IsoPROPEL project

IsoPROPEL is developing a new, sustainable approach to decarbonize hard-to-abate waterborne transport. The project focuses on isopropanol (IPA) as a renewable, rechargeable liquid energy carrier, produced from CO₂ and renewable hydrogen. Unlike conventional fuels, IPA can power direct isopropanol fuel cells (DIFCs) to generate electricity without CO₂ emissions or the need for pressurized hydrogen at any step of the energy carrier synthesis, usage and cyclic “re-charging” lifecycle. After use, IPA is regenerated from acetone under mild conditions, creating a waste-free, circular energy cycle.

The project combines advanced electrified chemical-looping, tandem catalysis, and fuel cell technologies with computational modelling and precision materials design. IsoPROPEL will validate IPA production as a renewable fuel of non-biological origin (RFNBO) and fuel cell operation at TRL 4, optimize logistics and on-board integration for inland waterways, and evaluate the technical, economic, and environmental performance through techno-economic and life-cycle assessments. By demonstrating this new renewable energy carrier, IsoPROPEL aims to provide a practical, high-density alternative to batteries and conventional fuels, enabling truly zero-emission inland shipping.

IsoPROPEL aims to decarbonize heavy-duty waterborne transport by producing isopropanol as a renewable liquid energy carrier from carbon dioxide and renewable electricity. High-density fuels are needed for such applications because batteries alone cannot meet the energy demands of heavy-duty vessels. Conventional options face major challenges: hydrogen requires costly compression and complex storage, ammonia is toxic and corrosive, and methanol produces CO₂ during reforming or electro-oxidation.

IsoPROPEL addresses these limitations by combining a hybrid conversion pathway (electrified chemical-looping to produce syngas followed by a single-pass tandem catalysis step) to selectively synthesize isopropanol. Energy is recovered on board via a direct liquid-fed isopropanol fuel cell, which converts isopropanol to electricity through selective electro-dehydrogenation, producing acetone as the only byproduct. The acetone is captured and returned for off-board re-hydrogenation, creating a rechargeable, waste-free energy loop that avoids the high-pressure storage and infrastructure challenges of conventional hydrogen systems. This approach provides a high-density, zero-emission solution for sustainable inland and coastal waterborne transport.

IsoPROPEL combines electrified chemical conversion, advanced catalysis, computational materials design, and fuel cell engineering to establish isopropanol as a rechargeable, zero-emission energy carrier for waterborne transport.

The project approach includes:

• Electrified CO₂ conversion to C₁ intermediates:
  A fast temperature-swing chemical-looping process, driven by radiofrequency induction heating of solid oxygen carrier materials, enables efficient carbon dioxide reduction to syngas. This is complemented by a pressure-swing, sorption-enhanced catalysis step for carbon dioxide hydrogenation to dimethyl ether with ultrashort cycle times.
• Selective tandem catalysis to isopropanol:
  Renewable C₁ intermediates are converted through a single-pass tandem catalysis process to acetone and subsequently to isopropanol, achieving high selectivity by optimizing the spatial proximity and mass ratios of catalytic functions.
• Computationally guided materials design:
  First-principles simulations based on Grand-Canonical Density Functional Theory and machine learning are used to design platinum-group-metal-free electrocatalysts and fluorine-free proton-exchange membranes with high performance and improved resistance to inhibition in direct fuel cell operation.
• Direct isopropanol fuel cell operation:
  Energy is recovered on board using a direct isopropanol fuel cell, which converts liquid isopropanol to electricity via selective electro-dehydrogenation, producing acetone as the only byproduct and eliminating carbon dioxide emissions.
• System integration and sustainability assessment:
  Advanced simulations support integration into inland waterway powertrains, including double-liquid fuel logistics, thermal management, and operational strategies. The overall concept is evaluated through a well-to-wake life-cycle analysis to assess environmental and system-level performance.

IsoPROPEL brings together a multidisciplinary consortium of nine European partners from Spain, Norway, Italy, France, Croatia, Germany, Austria, and the Netherlands. Together, they combine complementary expertise in chemistry and materials science, (electro)catalysis, fuel cell technologies, waterborne propulsion systems, inland shipping logistics, and sustainability assessment.

The project introduces pioneering concepts, including the first selective carbon dioxide conversion route to C3 oxygenates as renewable fuels of non-biological origin, and their use as rechargeable energy carriers in direct, liquid-fed fuel cells for zero-emission waterway transport. While targeting disruptive technologies, IsoPROPEL is strongly aligned with industrial and stakeholder needs to support future upscaling beyond the project. To this end, a Stakeholder Board has been established, representing the full e-fuel value chain, from carbon dioxide sourcing and fuel production to distribution and inland shipbuilding and operation, supported by broader outreach through the e-Fuel Alliance and Hydrogen Europe, connecting the project to over 700 stakeholders across Europe.

Acronym: IsoPROPEL
Duration: 42 months
Start date: 1^st November 2025
EC Funding: €3,995,636.25

IsoPROPEL is conducting research in the field of e-fuel production and will disseminate scientific results to peers in the field by means of scientific publications. All relevant publications will be posted on this page.