What is green hydrogen?

Green hydrogen is a clean fuel that allows renewable energy to be generated utilising electrolysis of water, using wind energy or solar energy
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Jules Verne told us about green hydrogen more than 125 years ago in his novel The Mysterious Island: "What are they going to burn instead of coal?... Water. Water broken down into its elements by electricity will one day be used as fuel."

However, we have not yet been able make what the author wrote about this type of renewable energy and the production of green hydrogen a reality. We currently use fossil fuels every day, both as part of our daily lives and in industrial development. A sustainable future, however, depends on whether we are able to achieve an energy transition by unreservedly committing to renewable energies and fuels such as green hydrogen.

Governments and institutions around the world are committing to achieving carbon neutrality in just a few decades. The European Commission, for example, advocates a climate-neutral Europe by 2050. Green hydrogen will be key in achieving this goal. Europe sees hydrogen as a key fuel and the development of technology is a priority for the Commission. Green hydrogen has therefore become one of the keys to the NextGenEu recovery packages.

 

What is hydrogen and how do we get it?

Hydrogen is the most abundant chemical element in the world. It is light, storable, dense in energy and alone it does not generate direct emissions of pollutants or greenhouse gases. Amazing, right? I can imagine what you're thinking: If it's so wonderful, why doesn't everything run on hydrogen? How is hydrogen produced for use as a fuel?

Today, we have various technologies that we can use to produce hydrogen, but not all of them are sustainable. A colour code distinguishing between the four types of hydrogen has been created in order to indicate the impact that they have and the emissions they generate:

  • Grey hydrogen: This is produced from fossil fuels and involves significant CO2 emissions.
  • Blue hydrogen:This is produced from fossil fuels with carbon capture and storage technologies and is less polluting than grey hydrogen. About three-quarters of the hydrogen produced today comes from natural gas. Blue hydrogen could be an initial solution while the production and storage capacity for green hydrogen is increased for industries such as the iron and steel industry. However, blue hydrogen only reduces carbon emissions and does not eliminate them entirely.
  • Turquoise hydrogen:  This is produced from natural gas using pyrolysis, but this process still involves a fossil fuel and is therefore not free from carbon emissions.
  • Green hydrogen: This is produced using renewable energy, making it is the most suitable method for a totally sustainable energy transition. The most widely available option for producing green hydrogen is water electrolysis powered by renewable electricity. This process involves the decomposition of water (H2O) into the gases oxygen (O2) and hydrogen (H2) using a continuous electric current that is passed through water with electrodes.

 

From grey hydrogen to green hydrogen

Around 5 % of the world's hydrogen is produced using electrolysis. Currently, hydrogen is primarily produced from natural gas and coal, which together account for the remaining 95 %. What's more, grey hydrogen production emits around 830 million tonnes of carbon dioxide per year, which is equivalent to the CO2 emissions of the United Kingdom and France combined.

Currently, only a small proportion of hydrogen is produced from renewable sources. The high cost of these renewable sources is one of the main reasons for this low level of production.

However, we are well placed at the moment to be optimistic about this situation: A new report from the International Renewable Energy Agency (IRENA) states that green hydrogen could be profitable in 2030. This is partly due to the ongoing gradual decline in solar and wind energy prices. This trend—a 40-80 % price decrease in the last decade—is expected to continue. In addition, IRENA estimates that the cost of hydrogen installations could decrease by 40 % in the short term, and by 80 % in the long term.

This future is closer than we think: The OCEANH2project, for example aims to design and validate Spain's first offshore green hydrogen generation, storage and distribution plant. The project will offer modular, flexible and intelligent optimisation adapted to new market trends based on offshore renewable electricity generation, combining floating wind and photovoltaic technology.

We have only just set out on the road to green hydrogen as an alternative to fossil fuels. We expect this solution to be key in moving towards the goal of sustainable development.

 

Sources: IEAInternational Energy AgencyBBC, European Clean Hydrogen Alliance, Cinco Días, IRENA