The benefits of a wearable solar system are clear: the ability to charge small electronics through a USB connection integrated into clothing would bring an extra layer of convenience for users, and if adopted widely, a corresponding reduction in power demand to charge devices could make a dent in the peak load issues being experienced by modern grid operators.

“With the availability of miniaturised solar cells we can generate power in a range of new ways, by utilising things like clothing, fashion accessories, textiles and more,” said NTU researcher Achala Satharasinghe, who developed the proof-of-concept textile square. “It will allow mobile devices to be charged in environmentally friendly ways which are more convenient for consumers than ever before.”

NTU’s prototype is the latest in a long line of wearable solar research over the last decade or more. Up until the last couple of years, the size and thickness of solar panels formed a key challenge for solar-charged clothing, with inflexible cells hardly conforming to the need for clothes that people would actually want to wear.

“The most decisive and restricting demand is the conformal flexibility of solar cells used for clothing integration,” wrote Stuttgart University’s Markus B. Schubert and Jürgen H.Werner in a 2006 article published in Materials Today. “Finding a compromise between the minimum total thickness and, hence, maximum conformal flexibility of iPV modules on the one hand, and washability, mechanical resilience, and durability on the other, is an important task that has not yet been solved for most of the flexible cell technologies described here.

Today, miniaturisation and increased flexibility of solar cells are solving some of these issues. In 2017, researchers at the University of Tokyo and research institute RIKEN unveiled a prototype ultra-thin PV device coated with waterproof and stretchable films to make them machine-washable.

With the milestones being reached today, the moment when solar clothing becomes a practical reality feels closer than ever. There are still challenges to overcome, including the cost implications of potentially thousands of embedded cells, durability issues over multiple washes and the need to design battery systems and connection ports that will allow these clothes to hold a charge. But with solar manufacturing costs falling fast and the clear commercial appeal of clothes and accessories that can charge a phone if its user is caught short, the potential is clear.