The supply chain behind today’s photovoltaics industry is vast, including materials suppliers, equipment manufacturers, cell and module manufacturers and balance-of-system providers. In this section, we recognize those companies that are playing a key role in developing the solar industry to date. These organizations are helping to make solar more broadly available, easier to adopt, more efficient or cost-effective, and develop new innovations.
Solar Frontier: Big-time CIS in Japan
Solar Frontier’s Kunitomi Plant is Japan’s largest solar module production facility, as well as the largest CIS factory in the world. With Solar Frontier’s existing plants, the company now has a total annual production capacity of around 1 gigawatt. The billion-dollar plant shipped its first commercial thin-film CIS solar modules in February, 2011, only 16 months after breaking ground.
“The Atsugi Research Center (ARC) functioned as a production laboratory where we were able to fine-tune processes from raw materials to finished modules until our modeling matched precisely what we wanted to see in production,” said Satoru Kuriyagawa, Solar Frontier’s Chief Technology Officer. “We increased the efficiency of the factory with ten-fold scale over Plant 2, added extensive automation while also increasing the size and efficiency of the modules coming off the Kunitomi production line.”
Solar Frontier says its modules are able to deliver higher overall power output (kWh) under real weather conditions. In operating conditions, the “light soaking” effect of CIS modules significantly increases output from initial values, while a lower temperature coefficient than crystalline silicon modules means more kWh produced under real conditions in a wide range of climates.
“We identified CIS thin-film technology in 1993 as having the greatest potential to succeed the maturing crystalline silicon standard. Successfully ramping up from breaking ground to gigawatt-scale production in just over 21 months demonstrates the comprehensive abilities of Solar Frontier,” said Shigeaki Kameda, CEO. “Not only are we proving the compelling features of our next-generation CIS modules though strong support from our customers, we have also now shown the world that we can scale this technology at speed.”
JinkoSolar: A quantum leap
JinkoSolar Holding Co., Ltd. recently announced commercial-scale production of its Q-1 Solar Modules, part of the Quantum Series. These modules are produced using pseudo-mono multi-crystalline cells, which combine the benefits of mono- and multi-crystalline cells to better align the crystalline structure and achieve a higher efficiency product, all while maintaining low production costs. The cells deployed currently perform at an 18.3% efficiency level. The Quantum-1 modules, with an array of 60 solar cells, can perform up to 250 Wp.
JinkoSolar has an integrated annual capacity of 900 MW each for silicon ingots, silicon wafers, solar cells and solar modules, and plans to expand its annual capacity to 1.5 GW each for silicon wafers, solar cells and solar modules by end of 2011.
When the new R&D center was announced in early 2011, JinkoSolar said it wanted to increase the conversion efficiency rate to more than 18.6 percent for monocrystalline solar cells and more than 17.5 percent for multicrystalline solar cells by the end of 2011. “We launched our new research and development center to focus on improving the conversion efficiency of our solar cells and next generation photovoltaic technologies,” said Xiande Li, Chairman of JinkoSolar. The company also recently announced a 10-year product warranty for Quantum-1 Modules, with the option for a positive tolerance of up to 0.3 percentin addition to an optional Linear Performance Warranty.
Roth & Rau: 20 percent output efficiency on 156mm wafers
The research line at Roth & Rau Switzerland AG has achieved an impressive cell output efficiency rate of 20 percent using 156mm industrial monocrystalline silicon wafers. How? Using heterojunction technology. Similar results were achived at the company’s pilot line in Hohenstein-Ernstthal, Germany, where the processes are already being scaled up for mass production. “The high level of output efficiency offered by heterojunction technology, combined with its excellent temperature coefficients (>5 percent additional energy yield per module), address the key cost factors in the photovoltaics market,” said Dr. Dietmar Roth, CEO of Roth & Rau AG.
The silicon heterojunction cells offer excellent surface passivation provided by H and extra band bending — due to the larger band gap of a-Si:H compared to c-Si — makes well-designed a-Si:H emitters superior to conventional emitters made by dopant diffusion. Furthermore, a thin layer of a-Si:H, doped the same as the base wafer provides a back collector with very effective back-surface field that reduces the recombination velocity.
The company has been developing high-efficiency solar cells based on heterojunction technology since May 2008. The latest achievement is the result of a joint development effort with EPFL/IMT at the Université de Neuchâtel. The two parties worked together to transfer the results of the Institute’s research then available into industrial processes and to systematically enhance these results.
Ferro: Focused on materials
While Ferro has become a leading supplier of materials to the thick film photovoltaics industry, Ferro knows widespread photovoltaic power generation will occur once grid parity is achieved and exceeded for all PV systems. The PV industry has long-recognized the dramatic effect that long-term outdoor exposure to harsh environments has had on module performance and lifetime. Because module failures and performance losses are the result of gradual accumulated degradation and corrosion, researchers at Ferro ECGM have spent much of the past year working to revolutionize solar module durability by taking the harsh environment out of the equation.
Ferro has recently commenced several large-scale projects to develop and commercialize materials that will strengthen solar modules at lower costs, thereby significantly reducing the Levelized Cost of Energy (LCOE). Ferro is currently partnering with Edison Welding Institute, StrateNexus Technologies, and The Ohio State University to develop and commercialize advanced durability sealing systems for solar cells. In this project, Ferro is engineering a vitreous frit system to provide reliable air-tight and water-tight seals for second and third generation thin-film solar cells. Ferro is also in the early stages of a project that will drastically improve encapsulation systems by developing and commercializing a high performance glass filled barrier coating. This coating will not only strengthen solar modules, but it will increase throughput by requiring less capital and less labor intensive methods.
Ferro’s contributions to the industry and innovative ideas have also been recognized by the Oak Ridge National Laboratory (ORNL), as they are currently collaborating to develop inks and pastes to be used for highly conductive layers in thin-film solar cell applications. Further, in March of 2011, Ferro reiterated its commitment to improving PV technology by opening a solar test lab in Taiwan to facilitate rapid product development for the country’s multitude of solar panel producers.
Astronergy: A thin film first in China
Astronergy deserves special recognition as the first large-scale producer of high-efficiency thin film PV modules in mainland China. “Since our founding in 2006, we have continuously created value for our partners and our customers, through the production of high-efficiency, clean renewable energy. “In 2009, we led mainland China in the manufacture of high-efficiency thin film PV modules, in addition to our exploration in the applications of building integrated photovoltaics (BIPV),” notes president and CEO Dr. Liyou Yang. “Utilizing manufacturing execution system (MES) and statistical process control (SPC) for quality management allows us to maintain the highest quality standards. Our large-scale construction efforts include Zhejiang Province’s first 2 MW rooftop solar installation, and a 10MW large-scale solar power station in Ningxia Autonomous Region, both already connected to the grid.”
Thin film experts at Astronergy have brought the company’s a-Si /µc-Si thin film PV to an efficiency rate of greater than 9%. Astronergy is also a provider of monocrystalline modules and polycrystalline modules, and, in collaboration with its parent company, the Chint Group, BOS components including inverters, array combiner boxes, DC protection, AC protection, and transformers.
Heliatek: Heading from the lab to the fab
Heliatek is entirely focused on organic solar cells based on oligomers. Founded in 2006 as a spin-off of the Technical University of Dresden and the University of Ulm, Heliatek uses proprietary tandem technology to develop organic solar cells from “small molecules” – organic dyes chemically synthesized from hydrocarbons. In October 2010, Heliatek set a certified record efficiency of 8.3% for its solar cells. Heliatek is currently undergoing the transition from lab to fab, first flexible modules will be available in fall 2012. The company has 70 employees and has secured renown investors, e.g. BASF, Bosch, RWE and Wellington Partners.
Starting in 2012, the modules will be produced in a roll-to-roll process, PET film serves as a substrate, similar to the PET used for plastic bottles. The organic, flexible modules will allow for a wide range of applications due to its outstanding design and performance parameters:
- Various module dimensions possible
- Modules can be produced translucent
- Extremely lightweight (0.7 kg/m²)
- Thin and flexible with a homogenous surface
- Highly efficient (certified 8.3 percent for an active area of1.1 cm²)
- Outstanding low light performance and no minimum incident angle required
- No efficiency loss with rising temperatures (zero temperature coefficient)
- Built of abundant, fully organic raw materials, no heavy metals within the cells
- Very short energy payback time: little material and energy input during production
Possible future applications include: Glass-integrated modules with a variety of colors and translucence, allowing for discreet and elegant design – perfect for BIPV or automotive applications; Flexible, lightweight modules that can be used for PV installations on flat roofs with low load-bearing capacities or for any other area where traditional modules cannot be applied; and lightweight modules for stand-alone PV systems in sunbelt regions and for rural electrification – applications where modules need to be break-proof, easy to transport and are exposed to hot temperatures.
Skyline Solar: 14X CPV
Skyline Solar reports that it has continued its rapid momentum in the CPV space, receiving seven patents related to the company’s field-proven concentrated photovoltaic (CPV) systems. The patents cover 108 specific claims related to innovations that reduce balance of system (BoS) costs and boost performance to lower the Levelized Cost of Electricity (LCOE). The company has also started shipments to a 500 kilowatt project in Durango, Mexico, which is expected to be the largest CPV plant in Latin America when completed.
“With tens of thousands of hours of performance data and several successful installations, Skyline Solar’s technology is amongst the most thoroughly proven in the CPV industry,” said Tom Rohrs, CEO of Skyline Solar. “Along the way, we’ve worked to patent and protect the key intellectual property elements that generate significant performance and BoS cost improvements that drive lower LCOE.”
In March of 2009, Skyline Solar unveiled its scalable CPV system. Two years later, the company introduced the Skyline Solar X14 System, which in sunny climates and with U.S. federal incentives can deliver an LCOE of less than 10 cents per kilowatt hour. The Skyline X14 System is named for its ability to concentrate sunlight 14 times using durable glass reflectors. Concentrated light illuminates the Skyline X14 Panels, which are made of silicon cells backed with metal cooling fins. An integrated single-axis tracker ensures that the Skyline X14 System is productive from dawn to dusk.
Skyline Solar’s growing patent portfolio covers the PV panel, reflector, optics, support structure, tracker and thermal management designs. Skyline Solar has a total of 34 patent filings in the US and 20 outside the US. The company was recently awarded three new patents related to its CPV architecture: U.S. Patents #7,968,791; 7,952,057; 7,932,461.
Skyline reports that the X14 System is seeing increased demand in North America, including the Durango, Mexico project and a contract with the Department of Defense (DoD) to install a 100 kW plant at both Edwards Air Force Base in California and Fort Bliss in Texas. Skyline Solar expects to see increased adoption of the Skyline X14 System in 2H 2011 and 2012.
Power-One, Inc., a provider of power conversion and power management solutions, recently unveiled its new Aurora ULTRA central inverter concept . With a capacity up to 1.4 megawatts, the new inverters are the first commercially available products using the company’s proprietary inverter concept.
To better meet the requirements of large commercial applications and solar parks, PowerOne developed a novel circuit technology and modular design approach, enabling voltage conversion at the industrial standard 690Vac while significantly reducing AC losses. At the same time, the inverter system offers industry-leading power conversion efficiencies of up to 98.7 percent over a wide input voltage range. Other core features of Power-One’s largest inverter system include multiple MPPT channels for optimized energy harvesting, a modular construction for all main building parts as well as an IP65 enclosure with passive liquid cooling.
“In achieving the maximum energy harvest for large commercial and utility-scale solar parks, the inverter system plays a critical role”, said Paolo Casini, Vice President, Product Marketing at Power-One. “Our new ULTRA central inverters increase the system uptime significantly, thus eliminating plant shutdown and reducing repair time. At the same time, the BOS costs are minimized.”
Partnering with the Institute for Solar Energy Research Hamelin (ISFH, Emmerthal, Germany), DEK Solarhas, with its PVP1200 print platform, helped enable a record crystalline silicon solar photovoltaic cell efficiency of 19.4 percent.
As stated by ISFH in March, this efficiency level is record-breaking among Cz-silicon solar cells using a screen printing metallization process. Through the use of a 200 nanometer Si02/SiNx double layer on the rear side of a standard PV cell in combination with DEK’s front-side metallization process, ISFH was able to achieve this result.
“DEK Solar’s print-on-print technology and PVP1200 platform accuracy were key contributors to this major efficiency gain,” explains Dr. Thorsten Dullweber, ISFH Group Leader for Solar Cell Production Processes. “The print-on-print process effectively increases contact finger height and reduces finger width, thus resulting in less shadowing loss and improved efficiency. Combined with our rear side cell modifications to increase the current and voltage of the cell, the DEK Solar technologies have helped facilitate this incredible nearly one percent improvement over our previous 18.5 percent efficiency level. Achieving a nearly one percent efficiency gain is a major step forward towards further reduction in the cost of photovoltaic electricity.”
DEK Solar’s PV1200 line combines high-speed and high-accuracy print functionality with Six Sigma capability. It joins the Eclipse metallization line, a scalable, high throughput platform capable of 1200-3600 wph.