Integration of renewable gaseous fuels and hydrogen into natural gas infrastructure: A review

The integration of renewable gaseous fuels into existing natural gas infrastructure, particularly biomethane and hydrogen, presents a pivotal opportunity for decarbonizing energy systems. The goal of this paper is to review European policies and its implementation in major EU member states and to assess the feasibility and impact of integrating biomethane and hydrogen into European natural gas networks, with the aim of identifying the main barriers and providing recommendations for overcoming technical, economic, and regulatory challenges. The findings highlight that biomethane is already commercially viable and scalable, with 1,548 plants in Europe producing 5.2 bcm in 2024 - France and Germany leading in injection infrastructure, and Italy emerging as a key developing player. Biomethane, with production costs ranging from €50 to €110/MWh, remains competitive even during natural gas price volatility and its production is projected to exceed the REPowerEU target of 35 bcm by 2030 and potentially reach 150 bcm by 2050. Regulatory mechanisms such as feed-in tariffs, GHG intensity targets, and biomethane mandates play a critical role in supporting market development. Hydrogen blending is technically feasible up to 20% under specific conditions but requires significant infrastructure adaptations. Challenges remain, including grid compatibility for hydrogen, high investment requirements, and the necessity of harmonized EU-wide policies. Overall, biomethane is currently the most deployable renewable gas for leveraging the existing infrastructure, while hydrogen integration demands strategic infrastructure development and cost reduction in green hydrogen production.