QUENTIN: Energy-efficient district development

The urban quarter of Tackenberg in Oberhausen centers of the project "District development based on local heating islands with flexible CHP systems and partial refurbishment" – QUENTIN for short. Energy-efficient and above all affordable living space combined with refurbishment concepts shall be achieved. Specifically, flexibly operated local district heating with CHP systems are built and investigated for four selected areas of the quarter.

The background to the project is the German government's energy concept. It calls for a virtually climate-neutral building stock by 2045. The key instruments for achieving this goal are the Building Energy Act (GEG) and the Heat Planning Act (WPG), which define standards for energy efficiency and the use of renewable energies. The challenge: as these standards can generally only be implemented at high cost, housing in the lower price segment with low rents is usually excluded from energy-efficient refurbishment.

This is where QUENTIN comes in: As part of the joint project, efficient, affordable concepts that can be implemented in the short term for the energy-efficient refurbishment of districts with a high primary energy saving potential are developed. The project partners encompass Energieversorgung Oberhausen AG (evo), Osterfelder Wohnungsgenossenschaft eG (GE-WO), Gemeinnützige Wohnungsgenossenschaft Oberhausen-Sterkrade eG (GWG), Servicebetriebe Oberhausen (SBO, a municipal enterprise of the city of Oberhausen) and Fraunhofer UMSICHT.

The project partners build on the results of the "FlexKWK" project completed in 2019, in which a new combined heat and power (CHP) concept was developed for an existing heating network in Oberhausen-Barmingholten: a combined heat and power plant, a large heat storage unit and an electric hot water generator supply in total 150 residential units. This has turned the estate into a flexible local heating district. Electricity is produced when it is needed. The resulting heat is stored and made available according to the requirements of the heating network.

Such local heat islands are set up for four selected quarters of the Osterfelder Wohnungsgenossenschaft and Sterkrader Wohnungsgenossenschaft housing association. This process is accompanied by the construction of low-temperature heating networks with central and decentralized heat storages, the refurbishment of selected buildings and the integration of public buildings of the SBO into the supply concept. At the same time, comprehensive analyses of the renovation status and primary energy reduction are carried out and renovation strategies are developed to evolve transferrable refurbishment concepts.

In 2021 and 2022, two local district heating systems in "Flöz-Matthias-Straße" and "Dirlingsweg" were put into operation according to the originally planned concept. The generously dimensioned heat storage tanks enable the decoupling of electricity generation through combined heat and power (CHP) and heat consumption in the neighborhoods. During the project, GE-WO and GWG refurbished various buildings for energy efficiency. Among other improvements, new windows and doors were installed, and facades and roofs were insulated. One of the most important results: Due to the switch to the local heating system, the integration of flexible combined heat and power plants (CHP) and the combination with partial refurbishments, CO2 emissions in both districts were significantly reduced – by 9.4 percent and 12.9 percent, respectively – despite grid and storage losses.

In addition, UMSICHT gained valuable insights into the use of decentralized heat storage systems and their integration into local heating networks. One example: optimized storage management reduced the required peak load to 50 percent of the original building connection capacity. This demonstrates that intelligent planning and implementation can minimize system technology and optimize its utilization.

We also conducted optimization calculations for the future development of local heat supply in the neighborhoods. The focus was on three core scenarios (persistence, focus on hydrogen and focus on electrification), which were examined from both qualitative and quantitative perspectives, such as energy prices, technology dominance, and political requirements. Conclusions:

• The use of large heat pumps and hybrid systems (CHP & heat pumps) enables significant CO2 emission reductions.
• The higher the share of renewable energy, the lower the operating costs for the whole district This trend is expected to become more pronounced in the future. This points to the need to further promote the integration of renewable energies and the adaptation of existing systems.
• Flexible and innovative approaches remain extremely relevant for the future heat supply in urban districts.

In summary, the use of local district heating systems not only offers ecological advantages in terms of CO2 reduction and energy savings but also reveals economic potential for municipal utilities and heating network operators. Local heating areas are suitable for both integrating renewable energies and continuously improving the efficiency of heat supply systems and can contribute to achieving the climate targets for 2045.

• Energieversorgung Oberhausen AG
• Osterfelder Wohnungsgenossenschaft eG
• Gemeinnützige Wohnungsgenossenschaft Oberhausen-Sterkrade eG
• Servicebetriebe Oberhausen – Eigenbetrieb der Stadt Oberhausen (SBO)

The project "District development based on local heating islands with flexible CHP systems and partial refurbishment" – QUENTIN for short – is funded by the Federal Ministry of Economics and Climate Protection.