energy network
energy sources
At the heart of the energy network are two central energy systems. They supply the connected properties with climate-friendly heating or cooling in a resource-efficient manner. The energy sources are river water from the Kempt river, treated wastewater from the Fehraltorf sewerage treatment plant and wood chips from the municipal forest. When completed,the two energy centres will be interconnected in order to better compensate for fluctuations in demand in the overall system and to increase redundancy.
All buildings within the network area can be connected. Connection is optional – environmentally friendly heating with local energy has many advantages, as it already meets the requirements of future energy laws. Property owners do not incur any risks: we take on the investments and bear financial and technical responsibility.
The ‘Heiget’ energy centre is located on the site of the former swimming pool at Fehraltorf school. It is equipped with a 2.4 MW wood-fired boiler and a 0.9 MW wood-fired boiler, which provide heat for the network. As wood absorbs the same amount of CO₂ during growth as is released during combustion, it is considered a carbon-neutral energy source. Around one third of the wood used comes from local forests, the rest from forests in the region. Felled and fallen hardwood and coniferous wood is suitable for the chips. The chips are stored in a storage facility with a capacity of 650 m³. This allows the wood-fired system to run at full capacity for a week. The annual wood chip requirement is between 12,000 and 17,000 m³.
Waste water and river water are used as heat sources
The second WTP energy centre is located on the site of the local wastewater treatment plant. Firstly, a cooling machine supplies commercial buildings in the nearby industrial estate with air-conditioned cooling through a separate network. Secondly, the treated wastewater serves as an energy source for two large-scale heat pumps with a total output of 4.4 MW. The wastewater has a temperature of 10 to 15 degrees Celsius in winter and 20 to 24 degrees Celsius in summer, making it an ideal heat source for efficiently operating both heat pumps, which use the natural refrigerant ammonia (NH3). In addition to wastewater, a second local energy source is utilised: the Kempt River. Its water is combined with the treatment plant’s wastewater in a collection shaft before thermal utilisation, partly compensating for fluctuations in volume and temperature. Over the course of a year, the wastewater provides slightly more than twice as much heat output as the river water.
The heat transfer station serves as a link
The link between the Fehraltorf energy network and the heating/cooling system of individual properties is the heat transfer station. It includes all the technology, such as heat exchangers, energy meters and controls. A transfer station usually takes up less space than a modern oil or gas boiler. The heating/cooling purchased is measured and billed by a calibrated meter. The supply temperature of the district heating network is 75 degrees Celsius and the return flow 50 degrees Celsius. This is also the way to generate hot water – there is no need for an additional heat pump at the end consumers’ location.
With a connection to the Fehraltorf energy network, we supply you with renewable energy for heating, producing hot water and cooling your property.
The following variants are available:
Connection and energy supply
- Connection of your property to the district heating/cooling network
- Supply of district heating and, where available, district cooling
Preparing for the connection
- Preparing for the connection of your property to the district heating/cooling network
- Supply of district heating/cooling at a later date, e.g. when replacing a heating system
We bear the financial and technical responsibility. You pay for the volume of energy purchased and the output power.
We monitor the supply to your property around the clock. You benefit from troubleshooting free of charge.
We supply you with heating and cooling from local renewable energy sources. They meet all legal requirements.
The price is made up of three components:
- Connection price: one-off set-up costs
- Price for heating and cooling: your consumption-based energy costs
- Base price: costs for infrastructure, servicing and maintenance as well as for the 24-hour on-call service
You can find the price list in our Document Centre or conveniently via our online information tool (in German).
