Nearly three percent of global greenhouse gas emissions come from shipping, prompting researchers to explore climate-neutral fuels, particularly e-methanol produced from sewage sludge. A new facility in Mannheim, backed by Transport Minister Volker Wissing, aims to convert sewage into this sustainable fuel. Despite challenges in scaling up green hydrogen production, the Mannheim plant could significantly reduce emissions. Future projects, including a larger site in Spain, depend on substantial funding and advancements in technology to meet shipping demands and environmental goals.
Shipping’s Greenhouse Gas Emissions and the Search for Climate-Neutral Fuels
Nearly three percent of worldwide greenhouse gas emissions originate from the shipping industry. In response, researchers are actively exploring climate-neutral fuel alternatives, with sewage treatment plants emerging as a promising source for these sustainable solutions.
Innovative E-Methanol Production in Mannheim
Transport Minister Volker Wissing recently attended the opening of a groundbreaking e-methanol production facility at a sewage treatment plant in Mannheim. Despite his departure from the FDP after the traffic light coalition’s collapse, Wissing continues to champion a diverse technological approach to combat climate change.
“We require climate-friendly fuels, particularly in maritime shipping, alongside electrification and hydrogen-based drives,” Wissing stated at the facility’s inauguration. The ‘Mannheim 001’ facility is set to transform sewage sludge into e-methanol, a climate-neutral ship fuel, according to David Strittmatter, managing director of ICODOS, the company that collaborated with the Karlsruhe Institute of Technology (KIT) to develop this innovative process.
Traditionally, sewage sludge in Germany is incinerated for energy generation. In contrast, the Mannheim treatment plant utilizes fermentation in large tanks to produce biogas and CO2. Following this, CO2 is separated and the biogas can be integrated into the gas network. The remaining CO2 is converted into e-methanol through a high-temperature reaction with hydrogen.
This summer highlighted significant challenges for shipping, as the Rhine River’s water levels dropped alarmingly low, impacting transport across the region.
The Future of Fuel Sourced from Sewage Sludge
For the production of climate-neutral e-methanol, green hydrogen is essential. This hydrogen is generated via electrolysis powered by renewable energy sources. However, the current scarcity of green hydrogen raises concerns among environmental groups regarding the feasibility of scaling up production for the shipping industry. “The scalability for the entire shipping sector seems challenging since the available quantities are not sufficient,” remarked Karsten Smid from Greenpeace.
Key considerations for new fuel production methods include the energy requirements and overall viability. Strittmatter states that around 2,500 kilograms of green hydrogen are needed annually for e-methanol production, equating to approximately 150,000 kilowatt-hours of electricity—enough to power 60 two-person households for a year. Given that shipping contributes about three percent of global greenhouse emissions, e-methanol may indeed become a critical component in climate efforts.
Projected reductions in fuel consumption for cargo ships could reach up to 90 percent, raising questions about the potential for this new fuel to gain a foothold in the industry.
Funding and Future Prospects
The Mannheim facility aims to produce around 15,000 liters of e-methanol per year. For context, the first methanol-powered container ship, the Laura Mærsk, has a tank capacity of 1.4 million liters and can cover nearly 11,000 kilometers on a single load. To meet shipping demands, larger facilities with greater production capacities are essential; ICODOS plans to establish a more extensive site in Spain with a capacity of 35 million liters annually.
This research initiative has received substantial funding from the EU, the federal government, and the city of Mannheim, totaling several million euros. The KIT has been refining the production processes in its laboratories since 2019, leading to the establishment of ICODOS to bring the technology to market.
Shipping faces challenges from droughts and storms, impacting global trade and logistics.
Environmental Impact and Market Viability
Strittmatter asserts that the new method can recycle up to 99 percent of the CO2 produced during sewage sludge fermentation, a level of efficiency that even surprises energy experts like Smid. Although burning e-methanol in ship engines does release CO2, it is offset by the emissions saved from not incinerating sewage sludge. “This creates a cycle that prevents additional fossil CO2 from entering the atmosphere,” Strittmatter explains.
The success of CO2 recycling for climate protection hinges on the availability of green hydrogen and the market price of e-methanol. Strittmatter projects costs could range between 700 and 800 euros per ton, particularly for the anticipated industrial facility in Spain. The Ministry of Transport remains optimistic about ongoing advancements in this area, even in the absence of Wissing, especially with the UN’s goal for global shipping to achieve climate neutrality by 2050.
This topic was highlighted by SWR 4 in the morning on March 24, 2025, at 6:00 AM.