Sector coupling of electric power and mobility has now been demonstrated by the partners of the P2X Kopernikus project on the premises of Karlsruhe Institute of Technology (KIT). The first liters of fuel were produced from air-captured carbon dioxide and green power. For the first time, a container-based test facility integrating all four chemical process steps needed was used to implement a continuous process with maximum carbon dioxide utilization and very high energy efficiency.
The combination of technologies from the project partners Climeworks, Ineratec, Sunfire, and KIT promises optimal use of the carbon dioxide and maximum energy efficiency, as mass and energy flows are recycled internally. The existing test facility can produce about 10 liters of fuel per day. In the second phase of the project, it is planned to develop a plant with a capacity of 200 liters per day. After that, a pre-industrial demonstration plant in the megawatt range, i.e. with a production capacity of 1500 to 2000 liters per day, will be designed. That plant may theoretically reach efficiencies of about 60%, which means that 60% of the green power used can be stored in the fuel as chemical energy.
Four Steps to Fuel
In a first step, the plant captures carbon dioxide from ambient air in a cyclic process. The direct air capture technology by Climeworks, a spinoff from ETH Zurich, uses a specially treated filter material for this purpose.
In the second step, the electrolytic splitting of carbon dioxide and water vapor takes place simultaneously. This so-called co-electrolysis technology commercialized by the technology venture Sunfire produces hydrogen and carbon monoxide in a single process step. The mixture can be applied as synthesis gas for a number of processes in chemical industry.
In a third step, the Fischer-Tropsch synthesis is used to convert the synthesis gas into long-chain hydrocarbon molecules, the raw materials for fuel production. For this, Ineratec, a spinoff of KIT, contributes a microstructured reactor that offers a large surface area on smallest space to reliably remove the process heat and use it for other process steps.
In the fourth step, the quality of the fuel and the yield are optimized. This process, called hydrocracking, was integrated into the process chain by KIT.
Due to its modular character, the process is of great potential. As a result of the low scaling risk, the implementation threshold is far lower than for a central, large-scale chemical facility. The process may be installed decentralized at locations where solar, wind or water power is available.