Sustainability

The problem of CO2 emissions

The production of hydrogen from fossil fuels provokes the emission of large quantities of CO2.
In order to avoid this problem, it would be necessary to collect and confine the CO2  produced in the larger plants, exploiting the experience of oil companies. It is also possible to plan a partial re-conversion that allows to produce hydrogen from hydrocarbons. The hydrogen would then be used in cars (the profits would go to oil companies). From the environmental point of view, this solution avoids CO2 emissions by a large number of cars, concentrating them in petrochemical plants. Here they could be caught by adequate filters, converted into liquid or solid state and then stored in deep geological deposits with suitable characteristics, in order to prevent them from going back into the atmosphere.
In our country, like in other countries, the main options are:
• Pumping in exhausted gas and oil deposits
• Storage into the so-called salt aquifers (piles of sedimentary rocks, that are porous, permeable and full of water), underground stable formations that otherwise would not be used, and on deep ocean floors (more than 1000 metres under the sea level) where CO2  would always keep in the liquid state due to the enormous existing  pressure.
A recent Italian project plans to pump carbon dioxide released from hydrogen production processes into exhausted methane wells of the plain of the Po. In this way the gas would not be dispersed into the atmosphere. In Italy there are many old wells that could contain the carbon dioxide released during a century of hydrogen production.
From the technical point of view these proposals can be implemented by adjusting the already-existing technologies, and allowing a gradual development of energy infrastructures and a reduction of pollutants in the short-medium term. However it is necessary to remember that the production of hydrogen from fossil fuels has to be considered as a sort of “technological bridge” towards the production from renewable sources (the most promising solution in the long run), since it would not solve economic problems deriving from the progressive depletion of fossil sources and the complementary cost of CO2.