International Day of Clean Energy: Turning Sunlight into Sustainable Fuels with SUNFUSION
Every 26 January, the United Nations marks the International Day of Clean Energy, a global reminder of the urgent need to accelerate the transition to affordable, reliable, sustainable, and modern energy systems for all. Clean energy is the cornerstone of the global response to climate change and sustainable development, calling for innovation that goes beyond electricity to include clean fuels for transport, industry, and heating.
Join us in celebrating this day by reading our blog post, where you will find more information about the International Day of Clean Energy, biofuels, and SUNFISION’s role in this day.
International Day Of Clean Energy: From Global Commitment to Collective Action
The International Day of Clean Energy was established by the United Nations General Assembly as a formal call to move from ambition to action. Through its resolution, the UN emphasises the need for a just and inclusive energy transition – one that addresses existing inequalities in energy access while reducing the environmental and health impacts of fossil fuel dependence. The day highlights that clean energy is not only a technical challenge, but a social one, closely linked to wellbeing, equity, and long-term development.
This focus is particularly relevant in regions where energy poverty remains widespread. Millions of people still rely on unsafe and inefficient cooking and heating solutions, with severe consequences for health and livelihoods. Addressing these challenges requires not only technological solutions but also coordinated international efforts that support countries in designing and implementing effective energy transition pathways.
In this context, 26 January also marks the founding of the International Renewable Energy Agency (IRENA), which was established to support countries in navigating their energy transitions. By fostering international cooperation and generating evidence on clean energy technologies, policies, and investment, IRENA plays a key role in turning global commitments into practical pathways for implementation.
Together, the International Day of Clean Energy and the work of institutions such as IRENA reinforce a shared message: achieving universal access to clean energy requires sustained collaboration between researchers, policymakers, and practitioners, alongside solutions that respond to local contexts and needs.
International Day of Clean Energy: Focus on Fuels
Globally, energy production remains one of the largest sources of greenhouse gas emissions, largely due to the continued reliance on fossil fuels such as oil, coal, and gas. Reducing the dependence on these sources is essential to limiting climate change while also protecting environmental and human health.
In this context, the International Day of Clean Energy emphasizes three broad goals:
- Reducing global greenhouse gas emissions,
- Accelerating clean energy innovation and deployment, and
- Ensuring equitable and sustainable access to energy.
The challenge is particularly evident in the transport sector, which accounted for 29.2% of the EU’s total energy consumption in 2021. In this context, biofuels derived from biomass offer a practical pathway to decarbonisation, especially for the aviation and maritime shipping sectors. This is where the SUNFUSION project plays an important role, advancing pathways that convert renewable energy into sustainable fuels.
This approach aligns closely with the broader scientific consensus: achieving climate and development goals requires a shift towards energy sources that are clean, accessible, affordable, and reliable. Renewable fuels and energy carriers derived from the sun, wind, water, biomass, waste, and geothermal heat are naturally replenished and emit little to no greenhouse gases or air pollutants. Their wider deployment not only reduces emissions but also limits exposure to harmful pollutants associated with conventional fuels.
Microalgae and Biofuels: A Sustainable Feedstock
Microalgae are gaining attention as a renewable biofuel feedstock due to their rapid growth rates, high photosynthetic efficiency, and capacity to produce valuable compounds such as lipids (Qin et al., 2025). These characteristics make them a strong candidate for sustainable biofuel production while also offering additional environmental co-benefits such as CO₂ sequestration and wastewater treatment (Qin et al., 2025).
Moreover, recent research highlights how algae-based biofuel production can be more environmentally friendly and economically promising compared with fossil alternatives, thanks to higher energy returns and the ability to recycle nutrients (Rai et al., 2025).
SUNFUSION: Solar Thermal Energy Meets Advanced Biofuel Production
The SUNFUSION project addresses a critical challenge: how to efficiently convert renewable energy into liquid fuels suitable for use in hard-to-decarbonize sectors. SUNFUSION develops an integrated process that uses concentrated solar thermal (CST) energy to supply high-temperature heat for converting microalgae and oleaginous yeasts into biocrude via hydrothermal liquefaction (HTL) and subsequent upgrading into transportable fuels.
Hydrothermal liquefaction is a thermochemical conversion method that efficiently turns wet biomass like microalgae into biocrude fuel without the need for energy-intensive drying. Recent studies confirm that valorizing by-products from this process, particularly the HTL aqueous phase, is important to enable a circular bioeconomy and improve sustainability (Bogarin Cantero, 2025).
Clean Energy in Practice: Policy, Innovation, and Sustainability
Clean energy transitions increasingly require approaches that go beyond renewable electricity generation to address the continued dependence on fossil-derived fuels, particularly in sectors that are difficult to electrify. SUNFUSION responds to this challenge by integrating solar thermal energy with advanced bioprocessing, enabling the conversion of renewable heat into storable, high-energy fuels.
By developing scalable and efficient pathways for sustainable fuel production based on solar thermal inputs and biological feedstocks, SUNFUSION demonstrates how technological innovation can support long-term decarbonisation while aligning with broader sustainability and climate objectives, including progress towards SDG 7 (Affordable and Clean Energy) and SDG 13 (Climate Action).
Looking Forward
On International Day of Clean Energy—and every day after—projects like SUNFUSION remind us that clean energy innovation is multi-dimensional. It encompasses renewable power generation, sustainable fuel production, and circular resource use. Harnessing the sun’s energy not just for electricity, but for fossil-free fuels, is key to achieving a low-carbon, resilient future.
Bogarin Cantero, B. C., Li, Y., Kalita, P., Zhang, Y., & Davidson, P. (2025). Recovery of Nutrients from the Aqueous Phase of Hydrothermal Liquefaction—A Review. Water, 17(14), 2099.https://doi.org/10.3390/w17142099
Qin, Y., Li, T., Nie, C., Geng, X., & Sun, X. (2025). Microalgae: Promising solutions paving the way toward a greener and more sustainable future. Frontiers in Fuels, 3, 1643675. https://doi.org/10.3389/ffuel.2025.1643675
Rai, S. K., Kim, G., & Song, H. (2025). Algae to Biofuels: Catalytic Strategies and Sustainable Technologies for Green Energy Conversion. Catalysts, 15(9), 806. https://doi.org/10.3390/catal15090806
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