Posted: 28 November 2007

Hydrogen is one of the most promising energy carriers for the future. It is a high-efficiency, low polluting fuel that can be used for transportation, heating and power generation in places where it is difficult to use electricity. Liquid hydrogen is the fuel that has propelled the space shuttle and other rockets since the 1970s, and hydrogen fuel cells power the shuttle's electrical systems, producing water as a by-product.

  • Hydrogen is not found in its natural state on earth, so must be manufactured, either by using high-temperature steam to extract hydrogen from natural gas (CH4), or by electrolysis. Hydrogen can also be produced by biological organisms and indirectly from the heating of biomass or fossil fuels.

  • Hydrogen fuel cells essentially do the reverse of electrolysis, combining hydrogen with oxygen and using the release of chemical energy to create an electric voltage.

  • The first widespread use of hydrogen will probably be as an additive to transportation fuels. Hydrogen can be combined with petrol (gasoline), ethanol (alcohol), methanol, and natural gas to increase performance and reduce pollution. Adding 5 per cent hydrogen to motor fuel can reduce nitrogen oxide emissions by 30 to 40 per cent in today's engines.

  • Hydrogen is also likely to be used as an aircraft fuel. Its high energy content means reduced weight and fuel consumption compared to current jet fuel, and it is non-polluting. Converting to hydrogen fuel would be easier for aircraft because the infrastructure is much simpler.

  • Hydrogen could also be added to natural gas to reduce emissions from power generating plants.

    Hydrogen fuelcell bus Madrid
    Hydrogen fuelcell bus Madrid
    Hydrogen fuel cell bus Madrid. Photo © Fuel Cell Bus Club
  • Under a €50 million EU programme, Clean Urban Transport for Europe (CUTE), 27 experimental hydrogen fuel cell buses operated in Amsterdam, Barcelona, Hamburg, London, Luxembourg, Madrid, Porto, Stockholm and Stuttgart, between 2003 and 2006. Altogether, the buses carried passengers over 840,000 km.

  • In a related project, three fuel cell buses operated in Reykjavik, Iceland, which plans to replace fossil fuels with hydrogen over the next 30 years and create the first hydrogen economy.

    See The clean car is coming, Iceland shifts to hydrogen economy and the Hydrogen Now! website.