FUELGAE: A zero-waste approach to turning CO2 into biofuels

In this interview, Dr. Silvia Morales de la Rosa and Dr. José-Miguel Campos Martín of CSIC explain how their project is converting industrial CO₂ into advanced liquid biofuels using microalgae to offer a practical pathway for Europe to achieve its decarbonisation goals to help meet these priorities.

FUELGAE is tackling some of the biggest challenges facing society today. At the same time as cutting CO₂ emissions to fight climate change, the project is helping to decarbonise hard-to-electrify sectors such as aviation and shipping, advance the circular economy and even improve agricultural productivity using biochar. Overall, it aims to demonstrate that carbon capture can be coupled with advanced biofuel production in a sustainable way that is also scalable and economically viable.

Dr. José-Miguel Campos Martín, researcher of coordinating partner CSIC, explains why biofuels are essential if Europe is to meet its decarbonisation goals. “If you want to reach the objectives of decarbonisation in the European Union, you cannot avoid this option. This is the only way to decarbonise several sectors that are difficult to electrify, particularly in transport. In aviation and shipping, it’s almost impossible to make a complete transition to electricity or hydrogen in the near term, so we need to decarbonise using biofuels.”

The holistic use of microalgae

FUELGAE’s approach is built on the cultivation of microalgae to capture industrial CO₂ and transform it into a wide spectrum of valuable outputs. What sets the project apart is its commitment to a holistic, zero-waste process. “Our approach is to use the whole part of the microalgae,” says Dr. Campos Martín. “We aim to have no residues at all, because all parts of the biomass will be used, whether for liquid biofuels, bioethanol, biogas, or as biochar for agricultural applications. It is a holistic approach that ensures every fraction of the microalgae contributes value.”

The choice of algae species is tailored to the source and quality of CO₂ to make this holistic use of the microalgae possible. Dr. Silvia Morales de la Rosa, also of CSIC and project coordinator, explains: “The quality of CO₂ emissions varies, so we are exploring different microalgae species. For example, from the biorefinery partner in Spain, we may choose one species that produces more sugars and polysaccharides, which can then be converted into ethanol. For CO₂ from the steel plant in Romania that we are using in the project, we may select another species better suited for lipid production for biofuels. Each CO₂ stream is matched with the most effective biological pathway.”

Digital twins for real-time optimisation

While algae cultivation is at the heart of the project, FUELGAE is also innovating in the use of digital twins, virtual models of the processes that enable real-time monitoring, simulation and, ultimately, the optimisation of the various processes involved in extracting the biofuels or bioproducts. “We are developing digital twins for each process, one for polysaccharides, another for lipids,” explains Dr. Campos Martín. “We then use this digital grid to optimise them in real time. This allows us to maximise production and adapt to changing conditions, such as weather or light, while minimising energy use.”

Dr. Morales highlights the advantage of mobility in terms of this adaptability for different conditions and the use of varying qualities of CO₂ by FUELGAE: “We are using a modular photobioreactor that can move between industries and locations,” she says. “That means we can test cultivation under different conditions – in Spain with its Mediterranean sun, or in Romania with its colder winters, for example. Combined with real-time data and the digital twins, the system can be adapted to work anywhere and with any quality of CO₂.”

The project is also developing dedicated probes for algae cultivation. These are sensors that feed directly into the digital platform. “This is one of the novelties of the project,” says Dr. Campos Martín. “These probes are designed specifically for microalgae, allowing us to measure growth conditions in the pilot plants and feed that data into the digital twins to optimise the process.”

FUELGAE is not only about technology but also about proving sustainability in practice. A full life-cycle analysis (LCA) and techno-economic assessment are embedded in the project to measure its environmental, economic and social impacts. “In previous microalgae projects, about 10 years ago, the economic analysis was very negative because energy consumption in developing biofuels was so high,” says Dr. Morales. “Now, by introducing new fractionation technologies that consume less energy, we are improving the balance. We are working to make the process both environmentally and economically sustainable.”

Dr. Campos Martín adds: “We merge two important concepts here: carbon capture, which is environmentally positive, and a process designed to achieve a favourable energy balance. At the same time, we use all of the biomass – the biofuels, biomethane, biochar – so nothing at all goes to waste along the process. This makes us confident that the environmental and social impact will be favourable when the results come in nearer the end of the project.”

Barriers and regulatory drivers

Despite these promising projected outcomes and favourable results to date, Dr. Campos Martín and Dr. Morales are clear that FUELGAE faces all the same challenges that are common across the biofuels sector. “To be honest, the main challenge for biofuels is price,” says Dr. Campos Martín. “All of these technologies are several times more expensive than petrol, well in part, because the cost of the pollution of CO2 emissions has not been taken into account for fossil fuels. That’s the critical point for market acceptance.”

One way to bridge this gap is through regulation, particularly in aviation and shipping, where mandates for sustainable fuels are already being introduced. “Regulation that favours the use of advanced biofuels can create a niche in the market,” explains Dr. Morales. “It is already mandatory to use biofuels or synthetic fuels in aviation and shipping, and this provides an opportunity. Road transport may follow with increasing mandatory shares for biofuels.”

FUELGAE is a research and innovation project at TRL 5, so its immediate goal is to prove that the technologies are technically viable and sustainable at pilot scale. But the project is pursuing multiple technological pathways, each of which could deliver value. Some may be ready to scale to industrial levels, while others may remain in development for future projects.

Dr. Morales is clear-eyed about this: “I’m not sure all of our technologies can scale up, but some of them, yes. For example, the conversion of lipids to biofuels is already close to industrial scale. Others may need further work, but we are providing the tools and knowledge to make that possible.”

For Dr. Campos Martín, the project’s value lies not only in its direct outputs but also in the evidence it provides to policymakers who will be critical in providing the regulation necessary to boost the market for biofuels. “Policymakers need technical support for their decisions. We can show that it is possible to capture CO₂ and produce biofuels at the same time. That combination helps meet climate targets and proves alternatives exist.”

Looking beyond 2027

By the end of the project in 2027, the FUELGAE team expects to have validated its processes in industrial settings, developed new tools for algae cultivation and advanced the digital twin approach. The next step will be scale-up. “Our aim after the project ends is to scale up the process,” says Dr. Campos Martín. “Not all the routes will be ready, but some are very good candidates for commercialisation in the future.”

Dr. Morales concludes with cautious optimism: “This project is about demonstrating what is possible. The hope is that in the next phase, with further support, we can move closer to industry-scale demonstration and, eventually, market adoption. FUELGAE is one big step on that path.”