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RePoSe - Real-time Power Supply for e-fuels

The world's largest pilot plant for synthetic kerosene in Hessen will be the first to demonstrate how the fluctuating availability of renewable energy affects the production of CO2-neutral power-to-liquid fuels.

Together with partners from research and industry, the RePoSe (Real-time Power Supply for e-fuels) project will investigate from 2022 to 2026 how the Firscher-Tropsch synthesis for the production of PtL fuels can be operated variably. Part of the pilot plant at Industriepark Höchst will be used for this purpose.

The Project RePoSe is funded with a total of 3.4 million euros by the Federal Ministry for Digital and Transport as part of the Funding Programme Renewable Fuels. The Hessian Ministry of Economics, Energy, Transport and Housing (HMWEVW) is also contributing one million euros to the project. The PtL development and demonstration platform is coordinated by NOW GmbH and supported by the project management agency VDI/VDE Innovation + Technik GmbH.


Fischer-Tropsch synthesis is a large-scale process for converting synthesis gas (CO/H2) into liquid hydrocarbons. So far, this technology has only been operated with a continuous hydrogen supply. A key question for subsequent industrial upscaling is how fluctuations in the power supply from renewable energies can be buffered during the production of the synthetic kerosene.

Since solar and wind power are not continuously available, very large hydrogen storage facilities are needed. Exactly how large they need to be is being calculated and tested in within RePoSe. Another particularly interesting aspect are the options for increasing flexibility in the production process. In addition to the technical testing of the operation, the effects of variable operation on the sustainability of fuel production (e. g. in the form of a life cycle analysis) and on the mechanical stress on the Fischer-Tropsch plant will also be determined.


In the PtL process, water is split into hydrogen and oxygen using electricity. The hydrogen is then used together with CO2 from industrial processes to synthesize liquid fuels. If the electricity used for this comes from renewable energies, the CO2 cycle can be completely closed. This means that when such PtL fuels are burned, only as much CO2 is released as was captured during production. In addition, fewer air pollutants are produced than with conventional fuels. The end product is CO2-neutral kerosene.


The partners in the RePoSe project are CENA Hessen, Fraunhofer IWKS, Fraunhofer LBF, Ineratec AG and Provadis University.

CENA Hessen is the project coordinator for RePoSe and is investigating the optimization of synthesis plant downtime and hydrogen storage sizing in this project. This includes obtaining and analyzing data on power availability from renewable generation, performing the optimization calculations, and the practical operation of a hydrogen storage facility.

As part of the project, Fraunhofer IWKS will investigate the system components replaced at specified intervals and their wear as well as any fatigue phenomena that may occur (cracking, surface damage) metallographically, structurally, microstructurally, and morphologically. This gives the opportunity to carry out targeted optimizations on the materials used and to investigate the effects from operation in combination with the effects of hydrogen.

Fraunhofer LBF is investigating the reliability of the system under variable loads. This includes the measurement and evaluation of local stresses on the plant, the derivation of fault-effect relationships for the evaluation of failure scenarios and their effects on the operating time as well as on plant efficiency and safety. Cyclic analyses of the polymeric and metallic materials used will be used to evaluate material degradation caused by the plant's contact media.

INERATEC plans to build a pioneering power-to-liquid (PtL) plant for generating e-fuels at Industriepark Höchst. It will produce up to 3,500 tons or 4.6 million liters of INERATEC e-fuels annually from up to 10,000 tons of biogenic CO2 and renewable electricity. The pioneer plant is made up of individual, standardized modules. One of these modules is to be incorporated into the RePoSe project in order to test a volatile power supply.

Provadis University will perform a life cycle analysis as part of the RePoSe research project. This will quantify the environmental impacts, such as the CO2 footprint and the use of resources, in detail and in relation to each process step. This makes it possible to identify at an early stage which process steps have a high environmental impact so that measures can be taken to reduce them. In addition, it can be deduced whether there are ecological advantages compared to continuous processes.

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