46 million cars are now rolling between Flensburg in the north and Füssen in the south of Germany – but only one percent of them are electric. Even though the forecasts vary and government subsidies can’t always be relied on, one thing is certain: the number of e-vehicles will increase dramatically in the coming years. However, success will come only to those who – in addition to the best vehicles – also provide the best charging systems.
The matter is crystal clear to Gunnar Bärwaldt, Group Development Coordinator for Charging: “Europe’s and also Germany’s grid operators are worried, because their power grids are currently not prepared for the boom in electric cars.” Of course, there must be investment in grid expansion to avoid overloads and even total blackouts. But that isn’t enough. Bärwaldt is convinced: “We need intelligent charging management to optimize the usage of the grid and to minimize the need to expand. Such solutions will already be necessary with an electric car share of 25 percent.” That would mean around twelve million vehicles in Germany.
The problem: If all their drivers come home in the evening and charge their e-car at the same time (the so-called Tagesschau – or evening news – effect), the negative consequences mentioned above would quickly become reality. Bärwaldt plans to avert this with an “energy management system” (EMS) for each household. The EMS is an intelligent computer that manages the energy requirements of e-vehicle and heating pumps. At the same time it also takes other available generating facilities (photovoltaic) and/or an additional house battery into account. Bärwaldt explains, “The charging time of an electric car is shorter than the time it is not in use at home or at work. That gives us flexibility in terms of timing and makes having an intelligent charging system all the more important.”
EEBUS is the future “language of energy”
which electricity users and electricity producers, including those in private households, can use to communicate. The idea: e-cars communicate with the home on how the electricity rates and availability are trending in the period prior to when they need to get back on the road. When is electricity the cheapest? When is the grid’s capacity utilization most advantageous? And, accordingly, when is the ideal time for the charging process? Based on the conditions, which can change hourly or even by the minute, the e-car identifies when it is best to charge itself – or even to feed electricity back into the house. The Volkswagen Group is already working on this technology with partners and other companies.
Don’t charge the electric car at 6 pm; do it when it’s best instead
In practice it goes like this: millions of e-car drivers may come home at around 6 pm, but they don’t charge their cars immediately. They do something else: they give the e-car the information on when they need the car again the next day and for which range.
The car transmits this information to the EMS. The EMS then factors in the energy needs that have just been entered and, in turn, supplies the vehicle with the current electricity supply information, such as price trends and availability. The e-car uses this information to determine its own charging schedule. In this way, all interests are accommodated successfully: the electricity requirements of other users in the house, the utilization of self-generated power and the grid operator’s price for using the grid.
That is by no means all that happens though, because the EMS can do even more: it can draw on the car’s residual energy (thus making it a temporary stationary energy storage unit) , in order to meet the occasional electricity needs in the home (e.g. for the heating pump). The prerequisite is that the vehicle has the technical capability of delivering energy to power grids. According to Bärwaldt, “The customer doesn’t have to do anything. All electricity producers, storage batteries and electricity consumers in the household communicate with the EMS independently. It is then the only point of intersection between grid operator and energy supplier.”
Should, however, a car need to be partially recharged right after arrival because its driver is planning to go out again in the evening, or the set minimum range hasn’t been covered, that’s not critical to the overall system. Then precisely that car would be recharged immediately. Most e-cars, though, have the flexibility to choose the time charging is to take place freely during the following 12 to 14 hours (at the theoretical departure time of 8 am). Namely whenever local electricity is being produced and is available, or when the electricity can be obtained from the supplier at an especially good price.
Why should households purchase an EMS at all? Bärwaldt is also a total pragmatist on that point: “They’ll do it if it makes financial sense to them.” The reason is the continuing decrease in the photovoltaic subsidies for new systems and the expiration of the subsidies for systems that have been in place for 20 years, meaning that private electricity producers will no longer receive attractive feed-in rates from the energy suppliers. It will then make more sense to homeowners to use the electricity they produce for themselves instead of feeding it into the grid. That is also managed by their EMS.
Unifying technical standards
Bärwaldt makes no secret of the fact that there’s still a long way to go before that happens. “First we have to – within the Volkswagen Group, but also with other manufacturers – continue developing charging standards jointly and to design the applications to be uniform.
Secondly, we need solutions for e-car drivers who don’t have their own parking space, e.g. those living in apartment buildings. That could entail electrified parking garages or big charging parking lots. Third, we want to win over grid operators and other industries into making sure their products are able to communicate with our products, i.e. electric vehicles.”
With this in mind, the Volkswagen Group and Gunnar Bärwaldt are also involved in the EEBUS initiative. The registered non-profit organization has the goal of creating a uniform language for all devices so that they can communicate with each other about energy – national and industry boundaries. A language that every device and every platform can use freely regardless of the manufacturer and technology.
Grid-integrated electric cars could help the grid operators with their work to some extent. According to Bärwaldt, “We are leaving our customary system parameters.” However, he is also sure that only those manufacturers that ensure convenient, worry-free mobility will sell electric cars in massive numbers. “I want to generate happy customers,” is what the industrial engineer says is his motto.
Currently there is still a certain amount of lead time because the mass registration of electric cars has been held up a bit. But, as Bärwaldt says, “We have to start developing solutions now. When the boom is already here, then it’s too late!”