Energy pioneers – the self-sufficient villageIRENE project in Wilpoldsried/Allgäu
Manfred Reichart is a farmer. His farm doesn’t produce milk or grain, but rather an invisible commodity that will increasingly become more valuable in the future: electricity. From a building behind the house, cables strung across poles lead to a small tower in which a transformer saves the electric energy in the cables of AllgäuNetz GmbH, a subsidiary of Allgäuer Überlandwerke. Reichart is an energy pioneer, but he is not the only one. Many of the 2,500 residents of the Wildpoldsried municipality are “prosumers”: they not only consume electricity, but they also produce some. Almost every building has a photovoltaic system on the roof or – as on the farm of Manfred Reichart – a biogas plant. Using grass, corn and plant debris, methane is produced through bacterial fermentation; the methane in turn is refined to energy with two gas engines.
Wildpoldsried has been looked at as the village of “Stromverrückten” (“energy crazies”) ever since Mayor Arno Zengerle called for a turnaround in energy policy in 1996 – long before the current federal government. Since then, all of the citizens have been helping to make the village self-sufficient in energy. A village heater was built; it was a small district heating grid into which various biogas power plants fed their waste heat. Electricity is already available in abundance – there is more than three times as much as what the households here consume.
This ensures an overload in the cables of AllgäuNetz GmbH. Since regenerative electricity is too valuable to throw away and the construction of new cables is too expensive, the Kempten-based company has embarked on an ambitious project called IRENE (Integration of Renewable Energy and Electric Mobility). Together with Siemens and the Kempten University of Applied Sciences, a smart grid has been built. The trial operation is to demonstrate how intelligent electricity grids could look in Germany in the future.
Around 200 measurement devices monitor the network stability on solar plants, biogas plants and transformers. They constantly provide data – about three gigabytes per day – to the control centre of the Allgäuer Überlandwerke. The experts want to get a sense of where, when and during which weather the trouble spots appear in the network. With this knowledge, inverters for solar energy systems, energy storage devices or variable transformers will then be controlled – a first for low-voltage networks.
The “brain” of the smart grid is SOEASY from Siemens. It is a self-organising energy automation system which automatically ensures that energy flows smoothly. It consists of autonomous software modules – so-called agents – which handle electricity, monitor power quality or create a business plan based on the weather forecast.
The main task of the smart grid is to find the balance between supply and demand. In the future, Manfred Reichart should be able to control his system so that it delivers a lot of electricity when the demand is high, such as on dark winter days. If the requirements are low, the excess fermentation gas inflates a big plastic bag which sits in the attic above the engines. It serves as an energy store and is much more efficient than storing generated electricity in devices such as batteries.
The pinnacle in the smart grid is the integration of electric cars. When at the charging station, their batteries can be used to take on excess electricity; if there is ever a shortage, it can then be fed in. However, the IRENE project has not yet made it this far. The 32 electric cars that are on loan to interested citizens in Wildpoldsried are initially being used to record information about driving habits. Manfred Reichart was able to test one of these electric cars and he is enthusiastic: “We are considering acquiring our own electric car at some point and charging it with our own green electricity.”
CC CM TW
Dr. Ulrich Eberl