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Every six seconds, in a factory on the northern edge of Stockholm, a secret printer churns out a sheet worth thousands of euros each. Each one contains 108 tiny solar cells, and they will soon be found in everyday gadgets, from keyboards to headphones, fundamentally changing how we interact with technology and, according to their creators, even rethinking our relationship with light.
Sweden might seem like an unlikely place for a solar revolution, but the lack of light during the winter months has led Exegur co-founder Giovanni Fili to look beyond the sun as a sole source of power for his solar panels. The company's groundbreaking technology can harvest electricity from virtually any light source, from direct sunlight to candlelight. It can even charge from moonlight, though it will be a while before it's ready for use in real life.
“Like the algae that live on the bottom of the nearly pitch-black ocean, we can efficiently harness tiny amounts of photons,” Phiri told The Independent, wearing a T-shirt that proclaims his company's technology is “world-changing” and could simultaneously address global energy needs and some of the planet's biggest environmental challenges.
Powerfoyle's solar cells are durable enough to be built into bike helmets and versatile enough to mimic leather or brushed steel and fit onto bags and speakers (The Independent)
Indoor solar panels have been around for decades – solar-powered calculators were first introduced in the 1970s – but limitations of the amorphous silicon cells used in those calculators make them too low-power, too fragile and too rigid to be built into other products.
The most recent innovation came from discoveries about dye-sensitized solar cells (DSSC) in 1988. Two scientists at the University of California, Berkeley in California invented a low-cost, highly efficient cell that was semi-flexible and semi-transparent, paving the way for commercial development of the technology.
A little over 20 years later, Fili and Exegur co-founder Henrik Lindström came up with a new electrode material that was 1,000 times more conductive, a breakthrough that became the basis for the Powerfoyle cells now produced at commercial scale.
Exeger's Powerfoyle solar cells are fundamentally different to conventional glass-covered panels as they do not require silver wires to act as conductors and are not affected by partial shading, which would significantly reduce the efficiency of the photovoltaic panel.
The patented skin-like material can transform into almost any substrate, allowing it to be seamlessly integrated into a wide range of products while remaining waterproof, dustproof and shockproof.
“It works in any light condition, it's more durable than any solar cell in the world, it's easy to manufacture, it can mimic any surface — leather, carbon fiber, wood, brushed steel — and it's beautiful,” Phiri says, “so it can be integrated into products that already sell in the billions a year.”
Exeger's Stockholm factory has the capacity to produce 2.5 million square meters of solar cells per year, making it the largest factory in Europe. At the factory opening ceremony in 2021, Phiri predicted that Exeger's technology will “impact the lives of one billion people by 2030.”
Exegur claims that its PowerFoil solar cells are the most durable in the world (Exegur)
Powerfoyle's solar cells are already in seven commercial products, including headphones, wireless speakers and bike helmets, with six more announced. Customers include Adidas, Philips and 3M, and the company is rumored to be in talks with Logitec and Apple.
A battery-free future
Exeger is one of several startups pioneering the commercialization of indoor solar panels that promise clean, limitless power, attracting researchers and entrepreneurs alike.
US-based Ambient Photonics entered the field, attracted by the “magical” potential of the smart home and the hope that it might be able to eliminate the need for disposable batteries.
“The scale at which smart electronics can be deployed has been limited by battery life and the use of traditional batteries, which require constant recharging, hindering product design and having a negative impact on the environment,” Bates Marshall, co-founder and CEO of Ambient Photonics, told The Independent.
Billions of disposable batteries are thrown away every year (Getty Images)
Samsung estimates that 3.1 billion disposable batteries are discarded each year, just from TV remote controls. The South Korean electronics giant has made the switch from alkaline batteries to solar power a priority to meet its sustainability goals, claiming it can reduce greenhouse gas emissions by about 6,000 tonnes per year.
“The more power density we can make our products, the closer we get to a future where the need for disposable batteries is greatly reduced, if not eliminated entirely,” Marshall says.
Ambient Photonics' DSSCs have been integrated into remote controls in the past, but limitations on the amount of heat and light they can be exposed to currently limit the technology to indoor use.
Exerger's Powerfoyle is versatile and durable, so its only limitation is energy-hungry devices like laptops and smartphones, but it can also significantly improve the battery life of these devices by 50 to 100 percent. Exerger is also researching solar-powered tablet covers that could provide enough power for occasional users so they don't need to be charged.
“Our grandkids will laugh at the fact that we had cable,” Phiri says.
Exeger's Powerfoyle solar-powered product prototypes include tablets, bags and curtains (Exeger)
One trend Phiri has noticed is that users of Powerfoyle products are becoming much more aware of the presence of light in their environments and in their lives. “We're making people more light-conscious, because light is power,” he says.
Phiri believes Powerfoil is a defining technology of the era. While Exeger is the first company to commercialize the technology on this scale, the technology is still in a relatively early stage, as Phiri sees every person on the planet as a potential user. Others seem confident in his claims, with Forbes magazine likening him to the likes of Jeff Bezos, Bill Gates and Elon Musk.
The technology behind Exeger's solar cells is a closely guarded secret, as are the printers that produce them. Even the purpose of the PowerFoil, currently being printed by the thousands every minute at the Stockholm factory, has not yet been made public. (Its elongated shape strongly suggests it will be used in a product that most of us use every day: the product in which this article is being written.)
“This is really big,” Phiri says. “We just signed a deal with the largest keyboard and mouse supplier in the world and are already partnering with some of the biggest companies and brands on the planet. This technology is going to take the world by storm.”
