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Nov 28, 2023

Researchers Develop Powerful and Affordable Pee

It actually runs on urea, which used to be made from urine. Scientists at the

It actually runs on urea, which used to be made from urine.

Scientists at the Korea Maritime and Ocean University developed a fuel cell that runs on urea, a chemical historically evaporated from urine but now synthesized from ammonia. We showed something like this years ago, usually with headlines with "Pee-Power!" but they used very expensive catalysts like platinum. The researchers have figured out how to do this much more economically. They describe urea as "a nitrogen-rich molecule widely applied in fertilizers and also largely present in wastewater"—that's the urine. Here is another good reason to stop flushing it away.

Former U.S. President Teddy Roosevelt once noted that "civilized people ought to know how to dispose of the sewage in some other way than putting it into the drinking water." Sami Grover, once described as Treehugger's official "pee and poop" correspondent, has noted: "Urine is a useful resource which we treat as a hazardous waste product. And rethinking its value can remind us that so much of what we throw away could be used for the good if we'd start getting smart about waste."

I have also noted that it used to be really valuable—about 1% of urine is urea. But it's now made from ammonia and carbon dioxide, using vast amounts of natural gas.

Korea Maritime and Ocean University

According to the research team led by Prof. Kyu-Jung Chae of Korea Maritime and Ocean University, the new direct urea fuel cells (DUFCs) are inexpensive and powerful. "We managed to realize a high power density in an urea-based fuel cell using inexpensive materials," highlights Chae. "Thus, our research extends the capabilities of urea fuel cells and encourages their commercialization."

The researchers believe urea could be recovered from wastewater.

But pulling urea out of wastewater is going to be a whole lot harder than getting it out of urine, which has been done for thousands of years through boiling or evaporation in solar pans. This might be yet another very good reason to have urine-separating toilets in our homes, especially in these times of energy insecurity and high prices. It's not hard to extrapolate and see some real advantages here.

Compare pee power to solar power. You need big expensive batteries to store sunshine, but you can store urine in a tank day or night, summer or winter. Then you pump it into your pee-powered fuel cell, and you have electricity when you need it.

Extrapolating further, we could have fuel-cell-powered cars that you fill up at a different pump when you hit the highway rest stop, a major collector of urine. It's not like we are not used to putting urea into our cars: the diesel exhaust fluid (DEF) used in Mercedes BlueTEC engines is just urea and water and the manufacturers of DEF had to issue warnings to car owners not to pee in the DEF tank.

This is not all a joke, but another reason that our current system of mixing pee and poop and washing them away with drinking water is such a terrible idea. They are both valuable resources that have been used for thousands of years. It is only the last 150 that we wasted them, only since the last 100 when we had the Haber-Bosch technology to make ammonia from natural gas. We recently saw what happened in the United Kingdom when gas prices went through the roof: they stopped making fertilizer and ran out of industrial carbon dioxide.

We have been rethinking everything in the face of the climate crisis. It's time to rethink our plumbing to capture the value from resources that we now dilute and flush away. Having alternative sources of urea that are not made from fossil fuels makes sense; the fact that we might get electricity from it is a huge bonus.

"Towards Affordable Clean Energy: Exploring New Catalysts for Urea-based Fuel Cells." National Korea Maritime & Ocean University, 2021,