In recent times we have seen the resurgence of hydrogen as a key promise in the decarbonisation of industry. News of projects in Spain such as Iberdrola, Acciona or Naturgy have renewed interest in hydrogen.

I still remember back in 2004 attending a talk by Jeremy Rifkin, the guru at the time of the so-called hydrogen economy that promised a new society based on cheap, clean and inexhaustible energy. That is why I must admit that, since then, I have been rather sceptical about the successive hydrogen hypes. Moreover, the fact that oil companies like Shell or BP have always been the biggest fans of hydrogen, has not helped much to improve my perception of the issue. But it is time to forget old prejudices and revisit the state of the art of hydrogen to discover whether we are really facing a viable option or, on the contrary, we are facing a new bubble.

1. Basic concepts

Hydrogen is basically an energy carrier that can be produced from various energy sources, that can be liquefied or transformed to be transported and that can be used directly as an energy source or for industrial processes…basically it is like having non-polluting oil or gas. Hence the great interest of the oil sector to push this option, since they have always seen it as the clean evolution of their business, where they could leverage their transport and distribution infrastructures.

Although it may seem like a new concept, hydrogen has been used for many years in the oil refining and chemical industry (through a derivative called ammonia).

Let’s look at the types of hydrogen generation that exist:

– Grey Hydrogen: is the one created with fossil fuel. It is most of the one currently produced and is a highly polluting process that causes large emissions of CO2

– Blue Hydrogen: it is like the previous one, but adding some CO2 capture process (CCS). This type of CCS technology is increasingly criticized for being an expensive and complex excuse (and with very questionable results) to continue maintaining highly polluting processes. – Green Hydrogen: is the one produced from renewables and the great protagonist of the future. It is the only one with zero emissions and its competitiveness is linked to that of renewables. Here, both wind and solar are trying to position themselves as the optimal source, with interesting concepts such as the one proposed by GWEC in its latest report to combine offshore and hydrogen

2. Technology

Hydrogen is produced with electricity through a process called electrolysis. The device used is an electrolyser, which is basically an anode and cathode immersed in an electrolyte liquid and separated by a membrane. Depending on the type of membrane, we have different types of devices such as PEM (polymer membrane), ALK (alkaline) or SOEC (solid oxide)

This is the key to the matter. Currently the H2 green is much more expensive than the others. According to IRENA’s report on hydrogen, the current cost is over $3.5/kg

3.        Cost

As Gniewomir Flis points out in this Twitter thread, the cost should be well below $1/kg in order to compete with grey hydrogen. Let’s see the challenges to reach those cost levels:

– Electrolyzer cost: it has to be reduced dramatically. This will be achieved by increasing the size and improving the technology. But this is something that will take years since it is a very immature technology and the manufacturers themselves like Enapter see it as a big challenge.

– Cost of renewable electricity: this part is simpler since there are already solar and wind plants that generate at less than 20$/MWh and in addition the excess electricity could be used (curtailment).

– Efficiency: currently the processes of production and treatment of hydrogen are very inefficient and losses of over 50% are generated. Improving electrolysers will improve these values, but this is one of the great challenges of the technology.

4.        Applications

– Replace grey H2: it is the most obvious but as we have seen in the cost part, it will not be easy at all. But it is increasingly urgent as the production of “dirty” hydrogen emits as much CO2 as the UK and Indonesia combined

– Heavy industry: steel, cement, chemical, aluminium and other industries are large emitters of CO2 and there are currently no solutions to electrify them. Hydrogen could be an option. In fact, there are already projects to incorporate hydrogen into steel production, for example.

– Energy storage: is another immediate application but here it has to compete with Lithium Ion batteries and even new technologies such as flow. I find it difficult that when hydrogen becomes cost competitive, the batteries will not be much cheaper, have more storage capacity and be safer.

– Heavy transport: here again hydrogen targets the heavy transport niche that will not be able to have battery solutions in the medium term such as ships, planes or heavy trucks

– Heating: this is one of the most promising applications because once again it is a great field where electrification has no chance of success.

– Light transport: again, it is difficult because it has to compete with batteries.

5.        Conclusions

This is a very promising technology that could be the missing piece in the puzzle of the electrification of the economy in fields such as heating, heavy industry or long-distance heavy transport. But to get there, there is a long way to go to mature the technology, reduce costs and improve efficiency.

However, in applications where there are already more developed and cheaper technological options (energy storage, light transport, etc), it seems more the desire of some companies to make hydrogen their table of salvation, than a viable and future reality. We are going to need all the technologies for the great challenge of decarbonization and I do not believe that we can rule out hydrogen but it seems that its role will be in the medium term to complement renewables and batteries to cover sectors where there are no technological solutions for clean electrification.