While 3M's renewable energy division was formed just two and a half years ago, it is by no means a small player. “A major component of the business is, of course, energy generation,” says Ellen White, global marketing manager. “We focus on a wide breadth of renewable energy technologies.”
As the company likes to say, it ‘captures the spark of new ideas and transforms them into thousands of ingenious products', and it has adopted this philosophy for its renewables business. “In solar alone, there are a variety of technologies from concentrated solar power to concentrated photovoltaics,” White says. “There is a very significant growing industry in rigid PV modules, both crystalline and thin film.”
The firm is also active in the wind power sector, adds Dr. Steve Hedrick, the company's technical director. “As a company that is highly focused on 45 technology platforms, including things like light management, material adhesives, coatings and weathering expertise, we are actually working across a breadth of applications; where can we actually help our customers reduce the cost per watt, cost per kWh? This applies whether it is a wind or a solar application.”
One exciting innovation, both White and Hedrick say, is the company's Solar Mirror Film 1100 for the concentrated solar power (CSP) market. “There are some really great advantages in being able to use a reflective film rather than a glass mirror as a solar collector,” White says. “It offers an advantage in form factor. There are a lot more things you can do with the design. You can also have a continuous mirror instead of the more common glass faceted mirror design. It also brings down the total cost.”
Another product is its Ultra Barrier Solar Film. “We are very proud of this product. It is truly enabling flexible construction of high efficiency solar modules in CiGS type applications,” Hedrick says. “It's a highly flexible front-side film that will take over a lot of the functionality you see in glass.”
3M has also been doing a lot of work around light management – around the efficiency of the silicon cells. “Our work is focused on reducing efficiency loss, due to loss of the light coming into the panels.”
The company has around 50 years' experience in understanding the impacts of weathering, having first established a basic weathering resource centre to test products for its original road sign business many decades ago. Today, it also has an outdoor solar weathering centre in Cottage Grove, Minnesota, U.S.
“For decades, 3M has vigorously tested the weatherability of its products in its accelerated Weathering Resource Centre and at multiple outdoor sites worldwide, to optimise designs and ensure reliability and performance over extended periods of time. This expertise is crucial to the solar industry, where systems are expected to perform for 25 years or more,” Hedrick says. “We are confident our new outdoor Solar Weathering Centre will allow us to further improve upon our solar product portfolio and better serve our global customers.”
This is the first centre of its kind built by 3M, but it is not its first basic “Weathering” facility, he notes. It joins 67 other facilities around the world that are used to conduct basic tests. “Arizona and Minnesota are very different from the UK or the Middle East. Each is a different solar environment and you also need to look at the impact of dirt on module performance. Each country in the world actually has very different soil,” Hedrick says.
There are two aspects to the work, Hedrick continues. The first part involves looking at energy conservation, something he notes is as important as energy generation. “It means getting the most use out of our existing resources and infrastructure,” he says. “We've spent a great deal of effort understanding the impact of outdoor weathering on how materials age. Our new solar facility adds to our ability to evaluate and understand, not only the positive impact of new technologies that define the performance of our customers' end products, but also [the effect that weathering has upon these technologies].”
The company's researchers at the new facility will conduct environmental testing of solar module configurations, aiming to bring more efficient products to market faster to meet customer needs. The facility is, he explains, tailored for side-by-side comparisons of solar energy systems using a variety of 3M's products. These products include its Ultra Barrier Solar Film, Scotchshield Film Backsheets and Solar Mirror Film 1100.
The company will install approximately 100 solar photovoltaic (PV) and concentrated photovoltaic (CPV) modules at the site, in multiple arrangements. There will also be parabolic troughs to test products used in concentrated solar thermal systems, while there are plans to add testing capabilities for Building Integrated Photovoltaics (BIPV) in the future.
The testing facility also has an automated data centre and weather station to monitor system output, temperature and humidity in harsh weather conditions. 3M will analyse data regularly to corroborate performance and direct future product development. “We have the ability to both purchase existing products, and to collaborate with our customers to take in their prototypes, modify and test them,” Hedrick says. “We also have the ability to create and test our own modules. This will significantly accelerate our product development and cycle time.”
The company, for example, is working closely with module manufacturer tenKsolar. The two companies have developed 3M's Cool Mirror Film 330 “to reflect only light that can be used to create electricity onto tenKsolar's modules”, explains Hedrick. Under its working arrangement with tenKsolar, 3M will be able study concepts for light management, such as its cool mirror technology, in depth, assessing how it enhances the output of traditional CPV systems: “So it is a wide breadth of undertaking,” he adds.
Meantime, the company has also established two new accelerated weathering facilities in China and Germany. White says these are designed for indoor accelerated aging on a smaller scale, but can accommodate outdoor testing for larger samples. “For these, we will typically contract out with other local weathering services,” she says.
“Because we already have these facilities all around the world – that look at the impact of the actual sun, weather and soil in each area as far as basic weathering – we can do controlled, comparative examples,” Hedrick adds.
“We have a proprietary model at 3M for service life prediction, and we've developed this over the past 50 years. We've basically developed ways of taking accelerated indoor ageing and applying that to outdoor phenomenon,” White continues. “These tests look at the particular failure mechanisms of materials, and then 3M uses these test results to develop improvements. Through correlated testing, we've developed these proprietary models so that we can understand how long these materials are going to last. We have a database that we've been gathering over time about how different materials with different additives will perform in any particular climate condition.”
One of the goals of material testing is to find correlations between materials and end product compatibility. White says that 3M tests a number of combinations. “This is particularly true in solar films that we've recently introduced. We've done quite a bit of testing to understand how they are going to perform on the different substrates that our end customers may choose. We can make qualified statements about how they are going to perform, depending on the choices that the customer makes.”
White notes, however, that at present most companies try to design products for an “any use” case, and want to ensure that wherever the product is used, it will meet the 25-year service life requirement. “That's how the solar industry is structured today. So, that is always our primary goal,” she says. However, “as the industry proceeds down the cost curve, it will become valuable to customise solar installations for a particular environment. We certainly see cases where we could provide a different material set, which would be less expensive, and could be very well suited for one climate, but not for another.”
She expects it to be these kind of projects that 3M will be working on with its customers more and more. “I see a future where the customer will tell us that they want to design a solar module that will excel in a specific climate, and ask us what the best materials would be to use [in that scenario].”
And she's optimistic for future growth. Despite the volatile global economy, energy demand is going to continue to grow, she notes. “This is true whether in an up or down economy. That's just a fact. You can't stop the need,” she says. “Renewable energy as a portion of the energy pie will continue to take a larger and larger slice. Solar will play a big part in that. Costs are continuing to come down and solar panels are competitive at face value in many markets today, and have the potential to do this in all markets.”
She adds: “There are also a couple of macro trends, [with concerns over energy independence] not to mention reduction of carbon emissions at play here. I don't think that the overall market is going to stagnate. It will be volatile in the short term, but in the long term, I know it will be one of the top markets that survives. The industry has a great record of bringing down cost and enhancing power output.”
About the author: 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.