How is hydrogen made?

Discover hydrogen: a key element in our universe and our energy future.
Biogas to hydrogen steam reforming plant

Hydrogen, the simplest and lightest of chemical elements, is proving to be a versatile resource at the heart of today's challenges. Used as a clean fuel, an essential ingredient in the chemical industry and a driving force behind decarbonisation, hydrogen offers innovative solutions to energy and environmental challenges. Find out more about its different forms, and discover the initiatives developed by Veolia, which is committed to producing low-carbon hydrogen from renewable sources.

What is hydrogen?

Hydrogen is the simplest and lightest of all chemical elements. It is very abundant in the universe and is often found combined with other elements. In its pure state, hydrogen is a colourless, odourless gas. 

Hydrogen is also highly flammable when exposed to a source of ignition in the presence of oxygen. It is used in a variety of applications, including as a fuel in fuel cells to produce electricity, in the chemical industry to manufacture ammonia and other products, and as a lifting gas in certain types of balloons. It can be found in water, oil and natural gas. 

At the heart of tomorrow's challenges, hydrogen is a key element in the transition to cleaner, more sustainable forms of energy, and has important applications in a range of sectors including energy, industry and transport.

The different colors of hydrogen:

The color of hydrogen, associated with its environmental impact, depends on the production method. Black" or "brown" hydrogen is produced from coal, while "grey" hydrogen comes from natural gas, with a "blue" variant if CO2 emissions are stored. Yellow" hydrogen is low-carbon, produced by electrolysis using nuclear electricity, and "green" if it comes from solar, wind or hydroelectric power. The French hydrogen strategy, announced in 2020, focuses on decarbonising industry, developing hydrogen-powered mobility and supporting research, with the aim of installing 6.5 GW of electrolysers by 2030 to develop the production of low-carbon and renewable hydrogen.

Green, low-carbon hydrogen

Because hydrogen is not a primary energy source like wind, sun or coal, it has to be extracted by separating it from the elements (water, hydrocarbons, biomass) with which it is associated. There are many different ways of producing hydrogen, all of which determine its environmental footprint. When it comes from fossil hydrocarbons, the steam-reforming technique is used: natural gas is exposed to very hot steam, releasing the dihydrogen (H2) it contains as well as the CO2. The problem? The hydrogen produced in this way is said to be "carbon-based" because the CO2 emitted is generally neither captured nor stored. This use is associated with significant greenhouse gas emissions. 

The water electrolysis technique, on the other hand, uses an electric current to break down the water molecules and recover the dihydrogen. Manufactured without fossil fuels, the hydrogen produced in this way is non-emissive and, in fact, "low-carbon" because it is produced by electrolysis of water using electricity from the electricity grid. Hydrogen is said to be "green" or "decarbonised" if the electricity used is renewable, such as solar, wind or hydro power.

While water electrolysis is undoubtedly the best-known process, it is not the only one that can be used to produce green hydrogen. Biomethane, a green and renewable gas obtained by methanisation from solid or liquid bio-waste deposits such as household waste or residual sewage sludge, is another source. Thanks to the reforming technique, the biomethane is then split into hydrogen and CO2, the latter of which can be captured before being released into the atmosphere or be biogenic and therefore have a perfectly neutral carbon footprint.

Hydrogen and decarbonisation: a national challenge

Since 2018, France has been among the first countries to consider green, low-carbon hydrogen as an effective way of reducing greenhouse gas emissions while remaining competitive. The country has therefore chosen to support the industry, devoting resources to it as part of its Future Investment Programme (PIA). And with the national strategy for the development of low-carbon hydrogen announced by the government in 2020 and the France 2030 plan, France is investing €9 billion to create a competitive low-carbon, renewable hydrogen industry. 

It should be noted that all industrial uses account for around 780,000 tonnes of hydrogen a year, produced mainly from fossil fuels and emitting 8.7 million tonnes of CO2 every year (source Ademe). Developing the production of green, low-carbon hydrogen will significantly reduce the environmental impact of all these industrial uses. 

And that's not its only advantage, as hydrogen is proving to be a perfect fuel for heavy mobility applications such as public transport (buses, trains, boats, etc.) and freight transport (lorries, freight, etc.). 


Production of green hydrogen: Veolia makes a commitment

From the production of hydrogen from biomethane or via electrolysis at its waste to energy sites, using the excess electricity generated by waste-to-energy conversion to dissociate oxygen and hydrogen molecules from water, Veolia is committed to developing these new sources of low-carbon energy on a regional scale as part of a circular economy and the preservation of resources. Green gases can replace fuel for heavy vehicles or be used in heating networks and industrial boilers, with the result that the chemical and steel industries are on the road to decarbonisation.

An example? Veolia produces hydrogen from biogas produced from sewage sludge and uses it as a fuel. Carried out in partnership with the Toulon Provence Méditerranée metropolitan area, this project offers obvious advantages: recharging with hydrogen is just as quick as recharging with petrol or diesel, and the only emission into the atmosphere is water vapour - in other words, no harmful gases! 
And that's not all. The project also aims to recycle the CO2 produced by growing microalgae. These microalgae have the particularity of feeding on this gas in order to develop, and can ultimately be used as animal feed for fish farming. This wastewater treatment plant, capable of converting waste into hydrogen, is a world first, and is currently being duplicated in Hong Kong.

The Group is also providing all its expertise to the players in the sector, supporting both the industry of this green hydrogen produced from renewable resources and that of blue hydrogen produced from natural gas by combining carbon capture and storage to avoid its emission into the atmosphere. Finally, the combination of innovative technologies and treatment services makes it possible to deliver high-quality water to improve the efficiency of water electrolysis.

All these innovative actions can be found in the GreenPath Zero Carbon offering, which brings together no fewer than 100 solutions designed to support our customers on their zero-carbon trajectory and reduce the impact of their activities on the climate. Through a tailor-made decarbonisation roadmap, the actions to be taken - to preserve and restore resources, optimise energy efficiency, create green energy loops or optimise the recycling of materials - are deployed. 
At a time of population growth, increasing scarcity of resources and climate change, energy is one of the major challenges facing the world of tomorrow. With needs constantly on the rise, it's becoming imperative to do things differently.

Alternatives do exist. There's only one thing to do: take action!