A new toilet in South Korea is giving poop a purpose. The "BeeVi" toilet, designed by a professor at the Ulsan National Institute of Science and Technology, powers part of a university building with human waste. Students are incentivized to use the toilet with an offer of virtual currency they can then trade in to buy freshly brewed coffee, fruit and books.
"If we think out of the box, feces has precious value to make energy and manure," Cho Jae-weon, the designer of the toilet, told Reuters.
Excrement has long been envisioned as a source of energy. In 2019, BMW announced it was partnering with a dairy farm to help fuel electric car charging in California with cow poop. Back in 2012, the Denver Zoo powered a vehicle with animal dung.
When someone uses the BeeVi toilet, excrement gets vacuum-pumped into an underground tank to save water. The waste is broken down by microorganisms and becomes methane gas, which then serves as a source of energy to power a gas stove, hot-water boiler and solid oxide fuel cell. The name of the human-powered toilet combines the words "bee" and "vision."
Students earn 10 units of a digital currency called "Ggool" -- "honey" in Korean -- each day they use the toilet. As part of this currency system, devised by Cho, students scan a QR code at a Ggool market on campus to pay for goods.
Cho said an average person defecates about 500 grams, or 2.11 cups, a day. This waste can be converted into enough methane gas, and then enough electricity, to support a car's journey for three-quarters of a mile.
But what do students think about offering their excrement to fuel the building? Apparently, some approve. One postgraduate student told Reuters they "had only ever thought that feces are dirty, but now it is a treasure of great value to me."