The headphones include active noise cancellation (ANC), and one hour of sun is enough for three hours of headphone power. Even indoor light will charge the internal batteries, but daylight is best. And that battery pack holds 50 hours of charge anyway. So, why aren’t all gadgets solar-powered? “The main problem is one of power,” renewable energy and landscaping specialist Dan Bailey told Lifewire via email. “Consider solar panels on a house. They have a massive surface area compared to your phone, and your home runs quite efficiently. Your phone requires a huge power commitment that can’t currently be converted from solar energy.”
Size Matters
Headphones sip energy. Advances in low-power computers and Bluetooth connections mean that you can run a pair of headphones just by harvesting the light that falls on them. The same has been true for smaller devices—watches, pocket calculators—for decades. But when it comes to phones, things get tricky. First, you need more power, and therefore more light, which translates to bigger solar panels. On a phone, where would you put them? The front is covered with screen, and the back is hidden by your hand, a tabletop, or the inside of your pocket. Headphones’ natural habitat is the open air. They sit on your head, always in the best spot for gathering photons. And because they’re on your head, you never leave them in a dangerous environment. If phones were solar-powered, you can bet that plenty of people would leave them in direct sunlight, where they’d overheat and die. If you ever bought one of those solar-panel chargers to top up your phone on camping trips, you’ll know that it’s not particularly practical, thanks to the phone’s relatively large need for power. “The simple answer is cost,” weed reviewer and solar panel installer Caleb Chen told Lifewire via email. “It isn’t as simple as taking a solar panel and taping it onto an existing product. The panels, themselves, and their wiring need to be integrated into the product body, itself.” Urbanista’s headphones use a material called Powerfoyle, which can be screen-printed onto fabric. It’s not as effective as standard solar cells at converting direct sunlight, but it works much better in lower light. That means overcast days or indoor lighting. It’s also less picky about the angle of the light falling on it.
Convenient, Not Green
The main point of solar gadgets is convenience. While it sounds good not to be drawing energy from the grid, any environmental savings for something as low-powered as a set of headphones may be offset by the added complexity of manufacturing. But what a great boon it is. “For the battery being charged, it can’t tell the difference,” says Chen “For the end-user, it makes a huge difference to be able to charge the device without mains [utility] power.” Imagine never having to charge your headphones again. Actually, it’s pretty easy to remember, because back when we used headphones with cables, we never had to charge them. So, should we expect solar charging for other gadgets? Probably not. Headphones are uniquely suited to this treatment, being relatively large, always out in the light, and requiring little energy to run. It also costs more to make a self-charging gadget, all else being equal. That’s usually fine for high-status items—people buy Beats headphones, even though they’re junk—but maybe not for something like solar power. Planet-wise, it makes more sense to focus on renewable energy, in general. In Costa Rica, the power grid is fed by close to 100% renewable energy. In Portugal, it’s 80%. That means that any electrical devices are, environmentally speaking, free to use. There is, of course, an environmental cost to building out the infrastructure, but that’s fixed. In other words, solar headphones will make no difference to the climate crisis. But that doesn’t make them any less cool.
