Debate on biomethane too often narrows to a comparison between the cost of the support scheme and the price of fossil gas. That framing misses most of what the sector produces. Our study for GRDF and France Gaz Renouvelable quantifies those effects over 2018-2030 under the sector’s own scenario, 70 TWh of biomethane from anaerobic digestion in 2030, equivalent to 30 % green gas in the networks.
Three values, each between €6 and 14 billion
These three categories cannot simply be added together, since they involve different beneficiaries and different kinds of impact. Taken together, however, they represent €26 billion cumulatively over the period.
- Avoided greenhouse gas emissions: around €7bn. The lifecycle emissions gap between biomethane, at 23.4 gCO2e/kWh, and natural gas, at 241 gCO2e/kWh, valued at the reference carbon price from the Quinet report, rising from €59/t in 2018 to €116/t in 2030.
- Economic value added: around €14bn. Wealth and employment created across the whole value chain, plus the value of digestate on organic farming yields, including tax revenue for the state.
- Trade balance impact: around €6bn. Lower imports of natural gas, on an import price of €40/MWh in 2030, and of chemical fertilisers, net of higher equipment imports.
A deliberately conservative estimate
The method excludes any value that cannot be quantified reliably today. Several sources of value are therefore absent from the figures.
- The full agronomic value of digestate in conventional farming.
- The health impact of replacing chemical fertilisers with digestate.
- The effects of cover crops on nitrogen management, biodiversity and soil quality, crops that would not exist without the sector.
- Jobs preserved on farms for which anaerobic digestion is a decisive income supplement.
- The employment surplus of injection over cogeneration.
The €26bn figure is therefore a floor, not a central estimate.
One clear improvement lever: the industrial supply chain
The only negative item in the balance is equipment imports. Foreign, mainly European, suppliers provide around 50 % of equipment, close to 25 % of total plant capex.
This is the main opportunity to raise socio-economic value. Building a French industrial supply chain for anaerobic digestion would have a double effect: reducing imports, and so directly improving the trade balance, while increasing value added captured domestically. At the scale of the scenario studied, the stake runs into billions of euros.
To go further, download our full analysis below or contact our experts.
