2024-06-19 06:30:29
In a report sent to the Élysée, the French scientific institution draws up a series of recommendations to remove the obstacles linked to the development of green hydrogen. This gas has many advantages and can play an important role in France’s energy strategy with a view to decarbonizing its economy, but under certain conditions.
High production costs, insufficient electricity production, electrolyser not efficient enough, etc. in a rapport transmitted to the cabinet of the Élysée and made public, the Academy of Sciences draws up a series of recommendations to remove the obstacles linked to the development of green hydrogen and ensure that it becomes one of the energies of tomorrow. For the authors of this document, this gas has long been the subject of both hopes and fantasies. Hopes that this fuel, rich in energy that can be used without CO2 emissions, allows us to envisage its large-scale use to defossilize a whole series of uses. But also fantasies that arise, among other things, from a confusion, unfortunately frequent, between energy source and energy vector.
Certainly, hydrogen exists in its natural state, it is then described as “white”, but its prospects remain very uncertain, according to the experts of the Academy. The latter recommend to support quickly and without hesitation the exploration projects of the French soil aiming to rigorously evaluate the real potential. Several deposits have been identified, one of which is located in Lorraine, and which some have described as “gigantic”, or even “the largest in the world”. However, it is still too early to know if this natural resource will be sufficient and exploitable, and the first step is to precisely determine the accessible volumes.
For the moment, the decarbonized hydrogen mentioned in all the scenarios is produced by water electrolysis. This hydrogen, described as green, therefore does not have the characteristics of an energy source, but corresponds to a secondary energy or an energy vector, i.e. a form of energy obtained by transforming another form of energy. Currently, France produces and consumes approximately 0.9 million tonnes of gray hydrogen per year, from the reforming of natural gas. It is mainly used for oil refining and the synthesis of ammonia, necessary for the production of fertilizers. By 2050, the volume could reach up to 3.9 million tonnes if significant quantities of hydrogen are used for road and air transport.
However, the conditions for meeting this growing need are still far from being met, according to the Academy of Sciences. And to hope to drive positive momentum in this direction, it recommends rapidly increasing additional electricity production capacities. Knowing that each million tonnes of green hydrogen produced by electrolysis requires approximately 55 TWh of electricity, the equivalent of 5 EPR reactors of 1600 MW. The level of hydrogen production and consumption must also remain compatible with the trajectories of the electricity mix defined within the framework of energy planning.
Lowering the cost of producing green hydrogen to less than 3 euros per kilogram
At the same time, experts from the French scientific institution advise rapidly increasing electrolysis capacities while improving the various technologies, particularly the less mature ones, such as high-temperature electrolysis. “This will make it possible to reduce the production price of green hydrogen, a necessary condition for it to play a significant role in the future energy system, write the authors of the report. The price is currently between 4 and 8 euros per kilogram of hydrogen depending on the technology (1.5 to 2 euros per kilogram of hydrogen for grey hydrogen) and the objective is to go below 3 euros per kilogram of hydrogen.
It is also appropriate to continue strong fundamental and technological research to improve the energy yields of electrolysers and hydrogen fuel cells and reduce their environmental footprint. Efforts must also be made to improve the stability and reduce the weight of hydrogen tanks, through the development of new materials, but also to make the use of ammonia as a hydrogen vector more efficient.
The aspect related to safety issues must also be taken into account, particularly in the field of transport. Accidents due to hydrogen could block its deployment and vigilance must be given to the safety of hydrogen-powered aircraft. The Academy of Sciences also recommends conducting a strict arbitration policy, to define priorities between the different uses of hydrogen. “Given that it will not be possible to hydrogenate everything, priority must be given to the use of green hydrogen for the decarbonization of industry and certain forms of transport, before other uses such as “power to gas” (heating homes and the tertiary sector) and “gas to power” (for example to power hydrogen cars, which are less energy efficient than electric cars, or for the flexibility of the electrical system)”the experts write in this report.
Finally, it is necessary to rigorously assess the carbon footprint on all value chains of new processes and new uses of hydrogen, as well as strictly control the level of hydrogen imports so as not to move from one strong external dependence (imports of fossil resources) to another (imports of hydrogen).
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