Energy is more expensive than ever. In the course of the energy turnaround, the expansion of renewable energies ought not only contribute to climate protection but also make us less economically dependent on fossil fuels. However, endeavours to use as much of the wind and solar energy generated as possible in the best way are currently still confronted with the problem of grid congestion. In the “Grid4Regio” research project, Professor Ingo Jeromin from the Department of Electrical Engineering and Information Technology at h_da and his project partners are working on better utilisation at regional level of the potential offered by already existing grid infrastructure, on lessening the load on transmission networks and thus on countering the partly contentious issue of grid expansion.

By Nadine Bert, 18.2.2022

Binselberg Hill near Groß-Umstadt on the edge of the Odenwald, a low mountain range on the border of Hesse. The blades of four huge, powerful wind turbines ponderously rotate atop the vast, hilly landscape. The electricity being generated here right now is fed directly into the regional power grid. So far, so good. Yet what happens on days when the wind turbines produce more electricity than the local grid can absorb? At present, due to lack of storage options, they either have to be switched off, resulting in the loss of precious energy, or the surplus electricity is “pushed up” into the upstream high-voltage grid. Professor Ingo Jeromin from the Department of Electrical Engineering and Information Technology (EIT) at h_da calls this the “energy highway”.

An interesting comparison, in which the region’s medium-voltage grid is a main road and the high-voltage grid a motorway: if, when there is increased traffic on the main road, everyone temporarily takes the supposedly quicker route via the motorway, and then takes the exit again towards their destination, the result is a traffic jam at the junction. If such congestion persists, the road network is often expanded – and exactly the same applies for the electricity grid. At the end of the day, both mean additional costs for the taxpayer. Professor Jeromin is convinced that this need not be the case. In the “Grid4Regio” research project – a collaborative EU-funded project between h_da, the Technical University of Darmstadt and energy supplier Entega – he wants to prove that by using new technologies and systems regenerative energy can not only be produced locally but also directly consumed there too. “Why build new energy highways when you can use the cart tracks which are already there and passable?” he says.

In this instance, it would mean distributing the “surplus” regenerative energy from wind and sun in the medium-voltage grid in the Groß-Umstadt region to neighbouring towns, such as Babenhausen or Groß-Bieberau, instead of leaving it unused by shutting down the wind turbines or photovoltaic panels or feeding it into the upstream high-voltage and extra-high-voltage grids and thus overloading them. The research team’s idea is to utilise existing infrastructure for the decentralised coupling of neighbouring grids, which would make curtailment unnecessary. The model region where this approach is being studied lies within e-netz Südhessen’s distribution grid, the electricity supplier behind the project.

Apart from the appeal of making renewable energy usable in an efficient and resource-friendly way that this scientific challenge has, the project focuses above all on making the energy turnaround both realistic as well as financially viable for society. For Jeromin, who is also politically active on Darmstadt-Dieburg’s district council, his research is therefore also clearly socially motivated: “You can’t simply keep pushing the expansion of renewable energies further and further without thinking about their rational use and the costs.” At present, he adds, too much surplus “green energy” is being used unwisely, but at the same time the extraction of fossil fuels is being ramped up. “I think this is a disaster for the economy as a whole. That’s why we want to contribute through our project to finding a solution, so that the expansion of renewable energies and the associated costs are kept as low as possible by using the energy already available as efficiently as possible,” says Jeromin.

Alongside “Grid4Regio”, he is also conducting research within other projects, such as the Smart Grid Lab for the modernisation of Germany’s electricity grids, which aims to integrate a higher ratio of renewable energies into electricity networks.

“Germany is pioneering in the renewable energy market and conducting important research in this field. Even though we won’t be able to conquer the climate crisis on our own, we can nonetheless show working models in the hope that others will follow suit,” summarises Jeromin. In view of the current political situation too, he adds, independence from fossil fuels is something not only important as far as climate change is concerned. The next goal is already set: “Once we’ve managed to make better use of the electricity generated from renewable sources, storing it is the next challenge that will have to be solved.”