What does green hydrogen consist of?

Within the energies of the future, hydrogen has always been talked about. Both for mobility and for the generation of electricity in general, it has been considered a key element. However, its use is still limited and, in addition, there are different types of hydrogen . The most interesting of these is undoubtedly green hydrogen . Therefore, we want you to know everything about him.

As we will see, not all hydrogen is created equal. For the creation of this fuel we have various techniques and it depends on whether it is totally ecological or not.

What is green hydrogen?

Green hydrogen is one that is produced using only renewable energy . These have very low or zero emissions, so that, during its production process, green hydrogen does not negatively affect the environment either.

As during its use as a fuel, for example, hydrogen of any kind does not produce harmful emissions either, green hydrogen would therefore be the most ecological alternative , since it would hardly have an environmental impact during its entire life cycle.

What other kinds of hydrogen exist?

Traditionally, the production of hydrogen has been done through the use of fossil fuels and, depending on the creation process, it receives a color designation, although hydrogen itself is always a colorless gas.

Thus, in addition to green hydrogen, we have:

“Brown” hydrogen: which is produced by gasifying coal or lignite.
“Grey” hydrogen: which is made by steam reforming methane, which typically uses natural gas as a feedstock.
Both production processes are not environmentally friendly , so in order to reduce that impact we also have:

‘Blue’ hydrogen: This gas is again produced by steam reforming of methane, but emissions are reduced by CO 2 capture and storage . This process could roughly halve the amount of carbon produced, but it is still far from emission-free.
Although there are other more effective attempts to reduce these emissions in hydrogen production (such as methane pyrolysis, which is sometimes called “turquoise hydrogen” and can trap up to 90-95% of CO 2 ), they are still in progress. a pilot phase and, due to cheaper renewable technologies, green hydrogen is much more interesting and practical right now .

How is green hydrogen produced?

The key is to separate the water (H 2 O) into its components: hydrogen and oxygen. For that, an external electrical current is applied to the water 

This process, called electrolysis , is the most efficient to produce hydrogen from electricity and the key is that said electricity is generated by renewable energies to consider hydrogen green.

Why is green hydrogen important?

Because, although the energy use of the future goes through a great electrification driven by renewables, it is not possible, nor efficient, to electrify everything .

For example, transportation, especially heavy-duty transportation, aviation, and the like, will require hydrogen as fuel. 

In the same way, green hydrogen helps alleviate one of the great challenges of renewable electricity, its difficulty in storing it . With green hydrogen we have a way to convert electricity into a fuel or energy source that can be storable, transportable and clean.

Especially in sectors or places where it is difficult to get electricity, or this is not the optimal way of use (as in that great transport), green hydrogen will be key.

An example of its importance is the role it has within the Green Deal of the European Union, which seeks to promote it.

What are the advantages of green hydrogen?

Knowing all of the above, the main advantages of green hydrogen are clear.

  • It is respectful with the environment: since it does not emit polluting gases or those that cause the greenhouse effect. Neither during its use as fuel, nor during its production.
  • It can be easily stored and transported: for example, we can even use the gas infrastructure we have to take it where it is needed (although mixing it with said gas).
  • It has multiple uses: once converted into hydrogen, it can be used again as a source of electricity, or as fuel gas for vehicles.

What are the disadvantages of green hydrogen?

As usual, not all are advantages. In fact, some of the main challenges that hydrogen faces have made it always seem like great promise, but its use is not massive. 

That’s because of these drawbacks:

  • It is expensive to produce: because electrolysis is not cheap . It is true that renewables do not stop reducing their cost and that works in their favor, but it is not a process that makes hydrogen profitable yet.
  • It has security risks: since it is a flammable and volatile gas, it requires security measures to prevent it from escaping or combusting.
  • It consumes a lot of energy in its production: being, in general, not very efficient in its manufacture.

All these challenges are what we want to overcome by promoting green hydrogen, in order to make it a key part of tomorrow’s energy mix .

As we can see, not all hydrogen is the same and green is the most environmentally friendly. Necessary to promote some sectors in a clean way, it is to be hoped that, with the price of renewables and the increase in investment, we will hear much more of its name in the near future.

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