The All Electric Society Factory on the Phoenix Contact premises is a flagship of DC technology far beyond the borders of Germany. But what does that mean and what makes the white and gray block in Blomberg, East Westphalia, so special? A walk from the roof to the basement of the innovative production facility shows how direct current works in practice.
A sunny afternoon in Blomberg. We shiver a little on the roof of the new factory building. A blue-black surface of solar panels undulates like a sea of glass on the 11,061 square meter roof in Blomberg. As soon as sunlight hits the semiconductor material, electricity flows. Thin metal strips on the solar cells transport it via finger-thick cables to the DC combiner boxes in which the solar energy yield is collected. Solar everyday life.
But this building is different: where elsewhere inverters live up to their name and ensure that the direct current from the solar system is converted into alternating current, here it flows directly into a local direct current grid. “The future belongs to systems like these: a DC grid optimizes the entire energy chain of generation, distribution, storage and consumption,” explains Tobias Lüke from Phoenix Contact. The project manager and DC expert likes to start his tours of the building on the roof. After all, renewable energies are an important reason why DC technology is on the rise everywhere: “It’s not just the generators, i.e. mainly solar and wind, that are increasingly working on a DC basis, but also energy storage and consumers: LED lighting has replaced the light bulb. Most electrical devices and production units work with direct current – and demand is growing.”
Petrol station included
Charging stations are now commonplace in modern industrial buildings, including at the All Electric Society Factory. And they are important consumers in the growing DC cosmos. Tobias Lüke therefore leads his visitors down to the first floor, where ten of the energy dispensers are lined up at the entrance to the building. They come from the specialist VTS Echarge. “They are also important components in our building concept,” says Lüke. “In future, company cars will not only be able to charge their vehicle batteries here via bidirectional DC charging stations (DC=Direct Current), but also feed energy back into the system as required.”
As soon as a charging station is opened, it becomes clear that Phoenix Contact is well positioned for the topic of direct current. “With our overvoltage and device protection, DC circuit breakers and DC charging connectors, we can ensure the safe operation of DC charging stations. The energy flows are optimally controlled by our power modules in combination with our in-house charging controllers.”
Bidirectional charging turns the electric vehicle into a kind of hermaphrodite in the energy system that can take on two different roles: When charging, it is a consumer in the DC grid; when feeding into the grid, it takes on the function of a battery storage system – and helps to stabilize this grid.
Taking the edge off loads
But that alone is not enough: Tobias Lüke closes the charging station again and points to the inconspicuous white container next to the entrance area of the building. “A stable energy supply based on renewable energies also includes sufficiently large and reliable storage systems to compensate for fluctuations when there is no wind or a dark doldrums,” explains the direct current expert. “We can use these storage systems to balance out peak loads compared to the public supply network and save considerable operating costs.”
In highly dynamic processes such as industrial production with irregular electricity consumption, for example when large machines start up, it is precisely the peak loads (peaks) that make industrial electricity so expensive. It has been shown that these peak loads can be reduced by up to 80 percent in direct current applications thanks to peak shaving, i.e. the provision of battery power called up at short notice. Every controller in the company is happy about this.
What is unusual about this storage system is not only that it is directly integrated into the DC grid. Phoenix Contact is cooperating with Voltfang, a start-up that works with traction batteries from the e-mobility sector. Tobias Lüke opens the container: “Cold, wet, fast charging or deep discharging – second-life batteries or batteries from overproduction for e-mobility generally have higher load capacities than batteries specially developed for stationary applications. This advantage of high cycle stability is exploited here. Optimized operating strategies and intelligent energy management maximize their service life and ensure their long-term efficiency for stationary applications. In a climate-controlled container like this one, these batteries do not have to withstand severe temperature fluctuations or perform at extreme levels. We give them a long second life.”
Think, steer and control
The story of generation, storage and consumption in the DC grid is not complete without the control center. Tobias Lüke takes us into the technical catacombs of the building. Past clattering production machines, we descend through the stairwell into the basement. This is where the central nervous system of the direct current supply is located. In the long room without windows, it still smells of new construction. Control cabinet follows control cabinet. The eyes of the man in his late thirties begin to light up as he walks down the long row: “This is where the heart is, the low-voltage main distribution board for our 650 V DC grid.”
The control cabinets not only integrate the photovoltaic system, battery storage system and charging stations into the system. This is also where electricity from the public grid is fed in if required – or surpluses are returned. “Our power modules are ideal for setting up industrial DC grids. They can also be operated bidirectionally – i.e. in both directions,” explains Lüke, opening a control cabinet in which the modules are lined up like drawers. “Thanks to the modular design, control cabinets can be equipped very flexibly and the power can be scaled very easily as required.”
Copper efficiency and electricity savings
One turn and the control cabinet is open. Lots of red and white in cozy togetherness – plus and minus in the DC grid. Immediately noticeable: The cables and other components are significantly smaller than in conventional distribution boards – another advantage of this technology: “DC grids require less copper for power transmission. Up to 55 percent of this expensive raw material can be saved in this way,” says Lüke. This is also where the white and red strings from the PV system end up in the control center. They feed the so-called DC bus via DC/DC converters with a total output of 120 kW.
The direct current is distributed from the main low-voltage distribution board to the production area. Here, the lighting works directly with the energy from the DC microgrid. Two branches lead directly to the production machines. “In the DC grid, we can use the braking energy from robots and drives and feed it directly back into the system,” says Lüke, explaining the next important advantage of direct current. “Depending on the application, this recuperation alone can increase efficiency by up to 20 percent.” If there is still surplus energy in the DC grid despite all the consumers and storage units, the bidirectional AC/DC converters feed it back into the public AC grid in a grid-compliant manner.
It becomes tangible
The brand new ELR HDC circuit-breaker is used wherever DC loads need to be switched safely in buildings. It combines the five device functions of protection, switching, monitoring, precharging and network capability. DC energy meters record the energy currents in the entire network. To connect DC loads to each other in a pluggable manner, the All Electric Society Factory relies on the ArcZero DC connector. It enables arc-free plugging and unplugging under load.
The PLCnext Engineer software platform from Phoenix Contact takes care of load management and higher-level DC grid management and combines the individual areas into a holistic system. The controller also integrates data such as electricity costs on the electricity exchanges, weather forecasts and daily updated data from the measuring station on the roof into the building’s energy management.
Not just talking
The All Electric Society Factory in Blomberg already has a reputation in the industry that extends far beyond the country’s borders. Not just talking, but also implementing – direct current is already working here and now. The implementation is not yet complete: “This system is also expressly designed for experimental purposes and operational tests,” adds Tobias Lüke. Overall, the creators of this pilot project hope to make further savings and increase efficiency. Plans include the construction of a small wind power plant, an electrolyzer for hydrogen production and fuel cells, which in turn generate electricity from the stored hydrogen.
Phoenix Contact has been committed to researching and establishing DC technology for many years and is a founding member of the Open Direct Current Alliance (ODCA). When planning for the building began, there were only a few components and standards for the use of DC technology on the market. Grid operators had little experience with DC systems – and the search for suitable planners and installers proved difficult. Today, things are different, emphasizes Tobias Lüke: “With the available components, regulatory progress, increasing expertise and cooperation with competent partners, it is also worthwhile for other companies to take the plunge.”
It has become dark in Blomberg, we are at the end of the tour and Tobias Lüke closes the gate to what is probably one of the most innovative factory buildings ever. The future has long since begun. And the All Electric Society Factory wants to be a blueprint for it.
