Researchers at Fraunhofer ISE are focusing on dimethyl ether as a hydrogen carrier for import to Germany. The institute has developed the INDIGO process for this purpose, which is expected to reduce production costs by more than a quarter compared to conventional methods.
“Dimethyl ether is the hidden champion of the hydrogen economy, not only because it has a significantly higher volumetric energy density than the ammonia mostly used so far, making it an ideal candidate for import. It is also a renewable alternative to fossil feedstocks in areas such as the chemical industry and the transport sector,” says Elias Frei, Head of Hydrogen at Fraunhofer ISE.
INDIGO process combines synthesis and distillation
The new process combines synthesis and distillation in one step. The heat released during the reaction flows directly into the distillation column. This reduces energy demand and makes the process particularly suitable for remote regions, according to the institute. In the importing country, DME can then be converted back into hydrogen via steam reforming.
In the international research project “Power-to-MEDME,” Fraunhofer ISE examined the process chain for large-scale production in Chile. In all six cases analyzed, the INDIGO process proved to be cheaper than the conventional reference. The project team plans a pilot plant in the megawatt range as the next step.
Antofagasta as a site with high potential
A site analysis by Fraunhofer ISE identified the Antofagasta region in northern Chile as particularly suitable. Photovoltaic and solar thermal plants there already produce such high electricity surpluses that grid feed-in has to be curtailed.
Fraunhofer ISE sees great market potential for DME. The current market comprises more than five million tonnes per year. According to the institute, it could grow many times over through new applications such as blending with liquefied petroleum gas (LPG) or the production of sustainable aviation fuels. The institute therefore aims to promote DME as a new key topic together with industry.
