Clean energy, but also very efficient in the production-storage-reuse chain. Hydrogen, H2, is a colorless, odorless, highly flammable gas. It is the lightest and most abundant element in the Universe. It has the peculiarity of having to be produced by water (even sea water). electrolysis. But why does it really have all the credentials to be the "battery" of the future, as a complement and powerful ally to electrochemical accumulators?
Here are some numbers. To obtain 1 kg of hydrogen from water, even sea water, you need an electrolyser that uses between 55 and 60 kilowatt hours (kWh) of electricity. Its use produces the equivalent (i.e. contains the same energy) as 2,1 kg of natural gas or 2,8 kg of petrol. So it has one very high energy density. It is true that to be transported or stored conveniently it needs to be compressed in special tanks or liquefied using cryogenic apparatus (therefore at very low temperatures), but its advantages in terms of specific weight per energy produced are particularly evident in comparison with current systems of electricity storage in batteries.
Of course, to power our car with hydrogen, for example, we must also consider the need for the equipment needed to manage the fuel cells that transform the hydrogen back into electricity, but today the process already has its advantages in terms of total weight. Not of cost, but very soon also economic competitiveness it will most likely be a reality.
