E-TANDEM project



Carbon neutral, high-energy density e-fuels are crucial to de-fossilize long-haul, heavy-duty road, marine and aviation transport sectors. Current e-fuels face hurdles for a swift market penetration due to incompatibility with current ICE fleets and fuel distribution network, and/or non-compliance with fuel norms in force. E-TANDEM aims to demonstrate a new, direct, hybrid-catalysis route for the production of a higher oxygenated diesel-like e-fuel (HOEF) based on higher alcohols and ethers from CO2, water and renewable power only.



Develop and validate a process for the direct conversion of CO2 and water, driven by renewable power, for the once-through production of higher oxygenate fuels.

Develop a laboratory-scale (<500 mL) slurry-phase, high-pressure reactor to effectively perform the direct e-syngas conversion by tandem integration of solid Fischer-Tropsch (FTS) and molecular reductive hydroformylation (RHF) catalytic functions, with high withhold rates for both catalyst functionalities.

Validate, at benchtop lab-scale (TRL4), a continuous power-to-fuel process for the production of higher oxygenates (C5+ fraction of aliphatic alcohols and C8+ fraction of aliphatic ether derivatives) with high carbon selectivity and energy efficiency and assess its dynamic response to temporal fluctuations in renewable power input.

Characterize the newly proposed higher oxygenate e-fuel (HOEF), in its two realizations i.e., a mixture of either higher aliphatic alcohols or higher aliphatic ethers, and assess its drop-in characteristics for current-fleet marine and heavy-duty road internal combustion engines.

Assess the technical, economic, and sustainability aspects of the new e-fuel production concept and set the basis for further upscaling developments beyond E-TANDEM.


E-TANDEM’s ambition is to unlock an efficient and direct production of a new higher-oxygenate diesel-like e-fuel for the marine and heavy-duty transport sectors. This oxygenated fuel is directly produced from CO2 as the sole carbon source, and renewable power as the sole energy input, in a once-through hybrid catalytic conversion process integrating three major catalysis branches: high-pressure electrocatalysis syngas production coupled to a tandem catalytic e-syngas conversion encompassing thermocatalysis with solid catalysts and chemocatalysis with molecular complexes. The project will demonstrate the new e-fuel production process at bench-scale, and assess its capacity to cope with fluctuating energy inputs.


The project aims to develop a disruptive route wherein CO2, water and renewable power are converted to higher oxygenate e-fuels in a once-through hybrid process integrating three major catalysis branches: “electrocatalysis” is applied in a robust high-pressure CO2/H2O co-electrolysis step to produce e-syngas (H2/CO), which is converted in a single-reactor, slurry-phase process combining “solid thermocatalysis” for linear hydrocarbon synthesis and “molecular chemocatalysis” for in situ oxo-functionalization via reductive hydroformylation. In this process, integration of catalytic functionalities in tandem, alongside an engineered interfacing of high- and lowtemperature conversion steps and energy unintensive membrane separation technologies, offer a blueprint for superior atom and energy efficiencies. Moreover, e-fuel formulation and life-cycle aspects are covered to fully realize the potential of the higher oxygenate e-fuel to distinctively unite excellent combustion properties (high cetane), exceptional reduction of tailpipe soot emissions, advantageous logistics as liquid at ambient conditions and compatibility with current-fleet fuel infrastructure and engine technologies, with emphasis on applications as diesel replacement in heavy-duty marine transport. An exploitation plan will be created together with international stakeholders, to consolidate EU’s capacity to export advanced e-fuel technologies to areas with vast green energy potential.


The results of the E-TANDEM project are documented in reports. The available reports are published here.

Facts and figures

Acronym: E-TANDEM
Duration: 42 months
Start date: 1 November 2022
EC Funding: 3,33 M€
GA: 101083700


E-TANDEM 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.

Project progress

© 2023 E-TANDEM

Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Commission. Neither the European Union nor the granting authority can be held responsible for them.

Funding_statement (1)