In addition to expanding renewable energy generation, a successful energy transition requires stable system operation at all times. To achieve this, renewable energies and storage power plants will have to take on extensive system services and essential grid-forming properties in the future.

In the “GFM Benchmark” project, Fraunhofer ISE developed a test procedure for grid-forming inverters on behalf of the four German transmission system operators and applied it to devices from various manufacturers. On the one hand, the project provided a comprehensive overview of the market readiness of grid-forming inverters.

On the other hand, the project results provide an important practical check for new national and European testing standards.

The fully integrated grid components with grid-forming properties planned by the transmission system operators will not be able to fully meet the demand for grid-forming power. Therefore, customer systems must also contribute to stabilizing the power grid: They should behave in a grid-forming manner, i.e., contribute to providing a grid voltage with stable amplitude and frequency.

But what exactly does that mean? In recent years, many scientific studies and publications have been produced on this topic, and some countries have grid operator documents that describe grid-forming behavior. However, there is no uniform standardization or definition, which leaves room for interpretation.

Therefore, in the first step of the project, the Fraunhofer ISE team worked with the grid operators 50Hertz Transmission GmbH, Transnet BW GmbH, Amprion GmbH, and Tennet TSO GmbH to develop a measurement and evaluation procedure for the stabilizing properties of inverters, incorporating findings from both grid operation and research.

Major differences in grid-forming behavior

“We wanted to see what manufacturers understand by grid formation and how they implement this in the programming of their devices,” explains department head Dr. Sönke Rogalla from Fraunhofer ISE. “So we invited them to put their devices to the test in our laboratory.”

Seven companies responded to the call and had their storage inverters, which cover a power range from a few kilowatts to five megawatts, measured according to the new test procedure. They came from different countries and were at different technology readiness levels, from pilot to prototype to series production.

The researchers used the tests to investigate the differences between the devices in terms of grid formation by exposing them to various operating conditions in the laboratory. In addition to normal operation, critical grid situations such as rapid frequency changes, short circuits, and phase jumps were simulated.

“The devices exhibited similar behavior under clearly defined requirements. In other cases, however, there were major differences, and we were able to provide the manufacturers with suggestions for optimization for almost every device,” explains project manager Roland Singer from Fraunhofer ISE. The willingness and commitment of manufacturers to advance the development of grid-forming inverters is high.

Proven verification methods are essential for market launch

At the same time, the project provided relevant practical experience in testing grid-forming inverters and optimized the test procedures. Important findings were incorporated into the ongoing standardization work at the European level even during the project phase. The Fraunhofer ISE team contributed its expertise to the creation of the VDE FNN note “Grid-forming properties.”

The recently published document describes the requirements and verification procedures for grid-forming units. It forms the normative basis for participation in the future market for instantaneous reserve, which will start at the beginning of 2026 and represents an additional interesting remuneration path, especially for battery storage systems.

With its experience in the “GFM Benchmark” project, the team at Fraunhofer ISE is ideally positioned to support manufacturers and users of grid-forming units with certification measurements in accordance with the FNN note. Standardization work at the European level is also progressing. ENTSO-E, the network of European transmission system operators, is working on an implementation guide with comprehensive grid-forming requirements, which should facilitate the transition to national regulations.

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Fraunhofer ISE

Some 15 people have died after the Gloria funicular railway car in Lisbon, Portugal, derailed and crashed on Wednesday local time.

Emergency services have also confirmed that more than 18 people were also injured, five of them seriously, in the tragedy, which occurred at the start of the evening rush hour.

It follows another accident on the same line in May 2018, when one of the cars derailed due to flaws in the maintenance of its wheels. No one was killed in that incident.

The exact cause of the most recent accident is not yet known. Witnesses have reported that the yellow-and-white tram appeared out of control as it sped downhill, before derailing as it rounded a bend and crashing into a building. Photos of the aftermath show a crumpled heap of cables and steel.

These cable car–like transport systems are rare relics of the 19th century, found in only a few very hilly places around the world. So how do they work? And why are they still in use?

How do funicular railways work?

Trains and trams typically only work on flat terrain. That’s because their steel wheels can’t get enough traction on steel rails on steep hills. As a workaround, railroad engineers often build tunnels through steep mountainsides.

Funicular railways, however, can go up very steep hills.

They usually feature two counterbalanced cars that are attached via a haulage cable.

As one car descends, it helps pull the ascending car up the hillside. The weight of the ascending car also prevents the descending one from careening out of control. Some now have electric motors to help power them and some are able to engage a one-way mechanical drive just for steep hills.

Even though funicular systems are typically quite slow and clunky, they are still popular with both tourists and residents in the places where they’re found.

Where are they found?

The Gloria funicular railway line in Lisbon opened in 1885. One of three funicular lines in Lisbon, it connects the city’s downtown area with the Bairro Alto (Upper Quarter).

But there are other examples of these transport relics around the world.

Switzerland has several funicular railways. The most notable is the Stoosbahn—the steepest funicular in the world. It covers a total ascent of around 744 meters, reaching a gradient of 47 degrees. It is a very popular tourist trip.

In Hong Kong, the Peak Tram is a funicular railway that has operated since 1888 and takes people to near the top of Hong Kong Island.

Last year, there was also some discussion about installing a new funicular railway system in the Blue Mountains in New South Wales, Australia, that would travel 14 meters every second.

The rise of trackless trams

Funicular railways still serve a purpose for people living in—or visiting—steep areas where they’re found. However, newer technology means more conventional forms of rail transport are now far less limited in traveling up and down hills.

For example, trackless trams are kind of a combination between a tram and a bus. They use GPS and digital sensors to move precisely along an invisible track and have rubber wheels, enabling them to ascend gradients of up to 15%. However, these have not yet been built for steeper hills.

I have enjoyed riding such funicular trams in a range of hilly cities, but this crash is likely to take the shine off the tourist experience. It’s about time we had a 21st-century option that is clearly safer.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Kristianne Egbert has worked in occupational ergonomics for nearly 20 years and is now a senior corporate ergonomist at Briotix Health, a workplace injury prevention company. Perhaps unsurprisingly, Egbert also says that repeated use of a laptop alone on a desk is going to have a huge effect on your overall posture.

Egbert referred to what’s known as the 20-degree rule. If you’re holding your neck at an angle of 20 degrees or more, you’re officially crossing the risk threshold. “You’re probably bending over because you’re leaning forward to see that screen and be able to reach the keyboard,” she says.

Sitting back farther in your chair might seem like a fix to the problem temporarily, but in reality, bending beyond 20 degrees isn’t the real issue. Most people aren’t comfortable holding that position for long periods of time, which means it’s what else your body does to compensate that’s problematic.

“Nobody really wants to bend their head that much more than 20 degrees,” Egbert says. “So, when you don’t want to bend your neck forward, then the rest of your body is going to try and accommodate.”

You might tilt your whole back forward to avoid that extreme neck posture to type on the keyboard and see the screen of your laptop. That’s where bad posture habits really form. It’s not that you need to just suck it up and have better posture. You need to change the way you’re working, not necessarily your discipline.

“The other thing that ends up happening when your back starts getting tired is you’re like, ‘OK, well, I’m gonna scoot back a little bit to keep my back a little straighter,’” she says, demonstrating the position over the Zoom call. “But then, my arms are going to come out a little bit more, and I’m anchoring my wrist down while I’m typing.” This position can cause all sorts of other problems.

It’s even worse for shorter people, who are often working from chairs that aren’t tall enough. Egbert often recommends putting the laptop down on the lap, so that your arms can be down “where they belong.” You can tilt the laptop screen and look down at it, cutting the risk of leaning forward too much.

What to Do Instead

Hansker Productivity Mouse

Photograph: Henri Robbins

Fortunately, there are some simple (and even affordable!) solutions to this ergonomic disaster. Both experts I interviewed indicated that your office chair is a good place to start for better posture and office ergonomics. (We have an excellent guide that can help.)