Dimethyl Ether: New Process Could Be Game Changer for Hydrogen Economy

Germany is preparing for a future reliant on imported hydrogen, and a new process developed by the Fraunhofer Institute for Solar Energy Systems ISE suggests dimethyl ether (DME) could be the key to making that transition efficient and economically viable. DME, a non-toxic and efficient gas, is emerging as a promising energy carrier, and Fraunhofer ISE’s innovative synthesis process aims to revolutionize its production, potentially unlocking a significant advancement for the entire hydrogen economy.

The Challenge of Hydrogen Import

The need for hydrogen imports stems from Germany’s ambitious climate protection goals and the desire for energy security. While green hydrogen production within the country is growing, it won’t be sufficient to meet future demand. Transporting hydrogen presents significant challenges, and alternatives like ammonia have drawbacks, notably lower volumetric energy density. DME offers a compelling solution, boasting a higher energy density than ammonia, making it a more practical candidate for large-scale import.

INDIGO: A New Approach to DME Synthesis

Currently, DME production is a complex and energy-intensive process. The Fraunhofer ISE has addressed this with a new process, dubbed INDIGO, which simultaneously combines synthesis and distillation. This simplification dramatically increases efficiency and reduces costs – by more than a quarter, according to the institute – compared to conventional DME synthesis. The key lies in utilizing the heat generated during the reaction to directly power the distillation column, minimizing energy waste.

“Dimethyl ether is the hidden champion of the hydrogen economy,” explains Dr. Elias Frei, Head of the Hydrogen Division at Fraunhofer ISE. “Not only because it has a significantly higher volumetric energy density than ammonia, which has been the most commonly used fuel to date, making it an ideal candidate for import. This proves also a renewable alternative to fossil raw materials as a platform molecule in areas such as the chemical industry and mobility.”

Beyond Hydrogen: DME as a Versatile Platform Molecule

The potential of DME extends beyond simply being a hydrogen carrier. It can serve as a versatile “platform molecule” for various applications, including blending with Liquefied Petroleum Gas (LPG) and as a feedstock for sustainable aviation fuels. Dr. Achim Schaadt, Head of the Sustainable Synthesis Products Department, highlights the scale of these potential markets: “The global LPG market comprises around 200 million tons per year. Added to this is the market for the production of sustainable aviation fuels, which is estimated to reach up to 400 million tons per year by 2050. This shows the enormous potential of DME.”

Power-to-MEDME: Testing the Process in Chile

The INDIGO process was tested within the international “Power-to-MEDME” project, which focused on large-scale methanol and DME production in Chile. Chile’s abundant solar resources make it an ideal location for producing green methanol and DME using renewable energy. The project analyzed the entire process chain, demonstrating the cost-effectiveness of INDIGO compared to conventional methods in all six cases studied. The Syn2X simulation tool was used to model the dynamic partial-load operation of the methanol plant, providing practical operating data under fluctuating conditions.

Chile as a Production Hub

Fraunhofer ISE has identified the Antofagasta region of Chile as particularly well-suited for large-scale production, due to its high solar power generation capacity. Currently, the region generates so much solar energy that excess power must be curtailed. Utilizing this surplus energy for DME production offers a solution to this problem, creating local value and contributing to regional development through the transfer of German technology.

Robert Szolak, head of the Sustainable Synthesis Products Department, emphasizes this benefit: “In addition to the more efficient use of electricity and local value creation, the project also contributes to the development of the region through the transfer of German technology know-how.”

Next Steps: A Pilot Plant in the Megawatt Range

Following the success of the Power-to-MEDME project, the next step is to establish a pilot plant in Chile capable of producing green methanol and DME at the megawatt scale. The Fraunhofer ISE research team is actively involved in analyzing process steps, developing and testing materials, and optimizing the integration of various processes to further reduce costs and increase efficiency. This pilot plant will be crucial in demonstrating the scalability and commercial viability of the INDIGO process, paving the way for wider adoption of DME as a key component of the future hydrogen economy.