• Question: Is hydrogen combustible?

    Asked by vintageflower22 to Josh on 27 Jun 2013.
    • Photo: Josh Makepeace

      Josh Makepeace answered on 27 Jun 2013:

      Hi vintageflower22 – yes, it is! The fact that hydrogen is combustible is one of the reasons why we’re interested in it as a fuel. Combustion is the main way we use to power vehicles.

      When we talk about combustion, we mean the reaction of a fuel (in this case hydrogen) with something called an oxidant (here, it’s oxygen) to release energy. So in current cars, you have a combustion reaction between petrol (which is mainly octane, C8H18) and oxygen. The reaction gives off lots of energy, and produces water and carbon dioxide.

      With hydrogen, the combustion reaction with oxygen releases about three times as much energy as for petrol (per kg of fuel), and only produces water, not carbon dioxide. This is a good thing because it means that there are less greenhouse gases being emitted, so less climate change 🙂

      For hydrogen, you can combust it in a few different ways – you can burn it with oxygen in a similar way to how current cars work, or you can react it with oxygen in a fancy battery called a fuel cell, which creates electrical energy.

      Hope this helps 🙂