Hydrogen in the municipal circular economy

The current hydrogen developments with new processes and concepts show: Hydrogen can be a useful partner for the municipal circular economy and water industry. This article provides an overview of the importance of hydrogen in Germany as well as a status quo within the municipalities.

Importance of hydrogen for Germany and the energy transition

Hydrogen (H₂) has a central role to play in the energy transition that Germany is striving for. According to the Federal Ministry for Economic Affairs and Climate Protection (BMWK), the hydrogen ramp-up is initially aimed at the economy – to transform industry. However, in the Ministry’s view, this does not rule out hydrogen production and use in municipalities. Hydrogen can be produced and used from renewable energies, for example, electricity from solar systems, wind or hydropower through water electrolysis, or from biogas. The German government’s National Hydrogen Strategy also mentions the production of hydrogen from waste or wastewater and running municipal vehicles on the energy-rich gas as other options worth funding with a municipal focus.

IFAT Munich 2024 with Spotlight Area Hydrogen

The international environmental technology trade fair IFAT Munich, which will take place at the Munich Exhibition Center from May 13 to 17, 2024, will trace the developments of the comparatively new partnership between the municipal circular economy and the hydrogen economy. Alongside approximately 100 exhibitors offering solutions in the field of hydrogen, the exhibition dedicates a 500 square meter special area in Hall A4, named "Spotlight Area - Hydrogen in the Circular Economy," where up to 10 exhibitors will present their projects and solutions. Integrated into the area is a stage, the Hydrogen Stage, where approximately 30 presentations and discussion sessions will provide further information. How can hydrogen be produced in a biogas plant, waste incineration facility, or wastewater treatment plant? What requirements do municipalities face in hydrogen production? What do educational and training opportunities for professionals look like? These and many other exciting questions regarding the production and utilization of hydrogen will be highlighted on the Hydrogen Stage.

The main partner of the Spotlight Area and conceptual sponsor of IFAT Munich is the German Technical and Scientific Association for Gas and Water (DVGW e.V.). Its CEO Prof. Gerald Linke emphasizes: “Hydrogen offers promising opportunities for companies in the circular economy. As a product of many local processes – such as waste pyrolysis or biomass hydrolysis – it can be fed into the local distribution grid, used as a fuel for municipal vehicles, or offered as a means of production for industries connected to the grid.” He says that hydrogen is an important component for linking energy sectors, especially where hydrogen is produced electrolytically from local electricity, hence making the energy system more resilient. The DVGW states that it has completed the regulatory work for hydrogen in the network infrastructure and has also developed conversion aids for the industry. That means that hydrogen networks can be planned on the basis of the gas network transformation plan, while the VerifHy database provides reliable information on the hydrogen suitability of components.

Converting biogas into hydrogen

BtX energy GmbH is one of the exhibitors in the Spotlight Area. The company from Hof/Bavaria offers a process that converts biogas into hydrogen through steam reforming. In a joint research project funded by the BMWK, a pilot plant connected to an agricultural biogas plant has been running in Krefeld since the beginning of 2023. “It can also be used without any technical problems in biogas plants that recycle municipal organic waste and is a financially attractive option,” says Dr. Andy Gradel. To that end, the BtX Managing Director is currently holding talks with plant operators in various cities, including BeB Bio Energie Bamberg. Its biogas plant in Pettstadt utilizes the fermentable fraction of the organic waste collected in Bamberg and the surrounding area. On this basis, around 150 tons of renewable hydrogen could be produced annually in the future and used, among other things, to power buses, commercial trucks or waste collection vehicles in a climate-neutral way.

Biogenic substitute fuels as source material

Biogenic substitute fuels can be a starting material for the climate-neutral production of hydrogen. These accumulate in large quantities not only in industry, for example, as fiber residue from paper production, but also in municipalities – keyword sewage sludge. The Pure_Bio_H₂ project, funded by the Federal Ministry of Education and Research, has been working on this since October 2022. The Fraunhofer Institute for Surface Engineering and Thin Films IST, the Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT, and the waste management company Veolia Umweltservice Süd GmbH & Co. KG are involved as research partners. In a first step, the project aims to produce a hydrogen-rich synthesis gas from the biogenic residues using a thermochemical conversion process. The plan is to subsequently separate high-purity hydrogen using metal-coated membranes.

Sewage gas becomes high-purity hydrogen

Producing of H₂ is also an additional way of turning the sewage treatment plants in cities and municipalities into power plants. The starting point is the sewage gas produced in many wastewater treatment plants. A classic solution for utilizing its energy content is power generation with heat recovery in a combined heat and power plant. A second approach is to convert the sewage gas into biomethane. Hydrogen production is now being added to these as a third option. One of the technologies that can be used is a steam reformer from the international energy technology company and IFAT Munich exhibitor Metacon AB, which produces high-purity hydrogen from sewage gas. Such a system will be installed at the municipal wastewater treatment plant of the Kempten Wastewater Association (AVKE) from this summer. The integrated steam reformer will then generate up to 110 kg of hydrogen with a purity of 99.999% from the existing sewage gas around the clock. The electricity required for the reformer and the peripheral plant components is provided directly on site through sewage gas power generation. The hydrogen produced can be used as a basic raw material, a carbon-neutral fuel for AVKE’s own vehicle fleet, and for regional public transport. Dr. Christian Hofmann, Chief Business Officer Reforming at Metacon, is certain: “With the successful implementation of this project, we will make an important contribution to the decentralized production of sustainable hydrogen and provide a building block for independent energy generation and fossil-free fuel production in Europe and beyond.” After all, he says, the potential is huge: In Germany alone, sewage gas is produced at over 1,200 sewage treatment plants (as of 2019).

Refining digester gas and biogas with hydrogen

In addition to the DVGW, the Hydrogen Center Bavaria (H2.B), which was initiated and financed by the Free State of Bavaria as a strategy and coordination center, is also acting as a partner of Messe München in organizing the Spotlight Area Hydrogen. Its Head of Technology and Innovation, Stefan Dürr, explains: “One of the promising options for the hydrogen economy is the refinement of gases rich in carbon dioxide. There is an interface here with municipal wastewater treatment.” According to Dürr, digester gas and biogas always contain “residual CO₂”, which can be converted into methane by microorganisms in combination with renewable hydrogen. This can then be fed into the gas grid. Dürr: “Bavarian companies such as Electrochaea GmbH from Planegg, which is represented in the Spotlight Area, are also active in this area.” Their process was also tested in Roslev/Denmark and Solothurn/Switzerland.

Another possible link between hydrogen production and wastewater treatment: Oxygen is essentially produced as a by-product of water electrolysis, which can be used in the aerobic purification stage of wastewater treatment plants. “However, this coupling only makes economic sense with preferably continuous H₂ generation,” notes Stefan Dürr.

Emission-free drives for waste collection vehicles

Waste collection vehicles are among the “municipal hydrogen users”. Of the approximately 12,000 garbage trucks currently in operation across Germany, 150 are powered by fuel cells, for example, in Berlin, Duisburg and Freiburg im Breisgau. “That makes Germany an international pioneer,” says Burkard Oppmann, Managing Director of IFAT Munich exhibitor FAUN Umwelttechnik. According to him, the hydrogen used for that comes mainly from renewable energy sources, and in some cases also from waste. “As far as the H₂ technology used in our waste collection vehicles is concerned, we are in a constant process of improvement. We find ourselves in an extremely exciting field here, comparable to the situation with the development of diesel engines 100 years ago,” says Oppmann. According to him, however, a suitable funding framework is currently still lacking for even broader market penetration.

Hydrogen-capable burners for waste-to-energy plants

H₂ could also play an increasingly important role in waste-to-energy plants in the future. The first hydrogen-capable burners went into operation at the Frankfurt waste-to-energy plant in September 2023. Previously, it was only possible to operate these “ignition aids” with heating oil. In future, it will be possible with hydrogen as well as natural gas. Dirk Remmert, Managing Director of Frankfurter Entsorgungs- und Service GmbH (FES) and MHKW GmbH, says: “We know from studies that the waste incineration plant in Nordweststadt meets all the requirements to also be a hydrogen producer. It is not yet entirely clear what role this fuel can play in the future, but we also want to get ourselves ready to use hydrogen in this plant, which is central to the future of energy generation in Frankfurt.”