AbstractDue to increasing global greenhouse gas emissions there is urgency to pursue all measures to develop carbon‐neutral energy technologies. The most attractive approach for large‐scale energy storage is perhaps in the form of synthetic fuels. In this work, a nitrogen‐based fuel consisting of an aqueous solution of urea and ammonium nitrate is evaluated for chemical stability and handling safety. The steady combustion of the fuel was demonstrated at 10 MPa. Thermal analysis under an ambient pressure dry air flow in the range of 25–500 °C showed that the monofuel does not react with atmospheric oxygen in a ventilated open system, and only endothermic thermal processes were observed in the condensed phase. Under applied pressure the fuel combusts exothermically above 300 °C, after water vaporization. The fuel described herein is an excellent gas generator with a potential effluent composition of 73.0 % H2O, 21.6 % N2, and 5.4 % CO2, which is an environmentally friendly working fluid.