"Yes, my friends. I believe that water will be used someday as a fuel, that hydrogen and oxygen, which constitute it, used alone or simultaneously, will provide a source of heat and light inexhaustible and of an intensity that coal could not see", Jules Verne in "The Mysterious Island" in 1875.
Hydrogen comes from fossil fuels at 95%. The objective of many countries is to develop green hydrogen that would not come from fossil energies emitting many greenhouse gases, but from renewable energies or decarbonated ones (including nuclear).
What is hydrogen?
6 things to know about hydrogen
- Dihydrogen (real name, because it is systematically composed of two hydrogen atoms, hence its chemical symbol - H2), hydrogen is produced by hydrocarbons (or fossil fuels like coal, gas, or oil) and water.
- Contrary to what we think, hydrogen is not an energy, but it is an energy carrier created from a primary resource and produced by a chemical reaction. That is the reason why it is always combined with other atoms.
- The three techniques to produce low-carbon hydrogen are: gasification, water electrolysis, and natural gas reforming from steam.
- Nearly 92% of the atoms present in the Universe are hydrogen atoms. It is the main element of stars and gaseous planets like Jupiter, Saturn, Uranus, and Neptune.
- Today, hydrogen is used in refining, the production of ammonia (NH3) for nitrogen fertilizers and explosives, the production of methanol for plastics manufacture, and the steel industry for iron and steel.
- “Green" hydrogen represents a future lever in the transition to carbon neutrality. But it currently represents only 1% of the world's hydrogen.
Green hydrogen, assets, and constraints
Since dihydrogen is often associated with another molecule, it must be extracted to isolate the atom. Moreover, as dihydrogen is composed of two hydrogen atoms, the molecule has to be split equally to have only one hydrogen atom. Different methods to produce hydrogen :
This green hydrogen production system consists of the combustion of a mixture of CO (carbon monoxide) and H2 (hydrogen) in contact with coal or other biomass. Methane is used because it is the main component of natural gas and its combination of atoms is simple (CH4), so hydrogen is more easily extracted. Indeed the reaction of this process rejects CO2 in solid state. So extracting H2 becomes easy.
The electrolysis of water
The water electrolysis mission is to separate the water molecule (H20) to extract the hydrogen and oxygen atoms. This solution is undoubtedly the most used because it results in no emission of CO2. The reaction rejects only oxygen in the form of water.
Cependant l’électrolyse fonctionne avec l’électricité ce qui la rend très onéreuse. De plus, la construction d’une électrolyse est également très chère. Afin que cette méthode soit rentable, il faudrait utiliser de l’électricité peu carbonée qui serait fournie par l’intermédiaire d’une énergie renouvelable comme le nucléaire, l’éolienne ou les panneaux solaires. Le manque de ces énergies renouvelables est un frein à la construction de nombreux électrolyseurs donc à la production d’hydrogène vert.
Steam reforming of natural gas
Steam reforming of natural gas is a chemical reaction of methane with water to obtain a mixture containing CO2. Through this process, carbon dioxide could produce decarbonized hydrogen.
We could use hydrogen to decarbonize some industrial sectors, store electricity, or power transportation.
Hydrogen has great potential to contribute to the reduction of greenhouse gas (GHG) emissions.
Completely clean, hydrogen emits no CO2 and is very light. If mass-produced, it participates in global warming reduction and is, therefore, the major player in the energy transition.
The storage of hydrogen is a real blocking point to its use. It has a high massive energy density but low volume because it is very light.
A plan is to make it liquid to compress it at a low temperature of -253°C (4l H2 = 1l petrol).
Mass production of low-carbon hydrogen is necessary to bring real positive changes to the climate. On the contrary, green hydrogen production in small quantities generates global warming.
Green hydrogen costs a lot because it depends on electricity, which is very high today. It is also necessary to reduce the costs of renewable energies which are the primary basis for the production of green hydrogen, as well as electrolyzers and fuel cells.
The deployment of this green energy also requires huge infrastructures that must have a capacity of production powered by renewable energies, a transport network to distribute them, and various storage locations.
What are the uses of green hydrogen?
Cars and trucks
Transportation in France is the leading sector emitting greenhouse gases, 30% of all GHGs. A hydrogen vehicle running on renewable electrolysis will emit only 15 tons of CO2, compared to 45 tons for a diesel vehicle. This solution would reduce the carbon impact by 74% compared to a thermal motor vehicle.
The most suitable system for the hydrogen engine is fuel cell use. Lighter than batteries and more efficient, it is also perfect for the environment. Indeed, the cells work by combining the hydrogen present in the engine with the oxygen in the air. This reaction produces electricity that will power the vehicle's engine. The only waste product is clean water.
Fuel cells have been used since 1839 to provide electricity onboard rockets. As the first ones were employed during the Gemini and Apollo space missions, they are used today to power rockets. Therefore the fuel cells are more easily chosen to provide "green" engines for heavy vehicles. Indeed, it would take too many electric batteries for enough power to run a truck, which would make the motor too heavy.
The big difference between electric and hydrogen vehicles is autonomy. While the hydrogen car can travel up to 600 km and recharge quickly, the electric car charges more slowly.
55% of rail lines in France run on electricity, the rest on diesel. That's why SNCF and other French companies are working to deploy more CO2-free fleets.
Alstom, for example, launched its first hydrogen train carrying passengers in Germany in August 2022. It operates on a hydrogen fuel cell.
Airbus wants to participate in this new energy rollout and is committed to building hydrogen aircraft by 2035. To do this, the company has to manufacture specific items, light fuel cells, and acquire powerful electric motors.
If hydrogen is transformed into methane, it has the ability to store a large amount of electricity. It thus can be used in case of failures of renewals, such as wind turbines or solar panels, which are subject to intermittency. These are effectively dependent on the climate so they might be subject to interruptions in electricity production.
Burning hydrogen automatically produces heat, so we could consider replacing coal with hydrogen.
For example, the production of iron and steel with coal emits huge amounts of greenhouse gas emissions. A factory in Sweden uses hydrogen for its iron production. The production of one ton of iron causes the emission of 25 kg of CO2, while the use of coal causes the emission of 1850 kg of CO2 for 1 ton of iron.
The manufacture of steel, which is done today by reducing iron ore via coal, could tomorrow be done via decarbonated hydrogen.
Development projects around the world
More and more companies are getting into the business of making green hydrogen to help with the energy transition and global warming reduction. Since hydrogen is a dangerous gas, these companies must secure their premises and protect their employees. Therefore we have more and more requests for hydrogen detection devices, such as the OLCT100 fixed gas detector, the X-am 2500 4-gas detector, or the GasBadge Pro single gas detector.
The NortH2 project is the largest hydrogen production project in Europe to produce green hydrogen using renewable electricity from offshore wind power off the coast of the Netherlands.
The German company H2Fly has already been specializing in hydrogen fuel cells for aviation for a few years. The first airplane was successfully launched in 2016.
The German company, Home Power Solution, is a pioneer in domestic solar hydrogen power plants (picea) production. It is pushing individuals to consume their energy to stop emitting carbon dioxide.
The Swiss company H2 Energy has set itself the mission of stopping global warming by making hydrogen from renewable energies an energy pillar.
France is investing more and more to make hydrogen the future energy for France. It follows the SNBC (National Low-Carbon Strategy) roadmap to achieve carbon neutrality through decarbonized hydrogen.
The France Hydrogène association gathers many economic actors (large industrial groups or start-ups) to accomplish the energy transition through hydrogen solutions.
Pau is one of the pioneer cities that set up a fleet of hydrogen-powered buses in early 2021. Thanks to electricity supplied locally by a dam, this reduces the cost of manufacturing.
The John Cockerill company specializes in energy transition and develops green hydrogen production and the construction of electrolyzers.
The company H2SYS in Belfort specializes in the development of fuel cells and the design of hydrogen generators.