A world in which every means of transport – from cars to trains, from trucks to planes – moves without emitting a single particle of CO₂. A world where water is the raw material of a silent revolution, and what comes out of the exhaust pipe is only steam. This is the dream that has accompanied the vision of hydrogen as the energy carrier of the future for decades. But today, with the increasingly urgent pressure of the ecological transition, that dream is back with a new guise: green hydrogen, produced with renewable energy. Next to him, fuel cells – the so-called fuel cells – which promise to transform that hydrogen into clean electricity. But the question remains: is this vision a real alternative or just a fascinating illusion?

The heart of the technology: how green hydrogen works

Green hydrogen is produced through a process called water electrolysis, which consists of splitting H₂O molecules into hydrogen (H₂) and oxygen (O₂) using electricity from renewable sources (such as solar, wind, or hydroelectric). This technique does not generate greenhouse gas emissions during production, making green hydrogen one of the most promising solutions for a zero-emission energy transition.

To better understand the environmental value of this technology, it is useful to distinguish between the various types of hydrogen, classified according to the production method:

• Grey hydrogen is currently the most widespread globally. It is obtained through steam reforming of methane (natural gas), an inexpensive, but highly polluting process, which involves the direct emission of large quantities of CO₂ into the atmosphere. It is therefore the least sustainable form.
• Blue hydrogen, which is more recent, derives from the same process as gray but is flanked by CO₂ capture and storage (CCS) technologies. This improves its environmental profile, but still ties it to fossil fuels and technologically advanced and expensive infrastructure.
• Green hydrogen, on the other hand, is considered the ideal "point of arrival". It does not involve climate-changing emissions, as long as the electricity used for electrolysis also comes entirely from renewable sources. At the moment, production costs are still high compared to alternatives, but technological progress and falling prices of renewables could make this option increasingly competitive.

Thanks to its versatility, green hydrogen can be used to power fuel cells, store energy from intermittent sources, decarbonize hard-to-electrify sectors such as heavy industry, aviation, and long-distance transport. However, to make this vision a reality, clear public policies, incentives, dedicated infrastructure, and a strong commitment to research will be needed.

Benefits that look like something out of a science fiction movie

The first advantage is visible to the naked eye: zero emissions during use. It is no coincidence that many major car manufacturers speak of "hydrogen vehicles" as true zero-impact mobility.
The second is in the refueling times: a few minutes for a full tank, just as is the case today with petrol or diesel. The third concerns heavy vehicles: for long-haul transport – trucks, trains, ships, planes – hydrogen offers a longer range with low weight, where electric batteries still struggle. Finally, there's flexibility: hydrogen can be produced anywhere there is water and sun or wind, offering energy independence and a smart way to store excess renewable energy.

But there is a price to pay

Like all emerging technologies, green hydrogen also has its critical nodes. The most obvious? The cost: producing hydrogen with electrolysis is still much more expensive than traditional methods. Then there is efficiency: between production, compression, transport, and conversion into electricity, up to 70% of the initial energy is lost. A sobering figure, especially when compared to the efficiency of batteries. The infrastructural problem should not be forgotten: there are very few hydrogen distributors, the logistics networks almost non-existent. And finally, the safety factor: hydrogen is flammable, light, difficult to manage – even if containment technologies are making great strides.

Between hydrogen trains and futuristic trucks: the first experiments are real

Hydrogen is not just theory. In Germany, the Coradia iLint hydrogen train is already a reality. In Italy, tests are being conducted to introduce similar trains on some regional routes. Urban transport companies, such as Toyota, Hyundai or the American startup Nikola, are developing fuel cell trucks and buses. Airbus even aims to fly a hydrogen aircraft by 2035. And in some European steel mills, hydrogen is already being used to reduce the use of coal, making heavy industry cleaner. The way is open. But not yet paved.

The truth lies in the middle

Green hydrogen is not a universal panacea, but neither is it an illusion. For private cars, battery electric is now more efficient, more accessible and with more developed infrastructure. But for trucks, trains, planes, industries, and long-term energy storage, hydrogen can make all the difference. Its credibility will depend on its ability to reduce costs, boost renewable production, and create a robust industrial and logistics supply chain. After all, every revolution needs time, vision and investment.

Sources and insights

• ENEA – The "colors" of hydrogen in the energy transition. Link
• The Automobile (ACI) – Hydrogen vehicles: how do fuel cells work? Link
• ACEA – Green hydrogen: what it is, how it is produced and advantages. Link
• iBicocca – Italy is betting on green hydrogen. Link