Customer application 7 July 2021

Solar Fuel – Even at Night

A lack of charging infrastructure, among other factors, is slowing the advance of e-mobility in Germany. Ingenieurbüro Fehringer (IBF), an engineering consulting firm from Dortmund, might be able to advance the expansion with an innovative solution. It has developed a solar EV charging station which can provide green energy around the clock, thanks to a combination of photovoltaics and batteries. WAGO technology manages the interfaces and ensures secure data communication.

How will the federal government’s goal of one million electric vehicles on the roads in Germany be achieved by 2020? Many experts have already labeled the proposal unrealistic; there is both a lack of affordable e-vehicles with acceptable driving ranges and also an insufficient number of charging stations for the e-vehicles currently on the road. To drive, for example, from Dortmund to Minden and back, an e-vehicle with a range of 200 kilometers would have to charge somewhere along the return trip. But where? Fear of insufficient range is scaring off potential buyers.

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The WAGO Telecontrol PLC handles all the communication and interface management.
An integrated GSM module enables secure email and SMS communication.
In addition to telecontrol functions, the controller also offers visualization.
Serial interfaces permit communication with other systems.

Solar Electricity instead of Gasoline and Diesel

But German car manufacturers are working proactively to address this. BMW, Daimler and Ford, as well as Volkswagen and its subsidiaries Audi and Porsche, plan to jointly construct quick charging stations across all of Europe. In the first stage, a total of 400 EV charging stations are to be installed along the largest European traffic arteries by 2017. By 2020, a dense network of charging stations should cover Europe, boosting electric mobility. Innovative companies are committed to advancing the development of new fuel station technologies in parallel. An EV charging station, where e-vehicles can charge using green electricity around the clock, is among these recent projects. The approach: A photovoltaic array on the roof of the station supplies the charging columns with solar electricity. If the solar modules produce more on a sunny day than is required for charging e-vehicles and can be accommodated by the electrical grid, then the excess is fed into lithium-ion batteries. These supply the charging units at times when the modules do not provide energy – at night – so drivers can use the charging station at any time.

Blunting Midday Peaks

The concept was developed by Ingenieurbüro Fehringer (IBF) from Dortmund. “Electric mobility is the future. In the next few years, the federal government plans to invest 300 million euros in expanding the charging infrastructure,” explains CEO Nicolaj Fehringer. To ensure that his company’s EV charging stations will be a candidate for this process, IBF has already constructed a demonstration system with a 36 kilowatt-hour storage capacity in Dortmund at the corporate headquarters. “The interplay of electrical generation, storage and charging functions perfectly in this project,” says Fehringer. In addition, the solar battery provides relief for the electrical grid by capping dangerous midday peaks on sunny days – an important contribution to an energy system that must incorporate increasing numbers of renewable energy producers.

Compactness is Crucial

Admittedly, the IBF engineers initially faced several challenging questions during the design of the electric fueling station: How can the individual systems – solar modules, lithium-ion batteries, charging columns, and inverters – be efficiently connected to the control technology? How can a secure data exchange be implemented between the individual components? Which controller is compact enough, despite the high technical demands, to be accommodated inconspicuously in the control cabinet while saving space? For collaborative projects in which different technologies have to be combined in limited space, compactness is an essential requirement.

WAGO Offers Key Technologies

During their search for suitable solutions, IBF came upon WAGO. WAGO’s telecontrol PLC (750-8207/025-001) handles all the communication and interface management in the EV charging station. Communication with the control center is carried out using the TCP/IP protocol IEC 60870-5-104 via a VPN tunnel. “This allows us to meet the requirements of the network operators and the highest security standards, like the BDEW White Paper,” explains Fehringer. Another advantage of the telecontrol PLC: As part of operations management, it can securely transmit SMSs and email via the mobile phone network thanks to an integrated GSM module. In addition to telecontrol functions, the controller also offers visualization. An integrated Webserver provides the engineers with configuration options and status information. “Normally, we would have to purchase this feature separately,” says Fehringer. With the option of expansion via serial interfaces, communication with additional systems within the charging station in not a problem. For example, one component communicates using MODBUS RTU, and another via a proprietary serial protocol. The controller offers the necessary flexibility and capabilities to satisfy all requirements, both at present and in future.

State-of-the-Art and Eye-Catching

In addition to the technical advantages, the EV charging station is also visually engaging, with colored LED lighting that creates a welcoming ambiance at the charging columns after dark. “We placed a lot of value on the overall design, because people spend time where they feel comfortable,” explains Fehringer. The combination of high technology and style has already generated interest among well-known companies. “There have been some high-profile contacts.” One possible application in the future might be to combine shopping or leisure activities with charging: The e-vehicle could charge while the owner dines or shops. Operating companies could use excess power to meet their own energy demand. For these types of applications, Fehringer plans to offer batteries with a capacity of 400 kilowatt-hours.

Rising Requirements on Telecontrol Technology

Another possible business model would combine multiple 400 kilowatt-hour batteries into a single, larger unit and operate them as a pool. This would allow operators to sell their output to the large network operators to help compensate for short-term fluctuations in the transmission network. According to Fehringer, the priority for a system like this would be to provide so-called primary reserve power, which must be available to the network within 30 seconds, unlike the five minutes and 15 minutes required for secondary and tertiary reserves respectively. The primary reserve places extreme demands on telecontrol technology, because it requires sophisticated measurement and control functionalities. This is not a problem for WAGO: Various projects have already proven that WAGO has the right automation solutions on hand.

Text: Daniel Wiese | WAGO

Photo: Fehringer GmbH

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