Grid utilisation: How electromobility challenges our grids

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Reading time: 5 Minutes
Electromobility Grid utilisation

Electromobility can no longer be stopped. According to the coalition agreement of the new federal government, around 15 million e-cars are to be on German roads by 2030. The question often arises, and rightly so, as to whether our grids will be able to cope with this at all. Since we don't want to settle for assumptions, we took the opportunity to talk to the distribution grid operator SachsenNetze.

 

The grid experts Irina Blümel and Steffen Klinger answer our questions on the topic of grid utilisation. Irina Blümel heads the Electromobility Grids project and its strategic orientation at SachsenNetze. Steffen Klinger is head of network planning for the medium and low voltage levels at SachsenNetze.

Steffen Klinger
Irina Blümel

Is there a solution for the network load? umschalten.de asks!

Have the planned market ramp-up (i.e. the increasing market share of electric vehicles in the future) of electromobility and the associated demands on the power grid already caused you sleepless nights?

 

Steffen Klinger: Fortunately, we don't lose any sleep over it, because we are well prepared for this task. We tested our grids for compatibility with e-mobility at an early stage.

 

Irina Blümel: Consumers will only buy the predicted millions of e-cars if the framework conditions are right. This includes our simplified procedure for registering and testing charging technology for the range of small connections up to 30 kilowatts of power. Interested parties can then build their charging technology in the shortest possible time or find out what is required for it.

Special charging facilities are needed for electric cars, not just simple household sockets. Why do they have to be reported to the grid operator?

 

Blümel: In the past, it was often said that you could charge your e-car at the socket. We strongly advise against this. Most conventional house connections are not designed for such a heavy permanent load. In the private customer sector, so-called wallboxes are now used as special charging devices with appropriate protection and power ratings mostly up to 11 kilowatts. The Low Voltage Connection Ordinance stipulates that charging devices with a power greater than 11 kW are subject to approval by the grid operator, i.e. by us as SachsenNetze. For smaller capacities, they are only subject to notification. This is particularly important for the future-proof planning of our grids.

 

Klinger: The current grids were planned when such power-intensive and decentralised plants in large numbers were out of the question. An uncontrolled proliferation would be problematic in terms of grid stability. In the meantime, registration works well, which is also helped by our simplified registration procedure. We are prepared for a growing number of charging facilities.

 

You can find all the important information on how to charge your electric car at home in our big Wallbox Guide 2022!

 

How is SachsenNetze adapting to this boom, which is certainly not making any inroads into Dresden and the East Saxon region?

 

Klinger: Reliable data is important for our task of planning the network with foresight for the next decades. Since 2015, we have been working with an external service provider, Mobilitätswerk GmbH from Dresden. At the beginning, we had individual network areas examined. In the meantime, the company has prepared a study for the entire eastern Saxon region. Now we have well-founded forecast values up to 2050 on the spatial distribution of charging processes. The electricity demand can be derived from the forecast charging behaviour. This allows us to better plan the requirements and expand our power grid in certain areas at an early stage. Since e-mobility develops very dynamically in connection with the market ramp-up and political decisions, the results of the study are updated every two to three years.

 

Blümel: We are also focusing more on partnerships with electrical installers in our region. We conduct training sessions to inform them. The installers are important partners on the way to the end customer. We seek professional dialogue with them, which also goes beyond electromobility. Other topics that are becoming increasingly present in the context of the energy transition are the installation of renewable energy systems or heat pumps. The demands on the grid of the future are very diverse, and the growth in e-vehicles is one of them.

Dresden Centre Map Charging
Charging processes Legend

Be prepared for tomorrow today:

 

In a study commissioned by SachsenNetze, Mobilitätswerk GmbH examined the effects of electromobility on the electricity grids in the East Saxon region. The graphic shows the expected spatial distribution of charging processes for the year 2050 around Dresden's city centre.

If a large number of electric cars are charged at the same time in the future, this could overload the power grids. How can we counteract this?

 

Klinger: Of course, charging electric cars increases the load on the grid. It helps us a lot if the customer allows us to control the charging equipment of his electric car. This does not mean switching it off, but reducing the power to around 60 per cent.

 

Blümel: This means that the vehicle is only charged at times when the load is low, which benefits grid stability. The customer who allows us this controllability also has financial advantages as a result and is well prepared for the future.

Source: Mobilitätswerk GmbH

A look into the future using the example of the municipality of Moritzburg:

 

If electromobility develops moderately, about 880 charging processes per day are forecast for the year 2040. While slightly more than half are charged at home, tourism promotes occasional charging at (semi-)public charging facilities to an above-average extent. It is interesting to note that according to the forecast, charging on private land will clearly outshine charging on (semi-)public land.

The batteries of electric cars can be used to store electricity. To what extent can this relieve the burden on the electricity grids?

 

Klinger: The experts talk about bidirectional charging. In the future, this will be an important topic. More and more end customers want to either consume or store the electricity they generate themselves. But the public supply grid must be stably available. We will actively accompany this development.

 

Blümel: This fits in with the digitalisation of the energy transition, in which smart metering systems play a decisive role. We will make progress here in the next few years and deal with new challenges. As a grid operator, we are very familiar with dealing with such new tasks.

 

 

You can find more information on this topic in our article on bidirectional charging!

What concrete measures are there to minimise network utilisation?

 

In summary, there are some ways to minimise grid utilisation as the market share of electric vehicles increases. The electricity grid is being expanded at an early stage, especially in areas where a high demand for charging technology is forecast. Due to the dynamic development of electric mobility, the studies forecasting demand are not set in stone, but are updated every 2-3 years. This means that the grid provider can always be one step ahead. There are financial incentives for private customers to have their own charging times controlled by the grid operator. However, this explicitly does not mean that you cannot charge during certain times. Rather, it is a reduction to a maximum of 60 % charging capacity during times of particularly high grid utilisation. The use of bidirectional charging as a grid-storage extension is also becoming increasingly attractive and, in addition to the possibility of reducing grid utilisation, also offers various advantages to end customers.

 

We hope that our two experts were able to answer some of your questions. In any case, it is reassuring to know that grid providers are already looking at the grid utilisation of tomorrow and the day after. For electric mobility to become the new standard, the framework conditions for end customers are the most important factors. We look forward to the future!

 

If you have any questions about grid utilisation or electromobility in general, please feel free to write to us at frag@umschalten.de!

A contribution by Marcel Duparré

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