It’s no exaggeration to call the transformation of many countries’ energy systems a technological revolution. Instead of having only a few centralized plants producing electricity from fossil fuels or nuclear power, the new paradigm is to have ever more distributed facilities feeding electricity into the grid. But given the fact that much of the electricity being produced by such sources varies with the weather, maintaining a steady balance between supply and demand is becoming a challenge – especially in view of the fact that failure to do so can result in reduced voltage quality and potential damage to connected electrical devices. Smart grids are the solution to this challenge. Carefully managed IT systems enable smart grids to combine a variety of energy producers and storage units with adjustable consumer devices in order to ensure grid stability. Moreover, smart grids can get actively involved in the sale of energy.
The Future of Energy
Plugging into a Decentralized Energy Future
Siemens is researching how smart grids can be optimally utilized to manage the decentralized energy environments of the future. The company is also investigating how technologies such as energy storage, autonomous microgrids, and virtual power plants can offer opportunities to grid operators and energy producers.
Integrated Energy Storage Devices
New energy storage devices play a key role in this evolving environment, because they mop up surplus electricity and release it when needed. Such systems can be used on a variety of levels – in single-family homes equipped with rooftop solar panels, in local grids for villages or cities, and in wide-ranging distribution networks that supply thinly-populated regions with electricity. As a result, Siemens heads a consortium called SENSIBLE (Storage Enabled Sustainable Energy for Buildings and Communities), a European Union project that is analyzing how energy storage devices can be optimally integrated into power grid architectures. In the consortium, Siemens has partnered with 13 businesses and scientific institutes, including universities in Paris, Nuremberg, Nottingham, and Seville, as well as with energy provider EDP, to carry out this research at three locations.
In Nuremberg, researchers are working on an office building scenario. To this end, they have equipped laboratory buildings on the Siemens campus in Erlangen and at the city’s technical university with a combined heat and power (CHP) plant, a simulated photovoltaic system, a thermal storage unit, an air-source heat pump, and a battery, among other things. “This combination of renewable and fossil sources of energy with storage devices, adjustable loads, and smart electricity management lets us develop optimal grid operation strategies that minimize, for example, the costs and CO2 emissions associated with the supply of heat and electricity,” says Dr. Michael Metzger, project manager for distributed energy systems at Siemens corporate research department.
Whereas the Nuremberg subproject studies the interaction of the various systems within buildings, the focus in Nottingham, England, is on the city’s Meadows neighborhood and its approximately 3,800 residential buildings. Because many of these homes have rooftop solar panels, they are now “prosumers,” which not only consume energy, but also produce it. “Here, we want to find out what role the storage devices in the homes and the few large storage systems in the area play for the reliable supply of electricity to an entire city neighborhood,” says Metzger. “Smart meters provide us with up-to-the-minute information about energy consumption and production. Whenever there is surplus electricity, a special service provider sells this energy on the electricity exchange.”
In the third SENSIBLE subproject, Siemens researchers in Évora, Portugal, are investigating how a local power network can be converted into an autonomous microgrid. Because more and more photovoltaic systems are being installed in this largely rural region, the existing power lines are reaching the limits of their capacity. Storage devices can help to solve this problem. In order to improve grid stability and voltage quality, flywheel energy storage systems are being used to absorb energy for a short time before releasing it again, while various battery storage systems store surplus electricity for longer periods. “This scenario is interesting for microgrids that also have to be capable of operating independently of the public power supply – on islands, for example, or in remote areas,” says Metzger.
Test Lab Town
Siemens has also partnered with businesses and scientific institutes to study issues similar to those of the SENSIBLE project in Wildpoldsried, Germany, where sun, wind, and biomass are already producing four times more energy than the village’s approximately 2,500 inhabitants consume. “Because the electricity mix here corresponds roughly to that expected for Germany as a whole in 2020, the village is considered to be a test lab for the entire country,” says Metzger. In another project, which is called IREN2, the consortium headed by Metzger is studying whether such complex microgrids can be operated autonomously and whether they offer the potential of replacing large conventional power plants.
Virtual Power Plants: The Basis for Future Energy Systems
The intelligent interaction among producers of renewable energy, storage devices of different sizes, and adjustable-demand consumer devices is a precondition for the operation of virtual power plants. However, such a demanding task can be performed only with the help of an intelligent system such as Siemens’ Decentralized Energy Management (DEMS) software. “DEMS combines and markets the flexible capabilities of various energy producers, storage systems, and consumers,” says Thomas Dürr, who is responsible for DEMS business development at Siemens. “This includes purchasing surplus electricity from businesses or flexibly feeding it into the public grid.” The participants of a virtual power plant can register their capacities and other information with DEMS via a Web portal. The software consolidates all of these capacities into a combined output, which it then offers on the electricity exchange or on markets for balancing power.
Siemens has integrated DEMS into its EnergyIP IT platform so that virtual power plants can encompass tens of thousands of participants. EnergyIP collects and processes the consumption data measured by smart meters and combines it, for example, with information about grid status, customer contracts, and billing. Grid operators can employ applications to analyze this data and use it, for example, for strategic planning and load management or to provide their customers with information. EnergyIP is a scalable platform, which means it can be expanded to almost any size. As a result, it can process huge amounts of data and thus create precise load and production forecasts. DEMS uses such forecasts to control large virtual power plants. An example of this is the RWE Smartpool project, in which Siemens intends to work with energy provider RWE to combine a large number of distributed energy systems, such as producers, storage devices, and loads. The project not only focuses on the supply of energy, but also on the flexible management of consumers that can absorb surplus electricity at short notice (demand response). The idea, in short, is to ensure that the power supply will be as reliable in the future as it was during the age of large, centralized plants.