Natural gas is a source of energy created by the decomposition over millions of years of organic matter, such as plankton and algae. It is 95 % methane. The world has abundant reserves of natural gas, with underground and subsea reserves being widely distributed around the earth.
It is transported to the point of consumption in two ways:
When burned, natural gas gives off mainly water vapor, and is soot-free, dust-free and smoke-free. . It emits 30 %1 less carbon dioxide (CO2) than fuel oil et 45 % less than coal, it also omits only half the nitrogen oxides (NOx) and very little sulfur dioxide (SO2).
The local-level conversion of fermentable organic matter from a broad diversity of sources (agricultural, industrial and catering waste, local authority waste, etc.) produces biogas. This type of renewable gas can be used directly as a fuel for industrial heating plants or district heating networks. This is called energy recovery.
Once odorized, controlled, metered and pressure-regulated, biogas becomes "biomethane" or "green gas". With the same quality as natural gas, it can be injected into the supply network, since it is perfectly suited to all the same uses: space heating, cooking, water heating, etc. It can also be used as a biofuel for vehicles.
Biomethane makes it possible to recover energy from waste as part of the circular economy, and to reduce greenhouse gas emissions. In practical terms, when waste decomposes, it releases methane. Waste collection and treatment avoids the release of these emissions into the atmosphere, and converts them to clean energy. The greenhouse gas emissions of biomethane are therefore virtually zero, because the CO2 produced by recovering the biomethane has previously been captured by the decomposed organic matter.
New technologies also make it possible to produce so-called "second-generation" biomethane from "dry" lignocellulosic biomass (wood and straw). The treated materials are dry residues from forestry, agriculture or the paper industry. This methanation process (oxygen-free gasification) implemented by the Gaya technological platform is more efficient (overall efficiency of more than 60%) and more environmentally friendly (reduction of the quantity of solid waste and emissions).
Looking further into the future, we will be able to cultivate microalgae, which produce the 100 % renewable gas known as ‘third-generation’ biomethane.
In Europe, the largest producer of biogas is Germany, which injects 10,000 GWh of this energy source into its supply networks from 190 production units. Then comes the UK, with 2,000 GWh of energy produced by 51 production units. Both countries benefit from attractive feed-in tariffs, and produce cultures dedicated to biogas production, which enable them to obtain the more consistent quality of raw material required to industrialize the recovery processes used for biogas and the methanation residues known as digestates.
In France, biomethane production is part of the national renewable energy development strategy. The French law of August 17, 2015 - the energy transition for green growth (LTE) law - requires that 10 % of all gas consumed in France by 2030 must be from renewable sources. In 2017, there are 31 sites injecting biomethane into the natural gas supply network operated by GSDF. ADEME (the French Environment and Energy Management Agency) forecasts that between 500 and 1,400 production units could be injecting between 12 and 30 TWh of biomethane energy per year into supply networks by 2030. This quantity of energy is sufficient to heat 2,500,000 homes and fuel 55,000 buses or trucks.
1Source : GRTGAZ
2ADEME : the French Environment and Energy Management Agency