One Town’s Energy Inspiration
Paul Kando
The Bavarian town of Wildpoldsried (pop. 2,600) produces 400% more renewable energy than it needs. It sells the surplus power to the grid, earning $7 million per year. And since 1997 the town reduced its carbon footprint by 65%. That year the town council decided to revitalize the local economy without incurring debt. Their plan was to reinvent the town by developing its renewable energy, green building, and water resources and get 100% of their electricity from renewable sources by 2020.
photo credit: Wildpoldsried, Germany
Things happened much faster than planned. The town now has five biogas plants, just shy of 5 MegaWatts of solar photovoltaic (PV) generating capacity, 11 wind turbines with a total capacity of more than 12 MegaWatts, a biomass-fueled district heating network, three small hydro power plants incorporated in the area’s flood control and wastewater system, and 22,600 square feet of solar thermal collectors that produce hot water. Local residents – many of them dairy farmers – have financed all but the first two wind turbines, which were partly financed by a small grant. After a payback period of 10 years those turbines will generate 80 percent of the dairy farms’ earnings.
The town’s district heating system, which generates 8.2 million BTUs of heat each year is fueled by waste wood from local forests. All public buildings, some 120 private residences, and several businesses are connected to it. Nine municipal buildings including the elementary school, the recycling facility, and the local sports center have rooftop solar PV systems, as do 200 of the town’s private homes. Excess electricity generated from solar, wind, and biomass is sold under a fixed-price 20-year power purchase agreement to Allgäuer Überlandwerk GmbH (AÜW), the area’s electric utility.
All this has been a huge success, but not without causing a headache for AÜW, which has to maintain grid stability. Fortunately Siemens, the manufacturing giant, was looking for a grid operator to test its new smart grid technology. So AÜW and Siemens teamed up in a $6 million project to test out the manufacturer’s new smart grid design. They installed measuring devices at each renewable energy generating system throughout the town. These measure current, voltage, and frequency and pinpoint problems that affect network stability by mapping, moment to moment who is feeding energy into the grid and who is consuming energy from it. If a problem is identified, a variable transformer automatically offsets voltage fluctuations. The town’s new 138 kiloWatt battery storage system also helps stabilize the grid by receiving or discharging electricity on command.
Siemens’ smart grid depends on a self-organizing automation system called SOEASY, which balances supply and demand to keep the grid stable. It factors in weather, electricity prices, power quality, and other variables in deciding whether to send electricity to the grid or to storage. It does this using five software modules: (1) Every energy producer in town has its own “personal energy agent”, which allows the producer to control how much power to sell, at what time, and at what minimum price, in 15-minute intervals. In essence the system operates like a distributed energy marketplace on a small town scale. (2) “Balance master”, installed at AÜW, decides which personal energy agents’ offers the utility will accept to cover the grid’s current demand. It can plan adjustments up to a day ahead, in response to changes in the weather, for example. (3) The “area administrator” helps the utility maintain network stability by modifying the energy in-flow from individual sources via commands to their personal energy agents. It sends energy to storage, for example, or adjusts the voltage through the variable transformer. (4) The “network transport agent” collects data from energy producers, consumers, and the grid, and makes it available to the area administrator, which intervenes if voltage is too high, and to the balance master, which determines how much power to accept without overloading the grid. Finally (5) the “energy police” makes sure that no power is illegally siphoned off.
Integrating electric vehicles into the smart grid also helps balance the grid. Wildpoldsried leases a fleet of electric vehicles to residents. When there’s an energy surplus, the vehicles’ batteries are charged. During power shortages the vehicles return electricity to the grid. The town’s energy revenues have allowed it to develop amenities it couldn’t otherwise afford. The renewable energy systems have created 140 new jobs, led to construction of an ecological training center, and increased tourism.
American architect and inventor Buckminster Fuller once said, “to change something, build a new model that makes the existing one obsolete.” Wildpoldsried is such a model. It shows what can be accomplished based on the initiative of a local population and its elected representatives. To say the least, the model is inspiring.