Is hydrogen really an ecological energy?

Is hydrogen ecological? Is there a solution to solve the climate crisis? Let's try to understand the prospects of hydrogen technologies in terms of ecological transition.

In recent years, there has been more and more talk of hydrogen as a solution to the ecological crisis. Recently, Europe even developed its “hydrogen strategy”. The goal is to develop hydrogen production techniques to “decarbonize” Europe. In France, we also want to bet on hydrogen: the country has even just ordered its first hydrogen trains.

Hydrogen is presented as a solution for mobility and air transport, for industry, but also for domestic heating. In short, hydrogen seems set to be at the heart of the ecological transition strategy for the coming decades. In theory, hydrogen has something to seduce: when it is used, it emits neither pollutants nor greenhouse gases, only water. But what is it really?

Is hydrogen really ecological? What are its ecological impacts, in production, in use? What are the challenges posed by hydrogen technologies? What will they really do? Let's try to understand.

Hydrogen: how does it work?

When we talk about hydrogen in the context of the ecological and energy transition, we are actually talking about dihydrogen. It is a molecule made up of two hydrogen atoms (H ₂ ) found in the gaseous state. Hydrogen can be used as fuel, or more frequently, indirectly via a fuel cell: the hydrogen is stored in a fuel cell which makes it possible to produce electricity on demand.

Hydrogen has several advantages. When hydrogen is used, its combustion produces only water. This is also why it is called hydrogen (hydro, water – gene, product). Hydrogen is also the most abundant element in the universe. It therefore has the advantage, unlike fossil fuels, of being available in large quantities: there is no risk of running out of it in the short term.

However, it must be understood that hydrogen is not an easily accessible resource. Although there are many of them on earth, it is always mixed with other chemical elements. For example, we find hydrogen in water, but coupled with oxygen atoms: it is H ₂ O – H ₂ dihydrogen, O oxygen. Hydrogen is also found in fossil fuels, for example in natural gas, but it is then coupled to carbon atoms. In methane, for example, it is in the form of CH ₄ . On the other hand, hydrogen is not found “alone”.