Hamburg University of Applied Sciences (HAW Hamburg) has completed the X-Energy research project after nine years. Together with over 20 partners, scientists from the Competence Center for Renewable Energy and Energy Efficiency (CC4E) developed solutions for sector coupling, power-to-gas, biological methanation, CO2 capture from the air, and carbon cycles, among other topics. The Federal Ministry of Education and Research funded the project with €10.9 million. At a closing conference in mid-February 2026 in Hamburg, the CC4E presented the most important results.
In biological methanation, hydrogen produced by electrolysis is converted with atmospheric CO2 by microorganisms into methane, which can be fed into the natural gas grid. Since green hydrogen alone does not enable sufficient value creation, X-Energy also addressed CO2 capture, which is required for the production of e-fuels and synthetic methane. The combination of H2 and CO2 obtained via direct air capture (DAC) is considered a key building block of the energy transition – for synthetic fuels and storable energy carriers as well as for the chemical industry. Moreover, DAC can contribute to decarbonization, as it enables climate-neutral production processes and potentially even negative emissions.
In the Hymspiel project, the CC4E developed an integrated system for local energy generation, storage, and supply. The goals are more efficient use of renewable energies, relief of the grids, and higher supply security. The core is a 100 kW PEM electrolysis plant that produces around 2.2 kg of hydrogen per hour. “The hydrogen is temporarily stored in a modular storage system with a low-pressure and a high-pressure stage (up to 300 bar),” explains Petrit Vuthi, a research associate on the project. “Reconversion to electricity occurs in the pilot plant through a hydrogen CHP unit and later a fuel cell.” Part of the concept also includes using the resulting waste heat to heat the buildings on site.
“Through flexible storage and demand-responsive reconversion to electricity, local energy supply is to be optimized in order to utilize the potential of hydrogen as an energy storage medium in the district,” explains Mike Blicker, co-project leader of Hymspiel and coordinator of X-Energy at CC4E. “Grid-supportive use of local flexibilities enables overall better integration of renewable energies into the electricity system.” This would also reduce the need for grid expansion. Additionally, the project investigates how buildings can benefit from one another through so-called prosumer models.
System integration was also addressed in X-Energy with the question of how to use wind power peaks for electrolysis or how to plan electricity, gas, and heat networks in an integrated manner. Other researchers optimized two-blade rotors and multirotor systems for wind turbines and, together with the University of Strathclyde, established an international annual conference for multirotor research. Furthermore, one of Germany’s first systems for demand-based night marking of wind turbines was put into operation. The innovations and efficiency improvements developed in the project increase the potential for renewable electricity – and thus also for green hydrogen.
With more than 20 partners from industry and trade who cooperated closely with the X-Energy engineers, the project went far beyond basic research – to applications already close to market in practice. Two spin-offs demonstrate that technology transfer has worked: one for intelligent control of heat and electricity generators and another in the area of maintenance strategies for wind turbines. “Cooperation between science and business is indispensable for the energy transition in our city,” emphasized Hamburg’s Second Mayor and Environment Senator Katharina Fegebank at the closing conference. The collaboration “accelerates innovation processes and contributes to the important transfer of knowledge and technology.”
An outlook on how research will continue was provided by Hans Schäfers, Professor of Intelligent Energy Systems and Energy Efficiency and head of CC4E. The infrastructure created by X-Energy is already feeding into follow-up projects such as the North German Real-World Laboratory (NRL). Because Hamburg, as Germany’s second-largest city and with a significant industrial area in the port – metals, chemicals – wants to become climate-neutral by 2040, urgency is required. Using green surplus electricity to produce hydrogen is obvious, but still difficult for regulatory reasons.
However, the potential is impressive, as a sub-project of the NRL shows. “According to initial findings, with an electrolysis capacity of approximately 2.3 gigawatts distributed across 52 sites at critical grid nodes in Schleswig-Holstein and Hamburg, around 80 percent of the surplus electricity from renewable energies that would normally be curtailed could be reduced,” Hans Schäfers tells H2Int. “The concept of decentralized plants can support the hydrogen strategy of the Free and Hanseatic City of Hamburg, which so far primarily includes central projects and facilities such as the Hamburg Green Hydrogen Hub (HGHH) at the site of the former Moorburg coal-fired power plant.”
He urgently calls for creating the political and legal framework now to build capacity to meet the projected demand for green hydrogen through both imports and domestic production.
Since X-Energy has intensively engaged with technologies that will likely only be deployed on a large scale in ten to fifteen years, it provides impetus for future storage strategies and the production of climate-neutral molecules. This should be of particular interest to investors, project developers, and municipalities. And it is also the timeframe in which the hydrogen economy will likely enter broad industrial application.
