It has 40 seats; travels the 13 mile distance between Bristol, England and the town of Bath; and can run 186 miles on a full tank of “renewable natural gas,” that is, fuel made from human waste.
That’s right, the bio-bus (or “poop bus,” as we prefer to call it) requires the annual waste of about five people to fill its tank. People don’t poop directly into the vehicle’s gas hole. Instead, the waste is converted into fuel at a sewage treatment plant through a process called anaerobic digestion.
According to the BBC, anaerobic digestion “uses oxygen starved bacteria to break down biodegradable material into methane-rich biogas.” Surprisingly, the fumes don’t reek like a McDonald’s bathroom — they’re virtually odorless, and produce up to 30 percent fewer carbon emissions than traditional diesel engines.
Also surprising, making fuel out of human waste is not an entirely new idea. Buses in Oslo and Germany have been running poop-buses since 2009. Bio-fuel proponents say they could decrease American gas dependency and help turn rural communities into profitable fuel producers.
But it’s important to know that methane alone won’t solve all our troubles. Methane still contributes to global warming — that’s right, every time you fart, you’re destroying the environment. And even though it stays in the air for about 12 years (compared to carbon dioxide’s 20 to 200 years), it also heats up the atmosphere much more quickly, making a reliance on poop-fuel a neat idea, but a stinky one for long-term eco-sustainability.