Ripple Control Receiver: What You Need to Know About § 14a EnWG

They say EV charging is simple. Then, you see a term like "radio ripple control receiver" next to it and you feel like you've been tricked.

Until recently, you didn't have to know much about the ripple control receiver to happily use a wallbox at home. However, as new regulations apply in Germany, you are required to install such a device in several cases. Which cases are these? We are about to tell you. 

Let’s start with the basics. 

The ripple control receiver is meant to act as a mediator between the large electrical consumers in your house and the energy supply company. You can simply think of it as a kind of remote control that helps to regulate the transmission of electricity from the grid to the appliances in the building. Only this remote control is not in your hands, but in the hands of your grid operator.

The ripple control receiver in your building works by receiving a special signal through regular power lines from your energy supplier. This relay in the electrical cabinet is able to turn off specific electrical appliances or reduce their power as set by the energy supplier. 

Such a situation can happen, for example, when the power demand in a particular area is higher than the amount of power available. When the demand in your area goes down, another digital radio signal is sent by your energy supplier: “the power can be increased.”

Not sure whether you should be happy about the new regulations? When you learn about the nice subsidies you can get, you'll see that it's actually a blessing in disguise.

In Germany, in exchange for letting the power grid control your devices, you can get a lower network fee. This mentioned in the §14a of the  Energy Industry Act (EnWG). Since January 1, 2024, it is mandatory in Germany that newly installed EV charging stations from 4.2 kW must be controllable by the grid operator. Therefore, these are also subject to registration. The government agency sets rules for these reduced fees based on different situations. There are two options: 

1. fixed amount reduction for grid fees - around €160 per year 
2. your consumption costs are reduced by 60%.

In the first case, the discount is nationwide and ranges from 110 to 190 EUR per year, depending on the network area. 
The case number two requires a separate metre. From 2025, it should also be possible to choose a time-variable grid fee, which will make charging cheaper at times when the electricity grid is less utilised.

In some countries under certain conditions, grid operators switch power off completely during the hours of high demand. But no worries. The new rules we’ve mentioned make it simple: 

• wallboxes need at least 4.2 kW, but it depends sometimes on your individual situation
• heat pumps or AC units can't go beyond 40% of their max power

1. Register your wallbox with the local grid operator. Be careful to not mix it up with your electricity provider. While the provider manages supply, the grid operator oversees grid maintenance and expansion. 
2. Once your wallbox is installed and registered, the network operator will reach out to discuss assuming control of your wallbox's power supply.

In Germany, the installation of a ripple control receiver is mandatory. For other countries, we suggest consulting a professional electrician, who specifically handles its purchase and installation. Get advice on whether you need it at all before making the final decision. 

Once installed, the ripple control receiver, managed by your system builder/installer, has the capability to adjust your feed-in power and control your consumption devices such as a home wallbox or heat pump permanently.

In principle, it should be possible to connect most charging stations to a ripple control receiver. How exactly this works depends on the charging station itself.  You might wonder if, for that, the charger needs to be smart. Intelligent features are not necessary for the ripple control receiver to function with your home wallbox. However, as always, we recommend you choose a smart charging station, which will not only make your charging cheaper but also significantly more sustainable.

Generally, our wallboxes can be used without a ripple control receiver unless there are local regulations requiring it. The newly introduced regulation such as the § 14a EnWG in Germany does require use of the ripple control receiver. 

What do you need to do to comply with this regulation? Well, there are several possibilities. 

The stationary go-e Charger Gemini has two data cables that can be hardwired into your electrical system. Your electrician simply needs to connect the potential-free output of the control box or the ripple control receiver to the white and red signal wires on the go-e Charger Gemini as shown in the instructions. 

But are there other ways? 

Yes! The three options below are suitable for both, the stationary go-e Charger Gemini and the mobile go-e Charger Gemini flex. 

1. Control via Modbus TCP using a PLC
2. Contactor circuit with connection to the grid operator's control box or ripple control receiver *
3. OCPP interface of the grid operator  

* It is the only variant in which the charging current cannot be reduced, but only a complete shutdown is possible during a grid overload.

We have summarised all the options for the go-e Charger Gemini series, including the Gemini flex mobile wallbox, in detail in this PDF document.

If you use a smart wallbox like our go-e Charger, you are able to increase or decrease charging power manually in the app or using the button on the device. You can also automate this if you take advantage of PV surplus charging or charge with flexible energy tariffs. 

But what if the ripple control receiver decides you are still drawing too much power from the grid? 

To put it simply, the receiver has priority over your home wallbox. 

How exactly does it work? 

Imagine you are using our smart combo – the go-e Charger with the go-e Controller. They keep an eye on how much power other things in YOUR home are using. You have already set a limit for how much power your whole house can use while charging your car. But on Monday evening, when lots of other homes are using huge amounts of power, the electrical grid in your area gets notified about it through the ripple control receiver. Therefore, it pauses your car charging temporarily or reduces charging current. It's a safety measure to help balance the power load and keep things stable on the grid.

The cost of the ripple control receiver is around EUR 100 to 600. Bear in mind that you will also have to pay extra for the installation. Setting up the radio ripple control receiver costs from around EUR 30. 

The most important thing the ripple control receiver does is protect the grid from overloading. But there are also other ways to make sure the electrical system in your area is safe: 

• OCPP: A smart charging station with the OCPP function, such as the go-e Charger, easily communicates with other charging stations and systems supporting the same function.

• API (Application Programming Interface): It's a tool that helps the charging station and the manager talk to each other smoothly and share information about the charging process. The better the communication, the higher the chances that the charging stations will draw an optimal amount of power whenever cars are charging.
• Peak shaving: If you use our smart combo consisting of the go-e Charger and the go-e Controller, you can activate peak shaving via simple menu settings. However, if you use a wallbox that does not offer such an option, and you connect it to the ripple control receiver, peak shaving will be done by the grid.
• Dynamic energy tariffs: This is possible with a smart metre or a digital electricity metre equipped with extra hardware like the Tibber Pulse. This enables you to take advantage of fluctuating electricity prices, charging at lower rates and in a more sustainable manner. Additionally, dynamic tariffs ensure charging occurs during periods of lighter grid loads, optimising efficiency. When flexible electricity tariffs are linked to the electricity price index, you can use a smart wallbox to monitor the prices and adjust electricity usage during off-peak hours. This will result in more economical charging. Such a dynamic control mechanism helps balance the grid and reduces costs.