The Circular Fuels project integrates concentrated solar heat, solar electrical energy, and thermochemical conversion of bio-based waste materials to produce sustainable aviation fuels. Coupling concentrated solar heat with fast pyrolysis to produce sustainable aviation fuels has not yet been achieved and requires technological innovation. Waste wood (A+B) and agricultural residues (straw), listed in the Renewable Energy Directive (REDII Annex IX), will be used as cheap and abundant bio-based waste material feedstocks. The feedstock will be first converted into renewable bio-oil in the new solar assisted fast pyrolysis. The use of solar energy removes the need to burn any fraction of the pyrolysis products to heat the pyrolysis process. The solar pyrolysis will produce valuable by-products, such as biochar, that can improve the economics of the process. The pyrolysis oil will be stabilized and upgraded to reduce the oxygen content to close to zero by slurry hydrotreatment and hydrodeoxygenation. These processes will employ green hydrogen, produced using optimized solar photovoltaic-assisted water proton exchange membrane electrolysis. Finally, the oil will be fractionated into sustainable transportation fuels by distillation. Our main objective is to maximize the fraction of jet fuel. In addition, we will analyze all component fractions suitable as transportation bio-fuel products, such as gasoline and diesel, to maximize the profitability of the concept. The proposed new thermal pyrolysis process pathway is not yet standardized for ASTM D7566 (Standard Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons). Therefore, we will perform compatibility and turbine combustion tests for the required standardization and inclusion into ASTM D7566. We aim for a sustainable aviation fuel production price of 1.5 €/kg. We will analyze the sustainability aspects of the technology and give policy recommendations for successful commercialization.