A methodological comparison for estimating renewable gas potential in France

Renewable gas is discussed frequently as part of a strategy to decarbonize Europe’s energy system and reduce dependence on conventional natural gas. In a previous analysis, ICCT found that there is a limited potential for renewable gas to decarbonize France’s transportation sector, and that it would be prohibitively expensive, even with strong policy support. Another analysis by Agence de l’Environnement et de la Maîtrise de l’Énergie (ADEME, 2018) found that 100% of France’s transportation energy needs in 2050 could be met cost-effectively with renewable gas. ADEME (2018) estimated the technical potential for renewable gas (including both renewable methane and hydrogen) in 2050 as roughly 16 times the value reported in ICCT’s analysis. In this working paper, we compare in detail the methodologies and assumptions in these two studies to elucidate the large difference in results.

The main differences between the ICCT analysis and ADEME’s are the identification of low-carbon feedstocks and assumptions about production costs and technology deployment. These are the most important differences:

1. The ADEME analysis assumes that all renewable gas feedstocks are climate-neutral. This does not align with the vast majority of scientific literature, which shows that forest stemwood in particular does not provide a climate benefit relative to fossil fuels over a 20-year time frame. The ICCT analysis does not include the potential for renewable gas from stemwood or other feedstocks associated with high-lifecycle greenhouse gas (GHG) emissions.
2. The ADEME analysis includes intermediate crops. The ICCT analysis excludes intermediate crops due to a lack of data on the sustainable availability of these resources in France.
3. Relative to ICCT’s analysis of methane production costs, the ADEME analysis assumes lower costs for some technologies and omits some cost terms. The ICCT analysis finds that renewable methane, from livestock manure in particular, will be constrained by high costs. For example, farms are widely distributed and affected by poor economies of scale.
4. The ICCT analysis accounts for deployment limitations for the gasification and power-to-gas conversion pathways, whereas the ADEME analysis does not. ICCT’s assumptions of facility deployment are designed to reflect limits on financing opportunities for advanced, capital-intensive technologies.

In this paper, we include a sensitivity analysis that attempts to align ICCT’s methodology with ADEME’s. We adjust select assumptions to match ADEME’s where that study’s approach is reasonable or superior to ICCT’s. In this sensitivity analysis, we find that the technical potential for renewable gas in transport in France could be 70 TWh, or almost twice ICCT’s initial assessment. This potential is still vastly lower than the 620 TWh technical potential reported in the ADEME baseline 2050 scenario.