Until now, solar energy's two challenges have been cost and acceptance. Dow is working to change all that. The Midland, Michigan, U.S.-based company has been developing BIPV building materials that enable solar to be incorporated directly into the design of commercial and residential building materials - such as roofing systems, exterior sidings, and fascias.

Despite a headquarters in the U.S., vice president Eric Peeters believes the company has a truly global perpective on the solar marketplace. “We are squarely focused on the single biggest challenge to the widespread adoption of solar energy: cost”, Peeters begins. “We believe that Si-based solutions can reduce the cost of ownership of solar modules and therefore help the solar industry quickly penetrate the energy market - with the goal of becoming economically competitive with conventional energy sources. Everything we develop and supply to the PV industry addresses at least one of the following market drivers: total cost/MWp reduction; improved durability; improved performance; or global availability of large supply capabilities”.

An example of this approach can be seen in one of the company's flagship products, currently under development - it's POWERHOUSE Solar Shingle - which delivers building-integrated aesthetics by integrating PV functionality into an asphalt roof-shingle form factor. It uses high-efficiency, CIGS-based, PV cells manufactured on a flexible substrate. These cells are laminated and subsequently over-moulded into the final shingle design using conventional materials and polymer processing methods.

The innovative product design reduces installation costs, because the conventional roofing shingles and solar generating shingles are installed simultaneously.

Competitive advantage

According to Peeters, Dow Corning is one of the few companies in the world able to provide advanced silicon-based solutions throughout the entire solar photovoltaic (PV) value chain. This includes cell manufacturing, module assembly, and installation. “From silicon feedstock to high-performance encapsulants, sealants, potting agents and coatings, Dow Corning develops, manufactures and markets a diverse portfolio of silicon-based material solutions,” Peeters says.

Dow Corning also works through joint ventures - with companies such as Hemlock Semiconductor, where both companies invested nearly US$5 billion in solar materials manufacturing over the past five years - as well as through its own proprietary technology developments.

Other areas of the value chain where Dow Corning has an involvement include the development of conductive materials for interconnections and thermal management; encapsulants; protective potting agents and sealing materials.

“We have a technology agnostic portfolio,” continues Peeters: “What I mean by that is while we are the leading supplier of materials for crystalline silicon, we also are the leading supplier for feedstock material for thin film technology. Many of our silicon materials are sold across the PV value chain for use in various applications”.

“Some manufacturers are using CIGS and CdTe technology, [but] we are also researching and developing CPV technology. While we do believe that Si-PV is going to stay prominent in this industry, we believe that we need to research all technologies and innovations that can help the entire field of solar to meet lower cost goals.”

Peeters says that China continues to be a primary market for Dow Corning's solar business, and the company has been actively investing and developing this market over the past 35 years. Today, Dow Corning has 6 offices and two manufacturing sites in the country – including China's largest integrated silicone manufacturing site in Zhangjiagang, Jiangsu Province, as well as a Business and Technology Centre.

Staffed by scientists, engineers and marketing professionals, Peeters says that Dow's Business and Technology Centres help create innovative solutions that address environmental megatrends, such as renewable energy, climate protection, water conservation and urbanisation for local, regional and global customers.

When looking at new programs such as the US Department of Energy's (DoE) new SunShot initiative, Peeters sees this as a great opportunity for game changing technology on a truly global scale. “It will change the energy balance for companies around the globe and in turn, it will create a huge and more tightly knit global market for all solar technologies. There is room for many different things. I fully agree with other experts who say there will be no single winning technology. It is essential that there be collaboration across the entire value chain and that all technologies complement each other to meet the ultimate goal. That is our strategy. We are trying to take a full systems approach to see how all the various components affect each other. We need to determine how they can all assist each other to completely optimise every link in the system chain which then, optimises the overall end system.”

Peeters goes on to note that historically there has been a lot of individual separatism in the solar industry. Some companies focus only on increasing the efficiency of a certain type of solar cell, but maybe that does not increase the total efficiency of the system because something else is blocking it downstream:

“That is why we view solar as a total system and are working toward delivering the lowest cost of solar energy possible. That is the only thing that counts. How do you decrease that end cost of energy? The final delivered end cost. You can do that by using less materials, increasing efficiency, increasing durability and increasing the longevity of the system. We are trying to look at a combination of all of those things,” he concludes.

A good example is the higher efficiency solar cells gain by utilising the full spectrum of light, including the UV or blue spectrum. “Traditional encapsulants are organic materials that do not resist UV rays. Therefore, you need to cancel out the UV to allow the encapsulant to survive, but that negates the use of the UV spectrum by the solar cell itself,” Peeters says.

“Therefore, the efficiency gains of the latest developments in silicon technology only work if you use a UV transparent encapsulant, one of many materials Dow Corning is researching and developing. It is another example of how you need to use a system approach. Fantastic innovation in cell technology still needs another innovation in a different area down the chain to ensure that it works at the ultimate level.”

Peeters goes on to say that research has different stages. Industry itself can support research that is only two to three years out. After that it is “rather difficult” because manufacturers need to make a profit. On the other hand, academia is often working on things that are 7 to 10 years out.

They “don't have the urgency that a manufacturer would have and great things come out of this,” he adds. “The gap between the two though, is where the truly great things can happen. That overlap from three to five years is where industry, in collaboration with academia, can really make some impressive strides. Bridging that gap will allow both of them to industrialise the innovations faster,” he says.

Dow Corning has set up Solar Solution Application Centres globally that are industrial-scale facilities. Customers are able to collaborate with Dow and get to market faster with more competitive products: “We currently have centres completed or under construction in Freeland, Michigan; JinCheon, Korea; Newark, California; Seneffe, Belgium; and Zhangjiagang, China,” Peeters says.

And he concludes by explaining that these centres will allow Dow Corning to take its agnostic technology approach to the solar challenge, to the “ultimate level”.

About:

• David Hopwood is Editor of Renewable Energy Focus magazine.
• Joyce Laird has an extensive background writing about the electronics industry; semiconductor development, R&D, wafer/foundry/IP and device integration into high density circuit designs.

Renewable Energy Focus, Volume 12, Issue 2, March-April 2011, Pages 58, 60-61