Firefly //

A new route to SAF

We’re pioneering a new and exciting route to SAF that repurposes an abundant, highly sustainable waste material – sewage.

By reusing sewage we are helping to lessen the environmental impact of aviation whilst supporting global biodiversity and public health.

Aerial view of wastewater treatment facility

We are moving at pace towards commercial SAF production in the UK, rapidly scaling up to multiple locations around the world.

Our Proposition At A Glance

Firefly will use processed sewage sludge as a feedstock.

This sludge is a globally abundant, inexpensive resource.

Our SAF emits 92% fewer greenhouse gases over its lifetime compared to fossil fuel.

Independent analysis shows that our fuel is almost identical to fossil (A1) jet fuel.

The Firefly Solution

Our process, hydrothermal liquefaction (HTL), uses a combination of high pressure and heat at lower energy levels, and is good for processing wet wastes. Using HTL we turn sewage into crude oil and biochar.

Biochar is a good option for carbon sequestration in construction or in agriculture, where it can also be used as a soil improver.

The crude oil, meanwhile, will be processed into sustainable aviation fuel (SAF), via proprietary processes derived from those used to synthesise fossil-derived jet fuels.

Our proposition at a glance


  • HTL (Hydrothermal liquefaction) is a very energy efficient way to create biocrude.
  • The simplicity of our process brings production costs down, potentially allowing our SAF to be competitively priced.
  • Our focus is on using sewage sludge, but our process is appropriate for use with other wet biogenic materials.
  • Our solution is widely applicable in multiple locations around the world, even areas where there are limited other options for generating sustainable energy.


  • Our LCA (Life Cycle Analysis) was completed by independent specialists at Cranfield University, who found carbon emissions to be over 90% lower than standard fossil jet fuel.
  • The carbon intensity of our process is just 7.97 g CO²e/MJ
  • Biochar produced during our process is excellent for carbon sequestration and could be used in construction or agriculture.
  • Our feedstock is a completely biogenic waste material – our process creates new value, transforming it from unwanted waste to valuable resource.


  • Our process can be implemented anywhere in the world where human waste is processed.
  • The global need for SAF far outstrips supply; there is a huge market for SAF and our simple, energy efficient process will allow us to produce it at a very competitive price.
  • National and international mandates for SAF uptake provide market stability and an economic incentive for future upscaling of production.