Sustainability

Clean hydrogen

Hydrogen is an extremely environmentally friendly fuel. Its combustion produces water and small quantities of nitrogen oxides. Moreover, hydrogen can be extracted from a range of compounds and this is one of the aspects that make it considered as the fuel of the future. In order to produce hydrogen it is necessary to consume energy, and this operation has certain costs. When hydrogen is extracted from fossil fuels, a large quantity of carbon dioxide is produced. Carbon dioxide is one of the gases that provoke global warming (greenhouse effect). The idea is to create big plants to produce hydrogen from fossil fuels and collect the produced carbon dioxide, preventing if from dispersing into the atmosphere. When hydrogen is extracted from water through electrolysis, carbon dioxide is not produced. But electric energy has to be used in order to carry out the process. If this energy is produced from a thermoelectric power plant, as it normally happens, we have to take into account the pollution that the plant generates. The production of hydrogen from renewable sources is to be considered a better solution than the production of hydrogen from fossil fuels because it does not produce any polluting compounds, neither during production nor during consumption (in this way also the environmental damage associated to the extraction of fossil fuels from deposits is limited. In fact, oil drilling, transport, refining and waste significantly contribute to the pollution of the planet). In fact, with electrolysis the whole production and consumption of hydrogen is environmentally sustainable, as long as a corresponding quantity of clean electric energy is available, in order to supply the electrolysis process. The sun could be a source for this energy. The sun can be exploited through the use of photovoltaic conversion plants, whose technology can be considered as technically reliable and adequate, even though it is not fully competitive yet. In fact, through the use of photovoltaic solar energy, it is possible to produce electrolytic hydrogen and oxygen that can react inside fuel cells in order to produce the electric energy we need. Pure water is then produced as a final waste, whose amount is very similar to the beginning quantity. In this way the cycle closes without any polluting emission. Last, it is needless to say that oceans are huge reserves of hydrogen: each kg of pure water contains 111 grams of hydrogen that, after being burnt, could produce 3,200 kilocalories of thermal energy. Therefore it would be possible to extract from water all the hydrogen needed to satisfy all human needs in a clean way.