Imagine driving to work on a tank of pee. It's not as far fetched as it may sound. A professor in Ohio, Gerardine Botte, is said to have invented a technology that transforms urine into hydrogen.
Botte recognized that urine contains two compounds that could be a source of hydrogen: ammonia and urea. Place an electrode in wastewater, apply a gentle current, and voila: hydrogen gas that can be used to power a fuel cell.
Her system operates similarly to the electrolysis of water, a process that can be used to produce hydrogen for fuel cells - except that ammonia and urea hold their hydrogen atoms less tightly than water does, so less energy is required to split them off. Botte isn't the only scientist with her mind in the sewer. A group of scientists in the UK, for example, is working on a fuel cell powered directly by urine.
Botte's technology has the greatest potential for power generation in settings where large numbers of people gather - airports and sports stadiums, for example. An office building with 200 to 300 workers could generate 2 kilowatts of power, Botte has calculated. Granted, that's not enough to power the building, but every drop in the bucket helps.
This technology is thought to be perfect for feedlots where a thousand head of cattle could generate up to 50 kilowatts of power.