Biomethane smells bad
FALSE
The contents of a digester do not come into contact with the ambient air and therefore cannot contaminate it. As for storing the most odorous materials, this is done in enclosed spaces where the air is naturally deodorized before being released back into the atmosphere.
The production of digestate, a byproduct of methanization, has harmful effects on soil and wildlife
FALSE
When properly dosed, digestate is a natural fertilizer with well-recognized agricultural benefits. It is also one of the few organic sources of mineral nitrogen.
Green gases are dangerous
TRUE AND FALSE
A methanization unit does not pose an explosion risk because the pressure inside a digester is very low. Additionally, safety valves are always installed on methanization plants. The safety measures comply with the requirements set by the Classified Installations for Environmental Protection. As for hydrogen, it has been safely used in industry for decades; it is a secure and regulated technology at both national and international levels. While hydrogen is more flammable than gas or oil, the risk of accumulation and formation of a “pool” of hydrogen is much lower due to its high volatility. It disperses 4 times faster in the air than natural gas and 12 times faster than gasoline vapors.
Hydrogen requires a lot of water resources
TRUE AND FALSE
The hydrogen sectors impact on water resources is much lower than that of other industries like agriculture, energy, or drinking water production. Additionally, electrolysis processes do not use drinking water and can use industrial wastewater or desalinated seawater. In France, for example, producing one million tons of decarbonized H2 by 2030 will represent less than 0.1% of water withdrawals and less than 0.5% of national consumption.
Biomethane production monopolizes fields and harms the agricultural sector
FALSE
In France, biomethane is primarily produced from our waste: household waste sorted selectively, and waste from the agri-food industry, large retailers, and collective catering (cooked meals, ice cream, bread, fats, etc.). Biomethane production also allows for the valorization of many agricultural wastes such as manure, slurry, and crop residues (bran, straw, leaves, etc.). Since October 2023, biomass purchased by ENGIE must meet the strict criteria of the European RED II directive on renewable energy sustainability, as well as demanding environmental standards. Intermediate energy crops represent only a minor source of inputs and are implemented when a soil cannot produce food crops, often in winter. Finally, the agricultural sector directly benefits from methanization as the process produces digestate, a green fertilizer.
Green gases are not that green
FALSE
Produced from residual biomass, green gases have a carbon-neutral balance. The CO2 released during the combustion of biomethane, similar to natural gas combustion, has been absorbed by plants through photosynthesis. Since this cycle is short, around two years, the combustion of renewable gas is considered carbon-neutral, as it does not add new carbon to the atmosphere. In contrast, natural gas releases carbon that was captured millions of years ago and stored underground. By replacing natural gas with biomethane, we avoid additional CO2 emissions.