The Fundación Ciudad de la Energía (CIUDEN), which reports to Spain’s Ministry for the Ecological Transition and the Demographic Challenge, has commissioned the Eurecat technology centre to develop an experimental pilot plant for research into the production of sustainable synthetic hydrocarbons. This strategic project aims to accelerate the decarbonization of air transport and other industrial sectors that are difficult to electrify.
The facility will enable the semi-industrial-scale demonstration of the production of both advanced biofuels derived from biomass waste and renewable fuels of non-biological origin (RFNBO). The objective is to produce renewable hydrocarbons that can act as direct substitutes for conventional fossil fuels and to facilitate their rapid commercialization on the European market.
The contract awarded to Eurecat amounts to 823,895 euros and the completion of the execution is scheduled for June 2026.
The plant will be structured around a Fischer–Tropsch synthesis reactor capable of converting different types of green synthesis gas into sustainable liquid fuels. This gas can be obtained through four complementary pathways: green hydrogen produced at the Cubillos del Sil Technology Development Center using PEM and SOEC electrolyzers, combined with captured CO₂; syngas from the biomass gasifier at the same center; syngas from the SOEC electrolyzer operating in co-electrolysis mode; or through the hybridization of the above, making the plant a unique and pioneering facility in Europe.
The plant design will allow testing of multiple catalysts and advanced materials, operating across a wide range of conditions, and will include sampling systems capable of collecting up to six different hydrocarbon fractions. Overall, the plant will have the capacity to process more than 40 tonnes of gases per year for the production of renewable fuels.
This pilot plant will be integrated with an additional methanol production facility awarded to Eurecat in early 2025, as well as another for synthetic natural gas, also based on green hydrogen and captured CO₂. Together, the three plants will form a biomass/power-to-X technology ecosystem aimed at transforming renewable energy generated at CIUDEN’s photovoltaic plants and utilizing residual biomass from the surrounding area.
The renewable electricity produced at CIUDEN will be managed and stored using three advanced battery systems—lithium-ion, sodium-sulfur, and vanadium flow—which will supply the two electrolysers responsible for producing green hydrogen. All of this will take place in a semi-industrial environment, enabling competitive integration with major implications for the commercialization of these technologies. This hydrogen will act as an energy vector to generate three distinct sustainable synthetic fuels: SAF (sustainable aviation fuel), renewable methanol, and synthetic natural gas.
The coordinated commissioning of these sustainable synthetic fuel production facilities is scheduled for mid-2026, positioning the Cubillos del Sil Technology Development Centre as a national and international benchmark in emerging technologies for the decarbonization of hard-to-electrify sectors in industry and transport—particularly long-haul heavy transport and aviation, where no alternative decarbonization solutions currently exist.
CIUDEN’s Technical Director of R&D&I, Alberto Gómez-Barea, stated that “with this facility, CIUDEN will consolidate its position as an international benchmark technology centre in the production of sustainable synthetic fuels, which are essential for achieving climate neutrality in sectors such as aviation.”
According to Agustí Chico, Director of Singular Projects at Eurecat and project director on behalf of the technology centre, “it is a great satisfaction for Eurecat that CIUDEN has once again placed its trust in us to design and build this new pilot plant, which completes the renewable fuel production ecosystem in Cubillos del Sil with a third facility.”
The integration of syngas derived from green hydrogen and captured CO₂, biomass gasification, or SOEC co-electrolysis “will allow us to validate, under conditions close to industrial operation, key technologies for producing sustainable synthetic fuels—especially SAF for aviation—making a decisive contribution to the decarbonization of sectors that are difficult to electrify,” Agustí Chico emphasizes.
This project is funded by the European Union’s Recovery, Transformation and Resilience Plan (RTRP), Next Generation EU, and aims to obtain technical data at industrial scale from the various implemented technologies, enabling the extrapolation of optimal operating conditions and supporting the decarbonization of industry.
Image: CIUDEN Technology Development Center in Cubillos del Sil.
