Audi steps up research into carbon-neutral synthetic fuels with new e-diesel pilot plant; power-to-liquids
Audi is systematically building on its e-fuels strategy. (Earlier post.) Together with the partners Ineratec GmbH (earlier post) and Energiedienst Holding AG, the company has plans for a new pilot facility for the production of e-diesel in Laufenburg, in Canton Aargau (Switzerland). For the first time, the energy needed will be supplied from the renewable source of hydropower. The planned facility will have a capacity of around 400,000 liters (105,669 gallons US) per year.
For some years now, Audi has been conducting research into climate-friendly, CO2-based fuels such as e-gas, e-gasoline or synthetically manufactured e-diesel fuel. (Earlier post.) The company is now taking the next step in e-diesel production.
At the project in Laufenburg, thanks to a new technology we are able to handle the production of e-diesel efficiently in compact units, making it more economical. The pilot facility offers scope for sector coupling, in other words combining the energy sectors power, heat and mobility, and makes it possible to store renewable energy.—Reiner Mangold, Head of Sustainable Product Development at Audi
Audi e-diesel has the potential to make conventional combustion engines operate almost CO2-neutrally. To produce it, the power-to-liquid plant converts surplus hydropower into synthetic fuel. The green power generated on site in the hydroelectric power station produces hydrogen and oxygen from water by means of electrolysis.
This hydrogen, together with carbon dioxide, is converted in a two-step power-to-liquid process. First, the CO2 and H2 are converted into syngas in Ineratec’s RWGS (reverse water gas shift) reactor. In second step, the Fischer-Tropsch reactor produces Audi e-diesel and waxes—which are put to use in other areas of industry—from the syngas.
The Fischer-Tropsch products are free of aromatics and sulfur compounds. The CO2 can be obtained from the atmosphere or from biogenous waste gases and, as with all Audi e-fuels, is the only source of carbon.
The core of Ineratec’s synthesis reactors is microstructured, thus providing a very large surface for heat and mass transport, thereby minimizing effects on reactor and catalyst performance. Highly exothermic reactions such as Fischer-Tropsch synthesis can be operated efficiently and safely in compact plants.
Ineratec says that its reactors are characterized by:
- Compact design due to the microstructure technology
- High syngas conversion per reactor pass and unique reactor productivity
- Excellent temperature control
- Short start-up and shut down times
- High load-flexibility
- Cost reduction for decentralized application
Audi and its partners plan to produce the first quantities of e-diesel in Laufenburg as early as next year. Audi and the project partner companies Ineratec and Energiedienst AG will submit the planning application for the facility in a few weeks’ time. Construction work is to begin in early 2018.
This is now Audi’s second partnership in a pilot facility that operates according to the power-to-liquid principle. Audi has already been working together with the energy technology corporation sunfire in Dresden since 2014.
There, sunfire is exploring the manufacturing of e-diesel based on the same principle, but involving different technologies. The other Audi e-fuels projects include its own power-to-gas facility in Werlte, north Germany, which makes Audi e-gas—i.e., synthetic methane—for the g-tron models A3, A4 and A5. The Ingolstadt carmaker is also researching the manufacture of e-gasoline together with specialist partners.