- Ammonia NH3
- Methanol CH3OH
Hydrogen carrier fuels are available today in many shades of green. They include ammonia NH3 and methanol CH3OH.
They are 3-4 times more energy dense than pure hydrogen, meaning they hold more potential power per volume, making them better suited for transportation and storage. Supported by the fertiliser industry ammonia is the second most widespread chemical available across the world – but today e-ammonia makes up a small fraction of this. The price, availability and greenness of carrier fuels varies by country and will vary overtime. As the hydrogen economy develops, a flexible approach to sourcing Hydrogen will offer a cost advantage.
Converting carrier fuels into pure hydrogen suitable for use in fuel cells is not straight-forward though. The electro-chemical process of a fuel cell requires the hydrogen to be very pure, at least 99.9% pure. Using impure hydrogen in fuel cells will impact their lifetime and running efficiency. However not all fuel cells are equally vulnerable to impurities. Hydrogen from ammonia is more suited to alkaline fuel cells, whereas hydrogen from methanol is more suited to Proton Exchange Membrane (PEM) fuel cells.