Phasing out coal, grid expansion, electromobility - the energy transition is not just a political issue. Grid operators in particular are facing the major challenge of positioning themselves for the future. The crux of the matter is that nobody can yet predict exactly where the journey will take us. Stadtwerke Gießen AG and its subsidiary Mittelhessen Netz GmbH are now tackling this issue with the support of Mittelhessen University of Applied Sciences.
When public discourse revolves around the complex topic of the energy transition, the focus is usually on major tasks that affect the entire nation. Consequently, the scenarios designed here deal with mammoth projects, such as the necessary grid expansion at the extra-high voltage level - keyword Südlink. However, less attention is paid to the regional perspective. "Wrongly," says Matthias Funk, Technical Director of Stadtwerke Gießen (SWG). Because the fact is that regional energy suppliers and grid operators play an important role in the energy transition. Stadtwerke Gießen (SWG), for example, has been driving this forward for many years. "We have never limited the topic to electricity generated from renewable sources," summarises Matthias Funk. In fact, SWG is pursuing the concept of linking different sectors together in a meaningful way. "Our district heating network with a total of 192 combined heat and power plants has always combined electricity and heat production."
Long capital payback periods
Although SWG already has a lot to show in terms of the energy transition, they have to change drastically in order to remain competitive. This applies above all to the infrastructure, i.e. the grids themselves. However, the framework conditions make planning almost impossible. This is because investments in the grid usually only pay off after decades. "At the same time, we have to design a network today that will still fulfil all requirements in twenty years' time," says Rüdiger Schwarz, Managing Director of Mittelhessen Netz GmbH (MIT.N), describing the difficult task. There are many things to keep in mind here. For example, more and more volatile green electricity is likely to have to be integrated into the regional grid in future. This requires the possibility of feeding electricity into the higher grid level under certain circumstances. No less exciting is the question of what will happen if electromobility, as it currently stands, becomes established. "We will then have to think about how we can get enough electricity to the many charging points required and distribute it intelligently," explains Rüdiger Schwarz. No less important: what effect will the increasing number of heat pumps have on the grid? They also require a relatively large amount of electricity, with comparatively large seasonal fluctuations.
Many options
For these two problems alone, there are a large number of conceivable development paths. This is precisely where the experts at the Technical University of Central Hesse (THM) come into play. In the Kommun:E project, they are developing realisable solutions for municipal energy suppliers in general and for SWG in particular. All of their forecasts take into account the expected increase in efficiency and the value of at least 80 per cent green electricity in 2050 as stipulated in the 2014 Renewable Energy Act. THM researchers also take into account the fact that renewable energies will also become established in the heating and transport sectors. The overriding criterion is also a secure, affordable, consumer-friendly, efficient and environmentally friendly grid-based energy supply as stipulated by the current Energy Industry Act.
"We received almost 600,000 euros from the Federal Ministry of Education and Research for our pioneering research work," says Prof Dr Thomas Stetz, who is responsible for the Kommun:E project at THM. This figure alone shows how highly the topic is now also prioritised by the federal government. There are at least three good reasons why SWG was at the top of the list of potential co-operation partners: THM and SWG have been working together successfully for many years in very different areas, and the close proximity should make much of the work to be done easier. The decisive criterion, however, is that MIT.N's electricity network proves to be exemplary in an ideal way: it covers city centre, suburban and rural regions in roughly equal parts. "This structural division and the regional interaction of the electricity, heating and transport sectors ideally reflects the German energy transition at municipal level. It is therefore to be expected that the results will also be applied beyond the project region," says a delighted Prof Dr Thomas Stetz.
Other partners
However, the scientists' investigations are not limited to the MIT.N network. Since the end of November, the immediate neighbour, OVAG Netz GmbH, has also been on board as an observer. This opens up the opportunity, for example, to calculate whether it makes sense to connect the two grids at the medium-voltage level at points that are still to be determined more precisely. "This could help us to mitigate any fluctuations that occur," explains Rüdiger Schwarz. If, for example, the wind farms in the OVAG grid area generate more electricity than is currently being consumed there, MIT.N could take some of it and distribute it in its grid. A much better option than switching off the wind turbines. Conversely, Giessen's combined heat and power plants or TREA 2 could help out if the wind does not blow as forecast.
The researchers in the Kommun:E project are also processing demographic data provided by the district of Giessen. "How many people need electricity when and where are crucial parameters for planning the corresponding infrastructure," says Rüdiger Schwarz. As part of the creation of the "100% climate protection" master plan, the district of Giessen has also created a comprehensive database on electricity and heating requirements through to mobility behaviour, which is also available to the project.
It also helps the THM team to address detailed questions. For example, how sales of electric vehicles could develop. The information from the district should make it possible to derive reliable forecasts in this regard.
Avoiding bad investments
Over the next 30 months or so, professors, research assistants, doctoral students and students working on their Master's or Bachelor's thesis will be working on the individual aspects of the extensive project. The aim is to present efficient and economically viable solutions based on the data obtained. "Of course, the scientists also calculate with certain variables, such as electricity storage systems that are currently being tested," explains Matthias Funk. And Prof Dr Thomas Stetz adds: "We also include smart grid technology that has already been successfully tested in the laboratory in our considerations."
If everything goes according to plan, Prof Dr Thomas Stetz and his team will be able to present the results of their research project "Transformation of municipal energy supply infrastructures under the influence of the German energy transition" in mid-2021. This will make planning much easier for regional utility companies such as the SWG Group. The research results should enable the development of expansion plans for grids that fulfil two important criteria: They will meet future requirements and harbour only a very low residual risk of bad investments with long-term effects.
14.12.2018