All Tech Considered
Wed October 16, 2013
Innovation: A Portable Generator Charges Devices With Fire
Originally published on Fri October 18, 2013 5:19 pm
Updated Oct. 18 to include comments from BioLite.
Hikers and campers can now keep their cameras charged with FlameStower, which uses heat from a campfire, stove or even candles to charge any device powered by a USB connection. While this can seem superfluous — powering up while getting away from it all — creators Andrew Byrnes and Adam Kell says the device can also bring power to people in developing countries where wireless technology has leapfrogged others, places where people have cellphones but not electricity.
Byrnes and Kell were both studying materials science at Stanford University and at first thought about a generator wired to a toaster, but they quickly dismissed that idea. They spoke to a business school professor, who told them something that's been their guiding principle since — build something that can cook a pot of rice and charge a cellphone at the same time.
The technology is fairly simple. The FlameStower has a blade that extends out over the fire, while the other end is cooled by a reservoir of water. That means one part of the blade is hotter than the other. The temperature difference generates electricity, and semiconductors amplify the voltage to a useful amount. It gives you the same charge as connecting your phone to a laptop. The Mars Curiosity Rover uses the same technology, though its heat source comes from decaying radioactive materials.
This phenomenon of heat to electricity is called the Seebeck effect, and it doesn't generate a lot of energy, which means it wasn't that useful until people started walking around with cameras and smartphones.
"Now you have these tools that are insanely powerful, and increasingly are stingy on their energy use, so that value of the low amount of electricity is getting higher," Byrnes says.
He and Kell want to bring the FlameStower not only to stores in the U.S. but to developing countries as well. Kell recently returned from a trip to rural Kenya and Ethiopia to refine the FlameStower for users there, because around 65 percent of people in Africa have cellphones, but only 42 percent have electricity.
"[The cellphone] has been the first technology that people in rural villages are actually buying," Kell says.
Kell says products sold in developing countries are usually made to be cheaper than their counterparts in the U.S., with the exception of energy, which is much more expensive and less reliable.
Kell and Byrnes aren't the only people to come up with something like this. The PowerPot will charge a device and cook your food or boil water at the same time, while the BioLite CampStove burns wood without releasing toxic smoke and also generates power. Kell says the people in developing countries often want to use their own pots and stoves, so the FlameStower founders focused on something that can work on any stove and costs less. Jonathan Cedar, the co-founder of BioLite, acknowledges that, but points out smoke from traditional cook stoves may be killing the people who use them.
At the moment a FlameStower costs $80, and the project is being funded on Kickstarter until late October.
Alan Yu is a Kroc fellow at NPR.