No, it does not involve hundreds of tiny exercise wheels. (Although that would be pretty damn cute, too.)
Instead, every month, the farmers process more than 400 pounds of guinea pig poop into combustible gas—and a liquid byproduct that works as plant food—by allowing bacteria to break the waste down in a warm, oxygen-free environment. It's called anaerobic digestion, and it's a process that's increasingly popular on American farms, as well. Dairy farms—with their easy access to lots of consolidated cow shit—in particular.
What's cool about this Peruvian model is that it shows you don't necessarily need fancy, expensive equipment to make anaerobic digestion work. The process can be applied at different levels of tech intensity, depending on resources, location and how much energy you actually want to produce. This Peruvian family makes enough gas for themselves, plus a little extra. Meanwhile, a dairy farm in Wisconsin uses the gas to make electricity that they sell back to the utility company. All told, there's enough to power 70 households.
Maggie Koerth-Baker is the science editor at BoingBoing.net. She writes a monthly column for The New York Times Magazine and is the author of Before the Lights Go Out, a book about electricity, infrastructure, and the future of energy. You can find Maggie on Twitter and Facebook.