Electromobility: Delay in bidirectional charging

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Why can the French do it – and Germany can't? This refers to bidirectional charging, abbreviated to V2G for Vehicle-To-Grid. In France, owners of the Renault 5 earn money if their car is connected to a special wallbox plus contract: the German company The Mobility House pays eleven cents for an hour on the cable. Meanwhile, the R5 is available as a buffer for electricity. Cheap in, more expensive out, that's the principle. Depending on the fluctuations in the stock market price. This significantly reduces driving energy costs and relieves the grid. The Netherlands and the UK will follow suit over the course of the year. Germany, on the other hand, is not yet at that stage: legal requirements are hindering implementation here. This could change quickly.

What is V2X?

Every electric car can charge and discharge electricity. Nothing else happens when accelerating and decelerating while driving. Most of the time, however, cars are parked somewhere. Time for V2X, the umbrella term for integrating the electric car into the power supply. A rather simple example of this is when the electric car has an external socket and supplies appliances ranging from hedge trimmers to induction stoves at the campsite. V2L(Vehicle-To-Load) is the name of this form of V2X. Many Hyundai and Kia models can do this either via the charging port on the outside or via a socket on the inside. The special feature is that the usual power from home (3.6 kW) is available. Incidentally, this also works with certain versions of the Dacia Spring. At Volkswagen, it has been stored in the software of some ID models for years. Others have not yet provided for this: Tesla or BMW? Not yet. Not yet.

Another possible interpretation of V2X is V1G, Vehicle-One-Grid. This is grid-serving charging depending on the electricity price in a dynamic tariff. This is rarely automated; it may be that a person manually analyzes the tariff curve over the course of the day or week and decides when charging is cheap. This form of V2X is the original version of smart charging, so to speak.

No legal equality for electric cars

The goal remains V2G, electricity price-dependent charging and discharging. The electric car is a market participant on the electricity exchange. To achieve this, mobile storage – i.e., electric cars – must be placed on an equal legal footing with stationary storage systems: This in turn means that electric cars will also be exempt from grid charges at least until 2029 and, if possible, from other levies.

“V2G can only be realized in the current ramp-up phase if no grid fees have to be paid for electric cars, just like for large storage systems,” explains Marcus Fendt, Managing Director of technology service provider The Mobility House, which offers V2G in France together with Renault. “Politicians did not decide this in the last legislative period,” Fendt continues. The Federal Ministry of Economics is responsible for this issue in cooperation with the Federal Network Agency.

Who benefits from the energy transition?

Without this legal framework, there is no business model and the whole thing doesn't work. The unequal treatment is problematic: while large companies are currently ordering and registering stationary storage facilities on a large scale, ordinary users have no prospect of earning money – precisely because, unlike the operators of large storage facilities, they have to pay grid charges and other levies. On the positive side, more and more hardware will be coming onto the market in 2025. On the one hand, these are intelligent wallboxes that work either with AC (alternating current) or DC (direct current), as is the case with Renault. On the other hand, there are the electric cars themselves, which more frequently fulfill the corresponding ISO 15118.

Stromversorgung und -kosten

• Smart Meter: Schnittstelle für lokalen Datenabruf
• Geld sparen mit dynamischen Stromtarifen
• Was Smart Meter leisten, was sie kosten und wie man sie bekommt
• Smart-Meter-Alternativen: Zähler-Leseköpfe & Co. im Überblick
• Einspeisevergütung und Förderung: Was künftige PV-Anlagenbesitzer wissen müssen
• Erfahrungsbericht: Ein Jahr dynamischer Stromtarif mit Tibber
• PV-Strom auf Mehrfamilienhäusern umsetzen: Wie Mieter und Vermieter profitieren

AC/DC wallboxes

The lively debate whether AC or DC is the better solution is of secondary importance for now due to the incorrect legal framework. In short, AC is currently cheaper, but more complex due to the many different communication protocols used by grid operators, the grid codes. DC wallboxes are more expensive to purchase, even when imported from China, at EUR 2000 to 2500, but are easier to standardize. If there is an integrated overall setup in a house with DC wallbox, photovoltaic system, heat pump and electricity storage, internal efficiency and investment costs are better in the medium term. One strikingly ambitious company in this context is Ambibox from Mainz. Ambibox is working on the certification of the DC wallbox, and the automotive industry has indicated that the product is being intensively examined and compared in internal field tests.

Slow ramp-up

The National Centre for Charging Infrastructure, a limited company owned by the Ministry of Transport, is therefore cautious about the medium-term outlook. According to this, a gradual ramp-up of V2G applications will not take place until 2026 to 2030. From background discussions with market participants, it is clear that 100,000 electric cars practising V2X by the end of the decade is already an optimistic estimate.

Preparations for V2G in Germany are being accompanied by the agonizingly slow conversion to digital electricity meters, also known as smart meters. The fact that we have an established structure of well over 800 supply network operators is an additional burden. So it's all bad? No. Of course, any government could immediately decide to exempt bidirectional charging electric cars in the same way as stationary storage systems. The easiest way to save money currently is still for owners who have their parking space and a photovoltaic system. This is the cheapest way to charge your vehicle.

(wpl)