The prospects of an imminent end of fossil fuels pushes researchers in the direction of identifying alternative fuels, among these, a possibility is given byhydrogen, H2. This is how the concept of hydrogen economy, the set of strategies aimed at exploiting the use of this fuel.
There are excellent reasons to deepen the studies onhydrogen. Its oxidation produces an amount of energy per gram, almost three times higher than fossil fuels. In practical terms, if we compare the energy produced byhydrogen with that generated by propane, a fuel used in some cars, it is found that thehydrogen it produces about 2.6 times more heat, which means more power.
L'hydrogen is considered one source of clean energy because, from its oxidation, the only product is water which does not create any environmental problems. L'hydrogen it could replace natural gas for domestic heating and even the petrol in cars. It is not a distant prospect when you consider that the Japanese car manufacturer, Honda, markets hydrogen car that exploit this element for the production of electricity that will power the electric motor.
Despite the current applications, there are problems to be solved and the technology should work towards the development of an economical method for hydrogen production, for its storage and to create an adequate distribution system.
L'hydrogen it is abundant on Earth but mainly as a constituent of a compound. Its elementary form must be obtained in extreme situations involving high temperatures. An example of this is the extraction ofhydrogen from the reaction of methane with water (steam reforming), alternatively, thehydrogen it can be produced by the reaction of coal and water. In such cases, carbon monoxide (CO) would also be produced.
Considering that the final purpose is to eliminate the use of fossil fuels, such mechanisms make no sense because they are based on solid coal and natural gas. This is why the production of hydrogen must take place starting fromwater.
L'electrolysis water supplies hydrogen, but to tear the H atoms from the H2O molecule (water), energy is needed which, in the example of the car manufacturer Honda, comes from photovoltaic panels and in the case of Germany there is a combination of various energy sources, including wind power.
The other problem concerns the hydrogen storage. The most intuitive method would be to storing hydrogen as a gas at moderate pressures. This principle might be fine for a Home heating or on a large scale, this principle would be impractical because at moderate pressures hydrogen would take up too much space. In reverse, storing hydrogen in liquid form or at high pressure it would require very small volumes but too sophisticated safety systems and equipment.
The ideal solution for storing hydrogen is based on the fact that some metals can absorb H2 and then release it. A form of hydrogen storage intelligent and practical, it involves the use of carbon nanotubes that allow H2 to be released even at room temperature and moderate pressures. There production of hydrogen it can take place starting from water but its storage and distribution must necessarily exploit different technologies.
Germany partially solved the problem by storing thehydrogen in the form of biogas (Read the article Energy Trio for Germany). For now all alternative sources are important, however, with current technologies an appreciable result can only be obtained with the combined use of more alternative energies.
edited by Anna De Simone