Soil That Grows Electricity

September 09, 2008

A startup based in Cambridge, Massachusetts, called Lebônê Solutions is currently working on providing electricity to Africans who live off the grid using dirt as a power source, according to a recent article in MIT's Technology Review. Before you're tempted to file this one under "yeah right," take a closer look at the technology being employed. It's pretty awesome.

Lebônê is the Northern Sotho word for "light." The organization, started by Harvard alums, uses microbial fuel cells to provide small amounts of inexpensive electricity in order to light LEDs for reading or recharge a cell phone. These fuel cells aren't enough to power a whole home or anything like that, but the fact that they're cheap and renewable makes them an attractive development for developing areas.

Here's how it works: graphite cloth (see photo) acts as the anode while chicken wire serves as the cathode in a bucket filled with salt water, sand, and microbe (bacteria)-laden waste such as cow pies or mud. The bacteria eat away, powering the circuit. A power management board delivers the electricity to a battery. The whole setup will light an LED for four to five hours, is expected to cost around $10, and can last up to 10 years. Tech Review reports that a trial just finished in Tanzania and a new one will be starting this December in Namibia.

One could argue that hand-cranked power is better for such small applications, but fuel cells have the advantage of turning waste into electricity using materials at hand. And I'm a big fan of anything that accomplishes that.

Image: An inexpensive and renewable microbial fuel cell. Credit: Lebônê Solutions via MIT's Technology Review.