District heating not only reduces the need for resources – it also protects the climate. With an average annual district heating production of over three billion kilowatt hours, EnBW is one of the largest district heating companies in Germany.
District heating – how does it work?
Construction of a district heating system, using the example of the Mittlerer Neckar district heating network
District heating is based on a highly complex supply system which, in addition to kilometre-long pipes, also includes co-generation plants, distribution points, transfer stations, and shaft structures.
About 90 % of the district heating is generated by combined heat and power generation at the Stuttgart-Münster, Stuttgart-Gaisburg, and Altbach/Deizisau power plants, as well as the Marienstraße peak heating plant. Fuels such as hard coal, waste, and natural gas are used.
The system support of the district heating supply, which consists of volume and pressure maintenance facilities, the circulation of the district heating water, and the maintenance of the required water quality, takes place at the three CHP plant sites.
A total of eight substations with pressure boosting stations are operated in the network of the Mittlerer Neckar district heating network. The substations serve to increase the pressure, as well as to mix and distribute the district heat to the hydraulically separated sub-networks.
The network covers approx. 260 km and is one of the largest in Germany. The hot water in the pipes reaches temperatures between 80 and 130°C. For safe operation, additional 1,700 shaft structures are required in the Stuttgart city area.
The region’s network is controlled from the central heat control station in the Stuttgart-Münster combined heat and power plant. This is where production and feed-in, as well as transport and distribution, are monitored. The 24-hour fault hotline is also located here.
In the Mittlerer Neckar region, some 7,800 transfer stations are used to supply customers. Whether a small house connection or a large transfer station for industrial applications – flow rate, temperature, and pressure are controlled here.
The approximately 300 employees at the generation sites, in the network, and in the head office, are responsible for the smooth operation of district heating, plant maintenance, and control of district heating activities in the Mittlerer Neckar District Heating Network.
Frequently asked questions
The savings that can be achieved thanks to district heating are enormous: On one hand, the utilisation rate of the power plants will increase to more than 80%. On the other hand, much energy that would otherwise be required for the separate generation of heat in individual heating systems is saved. Overall, district heating from combined heat and power generation can reduce primary energy consumption by up to 40 % compared with separate electricity/heat generation. The consequences: Fewer resources required and fewer harmful greenhouse gases emitted. The amount of pollutants also decreases. This is because the modern systems of our combined heat and power plants clean the exhaust gases much better than is possible with thousands of individual fireplaces.
- District heating offers a very high security of supply. EnBW’s excellent distribution network guarantees a reliable supply – even in cold winter months.
- A connection to the district heating network is cheaper than the purchase of a gas or oil heating system. An approval procedure for the heating system is not necessary. As a rule, the insurance premiums for household insurance are more favourable. Compared to your own heating system, district heating systems also require considerably less space, because, for example, no chimney and no surfaces are required for a tank and the boiler. Wall mounting is also possible. The installation room does not require sound insulation.
- The operating and maintenance costs are low because the customer uses components that are less susceptible to faults when supplying district heating. Expenses for chimney cleaning and compliance with safety regulations (e.g. for the tank and the burner) are eliminated. The district heating supplier is responsible for generating and transporting the energy. In general, district heating systems are less susceptible to faults than boiler systems.
- Because no open or closed fireplaces are required for the district heating system, there is no possibility of an explosion or the danger of a domestic fire caused by exploding pipes or tanks.
- For connection work and ongoing operation, we are personally on site for you. As a regional and personal contact, we offer you peace of mind even in the event of disruptions – day and night.
Would you also like to benefit from the advantages of district heating? Simply check whether your house or business is located in one of these areas and then contact us: Your EnBW customer advisor will answer all your questions on +49 (0)711 289-47860.
Further information can be found here.
District heating and its advantages
The economical use of fossil fuels, the drastic reduction of CO₂ emissions, and the targeted promotion of renewable energies are key topics of a sustainable energy policy. District heating from combined heat and power generation therefore has an important place in the mix of measures designed to make our energy supply fit for the future.
Clear plus for our environment
The savings that can be achieved thanks to district heating are enormous: On one hand, the utilisation rate of the power plants will increase to more than 80%. On the other hand, much energy that would otherwise be required for the separate generation of heat in individual heating systems is saved. Overall, district heating from combined heat and power generation can reduce primary energy consumption by up to 40% compared with separate electricity/heat generation. The consequences: Fewer resources required and fewer harmful greenhouse gases emitted. The amount of pollutants also decreases. This is because the modern systems of our combined heat and power plants clean the exhaust gases much better than is possible with thousands of individual fireplaces.
The lower, the better: Primary energy factor
The primary energy factor is a decisive factor when calculating the primary energy requirement of your building. District heating offers clear advantages in this respect. On 1 February 2002, the requirements of the Thermal Insulation and Heating System Ordinances were merged. Since then, limit values have applied to the heat loss caused by the building as well as the primary energy requirement of a building. The primary energy factor is decisive for the primary energy demand. The more environmentally friendly the form of energy and its conversion, the lower the primary energy factor.
Certificate of energetic evaluation of district heating of EnBW
EnEV
Previously, the heat demand of a building and how it can be covered were considered separately. In the Energy Saving Ordinance, the entire chain from the energy source to the finished heat is considered. This is where the advantage of favourable energy conversion with combined heat and power generation comes into its own: The simultaneous generation of electricity and heat considerably reduces the use of valuable primary energy. The favourable primary energy factor of district heating is therefore perfectly in line with current energy laws – in particular the Energy Saving Ordinance, which sets limits for the primary energy requirements of buildings. In the district heating region of Stuttgart, for example, the primary energy factor is 0.55, which is well below the values for other energy sources (e.g. 1.1 for heating oil).
EEWärmeG
The Renewable Energies Heat Act (EEWärmeG) has required owners of new buildings to use renewable energies since 1 January 2009. Because legislature practically puts highly efficient heat from combined heat and power generation on a par with renewable energies, district heating customers are ideally equipped for the future: They automatically meet the legal requirements.