World Energy Day: Advancing Solar-Driven Sustainable Fuels through the SUNFUSION Project
World Energy Day, celebrated annually on 22 October, provides an opportunity to reflect on global energy challenges and highlight innovative solutions that support the transition toward a low-carbon, resource-efficient future. As the world faces increasing energy demand alongside the urgent need to mitigate climate change, the development of sustainable, renewable, and resilient energy systems has become a priority for research, industry, and policy alike. Within this context, the SUNFUSION project represents an innovative effort to redefine how renewable energy can be converted into advanced, sustainable fuels for sectors such as shipping and aviation.
The Global Energy Challenge
Despite significant progress in renewable electricity generation, sectors such as marine transport and aviation remain heavily dependent on fossil fuels. These sectors require energy dense liquid fuels that are difficult to replace with direct electrification. According to international energy scenarios, sustainable fuels will be essential to meet climate neutrality targets while ensuring energy security and industrial competitiveness.
Solar energy, one of the most abundant renewable resources, offers big potential not only for electricity generation but also for direct conversion into chemical energy carriers. However, efficiently coupling solar energy with biomass conversion technologies remains a major scientific and technological challenge. Addressing this challenge is central to the SUNFUSION concept.
SUNFUSION: Integrating Solar Energy and Biomass Conversion
The SUNFUSION project (Advanced Sustainable Biofuels Production from Purified Microalgae and Oleaginous Yeasts via Integrated Solar Hydrothermal Liquefaction) is funded under Horizon Europe, officially launched on 1 January 2025, running for 48 months . Coordinated by the Centre for Research and Technology Hellas (CERTH), SUNFUSION brings together a multidisciplinary consortium of ten partners from academia, research organisations, and industry sectors.
The project’s core ambition is to demonstrate a solar-driven pathway for producing advanced biofuels from microalgae and oleaginous yeasts. Unlike conventional biofuel routes, SUNFUSION integrates concentrated solar thermal (CST) energy directly into the biomass conversion process, significantly reducing reliance on fossil-based heat sources.
Hydrothermal Liquefaction Powered by the Sun
At the heart of SUNFUSION lies hydrothermal liquefaction (HTL), a thermochemical process that converts wet biomass into biocrude at high temperatures and pressures. HTL is particularly well suited for microalgae and yeasts, as it avoids the energy-intensive drying steps required by other conversion technologies.
SUNFUSION advances the state of the art by coupling HTL with concentrated solar thermal energy, enabling solar energy to cover the thermal demands of the process. The project aims to operate the HTL reactor under on-sun conditions at temperatures exceeding 350 °C, targeting a solar-to-biocrude energy efficiency above 50%, an ambitious benchmark for sustainable fuel production .
This approach not only improves overall energy efficiency but also demonstrates how solar energy can be transformed directly into storable and transportable liquid fuels, bridging the gap between intermittent renewable energy and continuous fuel demand.
A Circular, Zero-Waste Vision
Beyond fuel production, SUNFUSION is designed around a circular and zero-waste philosophy. The project integrates:
- Innovative photobioreactors and open raceway ponds for optimised cultivation of microalgae and yeasts;
- Solar-aided thermal energy storage (TES) to enhance operational stability and flexibility;
- Hydrotreatment units to upgrade biocrude into advanced fuels compatible with marine and aviation standards;
- Recycling of aqueous and gaseous HTL by-products back into cultivation systems, minimising emissions and waste.
By closing material and energy loops, SUNFUSION aligns strongly with European sustainability principles and the EU Green Deal objectives.
Relevance to World Energy Day
World Energy Day emphasises not only the adoption of renewables but also the integration of innovative energy systems that can address sector-specific challenges. SUNFUSION directly responds to this call by targeting sectors where decarbonization is most difficult and by demonstrating how solar energy can be used beyond electricity generation.
The project contributes to several strategic priorities:
- Climate neutrality through reduced greenhouse gas emissions;
- Energy security by diversifying fuel sources;
- Technological sovereignty through European-led innovation;
- Industrial scalability
Importantly, SUNFUSION also explores the long-term vision of deploying its integrated technologies in mobile, off-grid platforms, opening new opportunities for decentralised fuel production in remote or energy-constrained regions.
Collaboration and European Impact
SUNFUSION exemplifies the collaborative spirit promoted under Horizon Europe. Its consortium includes leading research institutions, universities, industrial technology providers, and end users from Greece, France, Germany, Norway, Turkey, and Serbia, ensuring strong scientific excellence and industrial relevance.
Through continuous communication, dissemination, and stakeholder engagement, the project aims to contribute not only to scientific progress but also to public awareness and policy dialogue on sustainable energy solutions.
Looking Ahead
As the world marks World Energy Day, SUNFUSION stands as a powerful example of how solar energy, biotechnology, and advanced thermochemical processes can be combined to address some of the most pressing energy challenges of our time. By transforming sunlight and biomass into advanced biofuels, the project contributes to a future where renewable energy is not only clean but also versatile, resilient, and capable of powering all sectors of the economy.
World Energy Day reminds us that achieving a sustainable energy transition requires bold ideas and collaborative action. SUNFUSION embodies both, pushing the boundaries of renewable energy integration and paving the way toward a more sustainable, solar-powered future.