Properties of hydrogen

Properties Hydrogen Comparison
Density (gaseous) 0.089 kg/m3 (0°C, 1 bar) 1/10 of natural gas
Density (liquid) 70.79 kg/m3 (–253°C, 1 bar) 1/6 of natural gas
Boiling point –252.76°C (1 bar) 90°C below LNG
Energy per unit of mass (LHV) 120.1 MJ/kg 3x that of gasoline
Energy density (ambient cond., LHV) 0.01 MJ/L 1/3 of natural gas
Specific energy (liquefied, LHV) 8.5 MJ/L 1/3 of LNG
Flame velocity 346 cm/s 8x methane
Ignition range 4–77% in air by volume 6x wider than methane
Autoignition temperature 585°C 220°C for gasoline
Ignition energy 0.02 MJ 1/10 of methane

Notes: cm/s = centimetre per second; kg/m3 = kilograms per cubic metre; LHV = lower heating value; MJ = megajoule; MJ/kg = megajoules per kilogram; MJ/L = megajoules per litre.
Source: The Future of Hydrogen: Seizing today’s opportunities, IEA, June 2019.