Is hydrogen safe to use as a vehicle fuel?
Hydrogen is no more or less dangerous than any existing fossil fuels used today, it just has a different set of usage requirements based on its inherent characteristics as a gas. Compared to petroleum and natural gas fuels, hydrogen has two key properties that can provide safety benefits in its utilisation:
Hydrogen rapidly disperses into the atmosphere upon its release quickly diluting to non-flammable concentrations. Heavier gasses such as petroleum fumes and propane tend to concentrate at ground level posing a greater ignition risk. Hydrogen has a wide flammability range, 4% to 74% in air, but its natural dispersal tendency as the lightest element makes containment unlikely outside its designed containment device. Ventilation is a key design criterion in fuel cell electic vehicles (FCEV) to ensure the unrestricted dispersal of any released gas.
2. Low radiant flame heat
A hydrogen flame burns with low levels of radiated heat near the flame compared to a hydrocarbon flame, significantly reducing the risk of secondary fire. Tests performed on automotive hydrogen fuel tanks simulating the ignition of a hydrogen leak burned for less than two minutes with no damage to the interior of the vehicle, due to the low radiant heat of the flame.
Crash test and hydrogen storage tank safety testing
Automotive manufacturers who have announcied series production of hydrogen fuel cell electric vehicles (FCEV) in the 2015 – 2020 timeframe will have undergone rigorous crash test and hydrogen storage tank safety testing to ensure vehicle and passenger safety.
In January 2009 type-approval of hydrogen-powered motor vehicles was included in the European directive 2007/46/EC with the addition of regulation EC No 79/2009.
Directive 2007/46/EC establishes a framework for the approval of motor vehicles as laid down by the European Parliament and the Council. Hydrogen vehicle tank testing described in EC 79/2009 includes the requirements for impact damage testing, to provide evidence the tank can withstand specified mechanical impacts, and penetration testing to provide evidence that the container does not rupture when penetrated by a bullet.
Hydrogen is non-toxic and a release does not cause atmospheric pollution. It is a highly versatile natural energy carrier which if properly handled within defined guidelines can be safely integrated into widespread automotive vehicle use under existing, well established codes and practices.