Hydrogen in a few figures  [ Return towards  Hydrogen  ]

• Molar mass: 2.016 g/mol
• Content in the air: 0.5 ppmv
• Boiling temperature: -252.8°C
• Solidification temperature: -259°C
• Compressibility factor: 1.001 (to 1.013 bar and 21°C)
• Voluminal mass of liquid hydrogen: 70.973 kg/m³ (to 1.013 bar and -252,8°C)
• Vouminal mass of gaseous hydrogen: 0.085 kg/m³ (to 1.013 bar and 15°C)
• Specific volume of gaseous hydrogen: 11.986 m³/kg (to 1.013 bar and 15°C)

For more information consult the Air Liquide Gases Encyclopedia

• Energy density of hydrogen: 120 MJ/kg
• Energy density of gasoline: 42.7 MJ/kg
• Energy density of methane: 50.4 MJ/kg

• Voltage at the cell’s terminals: 0.6 volt
• Amperage: 0.6 to 0.8 Amperes per cm²

Characteristics for an average range car:

• Consumption: ~ 1 kg H₂ /100 km
• Autonomy: 500 km
• 5 kg tank of H₂: 125 l gaseous H₂ at 700 bar, 75 l liquid H₂ at -253°C
• Service station: 1 kg H₂ /min., completely filled in 5 minutes
• Local emissions of a hydrogen-powered car: 0 g CO₂/km and 90 g H₂O/km
• Local emissions of a car that runs on gasoline (7 l/100 km): 160 g CO₂/km and 75 g H₂O/km

• “Well-to-wheel” emission of a hydrogen-powered car⁽¹⁾: 90+0 = 90 g CO₂/km
• “Well-to-wheel” emission of a car that runs on gasoline (7l/100 km): 30 + 160 = 190 g CO₂/km
• Production yields of hydrogen ⁽¹⁾: 58%
• Production yields of gasoline: 88%
• Performance of an internal combustion engine powered by gasoline: 19%
• Performance of an electric engine powered by a fuel cell: 50%
• Energy efficiency of a car that runs on gasoline: 88 x 19 = 17%
• Energy efficiency of a hydrogen-powered car: 58 x 50 = 29%

• Cost of the fuel cell: $30/kW (or €2,200 for 100 HP)
• Life span: 5000 hr. (250,000 km for an average speed of 50 km/h)
• Cost⁽²⁾ of hydrogen: €3 to €5 (excluding tax)/kg, or €3 to €5 for 100 km
• Cost of gasoline: €3.5 (excluding tax) to drive 100 km (7l/100 km, €1.5/l, 66% taxes)

(1): The “well-to-wheel” calculations take into account the quantities of CO₂ emitted during production of the fuel (hydrogen or gasoline) and during its use in the vehicle. In this case, hydrogen is produced by the centralized reforming of methane and distributed by pipeline. Sources: Eucar-Concave 2007.

(2) Data from the DOE (Department of Energy, USA), costs excluding tax.