Today’s Solutions: December 19, 2025

We live in a world driven by consumerism. So, it’s fitting that Cho Jae-weon, an urban and environmental engineering professor and researcher at the Ulsan National Institute of Science and Technology (UNIST), has invented a toilet that turns what’s been literally consumed into green energy, which translates into a digital currency that students and staff can use to purchase a cup of coffee or a snack on campus.

When you make your, uh, deposit, the eco-friendly toilet, called the BeeVi toilet, pumps it into an underground tank (which already saves more water than a traditional toilet), and there, microorganisms break down the waste into methane, a usable source of energy.

A human produces an average of around one pound of excrement a day, which the toilet can turn into an astounding 50 liters of methane gas. This generates half a kilowatt-hour of electricity, which is enough to drive an electric car for three-quarters of a mile.

Cho cleverly came up with a corresponding virtual currency called Ggool, meaning “honey” in Korean. Every use of the toilet scores poopers 10 Ggool per day, which can be used to make purchases on the university’s campus. The result is quite the green circular economy.

Heo Hui-jin, a postgraduate student who has made and spent Ggool is enthusiastic about the new mindset he has on his own waste that has developed as a result of his experience. “I had only ever thought that feces are dirty, but now it is a treasure of great value to me,” he says. “I even talk about feces during mealtimes to think about buying any book I want.”

Source Image: UNIST

Solutions News Source Print this article
More of Today's Solutions

New method uses sound waves to map soil health, stop famine, and restore farm...

BY THE OPTIMIST DAILY EDITORIAL TEAM Across the world, soil scientists are trading in their shovels for something unexpected: seismic sensors. In a breakthrough ...

Read More

This simple 15-minute mindset exercise can ease anxiety, science shows

BY THE OPTIMIST DAILY EDITORIAL TEAM A growing body of research is revealing how a short, simple activity that is done in just 15 ...

Read More

3 habits of the happiest people

Think of the happiest people you know. Do you find yourself often wondering what they are doing to maintain a general level of joy? ...

Read More

Changemakers of the week: GRuB and SparkNJ

Every day on the Optimist Daily, we report on solutions from around the world. Though we love solutions big and small, the ones that ...

Read More