Liquid Methane

Liquid Methane is derived from natural gas that has been cooled to a temperature of -260⁰F where it has liquefied. Once liquefied the volume is only one six-hundredth of that of natural gas, yet it maintains the properties of natural gas. Benefits for the aviation sector also arise from the improved heating value and cooling capacity in comparison to kerosene.

Methane’s specific impulse, combustion temperature and average propellant density are intermediate between hydrogen and kerosene. Methane however, has only 65% of the energy density of jet fuel, considerably greater than 25% for hydrogen. Although liquid methane demonstrates a reduction in volume of more than 600 times, it occupies almost twice the volume of an equal weight of kerosene. This translates into a larger volume storage area, potentially increasing drag and fuel consumption. It is possible for this to be offset by a reduction in takeoff weight, for long range flights, as methane has higher specific energy than kerosene. For the same energy consumption, methane would also yield an approximate 25% reduction is CO₂ than kerosene. (Alternative Fuels to Kerosene, 1999)