“We research at system level”

The energy revolution is decentralised and is taking place in distribution grids. The “Department for Electromobility and Power Electronics” at the Technical University of Applied Sciences Lübeck (TH Lübeck) is researching how charging infrastructures can be integrated into these. The result of their work is a rapid charging station with a charging capacity of up to 1 MW. This is application-oriented research at a level unparalleled in Europe. It is made possible through partnerships with industrial companies such as EPLAN. We discussed this with Professor Roland Tiedemann and Clemens Kerssen.

Professor Tiedemann, the energy revolu­tion is advancing faster than anticipated, and the energy mix is changing. Companies have to be prepared for this, too. What is the current situation?

Roland Tiedemann:There is a general problem we face when it comes to the energy revolution – storing the energy. There has been too little attention given to this core issue so far. The country is virtually covered in wind and solar farms, and yet there’s a limit to what we can do. There is still a long way to go. In our research project, we therefore always view the energy revolution in parallel with the subject of electromobility. Why is that? Tiedemann:Electromobility is important for two rea­sons – firstly, as a consumer, and secondly, as a means of storage. At the moment, we can’t even pro­vide the energy that would be necessary for a whole­sale switchover to electromobility – our electricity grids simply don’t have that kind of capacity. The other key aspect is that electric vehicles can also act as a means of storage, but we are still a long way from where we need to be.

So much depends on storage technology, then ...

Clemens Kerssen:Absolutely. That is what we are focusing on here in the Department for Electromobil­ity and Power Electronics. To our mind, when we think about electromobility, we are also looking at the stor­age technology. Our energy supply used to be cen­tralised, but is now increasingly decentralised – for example with wind farms, solar panels, biogas, etc. – and the same applies to consumers. The interplay between electromobility, charging technology and decentralised energy supply and energy storage is therefore a core question for the energy revolution.

Who exactly is still running behind?

Kerssen:To put it simply – everyone. We’re all doing something somewhere, but we’re missing the big picture. We have issues on the technology side, in standardisation, in legislation and in availability. There are a huge number of questions that are yet to be fully addressed. What’s more, many companies are doing their own thing to bring their own, manufactur­er-specific solutions onto the market. From our per­spective, this is counterproductive and not conducive to the global energy and mobility revolution. We have really felt the weaknesses of the system for ourselves for the first time as a result of the Ukraine war. Storage should actually have been factored into the energy revolution from the outset. After all, it’s always been known that we will have to switch from continuous generation based on power plants, for instance, to sporadic generation based on wind farms and solar installations, for example. We have to create load distribution – and that means storage.

What is the specific question you are pursuing in your research project?

Kerssen:We were interested in how it might be pos­sible to build high-performance rapid charging tech­nology for electric vehicles, because combustion engines still have that key advantage of only taking minutes to fill up. We also realised that, to achieve high charging capacity, we would need intermediate storage in our electricity grid, too. Otherwise, the grid will be overloaded in the evenings when everyone is charging their cars. That’s how our Power 400 re­search project got started, which led us to develop high-performance rapid charging systems with inte­grated buffer storage.

And what does your current solution look like?

Tiedemann:We have produced the prototype for a DC rapid charging station, and can theoretically charge with one Megawatt at a single charging point. That puts us ahead of the pack at European level. By way of comparison, one Megawatt is what they use to charge submarines in Kiel. Our AC technology is based on a modular concept. We have a master-slave system, in which a single master can be used to con­trol and easily retrofit various different slave units. As a result, we don’t have to implement a complete standard plan immediately, but instead can wait and see how well used the charging park is. Our systems are already designed for buffer storage. We are cur­rently using electrical battery storage, but we are also working on a combination with fuel cell technology.

How much of your work, or that of TH Lübeck, has gone into this development?

Kerssen:Everything – and much, much more (he laughs). As we tell our students, this project covers everything you will learn when studying electrical engi­neering or IT. We build the hardware, we program the software, and we take on the circuit board manufactur­ing if there isn’t a standard circuit board available. Our system has an interface to the battery management system, features an energy management system, and is ready to interface with the grid and communicate with the battery or fuel cells. We have integrated everything from the payment system to the grid connection, and could even implement bidirectionality – so as far as we’re concerned, we’re good to go.

So at the end of the project, there will be a charging station with your name on it?

Tiedemann:Not necessarily. What’s important is that we have a product that can meet the current chal­lenge and that we are as open as possible to various perspectives. Let’s get that launched first and see how the field reacts and how it goes down. Some energy companies want to provide a nationwide charging infrastructure and the foundations of this have already been laid, more or less, but without do­ing any location analyses. That’s a big gap.