Assessment of Geo-methanation Potential from Biogenic CO2 inAustria under Renewable Electricity Constraints

Austria’s energy system is characterised by a high share of bioenergy, resulting in substantial biogenic
CO₂ emissions from industrial and energy-sector point sources. These emissions represent a potential
carbon feedstock for geo-methanation, enabling the production of renewable methane that is compatible with
existing gas infrastructure. This study presents a national-scale assessment of Austria’s geo-methanation
potential by integrating (i) a spatially resolved inventory of biogenic CO₂ point sources, (ii) benchmarked
capture efficiencies by sector, (iii) green hydrogen production constrained by surplus renewable electricity
and electrolyser deployment, and (iv) experimentally observed biological methane yields. Results indicate
that 9–12 Mt CO₂ a⁻¹ of biogenic point-source emissions occur nationally, of which 5–8 Mt CO₂ a⁻¹ are
technically capturable [1, 2]. Using Austria’s net electricity export balance of 6.8 TWh a⁻¹-derived from
annual import–export statistics, as an upper-bound proxy for surplus electricity, ∼0.7 Mt CO₂ a⁻¹ could
currently be methanated [3]. Laboratory geo-methanation experiments achieving approximately 20 % of the
stoichiometric methane yield reduce the methane output potential to 5–8 TWh a⁻¹, corresponding to 7–11 %
of Austria’s current natural gas demand [4, 5]. A phased ramp-up strategy is proposed to reach 10 %, 25 %,
and 50 % utilisation of the biogenic CO₂ pool through progressive electrolyser deployment and renewable
electricity expansion. The results demonstrate that Austria’s geo-methanation potential is fundamentally
constrained by the availability of renewable electricity and hydrogen, rather than CO₂ supply.