The WtEnergy-AS thermochemical conversion process is based on the transformation of solid fuels into clean and versatile synthesis gas, via the atmospheric gasification process.

The process takes place in a bubbling fluidized bed gasifier, where fuel and fluidizing agent react under autothermal reduction conditions to generate synthesis gas. This gas is then treated by the WtEnergy-AS reforming process to remove all contaminants present on the residue.