A UK startup called Firefly Green Fuels has developed a method to create jet fuel from human waste. The company aimed to find a way to make fuel from a low-value feedstock, and discovered that poop was both abundant and cheap. The fuel, which is currently being independently tested, has a 90% lower carbon footprint than traditional jet fuel while still functioning chemically like fossil-based kerosene. The UK’s entire sewage supply could only meet 5% of the country’s aviation fuel demand, but the technology has the potential to make a significant impact on reducing carbon emissions in the aviation industry. The UK Department of Transport has provided £2 million in funding for further research on the project.