The Community of Wüstenrot: Energy-independent by 2020
|Location of local community||71543 Wüstenrot, Heilbronn, Baden-Württemberg|
|Settlement in figures||30.02 km², 6,600 Einwohner|
|Developer, organizer||Gemeinde Wüstenrot|
|Settlement||New-build scheme with single-family homes and terraced houses|
|Utilisation type||Special residential area (energy-plus housing estate)|
|Housing estate area||14.703 m²|
|No. of residential units after implementation||25|
|Age structure||So far one building has been completed (KfW-55), four other construction projects are ongoing.|
|Heating system||All buildings will be connected to a cold local heating network with an agrothermal power plant.|
|Ownership structure||Own use|
The aim of the project is to develop a durable roadmap for the energy self-sufficient and energy-plus community of Wüstenrot. This shall be embodied in an energy usage plan for Wüstenrot and implemented by 2020.
The Community of Wüstenrot already decided in 2007 to become energy self-sufficient by 2020. As a first step, emw (energieversorgung mainhardt wüstenrot) purchased the electricity grid from EnBW, taking over the network in June 2012.
Wüstenrot lies to the south of the rural district of Heilbronn, has around 6,600 inhabitants and covers an area of 3,002 hectares (around 30 km²), of which 1,582 hectares is forest (52.7%). The community consists of five areas. The main scheme being implemented within the EnVisaGe project is a 14,703-m² energy-plus model housing estate called “Vordere Viehweide”, which is situated on development land. The first buildings are already under construction and the first residential building has already been connected to the cold local heating network.
As part of the EnVisaGe project, a durable roadmap for achieving an energy self-sufficient and energy-plus community of Wüstenrot by 2020 is being developed and embodied in an energy usage plan for Wüstenrot. For this purpose a GIS-based 3D urban model (currently being developed) is being used to analyse the potential for developing renewable energy sources and to calculate scenarios. To accompany this, strategies are being developed to exploit this potential economically. In addition, measures are being investigated and evaluated for increasing the energy efficiency in the existing building stock and in regard to the waste water disposal and fresh water supply.
The economic development of renewable energy sources in the electricity sector is influenced not just by the marketability, simultaneity of the generation and local consumption but also by the grid infrastructure. In order to achieve grid stability it is therefore essential that controllable loads, load groups, storage systems and decentralised energy generation systems are intelligently regulated via an intelligent electricity network (smart grid). Using emw’s electricity grid as an example, the interrelations in different scenarios are being investigated, assessed and bundled in guidelines. Specifically, simulations are being used to investigate the durability of the electricity grid for different development scenarios, localise weak points and determine necessary grid expansion scenarios and the requirements for intelligent grid and consumption control systems. In addition, the utilisation rate of the generation systems and thus the costs and benefits across a year are also being determined. An initial concrete step towards achieving an energy-plus community is being realised with the “Vordere Viehweide” energy-plus model housing estate, which includes a cold local heating network supplied via an agrothermal power plant and an intelligent load management system. For this purpose, all energy flows in the housing estate are undergoing detailed monitoring.
A GIS-based 3D urban model is being used to record the current overall state of the buildings in the community and calculate the status quo of the energy requirement and generation (via existing PV and solar thermal systems). The potential for using renewable energy (solar energy, wind power, biomass, geothermal energy) within the community’s boundaries will then be analysed and different scenarios calculated for their development. At the same time, the electricity grid is being investigated not just in terms of its durability and any necessary expansion but also in terms of implementing smart grid components for the intelligent load management.
With the energy-plus model housing estate, the first implementation measure is being realised that will bring the community closer to its aim of becoming energy self-sufficient. Further measures, such as a local heating network with a biomass CHP unit and decentralised solar thermal heating, will also be implemented during the course of the project. The energy-plus model housing estate will combine PV systems for generating electricity with decentralised heat pumps and thermal storage systems for providing domestic hot water as well as with batteries for storing electricity. An intelligent load management system is also being realised and investigated during the course of the project, which, in addition to optimising the self-consumption of PV electricity, also enables superordinate electricity grid-based load management via Vattenfall’s virtual power plant. As a particular innovation for the grid-tied heating provision of building development areas with low building densities and high thermal protection standards, the energy-plus housing estate will realise a so-called cold local heating network, which via agrothermal collectors and waste heat from a neighbouring supermarket will be supplied with low-temperature heat for the decentralised heat pumps.
As part of the EnVisaGe project, innovative funding models are being developed for implementing energy efficiency measures and realising renewable energy generation systems. The results will be summarised in funding guidelines and also made available to other local authorities.
The construction of the “Vordere Viehweide” energy-plus housing estate has begun. The first agrothermal array has been laid out according to the "Doppelacker System" and the first building has been connected to the network. The sales of the building plots are doing well and four further houses are currently under construction.
Monitoring concepts for the agrothermal array and the energy-plus model housing estate are currently being developed – 10 houses will be measured in detail. The survey for the database on the current condition of the buildings in the community area is almost completed, whereby the data will be incorporated into the 3D urban model.
Publications on the project
Dürand, Dieter: Vernetzte Welten. Wirtschaftswoche/Green Economy, 24.9.2012, S. 6-8.
Mietzker, Thomas: Eine schwäbische Gemeinde probt die Energiewende, cci Zeitung, 25.10.2012
Pietruschka, Dirk: Wärmeversorgung über ein kaltes Nahwärmenetz mit Agrothermie und Abwärme aus Kühlanwendungen. Vortrag, TWK Fachsymposium Kalte Nahwärme und Eisspeicher, 7. März 2013, Karlsruhe.
Kluge, Jürgen; Grosa, André: Agrothermie – Oberflächennahe Geothermie und Doppel-Bodennutzung. Vortrag im Rahmen des Energieforums Havelland-Fläming, 19. November 2012, Potsdam.