Andrés Sanz-Martínez_CIRCE – Research Centre for Energy Resources and Consumption

The wine industry releases significant amounts of biogenic CO₂ during alcoholic and malolactic fermentations, a valuable resource that is typically emitted directly into the atmosphere [1]. To address this, the EU FUELPHORIA project is demonstrating a pioneering circular economy solution at the Viñas del Vero winery (Somontano, Aragón, Spain). 

The value chain comprises: (i) CO₂ collection from multiple fermentation tanks; (ii) purification (99.95%) and compression for storage; (iii) green H₂ supply via electrolysis; and (iv) conversion in two-stage methanation reactors. Furthermore, the captured CO₂ has additional uses for the winery factory, such as (a) gas mixing of solid-liquid must in red winemaking to improve homogenization while reduce electricity demand, (b) inerting of tanks and presses to displace O₂ and mitigate microbial growing, (c) acidification of wash water to enhance cleaning efficiency and reduce water consumption, and (d) recovery of volatile aroma compounds captured within the CO₂ for reincorporation into the wine. 

This demonstration introduces three major industrial innovations to the sector: 

• It is the first winery-integrated CO2-to-CH4 system in Europe. 
• It utilizes advanced Ni-based catalysts that offer high activity and stability for CO2 conversion [2]. 
• It features a modular and scalable system design, tailored to accommodate the seasonal availability of CO2 during the harvest period. 

During the 2025 vintage (9th-26th of September), the system successfully recovered 17 tons of CO2. A portion of this captured CO2 was used to feed the methanation demonstrator. The tests, utilizing this real fermentation CO2, produced outlet gas containing approximately 80% CH4 (dry basis) and achieved a 90% CO2 conversion. These operational values are consistent with literature [2]. The reactor operated continuously for over 300 hours with no observed catalyst deactivation, proving high operational stability.  
Ongoing work is focused on improving thermal control to push the overall CO2 conversion closer to thermodynamic equilibrium, as well as validating numerical models and composition profiles to support future optimization and scale-up. 
Initial results demonstrate a viable and highly replicable technological pathway for wineries to valorize fermentation CO2 into renewable CH4. This innovation not only reduces direct emissions but also produces a locally usable fuel for heating, process energy or mobility, driving true circularity within this sector.

Andrés Sanz-Martínez¹, Sergio Iglesias¹, Christian Aragón-Briceño¹, Daniel Montané², Francesc Medina², Abel Toscano², Ricardo Fernández³, José María Ayuso³ 

¹ CIRCE – Research Centre for Energy Resources and Consumption, Parque Empresarial Dinamiza, Av. Ranillas 3D, 1st Floor, 50018 Zaragoza (Spain) 

² URV-Departament d′Enginyeria Química, Universitat Rovira i Virgili. Av. Països Catalans, 26. 43007, Tarragona, Spain 

³ Gonzalez Byass, Viñas del Vero, Carretera de Naval, Km 3, 7 22300 Barbastro, Spain 

References 
1. Gueddari A. et al., J. CO₂ Util., 2025, 96, 103094. https://doi.org/10.1016/j.jcou.2025.103094 

2. Tommasi M. et al., Chem. Eng. Res. Des., 2024, 201, 457–482. https://doi.org/10.1016/j.cherd.2023.11.060