (ILS). The Sunweb cell is based on the metal wrap-through (MWT) concept and has a unique metallization pattern on the front side, making it ideal for residential rooftop installations and BIPV markets.

CoreFlow’s wafer singulation system eliminates manual labour Applications: Crystalline solar wafer singulation process. Wafer thickness >120μm (± 30μm). Wafer size (rectangular) 156mm; 125mm (optional). Platform: SingFlow features stressfree wafer singulation with a unique control that ensures minimal contact force on the wafer. Availability: Currently available.

CoreFlow’s ‘SingFlow’ wafer singulation system is claimed to be the first automatic system that successfully deals with the delicate separation of wafers from blocks, thus eliminating manual labour. Based on a unique, stress-free, pure-shear singulation concept, this patent-pending approach delivers the first field-proven fully-automated production system, and improves production efficiency, throughput and yield of the manufacturing process. The modular system design supports the output to different configurations of lane-based cleaning systems, supporting five to six, or cassette loading for batch cleaning. System throughput with a two-head singulation configuration is 3,000wph with less than 0.25% breakage rate.

Indium’s Cu/Ga rotary sputtering target offers tight control of solar cell composition Applications: Indium’s CIG alloy targets are used to produce highefficiency CIGS solar cells. Platform: Indium employs a vertically-integrated proprietary process utilizing aerospace powder metallurgy technology. The production process output results in a consistently homogeneous alloy, with low contaminate levels and consistent density throughout the target. Availability: September 2010 onwards.

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Indium Corporation’s newly developed copper-gallium (Cu/Ga) rotary sputtering targets can be produced in chemistry ranges from 50% to 80% Cu atomic weight, with Ga making up the balance of the alloy. They are produced as a monolithic material, bonded onto the backing tube during the company’s unique hybrid consolidation process. The result is tight control of the final solar cell composition. Furthermore, as the sputtering process can produce expensive waste material, Indium is now offering reclaim and recycling services for most indium-containing materials.

MORE SOLAR POWER AMERICA? Sika® helps you reduce costs and increase quality. The infrared rays of the sun can be brutal on adhesive and sealants bond lines used in photovoltaic modules, thermal collectors and solar power plants. That’s why Sika created state-of-the-art, technologically advanced solutions that have been optimized to provide improved performance, quicker curing times and increased process capabilities. Our full line of sealants and adhesives allow for simplified PV in-frame constructions and back rail bonding mounting systems, simplified frame designs that creates fewer stress peaks on the glass panel. Sika’s high performance products enable simple automation of production and provide best-inclass load and weathering resistance. In short, we help bring out the best the sun has to offer. For more information, visit www.sikaindustry.com or call 248.577.0020.

Visit Us At Solar Power International 2010 Booth 528

Sika Corporation 30800 Stephenson Highway, Madison Heights, MI 48071

Phone: 248.577.0020 www.sikaindustry.com

Sika Solar Power-Single Page Ad_Photovoltaics International_Trim Size: 210mm x 297mm_CMYK w/Bleed

SunSil’s Integra module integrates electronics, micro-inverter and software Applications: A wide range of potential applications from commercial to residential markets. P l a t f o r m : S u n S i l ’s i n t e g r a t e d architecture means that the Integra can be assembled in a few steps with the use of their fully-automated and high-throughput manufacturing line in Denmark. Availability: Initial production of the Integra starts in Q4 2010 with volume in Q1 2011. The units, which cost around €900 each, are currently undergoing certification by Intertek.

SunSil’s Integra solar module is a fully integrated system that is claimed to increase yields by 30% or more while also reducing initial costs. It integrates all of the components of a standard PV system into one 230V 300W AC module using embedded electronics, micro-inverter and software to harvest the maximum amount of electricity from the sun under any conditions. The laser cuts each six-inch square cell into microcells; each of these is monitored and dynamically controlled by SunSil’s patented ‘Dynamic Microcell Optimisation’ technology to provide the optimum output for the whole module.

Manz Automation’s OneStep selective emitter system boosts efficiencies by 0.5% Applications: c-Si production applying n-type emitters and frontside metallization as well as existing lines (retrofit). Platform: Throughput: 1200 or 2400 wafers per hour (configurable); accuracy: ±10µm. Footprint (including automation): 4.7 x 2.7m2. Efficiency gain up to 0.5% absolute. Availability: Currently available.

Manz Automation has developed the OneStep selective emitter (SE) system for c-Si solar cells. This process consists of only one single process step, without any consumable usage, and is claimed to enable cell efficiency gains of up to 0.5%. Introduced between emitter diffusion and phosphorous glass (PSG) etch, the single step uses pulsed laser irradiation to locally scan the wafer surface, forming highly-doped areas by local liquid-state diffusion of phosphorous from the PSG layer. After anti-reflection coating, the metallization grid is deposited on top of the highly doped areas. The local doping leads to a reduction of the specific contact resistance from silicon to metal.

TRUMPF offers ultra-short pulsed lasers for high-precision thin-film applications Applications: Wide range of thin-film processing steps. Platform: TruMicro series 3000, 5000 and 7000 lasers have average outputs between 8 and 750W with pulse durations from the pico- to the microsecond range. Availability: Currently available.

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TRUMPF’s user-orientated microprocessing lasers from the TruMicro Series 3000, 5000 and 7000 range are suited to an increasing number of applications for thin-film processes including CIGS patterning steps. For TCO film ablation, the TruMicro Series 3000 offers a range of small, compact units with wavelengths of 1064nm and 532nm, ideal for P1, P2 and P3 patterning. Patterning of CIGS thin-film cells can be achieved using picosecond lasers, which feature ultrashort pulses that can ablate material without significant heating of the marginal zone of the process, thus preventing cracking, melting or exfoliation of the layers.

Kynar® Film: Protection for your Photovoltaic Modules By Ron Partridge, Arkema, Inc. Kynar ® PVDF – a legacy of performance

Kynar® 500 PVDF polymer has been used in the architectural coatings market for over 40 years and is recognized as one of the world's most weather-resistant architectural coating resins. For over 40 years, Kynar® 500 coatings have been used for the protection of metal building products due to the UV, moisture and pollution resistance of Kynar® PVDF. Since 1967, Kynar® 500 plaques have shown no signs of chalking, fading or dirt pickup on our test fence in south Florida. The excellent weathering performance of Kynar® PVDF is thanks to its chemical structure.

in the construction of PV modules. Legacy products in this market are well known for good weathering performance. As such, Kynar® film meets and exceeds all the industry weathering performance requirements needed to ensure the longevity and safety of crystalline photovoltaic modules. Because of Arkema’s legacy experience with Kynar® 500, weathering and materials performance testing are core competencies. Over the last 10 years, Kynar® films have been subjected to extremely aggressive weathering tests. The results of these tests are very similar to the performance of Kynar® 500 in these same studies.

Patented technology for protecting PV modules

Module makers

Based on the well-known performance characteristics of Kynar® PVDF, these patented films are produced using very flexible, cost-effective film technology. These fluoropolymer films are used widely in the photovoltaic industry where performance and longevity are very important.

Extremely durable performance

The photovoltaic market has turned to Kynar® film and others to meet the ever-growing demand for weatherable films used

Kynar® film is well recognized by major module makers around the world as an extremely durable and cost-effective material for photovoltaic backsheets. It is also gaining recognition with the flexible frontsheet module producers. Kynar ® backsheet protection film comes in a variety of widths and is available today in white and black. This product has been designed to work with roll-to-roll lamination processes used by backsheet producers worldwide. Photovoltaic modules produced using Kynar ® -based backsheets meet all of the requirements established by UL and IEC.

Photovoltaics Inter national

Main features and benefits of Kynar ® backsheet film

Based upon a patented multi-layer structure, these Kynar® films have many performance advantages over most other polymer films. These benefits are as follows: `` Excellent resistance to sunlight as well as complete UV opacity, which means that the PET core layer in the backsheet construction is protected from UV for many decades. `` Very good resistance to moisture, which significantly delays the hydrolysis of the core PET layer in the backsheet, resulting in a greater lifetime expectancy of the complete backsheet. `` UL has granted a provisional RTI rating of 125°C, which is among the highest available for a PV backsheet film. UL has reported that the final RTI rating will be higher. `` Kynar® backsheet films are produced using a very stable blown film process. They are completely continuous without holes or other defects, which would allow UV rays to pass through to the core PET layer. `` Excellent abrasion and chemical resistance, which further enhances the longevity of the film and resistance to weathering and pollution. `` Since the most commonly used films are white, Kynar® film was developed to have a very high solar reflectance (>83%), which helps to maintain lower operating temperatures for crystalline silicon modules. `` Kynar ® film is also very resistant to fire. Because of the chemical structure of PVDF, Kynar ® film possesses a much better level of fire protection than other available fluoropolymer backsheet films. UL has rated our Kynar ® backsheet film as VTM-0.

Main features and benefits of Kynar ® frontsheet film

Based upon many years of research and development and extensive accelerated weathering studies, Kynar ® films for frontsheet applications were launched in 2007. They have been shown to perform extremely well for frontsheet applications for both flexible PV module designs and for niche crystalline module constructions, where rigid backsheets and flexible frontsheets are used. Again, because of the chemical structure of Kynar ® PVDF and our extensive history with both field and accelerated weathering testing, Kynar® PVDF film for frontsheet applications are expected to exceed the requirements and expectations for weathering performance. The features and benefits of Kynar ® frontsheet film are as follows: `` Transparent Kynar ® film has excellent solar transmittance. Measurements made according to ASTM D1003 have exceeded 95% and are equal to or higher than other fluoropolymer materials used today for frontsheets. Since Kynar® PVDF does not absorb UV energy, very aggressive accelerated QUV-B weathering studies show no loss of solar transmittance or loss of mechanical properties for over 10,000 hrs. `` Kynar ® frontsheet film also has shown 50% greater abrasion resistance in both falling sand and taber abrasion measurements as compared to other fluoropolymer films, and possesses much lower oxygen permeation which makes it an excellent candidate for flexible CIGS modules. `` Kynar® PVDF also has a high limiting oxygen index compared with other materials and has excellent fire resistance properties. The performance of Kynar® PVDF in the wire and cable industry is well known. Kynar ® jacketing insulation is used to protect other materials when high-end fire performance is mandated by UL. 18

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`` Similar to our Kynar ® backsheet film, Kynar ® frontsheet film requires a surface treatment in order to obtain a good and durable adhesion. Once treated, excellent and longlasting adhesion has been seen to EVA and thermoplastic encapsulation systems.

Arkema invests in the PV industry

Arkema is committed to having a global presence to service its customers and support its markets. Our new production site in China, scheduled to open in the spring of 2011, will be dedicated to the production of resin for the coatings and PV industries. This new site, along with its other major production facilities in Europe and North America, will give Arkema a global presence to continue to support the growth of the PV industry.

Performance and cost-effective material

Among all other fluoropolymers, Kynar® PVDF resin and resultant films bring a cost-effective solution which can be adjusted to meet the customers needs. Laminated backsheets produced with our Kynar ® backsheet protection film are available worldwide with one or both sides of protection and can be found on the market under the trademarks KPE™ or KPK®. For Kynar®based frontsheet film, Rowland Technologies, Inc. produces a full range of thicknesses and widths to service the new and evolving flexible module market.

Protect your Investment

Specify Kynar® film in the construction of your PV module to ensure long-lasting performance and an excellent return on your investment.

For more information, please visit us at the Solar Power International show in Los Angeles in the South hall, booth number 3452 or contact Ron Partridge, ron.partridge@arkema.com Kynar® is a registered trademark of Arkema, Inc. KPE™ is a trademark and KPK® is a registered trademark of Arkema France.

KYNAR FILM PHOTOVOLTAICS PROTECTION TECHNOLOGY ®

For Backsheet or Frontsheet, Kynar® PVDF offers over 40 years of proven performance. Kynar® Film for Backsheet • Permanent UV protection • Superior weathering resistance • Superior thermal stability • Low permeation to gases and liquids • Very resistant to fire, UL VTM-0 rated • High abrasion & chemical resistance • High total solar reflectance • Globally available

Kynar® Film for Frontsheet • Excellent solar transmittance • Superior UV resistance • Superior abrasion resistance • Superior oxygen barrier • Excellent fire & chemical resistance • Flexible and lightweight • Good moisture barrier • Good adhesion to encapsulants

Please visit us at Solar Power International 2010 in South Hall booth 3452 or contact Ron Partridge: Ron.Partridge@Arkema.com

Protect your Investment: Specify Kynar® Film in the Construction of your PV Module

Arkema_PVILite 07.indd 1

21/09/2010 17:12:07

Large-scale PV power plants – new markets and challenges

Denis Lenardic, PV Resources, Jesenice, Slovenia

ABSTRACT

Earlier this year, worldwide cumulative power capacity surpassed 6GW (taking into consideration only PV power plants >200kW DC). Europe still holds the largest market share at 87%, but in comparison with the figures scored in 2008 [1, 2], the U.S. increased its market share to 7%. Estimated annual installed power capacity worldwide for the period from 2000 to 2009 [3] is presented in Table 1. The data are based on detailed figures taken from more than 3,400 large-scale PV plants put into service in recent years that had cumulative peak power capacity of more than 6GWp. D u e t o a s h o r t a g e o f re l i a b l e databases and national or international sources of statistical information concerning large-scale photovoltaic power plants, the statistical data presented here should be considered “conservative”. However, some national statistical sources of note include those provided by some Italian [4] and German [5] agencies.

Annual and cumulative installed power output capacity It is estimated that more than 1.7GW large-scale power plants were constructed and put into service in 2009 (Fig. 1) [3]. Market leader Germany has more than 650MW installed (see Fig. 5 for more details), followed by Italy with about 250MW and the Czech Republic with about 200MW installed power capacity. Fig. 2 shows a Europe-wide breakdown of installed cumulative power capacity as at December 2009.

Source: pvresources.com

Despite the collapsed Spanish market and the general state of the world’s economy, the past year was not a bad year at all from the perspective of installed power capacity of large-scale PV power plants. Installed power capacity surpassed expectations while also bringing new markets into the spotlight, which means that the traditional market leaders of Spain, Germany and the U.S. are no longer the only ‘key’ markets. With the exception of Germany, the past year’s most noteworthy market boost was seen in the Czech Republic and Italy, with similar shake-ups seen in the Asian tiger countries of China and India. With many large-scale PV power plants recently brought into commission in these countries, China and India are brimming with potential for the near future.

Figure 1. Annual installed power output capacity (MWp) from 2005 to 2009, taking into consideration PV power plants >200kWp. The market share of large-scale gridconnected PV power plants has been increasing continuously in recent years (see Fig. 3) in comparison with total annual installed PV power capacity [6]. In 2005, market share comprised less than 10% of the annual installed PV power capacity, while in 2007 market share of large-scale PV power plants reached almost 25% of the annual installed power capacity. In 2009, this figure was close to 30%.

New markets Significant progress was not restricted to the key markets of Germany and Italy, however. It is now estimated that the Czech Republic has about 200MW of new power capacity installed (large-scale PV power plants), with a resulting third-

place ranking after Germany and Italy. Data for the most important new markets is presented in Table 2. Belgium, one of the most interesting new markets, is a prime example of regionally-driven policy. While the Flemish region has seen more than 80MW (rough estimate) of large-scale PV power plants commissioned in 2009, other parts of the country have thus far only shown slow progress. As expected, developments in Bulgaria and Greece have resulted in the commissioning of some large-scale PV power plants. Small markets like Slovakia and Slovenia have also made first steps toward joining the prestigious “MW-range Club”. Progress in the French markets was lower than expected, but with the recent

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

Annual installed Cumulative installed

4.2 29.1

9.4 38.5

20.3 58.8

29.8 88.6

81.9 171

111 282

211 493

626 1119

2957 4076

1748 5824

Table 1. Estimated annual and cumulative installed power output capacity [3] worldwide of large-scale photovoltaic power plants (>200kWp) from 2000-2009. 20

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Map courtesy of U.Dewald, H.-J.Ehrig, RWTH Aachen

Figure 2. PV power capacity in MW (>200kW) installed in Europe as at December 2009. commissioning of some large-scale power plants, cumulative power capacity in France (including French overseas territories) is estimated to be more than 100MW. Some of these French

overseas territories have seen significant development in this vein, with plants like La Roseraye and La Mangassaye on Reunion Island completed this year; Guadeloupe and Mayotte are

also broaching the MW range in recent projects. PV market share figures for large-scale PV power plants in France and the French overseas territories are presented in Fig. 4. Although Europe currently retains the number one region position, other regions and countries such as Canada, China and India have also been showing quite rapid developments. Canada has recently commissioned some very largescale PV power plants. The 20MW Sarnia project has already undergone expansion, and following completion of the second stage at the end of the year, this particular plant will take pole position on the PV ranking list. Asia’s most important new market is China with some very large-scale power plants under construction, while some MW-range PV power plants were also commissioned in recent months in India and Thailand. From a short- and mid-term perspective, these Asian markets are the most promising markets worldwide; however, shortterm opportunities are more plentiful in the European countries of Italy, France, Greece and Bulgaria.

Future challenges With ongoing discussions in the EU in regard to the use of agricultural land (and similar areas) for PV power plants, the industry needs to always be on the lookout for new suitable locations. Large roofs hold significant potential for roof-

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Annual installed 2009 Cumulative installed

Belgium

France**

49 68

35 55

Portugal Bulgaria*** Greece 14 74

3.2 2.0

China*

14 18.2

70 75

India* Thailand *** 4 4.3

1.1 8.5

* Very promising new markets for the near future; significant progress expected this year. ** Including overseas territories. *** Significant progress observed in the first half of 2010, valid also for China and India.

Courtesy of EPIA, pvresources.com

Table 2. Large-scale PV power plants: annual and cumulative power capacity (MW) installed in 2009 for some new markets [3].

Figure 3. Large-scale PV power capacity as a percentage share of total PV power capacity installed.

mounted PV power plants, in particular the current state of play in Belgium where about 75% of PV power capacity is delivered by roof-mounted PV power plants. California’s market share of roofmounted PV power plants is also quite high. As shown in Fig. 5, Germany’s share of roof-mounted PV power plants remains quite low – this is also the case in many other developed countries. Roof-mounted power plants will undoubtedly have a much higher market share in the future in developed countries, whereas ground-mounted PV power plants will still dominate in desert areas and countries where scope is not an issue. For ground-mounted PV power plants, sites such as abandoned wastetreatment facilities or waste-water treatment facilities should be used more extensively: it is currently estimated that about 1% of the world’s large-scale PV power plants is located on such areas [3]. Germany and some other countries have adapted abandoned military areas for the construction of large PV plants, such as Lieberose (53MW), Finsterwalde (42MW) and Brandis (40MW) in Germany, and the 1.2MW Sault plant in France and the Czech Republic’s 13.6MW Stříbro plant (see Fig. 6).

“Other very important but often ignored issues are reliable and precise yield prediction and effective power plant monitoring.”

Figure 4. Market shares for France and French overseas territories as at June 2010 (large-scale PV power plants only).

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Several key issues will play major roles in construction and operation of PV power plants in the coming years. New markets for MW-range plants are completely different from those established European and U.S. markets that claim close to two decades of experience in the construction and operation of PV power plants. The first few large-scale PV plants in Europe commissioned about two decades ago had typical power outputs of 500kW and were usually the result of research projects. Those plants commissioned in new markets – China and India in particular – are very large-scale

to these issues is essential for accurate electricity price calculation. Possible investment price drops may end up lowering feed-in tariffs (or subsidies), and for owners and operators of PV power plants, the electricity price – especially once grid parity has been reached – will be the most important parameter for ensuring an economical plant operation. PV power plants that have implemented more precise monitoring and electricity price calculation measures will be more compatible in the long term with other renewable (and non-renewable) sources of energy.

Acknowledgements The author would like to express his very special thanks to Ulrich Dewald and Hans-Joachim Ehrig from RWTH University of Aachen for preparing the chart, and to S.A.G. Solarstrom for providing the photo of the Stříbro PV power plant.

References [1] Solarpraxis 2010, PV Power Plants 2010 Industry Guide [available online at www.pv-power-plants.com]. [2] Lenardiř, D., Petrak, S. & Dewald, U. 2009, Large-Scale Photovoltaic Power Plants: Annual Review 2008 (Extended Edition), ISBN 978-961245-739-6. [3] P V R e s o u r c e s d a t a b a s e [(partially) available online at www. pvresources.com/en/top50pv.php]. [4] Gestore dei Servizi Energetici (GSE S.p.A) [available online at http:// atlasole.gsel.it; www.gse.it]. [5] German Federal Network Agency/ B u n d e s n e t z a g e n t u r, E E G Statistikbericht 2008 [available online at www.bundesnetzagentur.de]. [6] EPIA 2010, Global market outlook for photovoltaics until 2014; May 2010 update [available online at www.epia.org].

Figure 5. Ground-mounted vs. roof-mounted (large-scale) PV power plants: estimated market share in German states (data correct as of June 2010) [3]. MW-range facilities that are anticipated to function reliably for at least the next 20 years. New markets require top-ofthe-range project planning, financing and construction quality, as failed projects could essentially lead to significant financial losses. In the worst-case scenario, they could also have negative

impact on regional renewable energy policies. Other very important but often ignored issues are reliable and precise yield prediction and effective power plant monitoring. In conjunction with some other activities such as precise maintenance cost estimation, attention

Ccourtesy of S.A.G. Solarstrom

About the Author

Figure 6. The Stříbro 13.6MW project, built on an abandoned military surface, is the largest Czech power plant put into service in 2009.

Denis Lenardi č holds a degree in electrical engineering from the University of Ljubljana, Slovenia. From 2004 to 2008 he served as chairman of the Slovene national section of the IEC »TC82« Technical Committee. He has been systematically collecting data regarding large-scale photovoltaic power plants for several years. The data that forms the basis of this article is available to the public free of charge at http:// www.pvresources.com/en/top50pv.php.

Enquiries Cesta Revoucije 3 SI-4270 Jesenice Slovenia Email: contact@pvresources.com Web: www.pvresources.com

Photovoltaics Inter national

Delivering on its Promise: Upsolar’s Best-In-Class Warranty is Unmatched in the Solar Industry By Tony Foster, North America Sales Director, Upsolar

One of the many benefits of solar PV modules is the longterm warranty included with the products. The warranty brings the peace of mind that – in the event that the purchase is damaged or malfunctions during the warranty period – it can be repaired at little to no cost. In the past, the validity and reliability of such warranties was not much of a consideration. Today, however, with commercial and utility-scale PV systems costing in the hundreds of thousands or millions of dollars, it is becoming commonplace for customers and their financial partners to consider not only the quality of the product, but also the type of warranty offered and how that warranty is backed up. It is important to understand that all warranties are not created equal. Warranties are not worth the paper they are printed on if the terms are so unfavorable to the customer that they offer little value, or if there is no guarantee that the company backing the warranty – typically the manufacturer – will remain in existence for 25 years. Upsolar is an international developer and producer of high-quality, reliable solar PV modules offered at competitive prices. Utilizing components from trusted manufacturers around the world, we provide customers with PV modules for commercial and utility-grade installations, including gridconnected field arrays, tracking systems and large-scale building-integrated photovoltaic (BIPV) projects.

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Beginning December 31, 2010, Upsolar’s PV modules will be backed by PowerGuard Specialty Insurance Services’ comprehensive PowerCLIP warranty. Upsolar’s PowerCLIP warranty is unparalleled in the industry, offering the most contractual liability coverage available for solar PV manufacturers. PowerCLIP securitizes and “back-stops” Upsolar’s warranty coverage – a significant added benefit for Upsolar’s customers as well as for the banks, lenders and investment firms who support them. The PowerCLIP warranty has many advantages. Chief among them is that it is non-cancellable, meaning the warranty will be honored over 25 years regardless of Upsolar’s solvency or existence. In addition, the PowerCLIP warranty provides protection from serial defects, delaminating of modules, backs Upsolar’s new enhanced Limited Peak Power Warranty and provides immediate coverage, as opposed to the usual two- to five-year waiting period imposed by other insurance policies. Most importantly, the PowerCLIP warranty provides u np r e c e d e n te d p rote c t i o n t h ro u g h h i g h l y r a te d , internationally recognized insurance providers (A.M. Bestrated “A” or better), thus guaranteeing they will be in business to honor all future claims. This “bankability” feature of the PowerCLIP warranty mitigates the risk to lenders and assures them that Upsolar products are a sound investment.

Guaranteed Module Performance

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Upsolar's Performance Guarantee 95.00%

Standard Tiered Guarantee 90.00%

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Indeed, the PowerCLIP warranty was designed with the aim of appealing to project lenders skeptical of a solar provider’s ability to honor a multi-decade warranty. With the availability of credit growing ever-more scarce, warranty issues may leave lenders feeling reluctant to lend against large-scale solar projects.

The regular feedback we receive from customers who use our products under harsh environmental conditions reinforces our confidence in their quality. To further elevate this confidence, we elected to invest in world-class warranties backed by highly reputable, internationally recognized insurance providers.

In order to best attract investors in commercial and utilityscale systems, and to enhance our contribution to the expansion of sustainable technologies, we are including the added layer of security offered by PowerCLIP. With its double coverage feature, the new Upsolar PowerCLIP warranty provides the safety net that developers and financiers of solar projects are seeking.

Upsolar’s PowerCLIP warranty also includes step-down Limited Peak Power Warranty with six trigger points; at years 3, 7, 12, 16, 20 and 25 (far superior to the industry standard output guarantee with two trigger points at years 10 and 25) and five-year product coverage for defects in materials and workmanship.

PowerGuard has historically accepted only five percent of warranty applicants. Their decision to back Upsolar’s products is based largely on Upsolar’s “Excellence at Each Step” integrated manufacturing approach. Upsolar’s independent third-party QC auditors and our rigorous testing procedures ensure that we deliver only the highest quality PV modules. Our state-of-the-art Test and Development Centre is focused on the testing of PV module materials, components and technologies. After selecting the best components, we develop prototype modules that are tested under harsh environmental conditions – including ambient temperature variations, high moisture exposure and ultraviolet rays – in order to validate their level of performance. In addition, our team at the Test and Development Centre works in conjunction with independent thirdparty laboratories to test our products and to update our certifications of conformity to international standards for each design. Once a component goes into production, quality control engineers are stationed at our manufacturing partners’ plants to guarantee that our high standards are met at each stage of the production process. 26

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The highly volatile solar industry will inevitably suffer attrition, leading to the eventual insolvency of many suppliers in the future. This will leave some customers with no support or warranties for their hefty investments. In contrast, Upsolar has chosen to provide our customers with what we believe to be the best warranty in the industry. We would do no less: our reputation as a leader and innovator in the solar industry is firmly based on our commitment to quality and our long-term relationships with our customers. While the solar industry is rapidly changing, Upsolar’s combination of high quality products, competitive prices, world-class warranties and bankability makes us the leading choice in the worldwide solar market.

Visit us at SPI 2010, Los Angeles at booth 3953 For more information on Upsolar, please visit the website at-

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DERlab round-robin testing of photovoltaic single-phase inverters

Omar Perego, Paolo Mora & Carlo Tornelli, ERSE, Milan, Italy; Wolfram Heckmann & Thomas Degner (DERlab coordinator), IWES, Kassel, Germany

ABSTRACT Interconnection of inverters to the electrical grid is a key issue for the widespread integration of distributed energy resources, especially when the scenario surrounding international standards is so unclear. As a prenormative research step, a round-robin test of two small-scale photovoltaic inverters was performed by nine DERlab laboratories during 2009. The test activity was focused on the verification of individual test procedures, common interpretation of standards and requirements, and determination of problems related to the equipment and facilities involved in conducting round-robin tests. Compilation of test results and first conclusions of this activity will be presented in this paper.

DERlab consortium The activities described in this article are a result of studies carried out by the DERlab team. DERlab is a European Project funded by the EC in the sixth F r a m e w o r k P ro g r a m m e ( F P 6 , n . 518299), armed with the mission of constituting a Network of Excellence (NoE) of DER Laboratories for PreStandardization activities. The main objective of the DERlab NoE is to support the sustainable integration of renewable energy sources (RES) and distributed energy resources (DER) in the electricity supply, by developing common requirements, quality criteria, as well as proposing test and certification procedures concerning connection, safety, operation and communication of DER components and systems. The NoE also acts as a platform for the exchange of current knowledge between the different European institutes and other groups.

has 11 members: IWES from Germany (coordinator); ARSENAL from Austria; KEMA from The Netherlands; INES-CEA from France; ERSE from Italy; LABEINTecnalia from Spain; University of Manchester from UK; NTUA-ICCS from Greece; RISOE-DTU from Denmark; TU Sofia from Bulgaria; and TU Łódź from Poland.

Round-robin motivation One of the objectives of DERlab is to support the development of European and international standards by executing exemplary research activities on specific topics and by initiating new research activities, which aim to provide the required technical information and input to the standardization bodies.

The organization’s main focus is not on the single, isolated device, but on the DERs integrated in an electrical network to highlight interface conditions. As most DER electrical interfaces to the grid are realized through inverters, this paper answers the need for particular attention to be paid to the testing procedures for these kinds of devices. In order to define a field of application that can be faced, considering also the large diffusion of these devices, this investigation has been focused on single-phase photovoltaic inverters of up to 6kVA of rated power that are connected to the PV field and intended for functioning in parallel to the grid. This activity is not intended to overlap or to substitute the work being

“During the data collection, each laboratory highlighted problems and difficulties occurring during these inverter tests.” In order to establish a durable network of DER laboratories, the members of the DERlab Consortium, together with other important European laboratories and research centres, founded the DERlab Association (DERlab e.V.) in September 2008. The test facilities of the DERlab members (with some relevant additions) are offered, free of charge, to European researchers for activities funded by the EC in the FP7 Research Infrastructures DERri Project (Distributed Energy Resources Research Infrastructure, FP7, n. 228449). The DERlab Consortium (see Fig. 1)

Figure 1. DERlab Consortium members.

Photovoltaics Inter national

Figure 2. Moment of test execution. undertaken by standardization bodies. Its purpose is to verify the applicability of the existing standards, identifying lacks, explaining difficulties and problems in test conditions and specifying testing equipment by collecting data in an intercomparison (‘round-robin’) approach among DERlab members. Appropriate and well-defined ‘PV inverter testing procedures’ (related to performance, grid interface and safety) have been prepared by DERlab experts as a basic prerequisite for the roundrobin test. This document defines some steps and guidelines to which each laboratory must adhere in testing PV inverter characteristics. During the data collection, each laboratory highlighted problems and difficulties occurring during these inverter tests. The main purpose of such a data collection study is to collect suggestions from the various experts in the field and transfer this experience to the standards committees. In fact, the analysis of the results and of the notes and suggestions collected during the test phase can be automatically forwarded to the relevant active standardization groups, where the engineers involved in the data collection for this paper are also directly involved in assessing and writing International and National Standards. This round robin will help in assessing, verification and modification of existing and proposed test procedures in order to fill the gaps, to harmonize, and to clarify.

Round-robin activities The data and information for the round robin were collected during 2008 and 2009, as illustrated in Fig. 2; the final analysis, the definition of recommendations and the dissemination of the results are currently in progress. In brief, a team of experts from DERlab partners has compiled a 28

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document for ‘PV inverter testing procedures’, related to performance, grid interface and safety. This document has been submitted and shared among all DERlab partners, together with a template of the test reports. Aurora Power-one PVI-3.0-OUTD-IT Nominal power (AC): 3,000W Voltage range (DC): 90 – 580VCC No. of MPPTs: 2 Protections equipments: detection o f D C c u r re n t i n j e c t i o n i n A C (transformerless inverter), min/max V, min/max f, df.

This document – which should not be considered a ‘standard procedure to test PV inverters’ because it is not produced by standard committees – defines some steps that nine DERlab laboratories have to follow to test two PV inverters within the remit of the round robin. Two inverters were circulated among these laboratories, and tested according to the indications of the procedures. The team of DERlab experts and technicians involved in the tests filled in the test reports with the results of these tests. At the end of the round robin, they reported their observations and suggestions in a questionnaire circulated in September 2009, which were then collected and analysed by a team of DERlab experts, who took on board the observations and suggestions on how to improve the test procedures in order to transfer this experience to relevant active standardization groups. DERlab experts had the opportunity to share their experiences during the round-robin timeline. Some experts visited partner laboratories, working in collaboration with local technicians, yielding data that were collected, c o m p a re d a n d a n a l y s e d b y t h e consortium meetings with the intention of SMA SunnyBoy 4000TL Nominal power (AC): 4,000W Voltage range (DC): 125 – 440VCC No. of MPPTs: 2 Protections equipments: detection o f D C c u r re n t i n j e c t i o n i n A C (transformerless inverter), min/max V, min/max f, df.

Table 1. Inverters circulated among DERlab laboratories for round-robin testing purposes.

Method of protection intervention requested by Italian grid code

Thresholds Mandatory/optional

MIN & MAX voltage detection

Mandatory

0.8 x Vn (t < 0.2 s) < V < 1.2 x Vn (t < 0.1 s)

MIN & MAX 49 or 49.7 Hz < f < 50.3 or 51Hz frequency detection (without any requested delay)

Mandatory

Frequency deviation df < 0.5Hz/s

If requested by the grid operator

Table 2. Method of protection intervention as defined by CEI 11-20 grid code.

Figure 3. Basic circuit for anti-islanding protections (contactor is normally open). collecting observations and improving the procedure steps.

PV inverters The investigation focused on single-phase inverters up to 6kVA that are connected to a PV field in parallel to the grid. The two inverters that were circulated among DERlab laboratories were the Aurora Power-one PVI-3.0-OUTD-IT and the SMA SunnyBoy 4000TL, the main characteristics of which are displayed in Table 1.

Tests The aim of the tests is to assess if the PV inverters are suitable for properly functioning in parallel to the grid and to measure the performances and characteristics of these inverters in different operative conditions. Some tests are identified as mandatory because they refer to problems related to the electrical interconnections of DER (grid compatibility and safety); the other tests are identified as optional, because they measure the performance characteristics of the inverters. The tests performed, divided into mandatory [M] and optional [O], are listed below: [M] – Harmonic current measurement (power quality test on grid compatibility) [M] – Anti-islanding protection detection (protection intervention test on grid connection) [M] – DC current injection measurement (power quality test on grid compatibility) [M] – PV leakage current protection detection (protection intervention test on safety) [O] – Efficiency measurements (performance test; see [2]), [O] – Measurement of MPPT (maximum power point tracker) accuracy when PV shadowing occurs (performance test). The round-robin test was conducted to adhere to the defined test procedures (described in the DERlab ‘PV inverter testing procedures’ document), using the same inverters under the same test set-up and according to the same standards but with different devices, instruments and environment. The DERlab partners decided to follow the Italian standards because, as there is no EU standard, the two inverters’ parameters are configured according to Italian standards. A common understanding of the differences and remarks collected during the analytic phase of the round robin yielded refinement of the testing procedures and the elaboration of suggestions to standard committees. The analysis of the results and considerations about the following mandatory tests are pertinent to this paper: yy Test on anti-islanding protections yy Test on harmonic current yy Test on DC current injection. The analysis of these tests is extended to general considerations and to open questions, the outcome of which will be reported later in the paper.

Figure 4. General architecture of anti-islanding protection measurement system.

Test on anti-islanding protections The aim of the test is to evaluate the inverter’s behaviour during lulls in grid connection in order to evaluate their capability for islanding prevention. In Italy, an anti-islanding protection test detects grid failures and disconnects PV generators to avoid feeding of the grid in an uncontrolled manner. Anti-islanding protection is steered by a European standard (EN-50348); however, this code contains many gaps and derogations that stipulate that each country has to provide its own grid code with different methods and values for anti-islanding protection. Italy’s MV/HV connections have to follow the specifications of CEI 0-16, the Italian standards committee, that include guidelines for LV connections and modifying the CEI 11-20 standard.

“The grid simulator must guarantee a maximum voltage THD (total harmonic distortion) less than 1%.” Although the EU standard committee is working on a common test procedure at international level (IEC 62116) for anti-islanding protection detection, the method of resonant circuit as defined by IEC 62116 is still missing the approval of CENELEC. Methods of protection intervention are implemented by the manufacturers themselves according to the national grid code. In Italy, the CEI 11-20 grid code for LV connections requires a set of protective measures to be implemented by manufacturers in the Italian market. Table 2 shows the threshold values of voltage and frequency that cause the protection intervention and the maximum delay allowed for this intervention. The method requested by the Italian grid code, based on minimum and maximum voltage and frequency, is intrinsically inadequate as it can fail when an equality between generated and used power occurs. Additional ‘active’ protections could be used to address this problem, an approach that is being 30

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investigated by the Italian National committee in the form of a new version of the CEI 11-20 grid code. Fig. 3 shows the basic circuit used by protections as requested by the Italian grid code for photovoltaic applications. Both low and high voltage protection methods and low and high frequency protection methods have been tested during the round-robin testing procedure for this study. Further protection methods such as the rate of frequency change, impedance tests, frequency shift etc. may be used in other EU countries as stipulated by countries’ grid codes, but this study’s remit is limited to the two protection methods mentioned above.

Test equipment and preparation The inverter is connected on the DC side to a PV field (or to a PV simulator) and on the AC side to an adjustable grid simulator, which allows the test operator to adjust voltage and frequency settings. The grid simulator must guarantee a maximum voltage THD (total harmonic distortion) less than 1%. A grid analyser is then positioned on the AC side, used to acquire both voltage and frequency AC signals (see Fig. 4).

Procedure The test procedure describes the steps that should be followed to measure:

yy the output limit values (AC voltage and frequency) for protection intervention; yy the time between the crossing of a frequency and voltage threshold and the intervention of the inverter antiislanding protection. Tests on anti-islanding protections are performed by the measurement of each threshold and the verification of the status of the disconnecting device (contactor). Furthermore, the operation delays are also measured in order to be in accordance with those results reported in Table 2. The test method depicted in Fig. 5 shows the continuous variance of the voltage and frequency of the grid simulator. The slope of the frequency variation must be lower than the value of the rate of frequency change threshold (if this intervention method is implemented by the inverter manufacturer; see [3]). The test begins from the central point (nominal voltage 230V; nominal frequency 50Hz), moving towards the first target until the device trips or a safety limit is reached. This action is then repeated for each protection. For example, in order to verify the high-voltage protection device, the voltage is slowly increased and the value that causes the trip is registered and noted as the high voltage threshold of the inverter. The initial conditions are restored, at which point an instantaneous variation of voltage is made from the same central point to a value above the measured high-voltage threshold. The time between the voltage step and the intervention of the protection is measured and noted as representing the time of high voltage protection intervention.

Results Tables 3 and 4 summarize the results obtained in three different laboratories for threshold values and times, respectively. Both of the inverters have respected the thresholds defined by the CEI 11-20 Italian standard (limit values regarding over and under frequency time are available in Table 2).

Table 3. Threshold values measured for an inverter in three different laboratories.

Table 4. Threshold times measured for an inverter in three different laboratories.

Figure 6. Harmonic current measurement configuration. Figure 5. Grid simulator test method.

Test on harmonic current The aim of this test is to assess the current harmonics injection of the PV inverter into the grid using between 5% and 120% of the inverter nominal power. Several tests have been performed in compliance with the requirements of EN 61000-3-2, Annex A (see [4,5]). Due to the fact that the actual voltage THD may have a strong impact on the inverters’ current THD, the requirements specify the limit values for test voltage and harmonic ratios of the test voltage: yy The test voltage shall be maintained within ±2.0% and the frequency within ±0.5% of the nominal value (230V and 50Hz for single-phase supplies). yy The harmonic ratios of the test voltage (U) shall not exceed the following values with the EUT connected as in

With: I1: Amplitude of the current component at basic frequency In: Amplitude of the current component at nth harmonic frequency Equation 1. normal operation: -- 0.9% for harmonic in order 3; -- 0.4% for harmonic in order 5; -- 0.3% for harmonic in order 7; -- 0.2% for even harmonic in order from 2 to 10; -- 0.2% for harmonic in order from 11 to 40. yy The peak value of the test voltage shall be within 1.40 and 1.42 times its r.m.s. value and will be reached within 87° and 93° after the zero crossing.

This requirement does not apply when Class A or B equipment is tested.

Test equipment and preparation The inverter is connected on the DC side to a PV simulator that provides the required harmonics measurements for different fixed power outputs (equal to 5%, 10%, 20%, 25%, 50%, 75%, 100% and 120% of the inverter rated power). The inverter is connected on the AC

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Table 5. Limit values for current harmonics.

Figure 7. THD measures for the same inverter in different laboratories. side to an adjustable grid simulator, or to an LV single-phase real grid (only if it fulfils the requirements of EN 610003-2, Annex A for voltage harmonics). A power analyser is then positioned on the AC side for the harmonics measurement. Fig. 6 shows the harmonic current measurement configuration.

according to the limits expressed by the IEC 61000-3-2 (Table 5). The current THD and the current harmonics from 2nd to 39th must be recorded for values of output power equal to 5%, 10%, 20%, 25%, 50%, 75%, 100% and 120% of the inverter rated power.

Procedure

The testing procedure measures the amplitude of the harmonic distortion of the inverter output current, relating to different values of the power supplied. Measures have been performed for single harmonic, till the 40th one and computation has been done for the THD factor as shown in Equation 1. Fig. 7 shows the trend of THD (%) related to the output power supplied

The test procedure describes the steps that should be followed to measure the current harmonics from 2nd to 39th. The inverter is turned on and the current harmonics are measured on the inverter output by means of a grid analyser installed on the AC output; the current THD and the current harmonics are recorded and their values are verified

Results

by the same photovoltaic inverter. The consistency among the measures performed in the different laboratories is quite good; the measures’ scattering increases when the power supplied by the inverter becomes lower. In spite of the good consistency of THD measures, some differences are observed for the measures of single harmonic components related to the same inverter situation (see Fig. 8). In order to increase the results’ repeatability, a better definition of the characteristics of the measurement equipment is necessary, as is a more accurate indication of the measures’ elaboration, in particular for the average computation. As a matter of fact, execution of the measures can produce a harmonic spectrum that is time dependent; for the harmonic calculation it is necessary to use a time slot large enough to represent the average level of the current harmonics. The value scattering shown in Fig. 8 can likely be produced by the use of time slots of different lengths and by application of an inadequate data average.

References [1] D E R l a b a n d D E R r i P ro j e c t s [available online at http://www.derlab.net; http://www.der-ri.net]. [2] I E C 6 1 6 8 3 : P h o t o v o l t a i c Systems - Power Conditioners - Procedure for Measuring Efficiency [available online at http:// webstore.iec.ch/preview/info_ iec61683%7Bed1.0%7Den.pdf]. [3] Groppi, F. 2007, “Testing of antiislanding protections for gridconnected inverters”, International conference on Clean Electrical Power (ICCEP2007), Capri, Italy. [4] EN 61000-4-30: Electromagnetic compatibility (EMC), Part 4-30. Te s t i n g a n d m e a s u r e m e n t techniques – power quality measurements methods. [5] EN 61000-3-2: Electromagnetic compatibility (EMC), Part 3-2. Limits, Section 2: Limits for h a r m o n i c c u r re n t e m i s s i o n s (equipment input current <16A per phase). Want to read more?

Figure 8. First 20 current harmonics measured in different laboratories (P/ Pn= 50%).

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Download part two of this article at the Photovoltaics International journal archive online at http://www.pv-tech.org/journal_archive Author information and contact details are also available online

Pre-construction, engineering and design costs of large-scale residential installations – part 1

Angiolo Laviziano & Ethan Miller, REC Solar, San Luis Obispo, California, USA

ABSTRACT PV industry module and component manufacturers have brought down costs significantly over the last four years. This trend is clearly evident as most publicly traded companies continue to increase revenue despite falling module and component prices. However, it is far less clear how downstream system integrators are handling the drop in system prices and contributing to value creation. System prices are generally higher in the U.S. than in Europe, despite lower module prices in the U.S. This disparity often raises questions on the part of European PV professionals where these costs come from, and secondly, what U.S. system integrators have done to reduce costs. This two-part series will shed light on how U.S. system integrators have undertaken tremendous efforts to decrease cost and add value through innovation by focussing on labour-intensive value creation in the downstream segment. Part I will focus on the residential market segment by delving into activity cost savings through innovation in engineering and construction, while Part II will illustrate how changes in sales, rebates, interconnection, and the supply-chain management over the last five years have reduced costs. Competitive pressures along with falling rebates in the U.S. residential market have forced a focus on cost reduction through the value chain. While the largest cost reductions have been the cost of modules, there have been major improvements in engineering and construction. Both manufacturers and downstream integrators must continue to innovate as system installation volumes grow and subsidies continue to fall. For integrators, the best-known areas for improvement and innovation include system design, installation labour, and BOS components. Each of these areas will be explored in further detail in this paper.

System design The most important paradigm shift occurring in residential system design today is a move away from the need

for custom engineering. Rather than engineered individual projects, residential PV projects are increasingly preconfigured. Five years ago, residential projects were all custom engineered. The PV integration business is finally catching on to techniques and business practices used by other far more complex manufacturing businesses. Primary areas of improvement in system design have been around site investigation, system layout, single-line drawings, bill of materials and permitplan set creation. The shift to repeatable configuration requirements in the residential business has led to faster execution and cost savings through simplified skill set requirements for each design, as shown in Table 1. A comparison of system design labour costs in 2005 versus 2010 shows how residential system integrators

2005 hours/kW

$/Watt

2010 hours/kW

$/Watt

Site investigation System layout Single line drawing Bill of materials Permit plan creation

1.56 0.67 0.40 1.00 1.60

0.05 0.03 0.02 0.05 0.06

0.93 0.39 0.23 0.22 0.82

0.03 0.01 0.01 0.01 0.03

Total

5.22

0.21

2.59

0.09

Table 1. Comparison of system design labour costs – 2005 vs. 2010. Data sourced from REC Solar’s analysis of system installation costs of approximately 5,000 residential systems.

are driving toward a far leaner system design process. Labour time has been approximately cut in half. Engineering skills are no longer required for every step of the process, thereby reducing labour cost. Leading system integrators have been able to reduce the $/watt component by 57%, primarily through reduced system design requirements

Figure 1. Solmetric’s SunEye 210 is an integrated shade analysis tool for solar site assessment.

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2005 hours/kW

$/Watt

2010 hours/kW

$/Watt

Warehouse pickup Travel Layout on site Racking installation Module installation Electrical installation Clean-up Parts house runs Testing of PV system Close out Documentation

1.50 3.00 0.89 6.67 4.44 3.33 0.44 0.33 0.22 0.33

0.05 0.11 0.02 0.17 0.11 0.16 0.01 0.02 0.01 0.02

0.50 3.00 0.44 4.44 3.33 2.22 0.44 0.33 0.22 0.33

0.02 0.11 0.01 0.11 0.08 0.10 0.01 0.02 0.01 0.02

Total

21.17

0.67

15.28

0.49

Table 2. Comparison of installation labour costs – 2005 vs. 2010. Data sourced from REC Solar’s analysis of system installation costs of approximately 5,000 residential systems. using improved design tools, standards and processes. All systems start with some form of site investigation to determine the optimum system configuration that meets customer requirements. Significant efficiencies have been gained through the introduction of readily available improved satellite imagery, electronic shade analysis tools (see Fig. 1) and online system configuration tools such as the REC Solar Widget, which allows customers to size their own PV system online and see both the layout on a satellite image overlay and the related economic benefits. By understanding site conditions and basic system design parameters prior to performing a physical site visit, all site investigations can be performed in an expeditious manner allowing for focus on key design constraints. The second critical improvement has been realized by many system integrators in their use of design tools. Templates and standard system designs have resulted in residential systems without custom engineering, while the myriad publicly available design programs and some proprietary solutions allow the designer to input basic system parameters to create an automated code-compliant system design. These tools have not only increased the speed of design but reduced the cost of labour as many integrators use these tools to radically shift their focus from engineering to configuration.

That being said, there have been many small changes in the construction labour process that have allowed for continuous cost improvements (see Table 2). Primary drivers in cost reduction include racking systems, tools, management of non-value added tasks, standardized training processes, and a larger workforce of skilled PV installers. The future will likely see further reductions in the areas of electrical installation, system prefabrication and improved technologies. Racking system design changes over the past five years have had a tremendous impact on the shift toward an overall ‘system design’ perspective (see example in Fig. 2). The system design perspective views the project as a whole rather than as a series of individual components to be left to an installer for assembly. This shift focuses on identifying and eliminating redundant requirements and inefficiencies, and albeit a low-tech component, racking has been a key driver in increasing installation efficiencies.

Installation labour and racking The highest cost component of a residential PV system – besides the modules themselves – is the installation labour. Residential installation is a n e x c e e d i n g l y l a b o u r- i n t e n s i v e process with very few revolutionizing opportunities to increase efficiency. 34

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Figure 2. The SnapNrack Clamp Assembly, an example of the ‘system design perspective’.

Figure 3. Specialized module lift mechanism. For example, many racking systems have moved toward utilizing a single driver for all bolts, eliminating the requirement of having multiple tools. Innovations have been developed in the areas of snap-in components, preassembled components, and a general reduction in parts count. What was once a construction process on the roof including drilling and cutting of rails has become an assembly process. Component assemblies are being established in warehouses by less skilled, lower-cost workers and delivered directly to construction workers for reduced field assembly time and cost. The system design approach and shift towards field or warehouse assembly rather than field fabrication has greatly reduced time spent on the roof. Newly introduced tools and equipment provide incremental improvements in installation labour efficiencies such as installation trucks and module lifts customized for effective solar installation, such as that shown in Fig. 3. The module lift can prevent installers from transporting modules one at a time up ladders, allowing for more time to be spent on installing rather than transporting. Customized trucks have greatly improved installation efficiencies. By having a vehicle with all necessary materials, tools and equipment, the installation team spends less time in parts houses picking up material and more time on the project. Less time is also spent loading and unloading the truck when properly sized and configured to accept ladders, pallets, conduit and other equipment. As volume has increased over the past few years, many integrators have developed internal processes to focus on optimizing installation. Getting installers out of the warehouse and into the field takes an effective back-end support

and training function. Using vendormanaged inventory systems helps reduce the possibility of running out of material on site, a situation that has traditionally forced construction crews to waste valuable time driving to and from part supply houses. Standardized approaches to field labour optimization have become an integral part of the residential integrator’s success. By shifting crew sizes between different projects, efficiency can be greatly maximized. It should also be noted that system integrators have become increasingly aware of safety issues as they have grown. In this light, module lifts have not only increased efficiency but also provided improved safety when it comes to transporting modules to the roof surface, especially for higher structures and steeper roofs. Needless to say, accidents drive up costs significantly in terms of insurance rates and lost time and can lower employee and management morale. Technical and safety training programs are therefore critical to keeping productivity levels up and costs down.

Figure 4. Multi-section inverters with integrated disconnects (left: SMA America; right: Fronius USA). to rails and thereby reducing labour time running long lengths of bare copper wire. These advancements in acceptable s y s t e m g ro u n d i n g h a v e b ro u g h t simplicity to installation and reduced equipment requirements. Some inverter design changes now include integrated disconnects eliminating the need to install a separate component (see inverter examples in Fig. 4). Many inverters are designed with two sections that are separable; one section contains all the electronic components, while the other contains the system wiring. When in previous years the whole inverter had to be removed and replaced in the event of failure, this was timely because the wiring had to be left in an electrically safe condition. Now, inverters can simply be unplugged and removed for shipment to manufacturers for repair or replacement. Module packaging is another i m p o r t a n t a d v a n c e m e n t c re a t i n g considerable savings in material handling time and waste disposal. Several years ago, most module manufactures utilized cardboard boxes as a form of packaging. Cardboard increased the installation time for unpacking modules, materials handling and disposal. New plasticcorner clips allow for negligible material disposal and far lower time spent on handling materials.

Balance of system components System component advancement has been another key contributor to recent cost reductions. Aside from improved racking systems, there have been major improvements in system grounding and inverter design. Ground clips are now designed to be assembled into module clamps, electrically grounding modules

Source: Wiley

Conclusions and outlook

Figure 5. Example WEEB used to bond solar modules to solar mounts.

As the PV industry continues to mature in the U.S., there will continue to be opportunities for streamlining the integration business. System costs would not be at the levels they are today and we would not have the thriving residential solar market we do were it not for the laser-focused effort on reducing system costs with respect to engineering, labour and components. From 2005 to today, the total cost for system design and installation has come down by 34% from US$0.88/ watt to US$0.58/watt. This has been achieved by making only minimal

changes to the module architecture. Improving module design by creating, for example, true plug-and-play solutions for system monitoring independent of specific modules or inverters will have a tremendous impact on total costs. Combined with continued innovation in installation and engineering efficiencies, the total cost reductions required to maintain a healthy residential market in the U.S. should be achievable despite the rapid decline of rebates.

About the Authors Angiolo Laviziano is the CEO of REC Solar and has over 10 years’ experience in the global solar market. He joined REC Solar in 2005, prior to which he was one of the founding members at Conergy AG and worked as CFO and Chief Sales Officer. Before that he worked at an investment bank in Hong Kong and at the Prime Minister’s Office of Laos. Angiolo has presented several papers in the PV field, and has a Master’s degree in business from the Koblenz School of Corporate Management in Germany and a Ph.D. degree in financial economics from the University of Hong Kong. As VP of Construction Engineering and Design at REC Solar, Ethan Miller oversees the implementation of all solar projects, including branch operations, engineering, installation and service, as well as driving the company’s expansion and product development. Since 2001, he has managed the engineering and installation of all REC Solar projects, and has a certification from the North American Board of Certified Energy Practitioners (NABCEP). He has a B.S. in mechanical engineering with a focus in renewable energy from California Polytechnic State University.

Enquiries Tel: +1 805 709 2768 Email: p.kerans@mainstreamenergy.com

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Atmospheric deposition techniques for photovoltaics

Heather A. S. Platt & Maikel F. A. M. van Hest, National Renewable Energy Laboratory, Golden, Colorado, USA

ABSTRACT With the never-ending need to reduce production costs, interest in atmospheric deposition techniques is steadily increasing. Even though atmospheric deposition is not new to photovoltaics, and in some cases is actually required to get the best cell performance, many of the fabrication processes for photovoltaic cells are vacuum-based. Due to the diversity in atmospheric deposition techniques available, there are opportunities for applications in thin film and patterned deposition. This paper discusses some of the deposition techniques and their applications, benefits and drawbacks.

Introduction Solar cell manufacturing involves a myriad of simple and complex thinfilm deposition techniques that include sputtering, evaporation, printing and chemical bath. Solid sources such as targets or powders provide the required elements and compounds to form films via the vacuum-based techniques, and there is a broad base of knowledge available for processing materials like ZnO or Mo into the appropriate precursor shapes. Vacuum-based techniques utilizing such precursors have traditionally dominated thin-film production, and steady improvements in material handling and processing conditions have led to dramatic decreases in the cost of photovoltaic-generated electricity to the current lowest prices of US$1.74/Wp for multicrystalline modules and US$1.07/ Wp for thin-film modules [1].

“Vacuum-based techniques utilizing such precursors have traditionally dominated thin-film production.” Also key to the vitally important decrease in the price of solar modules has been the more recent integration of solution-based thin-film deposition techniques like screen-printing and electro-deposition. While appropriate chemistries for the inks and baths are not fully established and often take time to develop, many of these liquid precursors are composed of low-cost materials such as water and abundant metal salts. Developing processes like aerosol jetprinting can produce patterns directly, so the inks are used efficiently and little waste is produced. Many of these techniques can also be used to deposit inks at atmospheric pressure – often simply in air, so there is no need for a vacuum chamber and the accompanying infrastructure. There are clearly some 36

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attractive aspects of solution-based thinfilm deposition techniques. We will review the atmospheric processing techniques that are already contributing to photovoltaic module production, along with other promising methods that are under development. These techniques are summarized for wafer Si and thin-film CuIn 1-x Ga x Se 2 (CIGS)-based cells in Fig. 1. The basic mechanics of each deposition methodology are described and further illustrated with specific examples and references for those interested in more details.

Direct patterning techniques Screen-printing For conventional wafer silicon photovoltaics, the most commonly-used technique to deposit contacts is screenprinting, which utilizes a woven mesh to support a mask with the desired pattern to deposit both of the contacts on the front and the back. The screen is placed in direct contact with the substrate, and paste is extruded through the screen onto the substrate. This process directly exposes the substrate to a force, which can result in breakage of the silicon wafer. Typical line widths that can be obtained are in the 100 to 125µm range; however, recent developments in screens and pastes have enabled line widths as low as 50µm [2]. Overall, screen-printing is a well-established deposition method in the photovoltaics industry. Silver pastes containing glass frit for hightemperature contact formation to silicon have been around since the 1970s. A close alternative to screen-printing is gravure printing in which the paste is transferred using a printing plate. Screen-printing can also be used for alternatives to the normal front grid contact structures, i.e. interdigitated contacts, although the highest efficiency has been obtained using vacuumbased deposition approaches. Screen-

Figure 1. Atmospheric deposition processes that have the potential to contribute to a) a standard Si solar cell, and b) a standard CIGS solar cell. The techniques already utilized in production are indicated by italicized text. printing is also used to deposit contacts on other types of photovoltaics, where the problem of breakage is limited since the substrate is either rigid, i.e. glass, or flexible, i.e. metal or plastic foil. Alternatively, screen-printing can be used to deposit films with thicknesses of several microns, i.e. CIGS or CdTe absorber layers.

Inkjet and aerosol jet printing In an effort to reduce the contact grid line width, and therefore the shadow losses, inkjet printing (Fig. 2) and aerosol jetting (Fig. 3) are being developed as noncontact replacement methods for screenprinting. In the case of inkjet printing, small droplets (1-30pL) are created in a controlled fashion within the inkjet nozzle. These droplets can be deposited onto a substrate with great precision and

Figure 2. A research multi-material inkjet system with Dimatix Spectra piezo inkjet heads mounted on a universal X-Y platform. This research system is part of the Atmospheric Processing Platform in the Process Development and Integration Laboratory at NREL [5]. reproducibility. In the case of aerosol jetting, a cloud of small droplets (~1pL) is created and then transported to a nozzle via a gas stream. In the nozzle the aerosol is surrounded by a second gas stream, which confines the aerosol so that it can be deposited in a narrow area. Droplet position is random within the deposition area. Inkjet printing can produce metal grid lines with widths of less than 25Âľm [3], and aerosol jetting can even push below 10Âľm line widths [4]. Besides the reduced shadow losses of a front metallization grid, benefits of using non-contact printing methods include thinner wafers (in the case of wafer silicon), therefore reducing the material usage. It also enables the development of alternative contact structures, i.e. doped contacts and multilayer contacts. The printing technologies permit changes to the printed pattern on the fly, which is ideal for prototyping.

Figure 4. A single crystal silicon wafer with silicon nitride anti-reflection coating and a metallization grid deposited by aerosol jet.

Figure 3. An Optomec research aerosol jet deposition system mounted on a universal X-Y platform. This research system is part of the Atmospheric Processing Platform in the Process Development and Integration Laboratory at NREL [5]. Multi-material printing systems enable deposition of interdigitated back contacts without the use of lithography. An example of a cell with aerosol-jetted contacts is shown in Fig. 4. The key to the success of non-contact printing methods in photovoltaics is the development of deposition tools with sufficient throughput and inks that work well with these systems and produce the desired material properties, i.e. conductivity, adhesion, line width, line thickness, contact resistance, etc. Both methods are under development and in their initial production testing phases. Several companies are developing noncontact printing tools for the photovoltaic industry that work at production throughput [6], while smaller tabletop printing systems for initial rapid solar cell application development are also available. Most of the screen-printing paste suppliers and some chemical companies are actively developing noncontact printable inks. The majority of metallization inks use nanoparticles as a precursor component; however, alternative inks exist that use metal organic decomposition precursors [3]. Non-contact printing methods can also be used for thin-film deposition, but their real strength is in the field of patterned deposits.

that are composed of abundant and low-cost reactants in aqueous solution. Bath-based deposition techniques have broad application, and as a result a dizzying number of variations exist. Here the focus will be on electro-, electroless, and chemical bath deposition to provide an overview of how such techniques are already contributing to photovoltaic cell production and where they may be utilized in the future.

Bath-based thin-film deposition techniques

Electroless deposition

Bath-based deposition techniques re q u i re l i t t l e u p - f ro n t e q u i p m e n t investment in that they can be carried out in almost any container that will hold liquid. In addition, many useful films and patterns can be deposited from baths

Electro-deposition In addition to the bath itself, the electrodeposition process requires an external current source [7]. This current is applied to the bath via two electrodes: the negative cathode, where positive cations migrate, and the positive anode, where negative anions collect. The most common use of this technique is to reduce metal cations to metal atoms at the cathode and thus form a coating. This cathode can be anything from a metal film or TCO-coated substrate to printed metal lines. For contact formation, electro-deposition can be used in a seed and plate approach to thicken seed lines deposited by a printing technique on a solar cell. While deposition of metals by means of this process is well established, a more recent and innovative application is the deposition of CIGS thin-film absorbers [8]. The very name of this approach provides a clear indication of the difference between this technique and its electrodeposition cousin. Instead of electrodes providing external current, chemical reducing agents are added to the bath to provide the driving force to produce

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individual metal or alloy coatings [7,9]. Not every metal or alloy can be deposited in an electroless fashion because a catalytic surface is required to drive the reduction process, so both the initial surface and the growing film must be able to fill this role. This technique can also be used to thicken previously deposited metal seed lines.

droplets. A gas flow can be used to carry this mist toward a substrate (Fig. 5). Many different spray nozzle configurations, shapes and sizes are available. Spray deposition is extensively used to deposit fluorine-doped tin oxide (FTO), a TCO commonly used in CdTe photovoltaics. In order to spray deposit FTO, a precursor solution is sprayed onto a hot substrate, and the desired material is acquired by means of pyrolysis on the surface. Due to the high temperature, this method can only be used to deposit a thin film on top of materials that can sustain such aggressive heating, such as glass.

Chemical bath deposition The compound films produced by chemical bath deposition proceed via a different mechanism than the electron-based electro- and electroless techniques. The final compound should be rather insoluble and also very stable in the typically aqueous bath, and the necessary ions must be generated slowly or the compound will simply precipitate from solution as largegrained powder [10]. The chemistry required to accomplish these stringent goals varies with the desired film, but once it is established the compound may be deposited on metals, plastics or ceramics. CdS is a widely-studied material that can be deposited via chemical bath, a technique that still produces the best quality films for buffers in CIGS solar cells [11]. CIGS layers have also been produced from chemical baths [8], and the deposition of metal oxide insulators and conductors have been widely explored [12].

Ink-based thin-film deposition techniques Deposition techniques such as screenprinting and non-contact printing can be used for the deposition of thin films, but might not be the most costeffective approach when a uniform

Figure 5. A Sono-Tek spray deposition nozzle. This nozzle is part of a research deposition system at NREL. coating is required on a large-area substrate. Alternative techniques that also have high material utilization used in production of photovoltaic devices are based on spray deposition and blade coating. Obviously, the main use for these techniques is in the deposition of thin film.

Spray coating Spray coating is a technique that can be used to deposit homogeneous films on large substrates. During spray deposition, precursor ink is pumped toward the tip of a spray nozzle, where the liquid is agitated (ultrasonically or otherwise), creating a mist of small

“During spray deposition, precursor ink is pumped toward the tip of a spray nozzle, where the liquid is agitated.” An alternative and less aggressive method using a spray-coating technique is to deposit the inks at a lower substrate temperature, and subsequently use moderate heating to drive off solvent. When using this method, in most cases, a post-deposition processing step will be required to obtain the desired material. If this processing step includes high temperatures, rapid thermal processing (RTP) can be used to keep the exposure time of underlying layers to a minimum. Spray deposition of films other than TCOs for photovoltaics is currently predominantly used on a research level, although it can be readily scaled to production-size substrates and throughput.

Blade coating

Figure 6. A Coatema easycoater with a 6” slot-die coating blade.

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Blade-coating techniques come in numerous variations, and slot die coating is one of the most widely used in photovoltaic production. In slot die coating, two metal or plastic plates with controlled spacing are used to create a small bead of liquid at the open end. The slot die is positioned in such a way that the bead touches the substrate surface but the applicator itself does not. The substrate is moved perpendicular to the opening in the slot die. Ink must be pumped through the slot die at a rate equal to the consumption at the substrate in order to get a homogeneous coating (Fig. 6). Slot die coating is extensively used in the field of organic photovoltaics as it allows for the deposition of extremely thin films (~100nm). Slot die coating is very versatile as it can also be used to deposit film with thicknesses of several µm, which makes it suitable for deposition of inorganic thin-film photovoltaics such as CIGS and CdTe. The thickness

of the deposited films is controlled by the properties of the ink, i.e., viscosity and wetability, as well as the slot die deposition parameters, i.e., substrate draw speed, slot width, slot-to-substrate distance and angle. As an alternative to slot die coating, knife coating can be used. Knife coating is less suitable for some applications since it is a contact deposition method, whereas slot die coating is a non-contact method.

Spin coating Like the other ink-based thin-film deposition techniques, spin coating starts with liquid ink containing carefully chosen components. This ink is applied to the substrate, and the substrate is rotated rapidly. Solvent is lost as the ink flows radially outward and thins, which increases the concentration of the remaining solids and the overall viscosity of the ink [13]. Ultimately, the ink viscosity reaches a critical point and the final solid film forms, although in many cases postdeposition heat treatment is required to decompose undesirable components. Spin coating was developed to d e p o s i t o r g a n i c p h o t o re s i s t s f o r patterning electronic components, and it is a favourite technique of the organic photovoltaics research community for depositing conducting or semiconducting polymers. Inorganic material scientists have also developed inks that can be spin coated to deposit high-quality films of materials such as ZnO [14] and CIGS [15]. While this technique is quite versatile and useful for small-scale precursor ink development, it may not be the best choice for the large-scale manufacturing regime where fast processing and high throughput are required.

Conclusions We have reviewed atmospheric thin-film deposition techniques that are already used in solar cell production, such as screen-printing, electro-deposition, and chemical bath deposition, as well as other techniques that are under development for future use. Many of these methods are simple enough that they can be implemented rapidly with low capital investment, although development of precursor inks is not always as straightforward. An excellent overview of chemical strategies for preparing such solutions for inorganic materials is available in a recent publication [16]. The ultimate goal of any efforts made toward precursor development and thinfilm or pattern deposition is to decrease cost, and based on this criterion the atmospheric processing techniques described here are not equivalent. While low up-front equipment costs are attractive, materials utilization over the lifetime of a manufacturing plant will have a more significant impact on the final

module cost. Spray and slot die coaters are able to deposit the majority of their inks as blanket-coated films, and the various printing techniques discussed utilize an even greater percentage of the precursor solution to create thinfilm patterns. By contrast, bath-based techniques convert a small fraction of the initial solution into thin films or lines. The photovoltaics community will undoubtedly continue to develop innovative approaches to reducing the cost of solar cells, and atmospheric techniques will play their part along with more traditional vacuum-based thin-film deposition methods. While it cannot be predicted which atmospheric processing techniques will gain wide acceptance within the industry, we are confident that at least some of them will provide stepping-stones toward the goal of grid parity.

References [1] Solarbuzz, “July 2010 Retail Price Survey”, [available online at http:// www.solarbuzz.com/]. [2] Essemtec press release May 3rd 2010, “Micro Structures with Nano Pastes”, [available online at http://www.essemtec.com/news. asp?id=10353]. [3] v a n H e s t , M . F. A . M . e t a l . 2008, “Direct-Write Contacts: Metallization and Contact Formation”, Proc. 33rd IEEE PVSC, San Diego, California. [4] Aerosol jet applications [available online at http://www.optomec.com/ site/aerosol_jet_home]. [5] Atmospheric processing platform capabilities [available online at http://www.nrel.gov/pv/pdil/ap_ capabilities.html]. [6] C h u n d u r i , S . K . 2 0 1 0 , “ J e t Speed, High Accuracy”, Photon International, Vol. 1, pp. 110-121. [7] L o w e n h e i m , F. A . 1 9 7 8 , El e c t r o p l a t i n g : F u n d a m e n t a l s of Surface Finishing, New York: McGraw-Hill. [8] Hibberd, C.J. et al. 2009, “Nonvacuum methods for formation of Cu(In, Ga)(Se, S)2 thin film photovoltaic absorbers”, Progress in Photovoltaics: Research and Applications, [Early view – available online at http://www3.interscience. wiley.com/jour nal/122607261/ abstract]. [9] Shacham-Diamand, Y. & Sverdlov, Y. 2 0 0 0 , “ E l e c t r o c h e m i c a l l y deposited thin film alloys for ULSI and MEMS applications”, Microelectronic Engineering, Vol. 50, pp. 525-531. [10] Hodes, G. 2003, Chemical Solution Deposition of Semiconductor Films, New York: Marcel Dekker, Inc. [11] Bhattacharya, R. 2009, “Chemical Bath Deposition, Electrodeposition, and Electroless Deposition of

Semiconductors, Superconductors, and Oxide Materials”, in Solution Processing of Inorganic Materials, D.B. Mitzi (ed.), Hoboken, New Jersey: John Wiley & Sons, Inc. [12] Hodes, G. 2007, “Semiconductor and ceramic nanoparticle films deposited by chemical bath deposition”, Physical Chemistry Chemical Physics, Vol. 9, pp. 21812196. [13] M e y e r h o f e r , D. 1978, “Characteristics of resist films produced by spinning”, Journal of Applied Physics, Vol. 49, pp. 39933997. [14] Meyers, S.T. et al. 2008, “Aqueous Inorganic Inks for Low-Temperature Fabrication of ZnO TFTs”, Journal of the American Chemical Society, Vol. 130, pp. 17603-17609. [15] M i t z i , D . B . 2 0 0 9 , “ S o l u t i o n P ro c e s s i n g o f C h a l c o g e n i d e Semiconductors via Dimensional Reduction”, Advanced Materials, Vol. 21, pp. 3141-3158. [16] Solution Processing of Inorganic Materials, D.B. Mitzi (ed.), Hoboken, New Jersey: John Wiley & Sons, Inc.

About the Authors Dr. Heather Platt studied the solution deposition of metal oxide thin films during her Ph.D. work with Prof. Douglas Keszler at Oregon State University. She is now developing inks to deposit metal films and lines on silicon wafers for photovoltaic cells at the National Renewable Energy Laboratory (NREL). She is extensively using direct-write deposition, spray deposition and RTP. Dr. Maikel van Hest is currently a senior scientist in the process technology and advanced concepts group in the National Center for Photovoltaics at NREL. His principal areas of research and expertise include: solution-processing for silicon and thin-film solar cell application, vacuum deposition and transparent conductive oxides. His current work focuses on the development and basic science of solution-deposited materials (metals, CIGS, CdTe and TCOs) and the development of next-generation process technology for materials and device development (direct write deposition, spray deposition and RTP).

Enquiries Maikel van Hest, Ph.D. National Renewable Energy Laboratory 1617 Cole Blvd. Golden CO 80401-3393 USA Tel: +1 303 384 6651 Fax: +1 303 384 6430 Email: maikel.van.hest@nrel.gov Web: http://www.nrel.gov/pv/pdil/ap_ capabilities.html

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Scaling up to Eclipse “Quite simply, the most versatile, best-designed metallization solution for the solar industry today” Anybody active in solar cell manufacturing today knows that repeatable printing precision is key to cell efficiency. This is because the silver energy-collecting conductors that are typically screen printed onto the frontside of a silicon-based solar cell actually block out sunlight, effectively stopping it from reaching the energy converting strata below. While it is important that these conductors are optimally distributed across the surface of the cell in order to mop up all the energy available, it is clear that the more surface area they cover, the more they will hinder cell functionality. This is why the solar industry is putting so much effort into reducing conductor widths. Currently in the region of 100-120μm, these are expected to drop to 50-60µm in the immediate future, reducing the shadow effect and improving cell performances considerably while saving on materials costs. Achieving repeatable accuracy requires a wealth of experience in process control and design. And this is where companies like DEK Solar come in. DEK has built repeatable accuracy into its systems ever since it opened for business 40 years ago. Now, with decades of expertise in designing and supplying advanced printing technologies for demanding industries like solar, electronics manufacture and the semiconductor sector, DEK offers printing platforms that are rated among the highest in the solar energy industry for their process control capabilities.

Modular scalability

Now, with Eclipse, its newly-enhanced cell metallization solution, DEK ups the ante still further. With multiple print heads that operate in parallel, Eclipse gives manufacturers top print speeds of up to 600mm/sec. This means throughputs of up to 3600 wafers per hour (wph) in an industry where the standard was 1200.

The great advantages of the system’s multiple heads include the fact that overall throughput can be increased even though each individual wafer is in fact processed at slower, more gentle speeds (1200 wph), maintaining DEK’s industry-leading levels of repeatable accuracy as well as ensuring that the wafers maintain their integrity throughout the print process and later, in the field. This is thanks to DEK’s advanced handling technology that treats the fragile silicon wafers with extreme care, while its state-ofthe-art vision alignment capabilities ensure high-speed, highprecision non-aggressive alignment to within just microns. Furthermore, multiple heads mean that the line does not stop if one head halts for operator attention – the others continue to operate during maintenance or set-up. Equally important in our fast-growing industry, where factory space is at a premium, DEK’s leading-edge printing capabilities come in an extremely compact package, offering cell manufacturers industry-beating capabilities on the smallest footprints available. But perhaps the most compelling aspect of Eclipse is the fact that it has been designed with change very much in mind. That’s because one of the most certain things about life and business is precisely that nothing is certain: we know where we are today, and we must of course plan for tomorrow, but who knows what is really round the corner? That’s especially true in an industry

Eclipse scalable metallization line.

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that is as dynamic as the solar industry. Today’s manufacturers know that their future success lies in being ready to embrace and run with changing circumstances, be they new market demands, technologies, customer locations, government policy or any of the myriad factors that impact the solar industry. Recognising this, DEK Solar has developed a solution that can be reconfigured on an ongoing basis according to budgetary and production needs. After all, why should a manufacturer invest in equipment before it is really necessary? With its new configurable design concept, Eclipse enables manufacturers to scale production up or down, to 1200, 2400 or 3600 wph, easily and simply. For those manufacturers who foresee this sort of production ramp, the metallization line can be designed accordingly, by inserting blank process modules equipped with conveyors where future production volumes will be added in. When the time is right to add in throughput volume, these blanks can simply be swapped out for additional print capacity. This saves the manufacturer from having to reconfigure the entire line to accomodate the extra modules, and makes the scaling process relatively simple, fast and cost effective. The primary process modules, including the print heads and unloader, incorporate master controls and are designated as master units. Additional process modules, which can be retrofitted in the client’s facility, operate as secondary “slaves”, hooking up to the master control units in the primary modules. By eliminating the cost of additional control units, DEK effectively makes the scale-up process even more cost effective. This unique approach to manufacturing configurability satisfies the demands of even the most progressive solar cell manufacturers, allowing them to protect their initial investments into the future, no matter how unclear that future may be, and enabling them to build their capabilities as their needs grow, with a selection of capabilities that make Eclipse quite simply the most versatile, best-designed metallization solution for the solar industry today. The advantages of Eclipse combine powerfully with DEK’s own manufacturing philosophy. Based on lean, extremely flexible approaches such as Kanban, this allows DEK to share common

cross-industry equipment platforms to keep production costs to a minimum while reducing turnaround times from months to weeks. Furthermore, with manufacturing facilities in Europe and China, and a global support infrastructure that places technical expertise and spare parts close to its customers wherever they may be, DEK is a true leader and a truly global technology partner. And this, combined with DEK’s foresight, its clear vision and its highly credible roadmap, is invaluable in enabling DEK’s customers to move swiftly and seamlessly with their changing circumstances. Once again, with Eclipse, DEK demonstrates that it is ahead of the field in terms of innovation, vision, and its deep understanding of the needs of its customers and of the solar cell manufacturing sector in general.

Visit the DEK Solar booth at Solar Power International, LA, Booth #853 www.deksolar.com

Photovoltaics Inter national

Expectations for the UK solar market

Emma Hughes, News & Features Editor, Photovoltaics International

ABSTRACT On April 1st 2010, the UK government’s Department of Energy and Climate Change (DECC) officially launched its renewable energy policy. The document includes the Carbon Reduction Commitment Energy Efficiency Scheme (CRC EES), designed to improve public and private sector organizations’ energy efficiency; and the generous feedin tariff (FiT) incentive, which pays 41.3p/kWh of solar photovoltaic energy generated. This article will look at the expectations for the UK solar photovoltaics market following the government’s policy launch. The paper will focus on the impact of the UK’s late arrival to the renewable energy market; why the FiT is so incremental for successful growth; what the expectations are for the development of the UK solar PV market as well as an investigation into whether the UK is really ready for this level of change.

Householders who install small-scale solar panel systems in the UK are now eligible to receive up to £1,000 a year – tax-free for 25 years – for the electricity they generate under the new government Clean Energy Cashback scheme, known more widely as the feed-in tariff. Government figures reveal that any UK resident who installs a typical 2.5kW PV system at their existing residence will initially be paid 41.3p per kWh generated [1]. Former Energy and Climate Change Secretary Ed Miliband outlined that such a set-up would result in a reward of up to £900 in the first year on top of a £140-a-year saving on energy bills (UK elections have taken place since this paper was penned). This policy was long awaited in the UK, as its residents became more aware of neighbouring European countries’ renewable energy success. However, the optimistic figures released by the government have been met with a great deal of uncertainty coupled with a severe lack of education in the sector. It remains to be seen just how successful the UK solar photovoltaics market will be, considering its infancy.

The UK feed-in tariff The generous financial incentive that is the UK feed-in tariff has set the market off to a good start. Its 41.3p/kWh rate is high enough to really push the investment in solar energy in the country. But who is really going to benefit from this incentive? The initial costs – an average installation spend of £8,000£12,000 – are simply too high for the average citizen to afford. The £8,000-£12,000 payout secures the customer full installation – including the site assessment, the modules, the inverter and the installer’s charge, yet this is still a large sum to pay out upfront. The varying issues and concerns surrounding this aspect of the market will be discussed later. The Department of Energy and Climate Change (DECC) claims that this initial 42

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Courtesy of Solarcentury.com

Introduction

Figure 1. C21e and C21t tiles installed on South Yorkshire Housing Association houses in Rotherham, England. cost is justified by the rate of return on investment (ROI), which it claims is 5-8% on a well-sited 2.5kW installation [2]. It also claims that a UK solar generator could ear n up to £1,000 a year, meaning that their initial costs would be earned back in a maximum of 12 years. Considering that a solar system usually has a lifetime of 25 years, the owner then earns up to £1,000 a year for an extra 13 years, marking an estimated profit of £13,000.

Size matters Since releasing the FiT policy guidelines, the DECC has faced the question of who can actually afford to install solar power systems, as the high expense of installation prevents solar from being available to the masses. A spokesperson at the DECC was quick to assure us that low-interest finance options will soon be available to cover these costs: “There are already signs that the finance market is looking to develop products in this area so that future FiT revenues can be used to pay off upfront loans.” UK installer Solarcentury has reported a fourfold increase in sales enquiries since the FiT was initially announced in February. Thus, supposing the funds are available, the UK residential market

looks set for moderate growth. But there is a problem. In the case of solar installations, size does indeed matter. Many UK residents’ homes may not have a well-positioned south-facing roof; furthermore, in the event that a resident does have such a roof, it may not be large enough to house the 2.5kW system required for the full ROI. In this case, they will not earn the full payback, and may even lose out on their investment altogether. Taking this into account, it looks as though the residential market will see success, but it may take a while to get going. However, one aspect of the solar market that looks set to experience growth is the farming sector. Given the large building sizes on most farms in the country, UK farmers are almost guaranteed to receive the ROI that has been quoted in all of the DECC documents. There is already evidence that the solar farmland market is beginning to pick up. Jonathan Scurlock, Chief Adviser, Renewable Energy and Climate Change at the National Farmers’ Union, sees the potential for this market: “For many farmers and landowners, it now makes environmental and financial sense to consider installing solar PV on farm

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buildings.” Scurlock agrees that farm buildings present a perfect opportunity for the installation of PV, and that it is most likely that the FiT will indeed drive the expected uptake. “Introduction of feed-in tariffs has resulted in a flood of interest in on-farm generation from farmers and technology providers, and substantial growth in an infant UK industry can be expected over the next five years,” he says. However, while Scurlock has already seen a great amount of interest from farmers in PV, he also admits that there is a lack of education in connection with the policy, explaining, “Some details of guidance are still lacking for applicants to the scheme.”

Following the leader Residential and farm building figures are reminiscent of the solar success of solar market-leader Germany. The early indications for the UK market – highlighting a fairly successful residential market and an even more successful farm building installation rate – draw parallels with the fully established German market. Dr Henning Wicht, iSuppli’s Senior Director and Principal Solar Analyst, says that 40% of the PV installations in Germany are residential and two-thirds of the 50% commercial rooftop installations in the country are on farm buildings. Wicht predicts that the UK market will mirror the success in Germany due to this striking similarity.

Supply and demand Modules

attractive option, as there is currently nothing else available on the UK market. Secondly, inverters have an average expected lifetime of 10 years. This is reflected in the product warranty, which on average is between five and 10 years. Based on the 25-year average life expectancy of PV modules, the customer could potentially be faced with having to replace the system inverter twice, costing well into the thousands of pounds on top of the initial £8,000£12,000 already spent. Such a scenario has to be considered when calculating the ROI, potentially extending the time it takes to earn back the initial expense. This becomes all the more aggravating when one considers the prices across Europe in countries such as Germany and Italy, which are significantly lower in comparison to the pound sterling. Due to the current lack of knowledge on these products in the UK, most installers and customers will be unaware of this price comparison.

Inverters In the UK, at the moment there is really only one inverter option widely available – the Fronius inverter. Fronius is not a market leader, yet it is charging a premium price for its inverters for use in the UK. Typically, a Fronius inverter will cost anywhere between £1,170 and £17,100 for systems ranging from 1,300Wp to 40kWp. Considering that this price is included in the initial installation expenditure, it is quite reasonable. There are, however, two other factors at play here. Firstly, the conversion efficiency loss of Fronius inverters is approximately 4-5%. If we compare this inverter with one of the market leaders, such as SMA’s Sunny Boy range, one notices that the price and conversion efficiency loss are not necessarily in synch. The Sunny Boy has a conversion efficiency loss of 2%, making it far more efficient than the Fronius model. The pricing of the SMA inverters (which are certified for use in the UK but not widely available) is around £800-£1,700. In comparison, the SMA option seems preferable, being cheaper as well as more efficient, but UK customers are being railroaded into buying the less

When the price is right

Courtesy of Sundog Energy Ltd.

N o t l o n g a f t e r t h e g o v e r n m e n t ’s passing of the UK FiT rates, there is an unfortunate shortage of top brand solar equipment. In the case of solar photovoltaic modules, there are two options: cheaper, less efficient modules, or over-inflated high efficiency modules. However, the choice of which product to use usually lies with the installer rather than the customer. If the installer arrives

with low-cost, low efficiency modules, such as the 170W Yingli modules offered by one installer in the UK, the system is unlikely to be any bigger than 1.2kW based on the average size of UK residents’ roofs. The customer will then have a system installed which is unlikely to ever earn them back the £8,000£10,000 they will have paid out initially. Yet if the installer opts for the expensive high efficiency modules, such as BP Solar’s range, or the Sanyo HIT module, one can expect to pay the very high-end price for the whole installation, costing £12,000 and approximately £6/W. This, according to iSuppli, is 50% more than customers in Germany pay for exactly the same products.

Figure 3. Integrated solar PV on a new build domestic home in south Scotland.

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It is necessary at this stage to consider why the products available in the UK are so limited, and why the prices of these products are so inflated in comparison to the more successful European markets. Many European PV leaders, including France, Italy and most significantly Germany, will experience cuts to their FiT rates in 2010. For Germany, the cuts will take effect from July 1st, meaning that the market at present is booming as projects are installed while the incentives are high. The UK market is being further impacted as global inverter and module suppliers try to meet demand for their products as a result of this market boom. On one hand, the UK has launched its financial incentives at the worst possible time, as the German market hits its peak and installations are plentiful. High quality products can be sold at low prices, as the demand is certain. For the UK, distributors are still unsure of the market’s stability, and so will charge the maximum for their products, and only supply what is not needed throughout Europe. On the other hand, this could be a positive start for the UK market. Since the UK is only a few months into benefiting from financial incentives for the installation of solar PV, a rush to install at this point is not expected. As the July 1st deadline was passed for Germany, it can be predicted that installations in Europe will slow down, quite possibly by a significant amount. As this decrease starts to take effect, the manufacturers – and, of course, the installers – working in Germany will begin to turn their focus onto the UK market. By this point, the country should be more aware of the FiT incentives available, and indeed more educated in the workings of the technology needed in the UK in order to promote success.

Courtesy of Sundog Energy Ltd.

Figure 4. Integrated solar PV retrofit on a home near York, England.

Light at the end of the tunnel Even with some uncertainty surrounding the UK solar market, expectations for its success are high. Ash Sharma, Research Director and Report Analyst at IMS Research, predicts that the UK’s feedin tariff will significantly accelerate the market, regardless of product availability and price. “Quite simply, the UK PV market will not grow to any substantial volume without large subsidies. The low insolation levels and high PV system prices would prevent any major uptake in the UK,” said Sharma. He foresees that the UK could see 40-60MW of installed PV in 2010, in comparison with the 5MW installed in 2009 when there was no FiT available. “From a demand point of view, I think UK consumers and investors are generally quite savvy and the FiT will be viewed very favourably. Many in the country invest heavily in property and the average age of a house-buyer in the UK is much lower than countries like Germany – [those in the UK] like investing money in property and adding PV systems will be an extension to this.” Although Sharma is optimistic about the growth of the UK market, predicting that 150MW of installations is achievable by 2011, he does recognize that the lack of inverters available could slow its progress. But despite this potential pitfall, IMS Research’s widespread study of other markets makes him confident that the UK’s solar growth will soon accelerate as he has seen the evidence of how the dynamics can change rapidly once full government support is given. “All indications in the medium term are positive: the FiT is reasonably generous and supports systems up to 5MW. And although the UK is not the sunniest country in Europe, it does have a reasonable amount of free roof-space and an appetite for investment,” he said. Independent solar expert Michael Pitcher from BFC Solutions, an associate

consultancy, also acknowledges the potential of the UK solar market. “Countries like Germany and Belgium have embraced PV and are already reaping the rewards, but solar panels perform very well in the British climate so there’s no reason why the UK shouldn’t also harness the benefits of solar energy,” he said. Energy companies such as npower and E.ON have also begun to show optimism for the future of the solar photovoltaics market. By May 1st, one month after the FiT took effect, npower was already seeing an 80% increase in customer interest in solar energy. Louisa Gilchrist, solar expert for npower, said, “It’s fantastic to see feed-in tariffs generating so much interest with homeowners and the scheme should be applauded for energizing the solar industry in the UK.” E.ON has also released positive feedback from customers in connection with the use of solar energy; however, the company also recognizes that many UK customers need assistance when choosing to install a PV system, due to the lack of knowledge on the products, installers and information available. As a result, E.ON launched the SolarSavers scheme, which provides a one-stopshop service for installing and generating solar power. Andrew Barrow at E.ON said, “Now that the UK is working to cut its CO 2 emissions down, we think it is important to offer residents the opportunity to be a part of this themselves.” Energy regulator Ofgem has also just released the first official set of figures [3] relating to the growth of the UK solar market. These figures reveal that 11.266MW of solar photovoltaics have been installed since April 1st (for the period ending August 3rd 2010). From April 1st, there were 409 PV installations in total (0.979MW); for the same period in May they reached 942 (2.290MW); in June, 1,406 (3.524MW), and by July the figures had climbed to 1,753 (4.592MW). This progressive growth is also good news for the future of solar in the UK.

Ignorance is not bliss All things considered, there is still this recurring theme of education, or indeed the lack thereof. At present, there is a severe gap in awareness of the subsidies available, of what products should be used and how they should be installed. The lack of education does not lie solely with the customer, but also with

the installers. This is something that will have to change dramatically before the market is able to progress into a noteworthy league. Sharma reinforces this point: “This will be one of the key restraints for the UK market. A great deal of education will be needed to allow the market to develop. It is also likely that a number of integrators from Europe will set up subsidiaries in the UK to target this market.” The migration of experienced European PV companies is highly likely as the majority of installers currently working in the UK are not PV specialists. While this is not a criticism of the UK installers, as the market was not nearly large enough to warrant UK-based s p e c i a l i z e d i n s t a l l e r s b e f o re t h e introduction of the FiT, it will be a great benefit to the market if experienced PV companies begin to move into the country, setting up subsidiaries in order to accelerate the uptake.

Conclusion The UK photovoltaics market certainly has some obstacles to overcome before it matures. While the country was late in receiving its FiT policy, this incentive is now set to drive the market forward in 2010. Its generous payback, combined with further gover nment financial support, will significantly increase the amount of PV uptake in the UK. While there is a lack of product availability in the country, there are positive signs of improvement, as European suppliers start to focus on the UK’s growing market, and foreign installers begin work in the country. Industry professionals predict a drop in product cost and an increase in product availability, and also foresee that an emphasis on customer as well as company education will occur within the coming months. The significant parallels with market-leader Germany only reinforce the experts’ predication that the UK solar market is set for success.

References [1] Department of Energy and Climate Change (DECC) report [available online at: http://www.decc.gov.uk/ en/content/cms/news/pn10_010/ pn10_010.aspx]. [2] ‘ T h e U K R e n e w a b l e E n e r g y Strategy 2009’, Department of Energy & Climate Change. [3] Ofgem Public Report V iewer [available online at http://www. renewablesandchp.ofgem.gov.uk].

Solar Power UK Conference 2010 is the first official event of the Solar Power Group, the voice of the Solar Power industry in the UK. The conference theme, “Enabling the UK Solar Market for 2011,” will focus on challenges of supply, cost and the rapid growth in demand for solar in the UK. Speakers include Alan Whitehead MP, leader of the PRASEG initiative; Rob Jarman, director at the National Trust; Ray Noble of the REA and Nigel Fox from the National Grid. An exclusive Gala Networking Dinner sponsored by Trina Solar will be held as an accompanying event to the conference, thus opening the opportunity for further networking and business development in an elite environment.

Don’t miss this solar PV highlight of 2010 for the UK market!

Photovoltaics Inter national

U.S. solar PV market – an overview

Joseph CG Eisenberg, Renewable Analytics, San Francisco, California, USA

ABSTRACT The U.S. solar PV market is suffering not from a lack of demand or high prices, but rather from an inconsistent labyrinth of rules and regulations which complicate and prolong uptake. There is significant pent-up demand in the U.S. among developers and especially manufacturers; there is not, however, a commensurate regulatory framework that will enable and encourage this demand to be realized. The U.S. political landscape is deeply divided, and policies that would directly or indirectly effect solar demand are no different from any other in this regard.

T h e re i s m a j o r o p t i m i s m a m o n g dealers, installers, and module makers who hope the U.S. will contribute significantly to 2011 global demand and shipments, and thus help absorb the ~70% increase in capacity coming on line and decelerating growth in Europe, bolstering prices. Renewable Analytics’ survey of North American dealers and installers demonstrates a dramatic increase in 2011 expectations. In July of this year, dealers and installers reported an average expected year-over-year increase in shipments of 111%. However, the sentiments expressed to Renewable Analytics have led the company to take a cautious assessment of 2011 prospects.

California Renewable Analytics reiterates the importance of the upcoming California gubernatorial election. Republican Meg Whitman seeks to suspend the state’s landmark 33% by 2020 renewable portfolio standard. Pro-renewable energy Democratic gubernatorial candidate Jerry Brown vs. this pro-austerity candidate Meg Whitman should be seen as a pivotal election. When module pricing falls to ~US$1.20/W (or possibly lower in the U.S.) by mid-2011, grid-parity will be approached in the sunnier areas of

California, Arizona and a few other states. It is unlikely that policy will catch up by then. The California legislature passed Senate Bill 32 last year, which provides for a feed-in tariff. However, the legislature left its implementation to the California Public Utilities Commission (CPUC), a very powerful utilities regulator. The CPUC, despite supposed independence, is largely influenced by utility companies and other interests, and has been known to time important decisions around the legislative agenda or elections. We expect the future of SB32 to be more apparent after the results of the November 2 election. In addition, an administrative law judge at the CPUC recently recommended a “Renewable Auction Mechanism,” which is effectively a reverse auction feed-in tariff. Projects 1-20MW in size would be allocated a total of 1GW through 201112, with 250MW allocated each 180 days. Only investor-owned utilities PG&E, SCE and SDG&E would be required to buy power under the plan. The mechanics are still being worked out. Proposition 23 will also be on the California ballot. Prop. 23, which is sponsored in large part by the oil and gas industry, would nullify the innovative Assembly Bill 32, passed in 2006,

120% 111% 100%

65% 60%

40%

20%

0% 2010 vs 2009

2011 vs 2010

Figure 1. Expected industry market growth in % shipped.

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New Jersey T h e s t a t e ’s re n e w a b l e p o r t f o l i o standard, which is set at 8.3% for 2011, moving to 22.5% by 2021, includes a specific carve-out for nonhydro renewables and within that, there is a further solar-specific carveout. Utilities must generate 306GWh of solar electricity in 2011, moving to 2.52TWh by 2021, and 5.3TWh by 2026. To accomplish this, the state has established its Solar Renewable Energy Credits program, which has contributed to significant demand growth, making NJ the east-coast leader. Utilities submit SRECs to the state, representing a certain portion of requisite solar PV generation. If a utility is not able to fulfill its requirement, it must pay a Solar Alternative Compliance Payment – essentially, fines with prices set by the Board of Public Utilities – or purchase SRECs on the open market from other utilities that have generated excess credits. Given data available from the state, RA estimates January–July 2010 SREC prices to be on average US$583/ MWh, compared to the US$693/MWh cost of SACPs set by the BPU.

Federal

80%

that requires California to reduce its greenhouse gas emissions to 1990 levels by 2020. Given that California is the world’s eighth largest economy and a forerunner of national environmental policies, this is a critical measure that, if approved by voters, would be a significant national setback.

W ith Republicans poised to make significant gains in the House and p o s s i b l y S e n a t e i n N o v e m b e r, a federal game-changing energy bill seems unlikely in the near future. US Senate Energy and Natural Resources Committee Chairman Jeff Bingaman (D-NM) said at a Reuters summit in Washington on September 22: “I’d be surprised if that kind [requiring national greenhouse gas reductions] of a comprehensive climate and energy bill could pass both houses of Congress in the next Congress, since they’ve been unable to pass in this Congress...”

Growth is extremely rapid

4.3

4.3 4.0

Growing rapidly, very promising

Feb-10

Developing, moderate pace

Mar-10 Apr-10

Very slow

May-10 Jul-10

Declining

Average of all other 17 states and provinces -2.8

California

New Jersey

Ontario

Figure 2. Market growth by state (California, Ontario & New Jersey). In late August, U.S. Vice President Joe Biden issued a memorandum regarding the success of the federal stimulus toward the “Transformation to a Clean Energy Economy.” It states: “… we are increasing our capacity to make the wind turbines, solar panels and other renewable energy components here in America. Recovery Act investments of up to US$2.3b for advanced energy manufacturing [puts the US on track to] double our capacity to manufacture these components by 2012 [and on track to meet] the goal of doubling our renewable energy generation, including solar, wind and geothermal, in just 3 years.” To achieve this, the administration must press for renewal of the Specified Energy Property in Lieu of Credits law that allows the Treasury to issue cash grants in-lieu of the 30% Investment Tax Credit. Most developers or companies that stand to benefit from the 30% tax credit do not have a sufficient tax liability for the credit to meaningfully add to returns, which is why the grant program is so critical. It will expire at the end of 2010, unless renewed. A recently introduced bill – which has not yet passed – would see the ITC be considered as tax paid, rather than a credit, and thus subject to a refund in the future, but would not extend cash grants. On September 22, Sen. Bingaman also introduced a bill requiring a 15% by 2021 national renewable portfolio standard, with 11% from renewables, and 4% from energy efficiency improvements. Sen. Bingaman expressed optimism that this bill, unlike a comprehensive one, may stand a

chance of passing. While encouraging, it does not address the fundamental lack of a uniform and efficient national system for solar PV uptake. This adds to the importance of California AB 32.Unsurprisingly, RA’s survey of North American dealers and installers lists California, New Jersey and Ontario among the most promising markets.

Outlook RA has received input from several largescale solar investors that suggests that lead-times required to realize a project in the U.S. are significantly underestimated. According to Hans Isern, Vice President of Engineering for Silverado Power, a leading US-based utility-scale PV developer: “Despite regulatory efforts to streamline the interconnection process in California, there is still a significant backlog of about 35GW of renewable capacity, much of which is unlikely to be built. For new projects seeking interconnection, study processes can be lengthy, with timeframes exceeding 420 days for small projects (<20MW) and 1000 days for large (>20MW). Combined with potentially expensive upgrades to the power grid, this can be a major risk for new solar projects’ development schedules and budgets.” The most substantial inhibitor to the solar growth the U.S. may be environmental and transmission issues. Permitting and regulations are fragmented and non-uniform – an installation requires myriad approvals from various local, state, and federal agencies, which adds to costs and delays. There is no streamlined process

or guaranteed buyer of electricity. Part and parcel with this, installers note a lack of experience in setting up new operations, understanding local requirements, and a general public unfamiliarity with challenges to growth. Developers have indicated that there are few companies that really understand how to navigate the largescale process, and notably, not many European companies – which could bring immediate scale to the business – understand the process. Overall, RA expects the U.S. to take longer than expected to be a primary global PV driver. The country is philosophically gridlocked at many levels and renewable energy is part of the fold. Political and regulatory signals are mixed and will take time to settle and mature. It is important to approach claims that U.S. allocation will substantially buoy demand, and thus global pricing in 2011, with a healthy skepticism.

About the Authors Renewable Analytics LLC is an industry research firm formed to address the underserved need for objective and timely supply chain research in the solar photovoltaic industry. Almost all of the research available in the market today is either investment banking-driven or tends to focus on broad themes and long-term trends. The founding team of Renewable Analytics has more than 20 years of combined relevant experience, including management in the solar industry, technology supply chain research, and fundamental analysis. Renewable Analytics conducts its research via typical channel checks, c o m b i n e d w i t h m o re s y s t e m a t i c surveys. Research reports track the changes in the variables that impact growth and profitability including but not limited to: end customer and market demand per country, subsidies in each country, pricing of silicon and other key components, cell equipment utilization rates, solar equipment shipments, technology transitions, foreign exchange and interest rates.

Enquiries Renewable Analytics LLC 268 Bush Street, #500 San Francisco CA 94104 USA

Photovoltaics Inter national

The PV-Tech Blog By Tom Cheyney

Local content: Heliene starts moduling operations at Ontario plant, but exports dominate order book

Image courtesy of Heliene.

No sooner had the “local content” provision of Ontario’s solar power feed-in tariff been announced than a steady stream of PV module, inverter, and other balance-of-system players said they would build manufacturing sites in the province to take advantage of the lucrative incentives. The fun really begins in January 2011, when the FiT rules will stipulate increased local content and significantly ratchet up the clamor for homegrown panels. In a new study released by ClearSky Advisors, the market research firm says that demand for “bankable” panels will exceed the estimated 386MW in production capacity due to come online in Ontario next year, which might trigger some project delays and premium pricing. Yet Heliene, one of those numerous companies getting into the locally-made module game, actually has a majority of its order book going to customers outside the province. I first spoke with Martin Pochtaruk, president of the Sault-Ste. Marie-based venture, in late February, when he was waiting for the weather to warm up and construction of the 18,000-squarefoot purpose-built facility to be completed. At the time, he told me of the plan to “get access to the finished building by the beginning of July,” with the equipment to be set up and tested at Heliene’s sister company in Spain and final installation coming in early August. The plan then was for the first modules shipping out to Ontario first, and then to the U.S. Midwest, by the end of August, beginning of September.

As it turns out, they’ve come close to hitting that schedule, running only a month or so behind the initial timeline. When I spoke to Pochtaruk in mid-September, he said that most of the equipment was in the factory, with the last few pieces arriving soon and his first group of employees returning back to Ontario from two weeks of training in Spain. Manufacturing for sales began in late September, with plans to be fully ramped, running four shifts 24/7 by January. But the initial IEC/UL-certified crystalline-silicon modules coming off the line will not be delivered to a customer in Ontario. “That’s a funny thing,” he said. “Our first client is a company in Saskatchewan. We have orders for export for October and November,” citing bookings from firms in the Midwest U.S. and Europe, specifically Italy and Greece. In fact, for the next quarter or so, less than half of the orders have come from Ontarian outfits, according to Heliene’s president. The company isn’t targeting any specific market sector. Pochtaruk characterizes his downstream channel partners and

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customers as “a group of installers with orders of 200-250kW per order, small utility-scale clients ordering 3-5MW per order, and distributors with recurrent volumes of 200-300kW per month on a yearly contract,” adding that the factory is sold out for several months. Because of improvements in manufacturing productivity, the moduling facility now boasts a 50MW nameplate capacity, up from the originally announced 30MW. He attributed this improved production cycle to some changes in the automation approach in the lamination section of the factory floor, with each of the six laminators processing nearly twice as many panels because of the addition of load/unload tables and doubletasking robots. Another enhancement involves a new handling tool, which takes the still-hot laminated panel up, elevator style, into a vertical tower for cooldown (thus increasing the cooling capacity without taking up more floor space) before transferring it to the flash tester, he said. Capacity could be increased to 80MW by adding a third soldering machine, although “that will depend on market conditions. If we see the market calling for the product, we’ll add the tool and increase capacity,” explained the pragmatic executive. “We have a cautious startup ramp, because the equipment is new, the building is new, the employees are new, everything is new. It makes it very sparkly,” he laughed, “but you need to be cautious not to overstretch.” There’s enough space for three full production lines, so the factory could eventually grow to 240MW, if all the capacityenhancing improvements were implemented. The plant will manufacture both multi- and monocrystalline modules, split about 25:75 respectively between the two product lines. Heliene has contracted three mono-cSi cell suppliers for 2011 – Suniva, Arise, and Bosch – and one multicSi vendor, Sunways. Pochtaruk also indicated that SaintGobain supplies the glass for the panels, and STR provides its EVA encapsulant materials. The production gear, except for the flash tester, has been made in-house by Heliene’s sister company in Spain. Since the factory construction and equipment set-up have gone reasonably smooth, what has been the most challenging aspect of getting things rolling? The newness of the PV industry in Ontario, according to Pochtaruk. “We’re not just starting up a new company, it’s a startup of the whole industry because solar in Ontario is new,” he pointed out. “No one knows what has to be done. Most of the developers you meet don’t know if they’re coming or going. Even with the volume of [project] approvals that the Ontario Power Authority has made, there’s not much going on yet. Everything else, like financing, engineering, still needs to get done. It will be happening, otherwise I wouldn’t be here. But it’s taking time.” Until things get going, Heliene continues to quote prospective customers in Europe, the States, and even a few in Ontario, biding its time until the local market finds its footing and the potential of that very promising FiT starts to be fulfilled. This column is a revised version of a blog that originally appeared on PV-Tech.org. Tom Cheyney is North American Editor for the Photovoltaics International journal and writes news and blogs for PV-Tech.org.

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