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District heating systems are a key technology when it comes to mitigating the effects of climate change in the buildings sector. In order to incorporate renewables and waste heat into these systems to maximum effect, they need to be operated at lower temperatures. Fraunhofer IEE has worked closely with AGFW (the German Energy Efficiency Association for Heating, Cooling and CHP) and European research partners to produce a guidebook that shows how existing district heating systems can be converted and new low-temperature systems created. In this publication, experts outline both the technical and the economic side of the issue, with numerous case studies proving that low-temperature district heating is technically feasible under all kinds of conditions — as well as being economically viable.

Batteries with lithium metal electrodes promise higher energy and power densities. However, electrochemical processes can occur in these batteries that impair their safety and performance. As part of the BMWi-funded “metaLit” project, the Fraunhofer Institute for Energy Economics and Energy System Technology (IEE) is developing models to simulate these processes. The software can be used to verify algorithms in battery management systems. This saves expensive and time-consuming tests with real batteries. The modeling is accompanied by experimental analysis by the Forschungsinstitut Edelmetalle + Metallchemie (fem) research institute.

Battery storage systems age faster if they have to repeatedly provide high power for short periods. This can be prevented by coupling them with supercapacitors to take over the peak loads. As part of the “SuKoBa” research project funded by the German Federal Ministry of Economic Affairs and Energy (BMWi), Fraunhofer IEE develops tools for designing hybrid supercapacitor/battery storage systems together with its industrial partner AVL and the network coordinator Skeleton Technologies. Furthermore, the partners develop methods for managing and controlling the hybrid systems. Hybrid storage technologies of this type can be used in electric vehicles and in stationary storage units for grid stabilization.

When conventional power plants are shut down, the inertia of the synchronous generators stabilizing the power grid is lost. Wind turbines could step in here. However, can they withstand the resulting mechanical loads? The “GridLoads” research project, successfully completed by Fraunhofer IEE and MesH Engineering GmbH, now clearly shows that the plants can basically cope well with this—provided that the control modules of the plants are equipped for the new task beforehand. To analyze the occurring electromechanical oscillation modes, the researchers have carried out complex simulations.

As part of the process of establishing a renewable energy system, artificial intelligence methods are evolving into tools for providing crucial support for forecasting, trading energy and dealing with complex challenges encountered in plant and grid operation. The Competence Center for Cognitive Energy Systems (K-ES) showcases the current state of research in exemplary spotlight projects. They are aimed at anyone seeking to gain a better understanding of what practical solutions might look like at the energy/artificial intelligence interface.

The objective of a digitalized energy transition is to harness data provided by a variety of decentralized electricity producers, such as wind turbines or PV plants, and loads so that the electricity system can run efficiently. This huge need for information calls for new concepts to establish how data can be exchanged efficiently and how organizations can preserve their digital sovereignty. Through a pilot project looking at the production of green hydrogen, four Fraunhofer institutes have now shown how this could be implemented in future using the concept of the International Data Spaces (IDS). A video has been made that looks into the details of the project, which will also be presented in an expert web session on May 27.

Although Chile and Germany are seperated by several thousand kilometers, the transformation of the energy system is confronted with partly similar challenges. Therefore, Chilean and German experts took the opportunity to discuss and share latest developments of the energy transition in their countries during the international workshop “Towards a Sustainable Future”. Highly topical issues from science and business as well as the political arena were presented, ideas exchanged and starting points for future cooperations explored. Originally planned as a personal meeting in Santiago de Chile in March 2020, the meeting was postponed due to COVID-19 and has now taken place in form of an online seminar.

In Germany and Europe, the energy policy discussion is currently strongly shaped by hydrogen as a universal energy source for the energy transition. However, the different sectors require a differentiated view. A study by the Fraunhofer IEE in Kassel examined the use of hydrogen in the future energy system with a special focus on building heat supply and related it to the direct use of electric power in heat pumps. An online presentation of the study and follow-up discussion will take place on: 22 July 2020 at 16:00 – 17:15.

Sulphur hexafluoride (SF6) plays an important role as an insulating gas in electrical switchgear at various voltage levels when interrupting and diverting current flows. At the same time, it is one of the most effective greenhouse gases with a very long lifetime and, although the concentration of SF6 in the atmosphere is currently still very low, it accumulates steadily over the years. The Fraunhofer Institute for Energy Economics and Energy System Technology IEE in Kassel and the Grenoble Ecole de Management (GEM) finalized a research study investigating the development of MV switchgear installations under different boundaries showing the impact on SF6 emissions, and analyzing the market acceptance of SF6-free alternatives, as well as barriers and drivers to adoption.

To keep pace with the latest changes to grid codes and testing standards the facilities of Fraunhofer IEE‘s laboratory SysTec have recently been upgraded by an over-voltage-ride-through (OVRT) test container. The new testing equipment is designed to analyze the dynamic behavior of wind turbines, photovoltaic inverters and combined heat and power units during short time over voltages of the supply voltage. Since the revision of grid codes in fall 2018 riding through short-term voltage swells now also became a requirement for generating plants installed in regional and local distribution grids.