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Pictures of the Future
The Magazine for Research and Innovation

Smart Grids and Energy Storage

Smart Grids Point the Way to a Renewable Energy Economy

Within IREN2, the researchers developed in Wildpoldsried sustainable grids for the integration of renewable energy systems. The experience gained now offers the opportunity to reap financial rewards, and Siemens has founded the egrid joint venture with this aim. The company has proven the feasibllity of this concept.

If Germany is to reach its target of generating 80 percent of its power from renewable resources by 2050, it will need to rely on thousands of communities that generate their own power. Yet to maximize stability, those communities – many of which will generate much more electricity than they need – will have to be capable of seamlessly connecting to the grid. Working with partners in a research project focused on microgrids, Siemens has proven the feasibllity of this concept.

Germany’s transition to a renewable energy economy is moving ahead at full steam. Already, renewables account for more than 30 percent of the power mix. However, a lot more electricity from renewables will need to be funneled into the grid if the country is to reach its energy transition target of an 80-percent share of renewables by 2050. In fact, this will require even more electricity from renewables than is currently needed in Germany during peak loads.

Working together with its project partners, Siemens has now achieved an important milestone on the path to achieving this goal. In the municipality of Wildpoldsried in the Allgäu region of southern Germany – an exemplary community with regard to the transformation to power generation supported by prosumers – a portion of the low-voltage grid has successfully been decoupled from the public power grid for the first time. This network, a so-called intelligent microgrid, has been operated with a high level of stability and without interruptions. What’s more, additional decentralized, -electricity-generating capacity, such as photovoltaic or biogas facilities, can be easily added to the community’s energy mix. Such local, independent networks could make an important contribution to maintaining energy supply security in the future by helping to fill demand gaps created by storms, flooding or blackouts.

Even today, the installed capacity of renewables in Germany is pushing the country’s grid to the limit. Smart grids are needed to ensure that distributed power systems can constantly supply sufficient electricity to consumers, even as electricity production fluctuates with the weather. Unlike today’s grids, such intelligent networks will be able to balance power generation and demand while distributing electricity, and they will do so all the way to the end consumer level.

The residents of Wildpoldsried also profit from the research projects. In 2016 their generated power exceeded their own consumption by a factor of more than five — much more than they required to cover their peak load.

To ensure the effectiveness of this approach, between 2011 and 2013 a research group led by Siemens built and tested the smart grid in Wildpoldsried as part of the country’s “(Integration of Regenerative Energy and Electric Mobility (IRENE)” project. As Dr. Michael Metzger, Project Manager for Siemens’ activities in the IRENE research network explains, Wildpoldsried was an ideal spot for the project to begin: “Even back in 2010, Wildpoldsried was using wind, solar, and biomass facilities to produce around twice as much electricity as it consumed. In other words, it already offered the conditions that we expect to see throughout Germany in the future.”

No Problem with Demand Peaks

The IRENE project was successfully concluded at the end of 2013. Its smart grid had proved able to flexibly balance the community’s fluctuating electricity supply-and-power demand, and thus maintain grid stability. Among other things, this was achieved with the help of two controllable distribution transformers and a battery storage installation. The community’s smart grid is also equipped with a sophisticated measurement system, a state-of-the-art communications infrastructure, and distributed, renewable power generation systems such as photovoltaic and biogas units.

Both the research partners and the people of Wildpoldsried benefited from the project. Thanks not least to the installed smart grid, the community’s  generated power today exceeds its own demand by a factor of more than five. That’s significantly more than needed to meet local peak loads.

Seamless Synchronization

IRENE thus enabled its project partners to establish ideal technical conditions for moving closer to achieving Germany’s ambitious energy transition target for 2050 with a subsequent research project. That project – IREN2 – kicked off in July 2014 and is running for three years and nine months.

Proof that low-voltage grids such as Wildpoldsried’s can operate successfully as isolated networks is the focus of the next piece of the puzzle on the path to achieving Germany’s energy transition target. To start with, experts working on this phase of the project intentionally initiated a power outage. Power in the affected grid section was then reinstated locally in the isolated network, which functioned smoothly while decoupled from the public grid. The partners’ next step was to, once again, synchronize the isolated network with the public grid without interruption, thus obviating any impact on the 32 affected connections located in several streets, which included a school, a kindergarten, a commercial building as well and numerous private households. Finally, the project’s experts demonstrated how the affected section of the grid on the isolated network could be switched back practically “at the touch of a button,” without disrupting the power supply in the process.

Siemens has installed a variable transformer that offsets voltage fluctuations in Wildpoldsried — such a device is normal in high-voltage grids but a complete novelty for medium-voltage local networks.

In spite of this success, achieving Germany’s energy targets will remain an uphill battle for some time.  “If four fifths of our power is to come from renewable sources rather than from conventional power plants by 2050, then — in terms of the current state of technology — we still face a major challenge,” says Torsten Sowa from RWTH Aachen University, referring to IREN2.  “That’s because power systems that use renewables are not capable today of providing so-called system services, such as making reactive power available to maintain the voltage in networks. In other words, we need a new solution if we want to achieve our target for 2050.”

Replacing Conventional Power Plants

And that’s where IREN2 comes in. Funded by Germany’s Ministry for Economic Affairs and Energy, the program is set to run for three years. Its goal is to use distributed power generation systems and components such as battery storage devices, combined heat and power plants, biogas units, and diesel generators to modify the grid that’s been built in Allgäu in a way that will enable it to deliver the system services that conventional power plants provide today.

IREN2 presented the opportunity to scientifically investigate and practically test the optimal operation of autonomous separate networks and topological power plants. New types of network structures and their management were studied with the aim of discovering how energy systems with distributed power generation and additional components can be technically and economically optimized.

From red to green to blue: The researchers from IREN2 will expand their test grid in Wilpoldsried step by step.

Monetizing Research Results

The Siemens experts now intend to work together with the Allgäuer Überlandwerk to commercialize the results. The Allgäuer Überlandwerk has set up the company egrid for this purpose. In May 2017 Siemens took a 49 percent shareholding in the company.

The joint venture advises operators of distribution networks how the expansion of smart grids can function with a high proportion of renewable energy generation. “We help by providing intelligence instead of copper,” says Metzger, referring to the need to avoid unnecessary expansion of the network. This is accomplished thanks to the optimized distribution network planning criteria that the Siemens experts have derived from the IRENE project. Two aspects stand in the foreground of this development: How can large amounts of power from decentralized generation facilities be integrated into the network and how can a decentralized distribution network be reliably controlled.

Municipal utilities, municipalities, and industry are among egrid’s first customers. “They all profit from our solutions for decentralized infeed and storage — practical solutions from the real world. In this way we, along with Allgäuer Überlandwerk, are actively supporting the new energy policy,” explains Michael Schneider, Head of the Power Technologies International business segment at Energy Management. egrid is more than simply a joint venture that arose from a research project and is now paying off financially — egrid will help to implement the new energy policy.

Sebastian Webel / Ulrich Kreutzer / Sandra Zistl
Picture credits: from top: 4. Picture AÜW