… and a bit of chemistry. Hydrogen for dummies.
| August 2003 issue
The oil and gas supply is running out. It took millions of years for fossil fuels to evolve. Hydrogen, however, is available now and in abundance. In fact, 75% of the universe, as we know it, consists of hydrogen. The hydrogen economy offers the perspective of an endless, sustainable energy cycle.
Hydrogen is not a primary energy source, like oil, gas, sun or wind. Hydrogen is an energy carrier like electricity. Hydrogen (H2) exists almost exclusively in a compound form. It is, for example, the element that is found in every type of oil and gas (hydrocarbons). Two thirds of the fossil fuel atoms that are burned every day around the world consist of hydrogen!
Hydrogen is a component of water (H2O). You can produce hydrogen by ‘releasing’ it from oil or gas. You can also produce it by running an electric current through water (electrolysis): something many of us will remember from chemistry class at school. Electricity splits the molecule H2O into hydrogen and oxygen (O2) atoms. You can then collect the hydrogen. If you ignite it there is a small explosion as the hydrogen reacts (burns) with the oxygen, converting it back into water and thus releasing warmth (energy). This is the basis for the sustainable closed circuit of the hydrogen economy. Water with electricity separates H2 and O2. When H2 and O2 subsequently react to one another, energy is released and you get water, and the whole process repeats itself.
Back in 1839 the British inventor Sir William Robert Grove invented the so-called fuel cell, an important development in the hydrogen cycle. In a fuel cell hydrogen and oxygen react, releasing electricity and water (vapour). Now – years later – it is mainly thanks to its use in astronomy that the fuel cell is now ready for commercial production. Leading car manufacturers have developed prototypes of cars with engines driven by fuel cells some of which will go into production next year.
One challenge remains for the closed circuit: the electricity that is needed for the electrolysis of water – in other words, to make hydrogen – must be sustainably produced. After all, if the electricity is made from an oil, gas or coal-powered energy station, it still generates pollution and threatens to create future scarcity. But if electricity is produced sustainably, with the help of solar panels or windmills, for example, it becomes an endless source of energy. That is to say, endless until the sun stops shining in a couple of billion years.