In the current scenario of mobility and stationary use of energy, hydrogen (H2) has experienced a very intense back-and-forth movement. There is a lot of talk about different routes, solutions, and technologies to adopt the smallest and most abundant atom in the universe. Everything gets complicated because the preferred form of energy to produce H2 is electricity which, in turn, must be produced from another form of clean energy such as wind, solar, nuclear, or hydroelectric. Another problem is that, ideally, electricity should be used as it is generated, otherwise it will be lost unless it is stored. After the production of H2, there are still two routes to use the high amount of energy contained in it: directly as a fuel resource in thermal plants, steel mills, cement plants, petrochemical plants, refineries, and combustion engines; or as feedstock for fuel cells, where it is directly converted from gas to electricity. But, unless there is no alternative, using electricity to produce hydrogen through electrolyzers and then using the opposite of the electrolyzer – fuel cells – to produce electricity again, is an energy flow design that is very poor in efficiency and rich in entropy. For this reason, it is interesting to note that more and more people are convinced that the best and most efficient way to store the power in electricity for later use is using batteries instead of hydrogen!!! This diversity of routes casts a shadow over all the hydrogen talk going on right now. Which route will prevail? There is still no simple answer. Be it a hospital, a steel mill, a car, a truck, a giant mining truck, or a passenger train. But some trends are emerging.
