Wuestenrot - Germany

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Residential consumers
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PV plants
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Heat pumps
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Home batteries

Introduction

By 2020, the community Wuestenrot wants to cover its energy needs through the utilization of renewable energy sources, such as biomass, solar energy, wind power and geothermal energy, within the town area of 3000 hectares. In order to elaborate a practicable scheme for realizing this idea in a "real" community and to develop a roadmap for implementation, the project “EnVisaGe” under the leadership of the Stuttgart University of Applied Sciences (HFT Stuttgart) was initiated. Accompanying particular demonstration projects are a) the implementation of a plus-energy district with 16 houses connected to a low exergy grid for heating and cooling, b) a biomass district heating grid with integrated solar thermal plants.

Project description

The community
Wüstenrot is situated in the south of Germany in a rural area near Stuttgart, the capital of the federal state of Baden-Württemberg. The community has around 6,600 inhabitants and covers an area of 3,002 hectares (around 30 km²), of which 52.7% is forest. Wüstenrot already decided in 2007 to become energy self-sufficient. As a first step, emw (energieversorgung mainhardt wüstenrot) purchased the electricity grid from EnBW, taking over the network in June 2012.

Project goal

The aim of the project is to develop a durable roadmap for the energy self-sufficient and energy-plus community of Wüstenrot. The roadmap shall be incorporated in an energy usage plan for the community, that shall be implemented by 2020 and brings Wüstenrot in an energy-plus status on the ecobalance sheet.

A main feature within the EnVisaGe project is the implementation of a 14,703-m² energy-plus model district called “Vordere Viehweide”. It consists of 16 residential houses, supplied by a cold local heating network connected to a large geothermal (“agrothermal”) collector. Here PV systems for generating electricity are combined with decentralised heat pumps and thermal storage systems for providing domestic hot water as well as with batteries for storing electricity.

Another demonstration project is a district heating grid fed by biomass and solar thermal energy in the neighbourhood “Weihenbronn”. It’s based on a formerly oil-fired grid for the town hall and was extended to an adjacent residential area.

Project steps
A GIS-based 3D urban model was developed to draw an energy balance and analyse the potential for utilizing renewable energy sources (PV and solar thermal energy) and calculate scenarios. The potential for using wind power, biomass, geothermal energy within the community’s boundaries was analysed as well and different scenarios calculated for their development. In addition strategies were developed to exploit the is potential economically.

 

The research team also investigated how energy efficiency could be increased in the existing building stock and regarded waste water disposal and fresh water supply as well. The GIS-based 3D urban model was used to record the current overall rehabilitation state of the buildings in the community and calculate different rehabilitation scenarios.


In order to achieve grid stability when extending volatile sustainable energy generation, the grid infrastructure was analysed. Using emw’s electricity grid as an example, the interrelations in different scenarios were investigated, assessed and bundled in guidelines. In Wüstenrot all controllable loads, load groups, storage systems and decentralised energy generation systems some day shall be intelligently managed via an intelligent electricity network (smart grid) on community scale.

 

An initial concrete step is being done in the energy-plus district “Vordere Viehweide” by integrating PV and heat pumps, thermal and electrical storage in an intelligent smart load management system in order to optimise the self-consumption of PV electricity, but also enables superordinate electricity grid-based load management via a virtual power plant. For this purpose, all energy flows in the housing estate are undergoing a detailed monitoring.

A second implementation measure that will bring the community closer to its aim of becoming energy self-sufficient, was realised with a local heating network with a biomass CHP unit and decentralised solar thermal heating.

Financing
As part of the EnVisaGe project, innovative financing models for implementing energy efficiency measures and realising renewable energy generation systems were explored. The results were summarised in funding guidelines and will be made available to other local authorities.

Evaluation
The monitoring concept for the energy-plus district is currently being implemented – 10 houses in “Vordere Viehweide” will be measured in detail. The CHP/solar thermal heating grid in Weihenbronn is being monitored in detail, too. On base of the results the cost-performance ratio will be determined.

Further information
www.eneff-stadt.info/de/pilotprojekte/projekt/details/wuestenrot-auf-dem-weg-zur-plusenergiegemeinde/

www.envisage-wuestenrot.de

 

Publication

Dirk Pietruschka et al: Vision 2020. Die Plusenergiegemeinde Wüstenrot. Hrsg.:pro:21 GmbH, Bonn 2016, Fraunhofer IRB Verlag, ISBN 978-3-8167-9545-2

Download: https://www.baufachinformation.de/Vision-2020/buecher/244215

Wuestenrot

Partners

Location

Use cases

Voltage Regulation

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Energy Storage

  • Plus-energy district: electrical battery storage systems < 10 kWh in 6 houses, thermal storage in each house
  • Heating grid: thermal storage in the heat station and in the house of a private solar collector owner who feeds into the grid

 

Demand Side Management

Plus-energy district: DSM (heat pump, storage control) with the goals

  1. increase self-consumption,
  2. reduce stress on grid and
  3. virtual power plant optimization (DSOs goal to balance generation and load in large area)