Hydrogen fuel cells
Hydrogen fuel cells operate by reacting hydrogen and oxygen gases together to make water. This process is exothermic – it releases usable energy. Although it uses both hydrogen and oxygen, it is called a hydrogen fuel cell because hydrogen is a fuel that’s burnt in the presence of oxygen to make water, exactly the same way that a fossil fuels burn, except that there’s no carbon dioxide made from hydrogen.
Hydrogen is considered a green fuel, and because of this it is an attractive future energy source. Scientists have envisaged a future where hydrogen gas could be a major source of everyday energy, reducing greenhouse gas emissions, reducing the problem of climate change, and letting us use our televisions and computers to our hearts' content.
The hydrogen fuel cell is a simple bit of kit. It’s lightweight, with no moving parts, so doesn't malfunction easily. To work, hydrogen loses electrons that then travel round an electrical circuit to join up with oxygen atoms, producing hydrogen ions (or protons) and oxygen ions. The hydrogen ions are small enough to travel through a semi-permeable barrier to where the oxygen is. Here, they react together to produce pure, clean drinking water.
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| Fuel cell. H2 is catalysed to H+ at the anode; electrons travel through the circuit to provide a direct current and meet oxygen gas at the cathode, forming O2-. H+ ions then travel through a semi-permeable membrane to combine with O2- ions and make water. Image via © TWDK. |
