Hydrogen is indicated by many as the energy source of the future, given that its combustion is among the least polluting in the world. When it burns in contact with oxygen, in fact, it emits energy and water. Water and not CO2, as in the case of fossil fuels, which makes it a much less impactful energy carrier.
Where is the hydrogen?
But the first thing to clarify when it comes to hydrogen is: it is not easily found. In theory it would be the most present element in the universe, but in practice on earth it is never found in its simple form. In fact, we always find it linked to other elements, such as oxygen to form water or carbon to form hydrocarbons. To obtain it, therefore it must be separated, and this is done through processes that in turn require energy and therefore a cost to pay. The most famous of these processes is the electrolysis of the water, which consists in breaking the water molecules through electric current.
How green hydrogen is produced and the difference with other types
How we produce hydrogen – and what price – is therefore a first fundamental factor. If the electricity to produce it comes from renewable sources, we will have the so -called “green hydrogen”. Instead, there is talk of “gray hydrogen” if it comes from fossil energy sources and “blue hydrogen” if at the end of the process we add the capture and seizure of carbon dioxide. Finished here? Not really, because that little hydrogen pure in nature, in the depths of the subsoil, can be extracted. In this case we speak of white hydrogen, but scientific research is still working to better understand their characteristics, location, quantities and in general the costs for extraction.
At what point are the projects on hydrogen in Italy
Cleger these differences you understand because, to date, we are moving above all towards the production of green hydrogen. In Italy there are specific projects for the realization of the so -called “Hydrogen Valleys”: one of these is “hydrogemus”, a production center in the Modena area which will be able to produce up to 400 tons of hydrogen per year, mostly intended for local public transport. The investment amounts to over 20 million euros, financed in part by the PNRR, and provides for the construction of a 6 megawatt photovoltaic park which will feed an electrolyser, or the device that extracts hydrogen from the water through the electrolysis process.
By widening the gaze, however, it is easy to imagine that in the future we will have several other poles in Southern Italy or North Africa, where there is a greater concentration of renewable, sunny and even winding energies. In this sense, it is interesting to note that Italy is in a strategic position, halfway between the producing countries and the importers. It is no coincidence that among the most important projects of Snam there is the construction of a transport system, the South2 Corridor, 3300 km long with which to bring hydrogen from Sicily to the south of Germany. This thing allows you to hook us to the next step of the supply chain: transport.
The transport of hydrogen: the experiments made
In 2019 an experiment was successfully conducted by Snam, to test the introduction of a mixture of hydrogen and natural gas within the existing network. In the test, the percentage of hydrogen entered was 5%, a percentage that would be equivalent to 3.5 billion cubic meters in one year, i.e. annual consumption of about 1.5 million families. This means that we potentially already have the transport infrastructures necessary for the transition, since 99% of the Italian network is ready, already today, to welcome hydrogen. The same project as South2 Corridor has almost 70% of the network only to be converted. Being able to use the infrastructures already present is a not small advantage, especially in economic terms. Hydrogen, such as natural gas, can then be transported also in liquid form on board the ships; In this case it occupies less space, but on the other hand the liquefaction of hydrogen is a very expensive process in terms of energy. In fact, to obtain a kilogram of liquid hydrogen are needed between 4 and 10 kWh, about a third compared to the energy that we would derive from its combustion: a loss to be taken into consideration.
How the storage of hydrogen works in the subsoil
Another theme is that of storage: like natural gas, hydrogen can also be preserved in the subsoil. Store hydrogen means to accumulate it when the request is minor, so as to guarantee a continuous supply. A very useful thing especially in relation to renewables, which can have different productivity based on the season of the year. The best natural hydrogen tanks are the
so -called “saline duomas”, that is, rocky waterproof rock formations. These are porous rocks that are “sealed” by waterproof layers and therefore manage to retain gases inside them. In short, natural containers much larger than any artificial tank, in which to store excess hydrogen.
What are the sectors in which it is most requested: the application for hydrogen in Italy
We talked about production, transport and storage, or everything related to a future hydrogen offer; Very often, however, we forget that, to create a real supply chain, you must also work on the other end, or the question. To date, the sector that is most by driving this transition is that of transport, with more and more hydrogen -powered means that therefore require this source of energy. For industries, on the other hand, the passage is more complex. In Dalmine, in the province of Bergamo, a prototype of electrolysis was installed to power a hot lamination system of pipes without welding. The goal is to monitor the production ecience of these activities when the source of fossil energy with hydrogen is gradually replaced. Objects of this experimentation are above all those “hard to abbot” sectors, such as the land industry, which need large quantities of energy to maintain themselves. Decarbonize these industries is a complex process, since they cannot change the energy source with which they are fed today. Therefore, testing the hydrogen directly to the structures is a way to prepare them, speeding up the transition process.
