Your own wallbox in the underground car park - the right to a better quality of life

Julien Oehler started at Mer five years ago - at that time still eeMobility - and is responsible for eeApartment in product management. In this interview, he explains how the new charging solution for apartment buildings works and what fascinates him personally about it.



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4 min


Mer Solutions GmbH


Mer Solutions GmbH

What exactly is eeApartment and how did the idea come about?

There are several million apartment buildings in Germany, including large buildings with 200 parking spaces. Not everyone has their own garage or a charging point on their doorstep, so the question is: How can a viable charging solution for electric cars be provided here? If you want to equip a large apartment building with charging points, you need a technically mature solution. This can't be done by the electrician next door, because you need comprehensive planning and expert installation. Last but not least, someone has to take over the operation of the stations, including power delivery, billing and load management. There aren't many providers who can take care of everything and bring the necessary expertise to the table. That's where we come in.


How does this work in practice?

In multi-apartment buildings, there is a house connection from where the electricity is usually distributed to the various apartment meters or apartments. For eeApartment, we additionally install a separate electricity meter for the complete charging infrastructure in the underground garage to separate it cleanly from the rest of the electricity consumption in the house. The electricity then flows from there to the individual wallboxes at the parking spaces. What sets us apart from other providers is that we supply clean green electricity and are electricity suppliers ourselves. Our parent company Statkraft is the largest producer of renewable energy in Europe - and this electricity flows into the cars.


How does that fit with Mer's mission?

In the future, we want to combine the energy transition with electromobility and use renewable energies when they are available. If a wind turbine is turning all night or the sun is shining, I can use this energy to charge electric cars during this period. We bring this energy to places where the vehicles are parked for a long time, because you can then time the charging processes - an apartment building with many parking spaces is optimal. The vehicles are parked there for a very long time, usually all night.


Which target group are you aiming at?

Our other products, such as eeFlat and eeCharging, are aimed at companies with electric corporate fleets. The target group for eeApartment is different: It's more interesting for property managers, cooperatives and housing companies that are looking into the topic. When the question of equipping their own many residential units with charging points comes up, a uniform solution is required. The companies do not want to spread the handling among different providers in several cities, but rather save themselves the administrative effort and have a single point of contact for everything. At Mer, we offer a supraregional, standardized solution. 


How does the payment work?

We bill the tenants of the parking space directly and send them an electricity bill. If the public charging network is used, for example by charging stations on the highway, we also bill the user. The property management or the owners' association has no expense and does not have to take care of anything.


What are the concrete advantages of eeApartment?

Charging an electric car is extremely convenient when the wallbox is at home, because around 80 percent of charging processes take place at home. You plug your car into the underground parking garage in the evening, let it charge at night, and can drive off in the morning. Our drivers no longer have to rely on public charging stations in the neighboring street or at the freeway service station.


What happens when all the cars in the underground garage charge at the same time?

At Mer, we have dynamic load management. This means that we continuously check how much power is being used in the house and how much power is just left over to charge the electric vehicles. We use the available power intelligently so that the fuse doesn't blow, so to speak. If there is just 50 kW available and ten vehicles are currently charging, each one gets 5 kW, to put it simply. Or: If only five cars are charging in the underground garage, these cars are charged with 10 kW. The available power is therefore optimally utilized for the drivers. Without intelligent control, in some cases you would have to extend the house connection and use much more power from outside to provide enough energy or power. For this reason, we look in advance at what the consumption has been in the past. In the initial planning, we make a query to the network operator or measure over certain period of time how much residual power is still there. If the buffer is minimal, we can still decide whether to expand the connection.  


Why is now the right time for eeApartment ?

Electromobility itself is developing at breakneck speed. There are countless models from the major car manufacturers and the number of vehicles on the roads is rising continuously. Naturally, this means that the number of charging points must also increase. In addition, it is now easier for tenants to install a charging box in the underground car park because there are legal innovations. They can no longer be prevented from installing the charging infrastructure for an electric vehicle.


Are there any other ideas to add to eeApartment?

In the future, we want to go one step further and apply the principle of eeFlatNeo to apartment buildings as well, i.e., move the charging processes to the nighttime hours and only charge the cars when a particularly large amount of renewable energy is fed into the grid. Otherwise, you may not be able to use the electricity from renewables or you may have to store or consume it by other means. In the worst case, the electricity is lost, because sometimes wind turbines, for example, are simply shut down if there is too much electricity in the grid. In addition to better grid expansion, we can contribute to this with our solution.

Another addition we are working on is the combination of eeApartment and carsharing. Our sister company Mer Germany has developed an eCarsharing model that can also be used for apartment buildings: There is a fixed parking space in the underground garage for an electric car that all residents* use. This could be a complementary model.


What motivates you personally to drive such projects forward? What fascinates you about Mer?

I work in an industry that is developing very quickly. The energy and transport industries looked very different twenty years ago. I can also influence decisions and help shape the path. Example: After extensive analysis, I could suggest we should offer this or that product, and if it's well thought out, there's a good chance it will be implemented. Of course, electromobility is an important topic in itself: My colleagues and I are working on something that fundamentally has a positive impact. When I see that competitors have big oil companies in the background, I'm glad that we have Statkraft behind us. Other providers are building the charging infrastructure, but clean electricity is secondary. Electromobility only makes sense if we rely on renewable energies and continue to expand them.

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