Municipal heat planning

On 23 June, the City of Chemnitz held an information event to present two climate protection projects that are nearing completion. The event showcased findings from the projects “Chemnitz: A Greenhouse Gas-Neutral City Administration” and “Model Solutions for Building Types”. Both projects highlight concrete ways in which energy consumption and greenhouse gas emissions in municipal buildings and the city’s existing building stock can be reduced in the long term.
 

Transition pathway for a greenhouse gas-neutral city administration

The “Greenhouse Gas-Neutral Chemnitz City Administration” project involved a comprehensive analysis of the municipal building stock, transport and technical infrastructure. The aim was to develop a technically and economically viable transformation pathway enabling the city administration to become largely greenhouse gas-neutral by 2035.

To this end, an energy and greenhouse gas inventory was drawn up, potential savings were identified, and specific measures were developed for municipal buildings, street lighting and transport. Furthermore, detailed energy analyses were carried out for selected municipal properties, and individual refurbishment roadmaps were drawn up.

According to the findings, the greatest potential for reducing energy consumption and greenhouse gas emissions lies in the buildings sector. Significant savings can be achieved through the energy-efficient refurbishment of building envelopes, the modernisation of building services, the expansion of district heating, the use of renewable heat generators, the installation of photovoltaic systems and the optimisation of lighting. For some of the buildings examined, primary energy demand can be reduced by more than 80 per cent.

The ongoing decarbonisation of district heating and the electricity sector also makes a significant contribution. For buildings that, in the long term, cannot be economically connected to the district heating network or fully electrified, the use of regionally produced biomethane was also considered as a possible alternative.

In addition, the project examined measures to electrify the municipal vehicle fleet, expand the charging infrastructure and promote climate-friendly forms of transport. The scenarios developed show that further emissions reductions are possible through the increased use of electric vehicles, as well as greater use of cycling and local public transport.

Overall, the studies confirm that a largely greenhouse gas-neutral city administration is technically achievable by 2035. This is conditional on the proposed measures being consistently implemented and supported by continuous energy and climate management.
 

Photovoltaic solutions for typical GDR residential buildings

The feasibility study ‘Model Solutions for Building Types’ examines how photovoltaic systems can be implemented, both technically and economically, on typical buildings from the era of industrial housing construction. The focus was on building types Q6, P2 and WBS70, as well as their different roof structures.

The results show that Q6 gable roofs with reinforced concrete rafters, in particular, offer good conditions for the installation of photovoltaic systems. In contrast, buildings with timber roof structures often require structural reinforcement.

For the flat roof types P2 and WBS70 examined, it is currently not possible to provide a calculated load-bearing capacity verification based solely on the existing documentation. However, an in-situ loading method developed and tested as part of the project shows the potential to provide the necessary structural verification in future in a cost-effective manner and with minimal structural intervention.

Furthermore, possibilities for increasing the self-consumption of the solar power generated were investigated. These include, in particular, battery storage and power-to-heat systems, in which surplus electricity is used for heating. These approaches can help to make better use of locally generated energy within the building and further advance the decarbonisation of the building stock.
 

Funding and project participants

Both projects are funded by the Free State of Saxony via the Sächsische Aufbaubank under the Energy and Climate Guidelines and co-financed by the European Union.

The ‘Chemnitz City Council: A Greenhouse Gas-Neutral Local Authority’ project was overseen by the city’s Environment Agency in collaboration with the Central Energy Management Department and the departments responsible for the vehicle fleet and street lighting. seecon Ingenieur GmbH was commissioned to carry out the study.

The feasibility study ‘Model Solutions for Building Types’ was overseen by the Environment Office in collaboration with the Central Energy Management Department and local housing associations. The technical work was carried out by the architectural and engineering firm Fellendorf GmbH.

The results of both projects form an important basis for further municipal climate protection work. They highlight both concrete courses of action for the city administration and transferable solutions for the energy-efficient refurbishment of existing buildings. In this way, the projects contribute to the energy transition and to the long-term reduction of greenhouse gas emissions in Chemnitz.