Dimethylether as Hydrogen Carrier

Dimethyl ether (DME) is produced, transported and used worldwide on a scale of millions of tons. DME is non-toxic and has a significantly lower global warming potential than methane. It can be used flexibly – for example, as a blending component for fossil LPG, as a propellant, or as a refrigerant. DME is particularly promising as a hydrogen carrier for large-scale transport. This expands the markets and is in line with Germany's 2024 hydrogen import strategy, which aims to achieve a resilient, diversified supply. Since a large part of future demand will be imported, the diversification of regions of origin and transport carriers (e.g., ammonia and DME) as well as robust value chains are key. Thermochemical hydrogen production (reforming) from carriers such as ammonia and DME enables flexible use in industry, mobility, electricity and heat generation. DME offers 47 percent higher hydrogen storage capacity than ammonia and is non-toxic. Currently, however, the energy-intensive provision of carbon and the complex reforming process limit its economic viability; CO₂ capture from the air (DAC) is still too expensive. One solution is to use DME in a closed carbon cycle: the CO₂ produced during reforming is separated at the destination and returned to the production site. This significantly reduces hydrogen costs at the destination (e.g., in Germany). The state of the art is based on methane or methanol steam reforming. At Fraunhofer ISE, we are currently investigating the low-temperature route (<400 °C), which requires less heat than the high-temperature route (> 700 °C). To this end, we are conducting experiments and developing models that identify catalyst limitations and optimization paths.