Flexible solar modules are a niche product. Often seen on a smaller scale attached to RVs, on backpacks and near tents, these nontraditional solar panels are touted for their off-grid portability. After all, who would lug a 50-lb glassed solar panel to a favorite camping spot?
But flexible panels are proving they’re not just for mobile applications. More powerful flexible modules are finding their way into sleek systems on roofs that can’t support the full weight of glassed modules. They’ll likely always be considered an off-grid product, but flexible modules are getting more flexible with their applications.
Sunflare manufactures flexible panels for the residential, commercial, recreational and transportation industries. The company uses CIGS thin-film encapsulated in polymer sheets for a 75% lighter solar panel when compared to glassed silicon. Sunflare’s solar panels are installed with adhesives, which allow for more moldability and lighter rooftop systems.
“For roofs, that means there are no penetrations and significantly less weight from installation mounting hardware,” said Elizabeth Sanderson, Sunflare’s chief marketing officer. “These features are perfect for roofs on expansive warehouses and distribution centers that have less structural reinforcement.”
Sunflare’s top product, Flex60, is the same size as a traditional 60-cell crystalline silicon module but doesn’t have a frame, only weighs 11 lbs and produces up to 185 W. The soon-to-be-released PowerFit 20 module fits between the seams of a standing-seam metal roof. The company also makes other panel sizes for “adventurers and overlanders” looking for more flexible designs.
Flexible modules aren’t limitless in their bendability; their name usually just means they aren’t hindered by the rigid constraints of glass. In fact, whether the flexible panel uses silicon or thin-film cells encapsulated in polymers, it likely shouldn’t be bent completely in half, but it’s still much more malleable than a glassed module.
“With Sunflare, the bend radius is roughly 10 in. (a 30° bend), which is equivalent to bending the panel around a basketball without causing damage,” Sanderson said. “While it is possible to physically fold the panel, that would create a permanent crease in the substrate and possibly damage the electrical connections.”
Although silicon is known for its brittle qualities, it too can be used in flexible modules with special designs. U.S. company Merlin Solar uses a grid of interconnects instead of traditional busbars to provide more stability to solar cells, allowing the crystalline silicon solar panels to be flexible when encased in polymers. Other flexible silicon panel makers include Lumeta and its Lynx modules for residential and commercial applications, and startup mPower with its DragonSCALES mesh-like silicon panels.
mPower’s modules have so far only been tested on satellites in outer space, and Merlin’s durable modules have lent themselves more to the transportation and military markets, but flexible silicon modules are finding homes on residential and commercial rooftops. Lumeta caters its production to rooftops and Merlin has completed a few commercial projects.
Crystalline silicon is a better performer than thin-film in almost all situations, especially in small-scale projects. Silicon solar cells are more powerful and more efficient in real-world conditions than thin-film, and the silicon supply chain is much more consistent. But thin-film will always be the best choice for flexible modules for flexibility’s sake. No matter the design, silicon cells do still need more structural support than thin-film.
When the goal is to have solar power of any kind on unique surfaces rather than hitting a certain power output, flexible solar panels can meet the challenge.
“Our mission is to reduce CO2 for a healthier future. This requires more solar adoption throughout the world,” Sanderson said. “In order to have more solar used, we need to have different kinds of solar, like flexible CIGS, that has different benefits and can go in new places.”