Biomethane: the keystone for reducing natural gas imports
Natural gas is the principal fossil fuel used in Italy for domestic applications and for producing electric power. Import levels currently exceed 90 percent, primarily from North Africa and Russia.
To reduce dependency on foreign imports and improve the environmental balance, there have been advances for some time in technologies for producing biogas and biomethane, renewable products alternative to natural gas.
Biogas contains a percentage of methane from 50 to 75%. An upgrading process is therefore required to separate out the carbon dioxide and obtain biomethane to feed into the gas networks for distribution and use. The energy efficiency of these technologies is high. Biogas is used to feed electric power generation plants with an efficiency of around 40 percent. The remaining energy, which can be utilized in the form of heat, is not usually massively exploited—only 11 percent of the entry heat power on the average—due to the lack of plants that exploit heat at production sites.
According to RSE calculations, published in a dossier entitled “Biomethane, Ready? Go”, each cubic meter of methane contained in biogas, net of power grid losses and combined cycle efficiency, affords a saving of 0.84 m3 of natural gas of fossil origin. The same m3 of methane contained in biogas, after refining, and net of the energy consumed by the process, replaces 0.94 m3 of natural gas with an energy benefit 13% greater.
Biomethane production technology, the RSE explains, is still little used in Italy. Only four small-capacity installations were built between 2013 and 2016, linked to demonstration projects. In the summer of 2017 the Montello plant, in Bergamo province, was the first to input biomethane into the Snam Rete Gas transport network. After publication of a new decree on the subject by MISE (Ministry for Economic Development), in March 2018, industrial projects are expected to develop in large numbers, although the 2018 decree only promotes the use of biomethane for transport uses.