SF6-free technology from Berlin

By Ingo Petz

“Such revolutions in energy technology only happen every 50 years,” says Stephan Jorra  as he strides toward the training center where customers learn how to operate their new switchgear. His steps echo in the hall – the plant here in northwest Berlin is immense and practically breathes history. For more than a century, the site has been a fountainhead of innovation in the development and manufacturing of equipment that helps supply the world with electricity.

Jorra, the General Manager at the Siemens Energy Switchgear Plant Berlin, knows the site like the back of his hand. When he speaks, interviewing the Switchgear Plant Berlin’s history with visions of the future, you can tell how committed he is to the tradition. “It’s clear,” he says, “without all the pioneering work here that’s gone into developing high-voltage facilities for over a century, we wouldn’t be able to drive this next epoch-making change.” 

Since 2016, Jorra has been working at Siemens Energy on the development and manufacturing of high-voltage products to advance the energy transition, making energy supplies not only greener, but also more decentralized and intelligent. That progress matters more than ever with the EU set on making Europe climate neutral by 2050.

“Fifty years ago, SF₆ breakers and switchgear were a game changer,” says Jorra. But the artificial gas sulfur hexafluoride, abbreviated SF₆, which does have excellent insulation and extinguishing properties, also has the highest global warming potential of all greenhouse gases – about 25,000 times more harmful than CO₂.

“Now we use Clean Air, a mixture of 20 percent oxygen and 80 percent nitrogen,” he says. “It doesn’t get any cleaner, more environmentally friendly or less toxic.”

Mark Kuschel, Principal Key Expert at the Siemens Energy Switchgear Plant Berlin, stands in front of a block of blue aluminum – an innovative new switchgear that will play a decisive role in shaping the future: the Blue GIS (gas-insulated switchgear), part of the company’s Blue portfolio of circuit breakers, switchgear and voltage transformers that are free of SF₆, F-mix gases and any greenhouse gas. The Blue GIS is currently available for 72.5-kilovolt and 145-kilovolt voltage levels.

Kuschel points to the heart of the GIS where vacuum technology is used to switch short circuits. “Vacuum switches have high mechanical reliability,” he explains. “Compared to SF₆ switchgear, they have a longer electrical life, allowing for more frequent switching. And there are no decomposition products toxic for people or the environment.”

Because Clean Air systems have a lower dielectric strength than SF₆ (causing arcs to form at lower field strengths), some critics complain that the systems need more space to guarantee the same insulation properties. More space means more resources and in turn would have a negative impact on the product’s carbon footprint.

But Kuschel counters, “Look, it simply doesn’t make sense to connect a wind farm that produces green energy with climate-damaging F-gas.” Clean Air, he explains, has no chemical fluorine and is completely nontoxic and harmless. “The little extra material needed for production is absolutely overcompensated for by replacing SF₆ with Clean Air. And compared to some fluorine gas-based solutions, the carbon footprint is positive.” 

Of course, it’s one thing to develop eco-friendly technology to create more sustainable power grids. But it’s equally important to develop and manufacture these products in an environmentally conscious way. Which is why the Switchgear Plant Berlin has already been using an entirely green energy supply since 2018.

Now the company is focused on further innovations to make the plant and the equipment greener, safer and more energy efficient in both their operations and their production, with the goal of becoming climate neutral by 2030.

“This is just one example of where our ideas on climate protection, high-class innovation and efficiency meet,” says Jorra, taking a step to the right and then pointing to what looks like an orange ring. This is the low-power instrument transformer (LPIT) that’s used to measure current and voltage within the GIS, and it differs radically from conventional instrument transformers. 

This LPIT delivers increased performance data, and its smaller dimensions allow for a reduction in weight, making it possible to embed it in cast-resin bushings installed directly into the switchgear. “The LPIT saves 1,500 kilograms of weight per panel,” says Jorra, “a significant reduction in material and a positive impact on our environmental balance.”

High-tech solutions like this are possible because the Berlin plant has its own expertise in casting resin and production. With an ultramodern and largely automated production, high-quality parts can be manufactured economically, even though cast resin production is highly energy intensive.

But thanks to new manufacturing technologies and an energy management system, Siemens Energy has already succeeded in making production much more energy efficient. For example, energy consumption for the cast resin plant alone has been reduced by 7 percent a year over the last years, which amounts to a savings of 200 tons of CO₂.

Kuschel continues on to the testing and inspection areas of the switchgear plant, where all new devices are tested and certified for their switching reliability and safety. In a high hall, where capacitors and coils are stacked meters high, he’s met by Lars Klingbeil, the switchgear plant’s Head of Accredited Test and Research Laboratories at Siemens Energy.

Klingbeil, with also nearly 20 years at Siemens Energy, is in charge of the testing facility  – one of the largest in the world. “Here, we develop and independently type test all our products, which is a highly important success factor of our location in Berlin,” he explains.

“We briefly generate the voltage that occurs when a circuit breaker has successfully switched off after a short circuit.” Thorough testing is a complex process that requires huge amounts of energy. “The demand on a switchgear is very high and rightly so. When there are short circuits in the grid, we’re dealing with huge amounts of energy that our switchgear have to manage – and that’s exactly what we’re proving here.”

This applies to the Blue GIS and all forthcoming products. “We’re developing completely new switchgear for various high-voltage levels, and it’s a major advantage to be able to accompany and safeguard the development and manufacturing process on-site with the necessary tests and certifications.”

Currently, for voltages above 145 kilovolts, only passive switchgear is available, but in the coming years, the portfolio of Blue products will be expanded to include 245-, 420- and 550-kilovolt voltage levels. With Clean Air products Siemens Energy is setting the standard for sustainability and has the leading market position on alternative products for SF₆; more than 1,900 Blue units have already been ordered, and more than 700 units are already in operation, including a showcase project at the Port of Bergen, Norway. 

Kuschel is certain that demand will rapidly increase. “Building the kind of complex new plants that we’re equipping has years of lead time. When planning them, customers are seeking forward-looking, climate-neutral technologies free of greenhouse gases. And with continuous innovations we’re making sure that our products remain competitive.  We’re already receiving inquiries from Asia and North America. It’s clear that Clean Air products will decisively shape the coming decades.”

According to the upcoming amendment to the European F-Gases Regulation and Chemicals Strategy, F-gases that are harmful to climate and health are to be cut back and eventually banned altogether in the future. Clear regulatory measures like this, Kuschel emphasizes, provide planning security for users and manufacturers alike.

Unsurprisingly, the vast grounds of the historic switchgear factory are being streamlined with new buildings and renovations, with new ideas and reimagining – all with an eye to the future. “It was clear that our production would continue to stay in Berlin,” says Jorra emphatically. The short distances between development, testing and production, and the experience and proximity to universities are crucial to driving highly complex product and process innovations. He looks over to the historic testing hall. “We’re doing this with the knowledge gained from history and a drive to shape a sustainable energy supply for the future. From Berlin for the world.”

February, 2022

Author and journalist Ingo Petz lives in Berlin, where he has written for some of the most prestigious publications in the German-speaking world, including the Frankfurter Allgemeine Zeitung and Der Standard.

Combined picture and video credits: Stefan Hobmaier