On June 2 and 3, 2025, the IWEN Energy Institute hosted a seminar as part of the DecarbonDHS project. We welcomed our partners from Poland, Lithuania, Sweden, and Denmark to Rostock. The two-day meeting was used to exchange ideas and gain valuable new experiences. The first day featured a seminar with specialist presentations. Participants learned a lot of new and interesting information and heard about best practice examples on the topics of municipal heat planning, optimization and efficiency improvement of district heating networks, the geothermal potential in Mecklenburg-Western Pomerania, and the role of biomass in the energy transition. On the second day, an excursion was made to the associated partner Stadtwerke Rostock. Here, participants were given a presentation on the current heat supply in the Rostock region and the energy supplier's future plans. This was followed by a tour of the Stadtwerke's production park, which included a visit to the 45 million liter, 55 m high heat storage tank.