UK-based company Firefly Green Fuels has pioneered a novel jet fuel entirely free of fossil content, derived from human waste. In collaboration with experts from Cranfield University, the company determined that its fuel possesses a carbon footprint 90% lower than current aviation fuels, as confirmed by independent regulatory tests. Despite not being commercially available yet, Firefly Green Fuels aims to introduce its sustainable aviation fuel to the global market, with the first commercial plant projected to be operational within the next five years. Securing a £2 million grant from the Department of Transport in 2021 for further development, the company has already established a partnership with budget airline Wizz Air, intending to supply fuel starting in 2028.
The innovative process involves sourcing waste from UK water companies and subjecting refined sewage to hydrothermal liquefaction, converting the liquid waste into a sludge or crude oil. Solid by-products from this process can be repurposed into crop fertilizer. The company asserts that the overall carbon intensity of this procedure, measuring the carbon required to generate energy, is 7.97 grams of carbon dioxide per megajoule (gCO²e/MJ). In contrast, conventional jet fuel records carbon intensity ranging from 85 to 95 gCO²e/MJ, according to the ICCT.
Firefly Green Fuels emphasizes that fossil fuels take millions of years to form from organic matter, while its approach allows to produce fuel within a matter of days, utilizing widely available human waste. The cost comparison with existing jet fuels remains unclear. CEO James Hygate highlighted the use of human waste as a “cheap and abundant feedstock that will never run out.”
The long-standing goal of achieving carbon neutrality in aviation has driven efforts from regulators and leaders in Europe and the US. While electric vehicles have made strides in the automotive sector, the prospect of battery-powered commercial jets remains distant. Consequently, solutions like environmentally friendly jet fuels play a crucial role in the interim.