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Pictures of the Future



Mr. Sebastian Webel
Mr. Sebastian Webel


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Pictures of the Future
The Magazine for Research and Innovation

Smart Grids and Energy Storage

Island Laboratory

Bornholm, Denmark is a Smart Grid test site with 1,900 participating households. The site is ideal because it is a closed system, yet it is representative of the rest of the country in terms of economy and demographics.

There’s more to sustainable energy than just saving electricity. That’s why the Smart Grid EcoGrid pilot project on the Danish island of Bornholm is using Siemens technology to determine how electricity demand can be adjusted to match supply.

Cutting electricity use doesn’t always save power. “When I was growing up in Bornholm, my parents sometimes urged me and my brother to take long hot showers and turn the heaters up in our rooms,” recalls Maja Bendtsen, 34, an engineer. But Bendtsen’s parents had a good reason for their “wastefulness”: wind. Back in the early 1980s, when a stiff breeze blew across this Danish island on the Baltic Sea, the wind turbine on the Bendtsen family’s property turned especially fast. The result was a sudden surplus of energy and a big incentive to run the electric boiler.

This childhood experience stimulated Bendtsen to appreciate the concept behind “EcoGrid”, which, with its 21 million Euro budget, is the biggest smart grid project in Europe. Bendtsen is the onsite manager of the project for Bornholm’s local power company, Østkraft. As part of the project, some 1,900 households — almost a tenth of the island’s homes — were equipped with newly developed smart switching devices from Siemens and IBM in 2013. Every five minutes, when they receive updated kilowatt-hour prices, the devices determine how much electricity is available. Depending on the data, the devices switch electric heating systems and heat pumps in private homes on or off automatically.

Harmonizing Supply and Demand

The principle behind the project is simple. The price of electricity fluctuates in accordance with the volume of renewable energies. Smart control units calculate how to manage energy demand cost-effectively. As a result, electricity customers save money — and that’s not trivial in a country whose end customers pay the highest electricity prices in Europe. “But that’s not the most important factor for the electricity supplier,” says Bendtsen. “EcoGrid is primarily designed to help manage power demand intelligently in the era of environmentally friendly electricity. If we use more energy when there’s a surplus, that helps to avoid overburdening the electricity network. If too little power is available, energy use is reduced, and Østkraft buys additional electricity from the mainland.”

An Ideal Test Bed for Energy-Saving Technologies

For years, wind energy has played a key role on Bornholm. In fact, almost half of the island’s energy demand is covered by wind turbines with a peak output of 30 MW. In Denmark, wind energy accounts for 30 percent of the total energy supply. And this percentage is set to grow. By 2020 this small kingdom plans to draw about half of its electricity from renewable energy sources such as wind, photovoltaics, and biomass. By 2035 that percentage is expected to reach 100 percent, and by 2050 Denmark should be independent of fossil energy. Bornholm is an appropriate test case; it’s a closed system, yet it is representative of the rest of the country in terms of economy and demographics.

Wind turbines with a peak output of 30 megawatts cover almost half of Bornholm’s electricity needs.

To date, imbalances have been compensated for by the “Bornholm Cable,” which connects the island with the grid on the Swedish mainland. According to need, power is exported or imported via this cable. However, the goal is to use the energy produced here as locally as possible in order to avoid further expansion of transport capacities, such as high-voltage transmission lines.

Energy Lab for Europe?

Because this situation applies to all of Denmark, Bornholm has become the country’s renewable energy laboratory. But this field trial is also relevant for Europe as a whole. Indeed, plans call for a fifth of Europe’s energy to come from renewable sources by 2020. That’s why Brussels is financing part of the EcoGrid pilot project, which began in 2011 and will run until 2015.

The only question is: are end customers going along with the plan? To find out, the project’s initiators — Østkraft,, the Technical University of Denmark, Siemens, IBM, and a dozen others partners from ten European countries — organized the 1,900 private households into four groups. The first group will serve as a statistical control group. These households received only a smart electric meter that precisely keeps track of their energy use. The second group can see online how much energy they are using and how much it costs — and can change their behavior in response.

Saving Energy without Cutting Comfort

The third and fourth groups have been equipped with automatic control units. The former uses a system from Siemens Smart Grid and Building Technologies Divisions that controls electric heating systems and boilers. The fourth group has a similar technology from IBM that controls heat pumps. “We expect the kinds of power control units being tested here to become a standard element of the future smart grid,” says Andreas Arendt, who manages Siemens Smart Grid Division’s activities in the EcoGrid project.

Arendt’s colleague from the Building Technologies Division, Werner Ziel, believes the solution he has developed for the EcoGrid project will be a key element for the smart buildings of tomorrow. “We’ve succeeded in efficiently integrating smart grid functions into automatic building management systems, thus meeting customers’ needs with regard to comfort, energy savings, and reduced energy costs,” he says.

Living Laboratory for Intelligent Grids

One of the persons in the Siemens group of test households is Morten Kjær Andersen, who lives in a bungalow on the coast south of Rønne. In a gray box in his home’s entry area is a computer that receives the current price of electricity per kilowatt-hour at five-minute intervals. On the basis of this information, the probable development of electricity prices, and the customer’s preferred temperature, the Siemens system calculates the best way to proceed. For example, if the price of electricity rises at noon or in the early evening, the system can decide to switch on the electric heating system earlier, when power is cheaper than it is expected to be later in the day.

“Every day I watch the heating system switch on automatically,” says Andersen. He appreciates his lower electric bill, but he also hopes that this development will make the islanders’ lives more attractive. “In the past, 50,000 people lived here; now there are only 40,000. If we want to realize the vision of a ‘green island’ on Bornholm — with renewable energy sources, electric cars, and environmentally friendly agriculture — that might help to make the island a more attractive place to live. The EcoGrid project is a part of this vision.”

Maja Bendtsen not only manages the project but also participates in it. She uses an app on her cell phone to monitor power use in her house. A graph shows her that her heat pump, which is controlled by IBM, has just been switched on. Because power is inexpensive at the moment and her family will come home soon, as usual, the heat pump is warming up the house. “We’ve entered a command online that the temperature in the living area should be 20° Celsius starting at 6 p.m. on weekdays,” she says.

Enhancing Convenience with Home Automation

Of course EcoGrid is still just a demonstration and research project. The control units are only being used for the electric heating systems, boilers, and heat pumps. Dishwashers and washing machines, for example, cannot be easily integrated into the system, because they don’t speak the same digital language. The devices that are suited to the project are mainly those whose operation is flexible. That includes heating systems, because the exact time when heating is on is less important than a constant pleasant temperature. In the future, solar cells and electric vehicles will be integrated into the system, but even the success achieved to date is impressive. “If we use the data we have already accumulated from the Siemens houses to calculate how much energy was used during periods of peak supply,” says Per Lund, the Chief Engineer at, “we can already conclude this technology can help the Danish power system to integrate renewable energy sources and to operate in balance.”

The interim results also clearly show that automation is the best solution. That has been demonstrated by the behavior of the group of households that manually switched appliances on or off based on electricity prices provided over the Internet. Those households hardly reduced their electric bills at all.  “At first it was fun to follow our power use on the Internet,” says Group 2 participant Niels Erik Rasmussen. “But in the long run it was just too much effort.”

Rasmussen’s opinion reflects experience in other energy markets, such as the U.S. For example, in 2008 researchers from the Xerox Research Center provided labels for appliances in Californian test households to inform owners about the cost of electricity at various times of th day. But people continued to use their appliances whenever they needed them, rather than at the times when power was cheapest. “If we want to stabilize the electric grid, energy demand will have to be adjusted automatically,” says Professor Jacob Østergaard from DTU Technical University. “The electric bill will then shrink by itself. Customers will only need to enter their preference settings.”

Østergaard has built a replica of the control room of the Østkraft electric company at his university. “In theory, we could intervene in the power grid,” he says. “However, we’ve deactivated these functions; we only want to collect measurements.” His projects include not only EcoGrid, but also a network of about 50 refrigerators in supermarkets. When the frequency in the grid decreases, the cooling units are automatically switched off. After the frequency stabilizes, the cooling units are switched on again. Either some or all of the units can react together, depending on the degree of fluctuation in the grid.

Learning from Bornholm’s Smart Grid

Another research project further supports the island-wide introduction of EcoGrid’s technologies. Until 2012 engineers carried out a study called “Edison” on the island together with grid operator and Siemens, to investigate how electric cars and hybrid vehicles could help to store surplus energy and return the energy to the grid. The study was a success, but it has not yet been implemented. One reason for that is that there are only around 20 electric vehicles on the island. “We hope that will change. Our goal is to integrate electric vehicles into a concept for balancing the electric grid,” Østergaard says.

Siemens is also refining its technology. On the Dutch island of Texel, the local energy cooperative has started an initiative with 300 households that, like EcoGrid, aims to use energy when sufficient amounts are available. It was launched in January 2014. Siemens is supplying an energy management system that helps to calculate the price per kilowatt-hour on the basis of electricity availability. Bornholm is setting an example. “The EcoGrid project demonstrates that every customer can help balance the supply and demand of regenerative energies — without freezing or sweating,” says Arendt.  

Hubertus Breuer