In the poorest parts of the world, energy is scarce. That is why some scientists are excited about the prospect of generating electricity from urine. Human waste, after all, is the one product that every community has in abundance, and research has demonstrated that a little urine can be used to produce small amounts of electricity in a device called a microbial fuel cell, which relies on bacteria to generate power. The average person puts out a quart or two of urine daily. The problem is the high cost of fuel cells relative to their modest power production. But recently scientists in the U.K. have come up with a way to cut the cost of an experimental fuel cell while boosting its output. The result is a urine-powered fuel cell that is less than an inch square and costs between $1.50 and $3. Power output is still tiny—the cell […]