For decades, gas distribution networks have been a critical infrastructure for ensuring thermal comfort across homes, businesses, and industries. In Catalonia, more than 2.2 million supply points are connected to this consolidated network. Today, amid a full-scale energy transition, these same infrastructures have the opportunity to take on a new role. At Aiguasol, we set out to explore how existing networks can be reused and adapted to support the integration of renewable gases—such as biomethane and green hydrogen—and thereby contribute to a clean, efficient, and distributed energy system, within the framework of the REGENERA project.
Direct electrification is undoubtedly a key pillar of decarbonization. However, not all energy uses can be easily electrified. Certain industrial processes—particularly those requiring high temperatures—will continue to depend on combustible fuels. In the residential sector, gas boilers still offer efficient thermal performance, compact size, easy maintenance, and long service life.
Nevertheless, the source of this gas must change. Natural gas—despite being cleaner than other fossil fuels—is still a non-renewable energy source. This is where renewable gases come into play. We already have a widespread, robust, and fully operational gas network. Why not repurpose it to transport gases that do not generate emissions?
Integrated solutions for the energy transition
One of the most mature and ambitious options is biomethane, which is produced from biogas generated through the anaerobic digestion of organic waste—from agricultural, livestock, or municipal sources. Once purified, this biogas becomes biomethane: a molecule virtually identical to natural gas, but of renewable origin and suitable for injection into the existing grid.
Throughout the REGENERA project, we have confirmed that this pathway is not only technically feasible, but also significantly more efficient than traditional biogas applications such as combined heat and power (CHP), particularly under current regulatory and market conditions.
Image: Enagás
Traceability and integration are key. Thanks to guarantees of origin (GoO) certificates, it is possible to ensure that renewable gas is consumed transparently. Real-world examples are increasingly common: from plants such as Noguera Renovables and Biometagas La Galera, to public initiatives like the BioVO project in Vallès Oriental, which uses waste-derived biogas to generate biomethane for municipal vehicle fleets.
The other major vector studied under the REGENERA project is green hydrogen, produced from renewable electricity via electrolysis. Hydrogen has a wide range of applications—from energy storage to the partial replacement of fossil fuels. A realistic short-term strategy is blending: the introduction of a small percentage of hydrogen into the existing natural gas network. This approach allows hydrogen to enter the system without requiring major technical modifications or excessive costs. Pilot projects—such as Redexis in Mallorca—already demonstrate its viability.
That said, it is important to acknowledge that current gas networks are not designed to carry large volumes of hydrogen. In the long term, a widespread deployment of this energy vector will require dedicated infrastructure. However, during transitional phases—as confirmed in the REGENERA project—blending can serve as a valuable tool for gaining familiarity with hydrogen’s technical, economic, and logistical behavior.
Image: AtlantHy
We also assessed alternative pathways, such as synthetic methane production—through the combination of captured CO₂ and green hydrogen—or green methanol. Although these technologies hold promise, they remain in the pilot stage and are currently associated with high costs. For the time being, direct injection into the gas grid remains the most efficient and immediate way to valorize these gases.
As REGENERA’s technical partner, AIGUASOL led the economic analysis of these solutions. The findings clearly point to a future model in which existing gas networks play a vital supporting role in the energy transition, provided they are progressively adapted to accommodate renewable gases.
Rethinking the energy system through renewable gases
Decarbonization requires more than just switching energy sources—it involves rethinking the entire energy system. This includes making intelligent use of existing infrastructure. The REGENERA project has demonstrated that this transformation is not only feasible but also necessary and cost-effective. Renewable gases are no longer a future promise; they are a technical reality with concrete, scalable applications and a direct impact on the sustainability of our energy system.
Image: REGENERA
At AIGUASOL, we are committed to making energy innovation practical, applicable, and sustainable. The REGENERA project is a clear example of how technical expertise and strategic vision can be combined to transform environmental challenges into tangible solutions. We will continue to support initiatives that, like this one, give new life to existing infrastructure and move us closer to a climate-neutral future.