Urban and environmental engineering professor Cho Jae-weon of Ulsan National Institute of Science and Technology (UNIST) in South Korea has created an eco-friendly toilet that converts human excrement into energy.
The toilet, named BeeVi (for "bee" and "vision") used a vacuum pump to send excrement into an underground tank where microorganisms break down the waste and produce methane, a biogas that is used by the school to create energy.
An average person produces enough excrement daily to create 50 liters of methane gas, which in turn can produce 0.5 kilowatt-hour of electricity.
To "reward" students for their, ahem, deposits, Cho created a virtual currency called Ggool (or 'honey' in Korean). Each person that use the toilet earns virtual currency that can be used to buy goods on campus - from coffee to instant cup noodles, snacks, and even books.
Image: Ulsan National Institute of Science and Technology