Power-to-X technology – how do we make renewable hydrogen and other green fuels?


Power-to-X means using renewable electricity to create something else (‘X’). The ‘X’ created is usually hydrogen, which in turn can be synthesised into other green fuels, such as e-methanol, e-kerosene, and e-ammonia. 


 

Using water and renewable energy to make hydrogen gas



Hydrogen is the most abundant element in the universe. On Earth, it’s mostly found in water, where it’s the H in H20 – but for us to use it as an energy solution, we need it in gas form.

Hydrogen as a gas can for example be used to power the transport sector. It’s produced by splitting water into hydrogen and oxygen using electricity – a well-established process called electrolysis.

The hydrogen is collected and used, while oxygen is released as a by-product if there’s no need for it locally. The electrolysis process also produces heat, which can be used in district heating systems. 

Hydrogen gas can be produced using fossil fuels, biogas, nuclear power, or renewable energy. At Ørsted, we’re only focusing on projects that will use energy from renewable sources to produce renewable hydrogen, ensuring that the fuel is carbon-neutral. 

Turning hydrogen into other green fuels



Green fuels are liquid or gaseous fuels produced from renewable energy. The most basic type of green fuel is renewable hydrogen. 

Hydrogen is a gas with a very high energy content per kilo but a very low volumetric energy density, meaning that it takes up a lot of space per kilo. 

Therefore, industries like deep ocean shipping and aviation, where cargo space is important, generally need alternatives to renewable hydrogen that have a higher energy density, such as e-methanol, e-ammonia, or e-kerosene. 

These green fuels, or e-fuels, are produced by combining renewable hydrogen with other elements – this could be carbon, which is used to produce e-methanol, or nitrogen, which is used to produce e-ammonia.

More on Power-to-X

Power-to-X will become a solid pillar in the energy system. Find out about how it will decarbonise the transport and industrial sectors.