Solar roof tiles have been a little slow on the uptake, but the idea of generating solar power from roofing materials has been branching out in all kinds of other directions. One of them involves metal roof cladding combined with the up-and-coming technology of perovskite solar cells. Metal cladding is a bit on the pricey side compared to other roofing materials, but the solar add-on could offset the cost and then some.
The Age Of Solar Roofing Has Just Begun
Solar roofing materials fall into the category of building-integrated solar. Much of the excitement in the building-integrated area has to do with transparent PV panels that function as windows. PV-enabled roofing materials have also come in for their share of the media spotlight, thanks partly to Tesla’s activity in that field
While Tesla has been hammering away at its technology, legacy roofing firms like the asphalt tile specialist GAF are beginning to take notice of the new opportunities to make bank. Earlier this year, GAF launched its new Timberline Solar™ shingle, which it describes as a “the only roof system to directly integrate solar technology into traditional roofing processes and materials.”
By that, they mean that any roofer can install their solar shingles just like any other roofing material.
“Over five million new roofs are installed on U.S. homes each year. One out of every four of those roofs come from GAF, the sister company of GAF Energy and the largest roofing and waterproofing company in North America,” GAF adds. “With access to GAF’s national contractor network, GAF Energy is uniquely positioned to bring residential solar to the mass market, transforming more roofs into solar roofs each year.”
Is it all true? Ask the folks at Sandia National Laboratories. They worked with GAF on verification of key standards and market-readiness.
Here Comes The Perovskite Solar Cell Roof
GAF comes under the umbrella of the sprawling Standard Industries enterprise, which is another reason why the firm is probably off to a comfortable start in the solar roofing business, at least as far as shingles go. However, shingles are just one part of the roofing business. There are other fish to fry, and one of them is the field of metal roof cladding.
That’s where the multinational, India-based firm Tata Steel comes in. The company bills itself as “one of the world’s most geographically diversified steel producers,” so its interest in the perovksite solar cell field could have significant implications for global roofing market.
Perovskite solar cells first caught the eye of researchers just a few years ago, as a relatively inexpensive, synthetic form of the naturally occurring mineral perovskite. Initial attempts to exploit the unique optical properties of synthetic perovskites crashed out, one main problem being a tendency to fall apart under humid conditions. Various workarounds have emerged since then, and perovskite solar cells are beginning to emerge in the commercial market.
One key advantage of perovksite solar technology is its printability. Perovskite solar cells can be created in a solution that can be printed, sprayed or painted onto practically any surface.
In addition to its relatively low cost, the nature of solution-based solar cell fabrication also enables the kind of high volume, high throughput process needed to accelerate the pace of solar adoption, making it a good fit for application to metal roof cladding.
A New Revolution In Steel Coatings Is Coming
Of course, the devil is in the details. Tata is not promising perovskite solar cells on your next order of metal roof cladding, but they do see it in your future.
Last week, Tata Steel drew attention to its solar roofing collaboration with Swansea University. The school and the company recently signed a new Memorandum of Understand aimed at expanding their existing “Active Buildings” concept for building-integrated PV.
Under the MOU, Tata and Swansea will assess different types of steel products that could accommodate perovskite solar cells, under the STRIPS/Tata Steel Industrial Acceleration program.
That may seem a bit dry, but it could dovetail with a broader R&D acceleration program supported by Tata and Swansea, among other partners, called the Rapid Alloy Prototyping project.
“The project is focused on accelerating the development of new alloys (substrate and coatings) through rapid alloy prototyping,” explain the folks at RAP. “This new, innovative approach combines a range of physical production, processing and testing from 20g to 30kg together with a range of computational and data modelling techniques to rapidly plan, manufacture and optimise hundreds of steel alloy and coating chemistries.”
What To Expect From Your New Perovskite Solar Cell Roof
Tata envisions its perovkite solar roofing material as the heart of a building-integrated miniature power station.
“The future is about solar energy technology being built in, not added on afterwards. These printable solar cells can be built into the fabric of our homes, shops and offices, allowing them to generate the power they need, and more besides,” Tata enthuses.
“The solar roofs would enable buildings to generate, store and release their own secure supply of electricity,” they add. “The aim of the new research is to explore the potential of this technology further and speed up the process of turning it into products for industry to manufacture.”
The company has zeroed in on the potential for perovskite silicon technology to step in where conventional silicon solar cells are impractical or too costly. Specifically, a perovskite solar cell solution could be screen-printed directly onto coated steel.
Tata also points out that perovskite solar cells can be manufactured locally, and that the manufacturing process involves a lower carbon footprint than conventional solar cell manufacturing.
Onward & Upward For Green Steel
For those of you keeping score at home, the two Active Buildings projects are located at Swansea’s SPECIFIC Innovation Centre.
The Active Classroom is billed as the first “energy positive classroom” in the UK. It was followed by the Active Office, built in 2018 with a CIGS thin film solar roof from the firm BiPVco. Swansea describes the roof as the first commercial application of CIGS technology to a curved surface.
Stay tuned for word on the application of that perovksite solar technology on steel. In the meantime, Tata has a hand in the offshore wind business, which could dovetail with its emerging interest in hydrogen for low-carbon steelmaking.
Follow me on Twitter @TinaMCasey.
Photo credit: “Flexible perovskite solar cell – A major advantage of these cells over silicon-based cells is that they are flexible rather than rigid. This means they can be printed, using techniques such as screen printing, directly onto a material such as coated steel” courtesy of Tata Steel.
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