In a bid to aid in solving the global warming crisis, Toyota might soon start using human waste to power its upcoming electric cars. Apparently, the Japanese auto giant has found a way to convert sewage sludge, which is mostly made up of human waste, into hydrogen that can fuel cars like the Mirai.
Apparently, for this special project, it looks like Toyota is working in conjunction with the Fukuoka City Central Water Processing Plant, in Fukuoka, Japan. Usually, sewage in such water treatment plants is separated into liquid and solid waste. The solid waste called sewage sludge, which is a foul-smelling, brown lump that mostly ends up in landfills. But the folks at Fukuoka try to extract as much good from it as possible. Microorganisms are added to the mix, which breaks down the solid waste, creating biogas that is made up of about 60 per cent methane and 40 per cent carbon dioxide. Then, workers filter out the CO2 and add water vapour, which creates hydrogen and more CO2. They extract the CO2 again, and voila: pure hydrogen.
Now before you go ahead and start praising the Japanese for their smart idea let us tell you, the process is not new or any advanced technology. In fact we Indians have been doing the same thing for years, and that is exactly what Marc Melaina, a senior engineer at the National Renewable Energy Laboratory in Denver pointed out. He said, “In India, they have loads of biogas plants in villages and such that are just part of their energy infrastructure.”
Essentially the sewage sludge, as mentioned earlier, is usually dumped in landfills, and in the case of biogas, it’s most often burnt. In other words, there’s no downside to using it to produce hydrogen instead. “They have to treat the water, and biogas is a natural by-product of that process,” Melaina says. “You can burn it, you can turn it into electricity or you can turn it into hydrogen.”
Now, Toyota has been one of the few carmakers, who have been continuously working to find new natural and sustainable fuel source to build zero-emission cars. While hydrogen fuel cells have proven to be an excellent option, Yoshikazu Tanaka, the chief engineer of the Toyota Mirai, Toyota’s hydrogen fuel cell car, calls it a “chicken or the egg” problem. Apparently, no one wants to purchase hydrogen cars because there are no hydrogen fuel stations, and nobody wants to build hydrogen fuel stations because there are no hydrogen cars.
This is why Tanaka and several other experts feel that making hydrogen from sewage is probably one of the most economical ways to get sustainable fuel source for hydrogen-powered electric cars. To prove his point Tanaka said that currently, the Fukuoka plant produces 300 kg of hydrogen per day, enough to fuel 65 Mirai vehicles. If all the biogas produced by the plant were converted to hydrogen, that number would jump to 600 cars per day.