In the joint research project BioFleCCS, several research institutions and an industry partner are developing a concept to expand the role of existing biogas plants beyond pure energy generation. The goal is to produce both biohydrogen and biogenic carbon dioxide from biogas, with the latter being permanently sequestered. The project partners describe the approach as an upgrade for Carbon Dioxide Removal (CDR).
Methane Steam Reforming Designed to Capture All Carbon
The technical core of the concept combines biomethane upgrading with methane steam reforming (SMR). In this process, methane reacts with steam to produce a hydrogen-rich gas stream and carbon dioxide, enabling the separation of carbon that was previously locked in the methane. According to the project partners, capturing both CO₂ streams — from the biogas upgrading stage and from the steam reforming stage — makes it possible to remove virtually all of the biogenic carbon contained in the biogas.
In conventional biogas upgrading to natural gas quality, CO₂ is separated from the biomethane. However, this only removes about half of the biogenic carbon. The remainder, bound within the methane, is released back into the atmosphere when the gas is eventually used.
The chemical energy contained in the methane is largely preserved during steam reforming and made available in the form of hydrogen. The energy required to drive the process is intended to come from surplus renewable electricity, according to the project partners. The resulting biohydrogen could be used in industry, transport, and other sectors that are difficult to electrify. The captured biogenic CO₂ is earmarked either for industrial applications and food production or for permanent storage via Carbon Capture and Storage (CCS).
Flexible Operation Based on Market Demand
The project partners plan to operate the upgraded plants flexibly. Depending on market conditions, the facilities would supply either biogenic CO₂ and biohydrogen, or biogenic CO₂ alongside biomethane or electricity and heat. A static conversion of existing biogas plants into dedicated biohydrogen and CCS facilities would be undesirable, the partners say, since biogas plants will continue to play an important role in balancing fluctuating renewable energy sources.
Potential of 5 to 6 Million Tonnes of CO₂ Per Year
According to the University of Hohenheim, nearly 10,000 biogas plants are currently operating in Germany. The project partners estimate the total annual potential of the BioFleCCS concept at 5 to 6 million tonnes of negative CO₂ emissions in Germany — equivalent to roughly 15 percent of the country's remaining greenhouse gas emissions in 2045.
Pilot Testing at Hohenheim Research Facility
The project will begin with a full simulation and optimisation of the entire biorefinery. The team then plans to expand the existing infrastructure at the University of Hohenheim with an SMR unit supplied by WS Reformer to test the innovations and demonstrate their feasibility. The Universities of Hohenheim and Stuttgart are contributing expertise in simulation and experimental work, while WS Reformer is providing the SMR technology. The University of Hohenheim is also developing a process for separating CO₂ from biogenic gas mixtures. Fraunhofer IPA is responsible for sustainability assessment, market integration, and business model development, and will benchmark BioFleCCS against existing alternatives.
The project is led by Sonja Ziehn of Fraunhofer IPA. Other partners include WS Reformer GmbH, the State Institute of Agricultural Engineering and Bioenergy (LAAB) at the University of Hohenheim, and the University of Stuttgart. According to the partners, the project runs from 1 March 2026 to 28 February 2029.
