SIEMENS

Ignaz Einsiedler climbs nimbly up the ladder to the huge gray bubble that arches above a massive tank. A brown brew consisting of grass, corn, and other types of biomass mixed with slurry bubbles underneath the rubber covering — “like a giant cow stomach,” as the 63-year-old farmer describes it. This “stomach” digests the biomass and transforms it into methane, which is burned by two gas motors in Einsiedler’s basement to produce electricity. Einsiedler feeds the electricity from the biogas generator — and from three photovoltaic units on his roof — into the power grid operated by Allgäuer Überlandwerke GmbH (AÜW).

Like many of the 2,500 inhabitants of the village of Wildpoldsried in the Oberallgäu district of southern Germany, Einsiedler is an energy pioneer. Almost every roof here sports blue solar cells that shimmer in the sun. Exhaust gases from combined heat and power (CHP) plants that run on methane produced by biogas fermentation rise from metallic chimneys in many barn yards. Numerous houses get their heat from a 4.7-kilometer district grid that Einsiedler and other local citizens built and financed through a cooperative established for this purpose. Einsiedler also owns shares in a network that delivers gas to three other co-generation plants and in five wind energy facilities that the villagers jointly financed without any outside investment.

“The people in Wildpoldsried are crazy in a positive way,” says Guido Zeller, an attorney at AllgäuNetz GmbH & Co. KG, which operates the local grid. The craziest one of all is probably Arno Zengerle, who has been the village mayor since 1996. At the start of his first term, Zengerle asked citizens to vote on the village’s development goals. “Climate protection can only be effective with the help of the people, not against their wishes,” says Zengerle. And the people are behind it, as Wildpoldsried now generates more than twice as much electricity as it consumes. Indeed, many of the villagers have become both producers and consumers — so-called “prosumers” — of energy.

Energy Surplus Headache. Wildpoldsried offers a preview of what’s in store for all of Germany over the next 20 years. However, things aren’t as easy as they look. Simply building solar, wind, and biogas power generation facilities isn’t enough. The electricity produced by renewables has to get to consumers, and a system must be in place to maintain a balance between energy production and consumption. Still, Wildpoldsried’s problem today is one every community would like to have. It has far too much electricity. In fact, fluctuations in the grid feed can cause output variations of as much as eight megawatts in just half an hour.

This energy surplus is a big headache for Robert Köberle, who works ten kilometers away in Kempten, where he’s responsible for maintaining the stability of the AÜW grid regardless of how much electricity is being fed into or taken out of it at any given moment. In 2010, AÜW chose Wildpoldsried as the site for an ambitious experiment that involved establishing a smart grid that automatically stabilizes the power network. Smart grids hold the key to the energy systems of the future, because they make it possible to distribute energy from renewable sources without putting electricity networks at risk.

While AÜW was making its plans, Alexander Hammer from Siemens’ Infrastructure and Cities Sector was looking for a grid operator as a project partner for testing new smart grid technologies. Siemens and AÜW signed a cooperation agreement in April 2011 to set up IRENE (Integration of Regenerative Energy and Electric Mobility), a roughly €6 million investment project. One third of the money is being contributed by the two partners; the rest comes from Germany’s Ministry of Economics and Technology, which quickly realized how important the project was.

Much has happened since IRENE was launched. For example, AÜW has installed around 200 measurement devices — black boxes with mobile communication links — at solar and biogas plants and in transformers. Weather measurement data and Webcams are also being used to monitor cloud movements. The goal is to gain an overview of who’s feeding power into the grid or extracting energy from it, when and where they do it, and how all of this affects the network’s stability. “We need to manage the dynamics of the network,” says Hammer, who points out that around three gigabytes of data are sent to AÜW headquarters in nearby Kempten every day.

Once the key points in the grid are identified, targeted measures can be taken to correct problems. To this end, Siemens has installed a variable transformer that offsets voltage fluctuations — a device that is normal in high-voltage grids but is a complete novelty in secondary-voltage local networks.

Also new is a system for remotely controlling the inverters in photovoltaic units. When the sun shines over the Allgäu mountains, the solar modules there collect so much electricity that the resulting output of alternating current is too high. Managing inverters from a central location safeguards voltage quality and stabilizes the grid. “Actually, you’re not allowed to do this even if the lines start smoldering,” says Hammer. The problem is that Germany’s Renewable Energy Act requires all power generated from renewable sources to be taken in by grid operators. But IRENE partners were able to obtain an exemption from this stipulation, and they now expect that precise data collection and their system’s sophisticated controls will keep losses to a minimum for Wildpoldsried’s energy farmers.

Intelligent Balance. The centerpiece of Wildpoldsried’s smart grid is Self-Organizing Energy Automation System (SOEASY) software, which cleverly balances supply and demand and keeps the grid stable. But SOEASY isn’t as simple as its name suggests. The distribution networks that bring electricity to households have several times as many components as the main high-voltage transmission grid.

To ensure that things don’t get too complicated, engineers and computer scientists at Siemens Corporate Technology (CT) have developed scaleable hardware and software modules, so that even as the smart grid expands, the costs associated with it will increase only moderately. All the components for collecting and transmitting data and remotely controlling facilities are plug-and-play-enabled and thus can be installed in solar power inverters without any need for additional programming.

Several SOEASY components operate in a decentralized system — but “a central control unit that balances out everything increases the distribution grid’s ability to absorb electricity from renewable sources,” says Dr. Michael Metzger, project manager for IRENE at Siemens CT. Personal Local Energy Agents — autonomous software modules — control the interaction between decentralized consumers and producers and the grid. Every “prosumer” has such an agent, which can be used to reserve centralized services such as weather forecasts or system optimizations via a marketplace. There’s also a Network Transport Agent that monitors grid status in real time, an Area Administrator that maintains network stability, and a Balance Master, which plans key adjustments hours or days in advance on the basis of parameters such as expected changes in the weather.

All of these software agents are highly interconnected and automated. They control the actuators in the grid in a way that ensures good voltage quality. Such actuators include new variable transformers for the local grid, battery storage units that will soon be installed, and inverters in photovoltaic systems. A power exchange that will allow agents to negotiate electricity deliveries will also be set up before the project is completed.

Another special feature of the project is the fleet of 32 electric vehicles that are available to Wildpoldsried residents. The cars are already integrated into the village’s smart grid and serve as a buffer for electrical energy. If there’s an energy surplus, the vehicles’ batteries will be given recharging priority. IRENE might also examine the use of vehicles that can return electricity to the grid in the event of power shortages.

The electric cars in Wildpoldsried still aren’t an active part of the smart grid; the idea at the moment is to monitor their use. That’s why they’re equipped with navigation devices that report their position. Researchers want to use their movement profiles to determine the extent to which the batteries can be used as grid buffers. The latter sub-project is being carried out by scientists at the Kempten University of Applied Sciences, who also analyze asymmetrical load flows in the grid and work out logical measurement point arrangements. The second IRENE research partner is RWTH Aachen University of Applied Sciences, which is using the vehicle movement profiles to develop simulation models for larger smart grids containing thousands of electric cars.

Although IRENE will conclude in the fall of 2013, the residents of Wildpoldsried will ensure that AÜW and Siemens still have plenty of research to do. They plan to generate all of their electricity and heating by 2020, and they already have initial ideas for using wind power to produce natural gas from CO₂ and water. Some residents even plan to get their own electric cars when the leased electric vehicles are returned. Such vehicles would be completely emission-free. After all, there’s more than enough environmentally friendly electricity in Wildpoldsried.