TransnetBW starts modernisation of Daxlanden substation

04.11.2020

The Daxlanden substation near Karlsruhe is an important node in the transmission grid of TransnetBW, the German transmission system operator (TSO) from the federal state of Baden-Württemberg. It is also the central link between two 380kV grid reinforcement projects included in the German National Grid Development Plan for Electricity. To prepare the substation for its future tasks, the TSCNET shareholder began with the upgrade and expansion of Daxlanden at the beginning of November.

The preparatory works will be completed in spring 2021, after which the TSO will start to replace the existing 380kV outdoor switchgear with two new gas insulated switchgears (GIS). For the Daxlanden GIS facilities, the TransnetBW has opted for the so-called Clean Air technology, which exclusively uses processed air as an insulating medium instead of sulfur hexafluoride (SF6). The greenhouse effect of the switchgear is thus radically reduced. Alongside this, the 220kV line between the Daxlanden and Eichstetten substations will be substituted by a 380kV line. The first switchgear is scheduled to be commissioned in 2024 and the second in 2027. The entire installation and grid connections are expected to be completed in 2030.

TransnetBW has commenced the modernisation of the Daxlanden substation (computer simulation of the future Daxlanden substation: TransnetBW)

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Middle Axis increases capacity sevenfold

27.10.2020

Since the 60s of the 20th century, a 220kV overhead line has been in operation between Hamburg and Denmark, thus crossing Schleswig-Holstein, the northernmost of the German federal states, in its entirety. Schleswig-Holstein is a true “wind power state” in terms of generation, but consumes very little energy in comparison to the southern and western German states. The green electricity produced here therefore has to be transmitted to the centres of consumption. As a result of the energy transition with increasing shares of wind energy, the capacity of the old line has long since been insufficient, resulting in grid bottlenecks. The Dutch-German transmission system operator (TSO) TenneT, whose control area includes the state between the North and the Baltic Sea, thus has replaced the old line with a new 380kV line capable of transmitting seven times as much green electricity.

The new overhead line is called Middle Axis (“Mittelachse”), as it is flanked by two other line projects of the TSCNET shareholder, the East-Coast-Line and the West-Coast-Line. On the Danish side of the border, the Danish TSCNET customer Energinet continues the Middle Axis from Frøslev to the Kassø substation, thereby increasing the electricity trading capacity between Denmark and Germany. On 21 October, TenneT put officially into operation the two northern sections of the Middle Axis between the Audorf substation near Rendsburg and the border with Denmark. With a symbolic push of a button at the substation Handewitt near Flensburg, Thomas Bareiß, Parliamentary State Secretary at the German Federal Ministry for Economic Affairs and Energy, Jan Philipp Albrecht, Minister of Energy, Agriculture, the Environment, Nature and Digitalisation of Schleswig-Holstein, Henrik Riis, CEO of Energinet-Eltransmission, and TenneT COO Tim Meyerjürgens connected the new 82 kilometres long power line to the grid.

The southern section of the Middle Axis from Hamburg/North to Audorf with a length of 70 kilometres was commissioned by TenneT in early 2018. Since 2015, a total of 388 new pylons have been erected along 152 kilometres between Hamburg/North and the border with Denmark, including the required substations Audorf/South, Schuby/West and Handewitt. The extension of the line by Energinet across the border by 30 kilometres into the Danish grid area increases security of supply for both the German and Danish electricity markets and enables the exchange of renewable energy between the two countries.

Tim Meyerjürgens explained: “With the 82 kilometres from Audorf to the Danish border, we are completing the important Middle Axis in the energy transition region of Schleswig-Holstein for the transmission of electricity from renewable sources between the river Elbe and Denmark.” Henrik Riis added: “The Middle Axis is a tremendous success, and it provides a new, continuous electricity highway that runs all the way from Denmark to Hamburg and on to Lower Saxony across the river Elbe. A strong cross-border infrastructure and well-functioning energy markets are essential for all of us – both at national and European level – to shape a future with high security of supply, large amounts of renewable energy and an efficient green energy transition.”

TenneT and Energinet commissioned the northern section of the Middle Axis, a new 380kV line from Denmark to Hamburg (picture showing from right to left Thomas Bareiß, Henrik Riis, Tim Meyerjürgens and Philipp Albrecht at the far left: TenneT)

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Wilhelmshaven-Conneforde line put in operation

05.10.2020

With the Wilhelmshaven-Conneforde line, the Dutch-German transmission system operator (TSO) TenneT has commissioned an important grid expansion project for the German and European energy transition. The 380kV line from the new substation Fedderwarden near Wilhelmshaven on the German North Sea coast to the Conneforde substation in Ammerland, both in the federal state of Lower Saxony, is not only crucial for the transmission of mainly wind power and electricity from regional generators, but also for strengthening security of supply in northern Lower Saxony. Furthermore, it represents a novelty for the TSCNET shareholder in terms of technical implementation: “With this new line, we have put into operation the first pilot project with two underground cable sections in three-phase technology and connected it to the meshed power grid in Germany,” explained Tim Meyerjürgens, COO of TenneT.

The commissioning ceremony on 2 October 2020 in Fedderwarden was attended by representatives from politics, including Andreas Feicht, State Secretary at the German Federal Ministry for Economic Affairs, and Energy and Olaf Lies, Minister for the Environment, Energy, Construction, and Climate Protection of Lower Saxony. The new line is only about 30 kilometres long, but – together with the new construction of the Fedderwarden substation – “of great importance for the entire European electricity trade”, commented Olaf Lies. The Minister was impressed by TenneT’s latest milestone in the energy transition. State Secretary Feicht referred to the newly gained potential for integrating large amounts of wind power into the German electricity market and the technical relevance of the pilot project: “Knowledge obtained in such pilot projects about the construction and operation of the technology will be of great benefit for further power grid expansion in the future.”

The line project was successfully completed after less than two years of construction. Almost 5 kilometres of the line were implemented as underground cables. However, even if TenneT can be satisfied with what has been accomplished so far and is strongly committed to expanding the transmission of green electricity throughout its entire grid area, Meyerjürgens sees a need for further action, especially in view of the increasing offshore wind volumes: “Still, we already see today a further demand for expansion in the Wilhelmshaven and Friesland region.”

TenneT commissioned the new Wilhelmshaven-Conneforde line (picture: TenneT)

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Tunnel drilling for last section of the Nant de Drance connection

03.10.2020

The Nant de Drance pumped storage power plant in the Swiss canton of Valais is one of the most powerful power plants of its kind in Europe, generating around 2.5bn kWh per year, when it goes fully operational in 2021. The plant has been commissioned successively in sections in recent years. TSCNET shareholder Swissgrid, the Swiss transmission system operator (TSO), is responsible for connecting the power plant to the extra-high voltage grid and for transmitting the hydropower to urban areas in Switzerland. Two of the three sections of the extra-high voltage link to Nant de Drance – an underground cable of 6.5 kilometres between the power station and the Châtelard substation via the access tunnel of the plant and an overhead line of 12.5 kilometres between the Châtelard and La Bâtiaz substations – have been in operation since the end of November 2018.

Tunnel boring has now begun for the third and final section between the substations of La Bâtiaz and Le Verney, which belongs to the municipality of Martigny. The mini tunnel boring machine, weighing around 60 tonnes, was traditionally given a female name on 2 October 2020 at the construction site in Le Verney and will in future be known as Giorgia. Shortly after its christening, it was lowered into the shaft, where it will take around eight months to dig and secure the tunnel between the substations. The tunnel will have a diameter of 2.5m and is dug 12 to 20m deep into the ground. Giorgia is controlled entirely from the control centre at the construction site in Le Verney.

Construction of the underground cable link commenced in June 2020 with the excavation of the shaft at Le Verney and will take two years. The shaft at La Bâtiaz will be dug at the same time as tunnelling work. The finishing work in the tunnel will follow from summer 2021, after which the gantry to connect the Nant de Drance link to the 380kV Chamoson-Romanel overhead line in Le Verney will be built. Finally, the cables will be laid in the tunnel. Commissioning of the 1.2km long underground line is scheduled for 2022. Nant de Drance is already now connected to the transmission grid even before the last section of the link is commissioned: An interim solution was introduced in 2019 by increasing the voltage of one of the two overhead lines between La Bâtiaz and Le Rosel to 380kV.

Swissgrid has started tunnel drilling for the final section of the connection of Nant de Drance to the national 380kV grid (picture: Swissgrid)

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TenneT commissions North German grid node

02.10.2020

The town of Wilster is located about 10 kilometres north of the Elbe river in the German federal state of Schleswig-Holstein, which falls within the control area of the Dutch-German transmission system operator (TSO) Tennet. Schleswig-Holstein is of eminent importance for the generation of wind power. In Wilster, after a four-year construction period, the TSCNET shareholder commissioned the renewed Wilster/West substation on 1 October, a significant grid node for the energy transition in the north and beyond. This is because the so-called Westküstenleitung (West-Coast-Line), the NordLink interconnector, which directly links the electricity markets of Germany and Norway, are converging here – and later also the SuedLink “electricity highway” for the transmission of green electricity to the German consumption centres.

For the two high-voltage direct current (HVDC) transmission projects NordLink and SuedLink, the capacity of the former Wilster/West substation was no longer sufficient. An extension of the switchgear was necessary to exclude impermissible load flows and guarantee the short-circuit resistance required in future. Thus, a new 380kV switchgear was built on the ground of the former 380kV substation and the new construction now replaces the old substation on the same site. Furthermore, the connection facilities for the converter stations of SuedLink and NordLink had to be provided. And finally, a 110kV switchgear was installed, which enables the dismantling of the 220kV switchgear in the near substation Itzehoe-West.

“This substation is a central hub for electricity transmission from north to south,” explains TenneT’s COO Tim Meyerjürgens. “Here, electricity from renewable sources is fed into the grid and distributed to regions with high consumption. The Wilster area is of outstanding importance for the energy transition. Because in the grid area between Wilster, Brokdorf, Itzehoe, and Brunsbüttel, three new extra-high voltage lines from TenneT converge: the Westküstenleitung, NordLink, and later also SuedLink.”

TenneT has put into operation the new substation Wilster/West (picture: TenneT)

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€30m for secure electricity supply in East Tyrol

28.09.2020

Since autumn 2016, the Austrian transmission system operator (TSO) APG has been gradually renewing the 220kV switchgear at the Lienz substation in the eastern part of the Austrian state of Tyrol. The substation in Nußdorf-Debant near the medieval town of Lienz is of particular importance for the region’s electricity supply, as it is the only feed-in point from APG’s 380/220kV high-voltage grid for the whole of East Tyrol. For this reason, the TSCNET shareholder is pursuing an extensive investment programme of €30m for the substation to improve the electricity supply in East Tyrol and to enhance the integration of green electricity into the Austrian transmission grid.

The upgrade project also includes a new 380/220kV transformer. Due to its dimensions, it was transported by rail in three individual parts of 167 tonnes each from the Styrian Siemens plant in Weiz via an individual siding directly to the substation. Now the last part has arrived in Lienz and has been placed on its foundation. The total weight of the finished system is 816 tonnes. The state-of-the-art device will be operational from June 2021 and APG expects the upgrade of the entire substation to be completed in autumn 2022.

The Lienz transformer is of supra-regional relevance as it increases system security in all of Austria and also facilitates the country-wide use of climate-friendly wind energy. This is because the transformer strengthens the connection between the pumped storage power plants in the west of the country and the wind turbines in the east. With its investments, APG thus supports the national goal of covering 100% of the electricity consumption in Austria with green electricity by 2030. Company spokesperson Christoph Schuh comments: “All APG grid expansion, modernisation and maintenance projects are crucial for reaching Austria’s climate targets and indispensable cornerstones for guaranteeing the republic’s security of supply.”

APG is investing €30m in the upgrade of the Lienz substation in East Tyrol (picture: Michael Stabentheiner / APG)

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Foundation stone laid for ULTRANET substation

17.09.2020

On the site of the former Philippsburg nuclear power plant, which was shut down completely on 31 December 2019, a new DC substation for the German supra-regional “power highway” ULTRANET is being constructed. The Philippsburg substation in the German state of Baden-Württemberg represents the southern end point of ULTRANET, where the high-voltage direct current (HVDC) line will be connected to the regional 380kV AC grid. The new substation is thus to become one of the most important energy hubs in Germany’s future energy landscape. It is being built on behalf of TSCNET shareholder TransnetBW, the transmission system operator (TSO) from Baden-Württemberg. In its entirety, ULTRANET is a joint project of TransnetBW and further German TSCNET shareholder Amprion. It will transmit wind energy generated in the northwest of Germany to the industrially highly developed southwest. On the other hand, the Philippsburg substation will enable the conversion of AC to DC, e.g. to transport excess photovoltaic electricity from the south to the north.

In March 2020, the construction of the ULTRANET substation was approved by the competent authority and in May, the demolition of the two cooling towers of the former power plant created the necessary construction space of around 100,000m². Now, the ceremonial laying of the foundation stone took place in Phillipsburg in the presence of high-ranking representatives from politics, business, and society – and in strict compliance with the Corona regulations. Dr. Werner Götz, Chairman of the TransnetBW Executive Board, commented: “It was nevertheless very important to us not to let this important day pass without expressing our thanks to politicians, partners, and the project team.”

Andreas Feicht, State Secretary at the German Federal Ministry for Economic Affairs and Energy, recognised the progress of the European Project of Common Interest (PCI): “The converter in Philippsburg illustrates that the grid expansion is progressing in large steps.” Franz Untersteller, Minister of the Environment, Climate Protection, and the Energy Sector of Baden-Württemberg, emphasised the specific nature of the location and its symbolic value: “There are few places where the energy transition can be visualised in such a condensed form as here in Philippsburg. After the two cooling towers were detonated in May of this year, the old world made way for the new.”

TransnetBW has celebrated the laying of the foundation stone for the ULTRANET substation in Philippsburg (picture: TransnetBW)

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Power outage in July in Valais cleared up

09.09.2020

As in many European countries, the Swiss transmission grid already today – at the beginning of the energy transition – has structural bottlenecks. Here, as elsewhere, these must be eliminated to increase security of supply and maintain it in the long term. Tense grid situations may pose problems to the connected system, as the Swiss transmission system operator (TSO) Swissgrid experienced on 17 July 2020, when the protection equipment of the 220kV grid node Creux de Chippis was accidentally tripped, which in the further course of events led to supply interruptions in the Valais distribution grid. The TSCNET shareholder immediately initiated extensive investigations into the event, the results of which have now been transparently communicated.

An extremely complex chain of technical and human factors is behind the Chippis incident. First the technical aspects: The transmission grid capacities in the region around Chippis are insufficient in summer due to the high generation of Alpine hydroelectric power plants. Because of this, Swissgrid for some time now had to completely disconnect the transmission grid in the Mörel substation in east-west direction for around 15 weeks a year to guarantee grid security and transmission capacities in the region. This reduces fault tolerance in the regional transmission system. In addition, several extension projects are currently being implemented in the Chippis area, which made adjustments to the operation of the Chippis substation necessary. These settings – also affecting the protection settings of the system – were carried out by the contracted service provider in December 2019.

As regards the human factor in the chain of events, necessary and scheduled tests of protection parameters were performed by a contracted specialised company in the Chippis substation on 17 July. During these tests, the system was not put into revision mode, which is why the system protection function unintentionally detected the test signal. This triggered the so-called busbar protection. The switchgear in the Chippis substation was subsequently disconnected and, due to the special grid situation, the switchgears in Stalden, Bitsch, Zermeiggern, and Mörel were also affected by the voltage loss, leading to a regional supply interruption in the distribution system.

The result of this combination of occurrences was a power failure in 60 municipalities in the district of Sierre and in most of the Upper Valais. After one hour, all affected switchgear and Swissgrid lines were back in regular operation. Thanks to the good cooperation between Swissgrid and the concerned distribution system operators (DSOs) of the lower voltage levels, electricity supply was gradually resumed and after less than two hours, almost all customers were back on power. Adrian Häsler, Head of Grid Infrastructure at Swissgrid, classifies she supply disruption in Valais as “an extremely rare occurrence”, but nevertheless apologises to those affected. And though the tests themselves were not negligent, the findings from the incident are incorporated into the company’s training and education of internal and external experts. Häsler also emphasises that Swissgrid drew attention to the bottlenecks in Valais some time ago: “Incidentally, we recognised these grid congestion problems in the context of ‘Strategic Grid 2025’, the TSO’s ambitious grid modernisation and extension plan, and addressed them in 2015. The grid expansion as planned by Swissgrid is essential to maintain the long-term security of supply.”

Swissgrid is investigating the voltage loss in the switchgear of the Chippis substation in Valais on 17 July (picture: Swissgrid)

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TenneT commisions “green” substation

04.09.2020

In recent years, the seaport of Eemshaven in the province of Groningen in the north of the Netherlands has become more and more important for the Dutch energy transition. Eemshaven has taken on the role of an energy port: with power plants, sustainable generation, connections to offshore wind farms, and submarine cable interconnectors to Norway and Denmark. The Dutch-German transmission system operator (TSO) TenneT – together with regional distribution system operator (DSO) Enexis Netbeheer – now has commissioned the new high-voltage substation Eemshaven as the first substation entirely built for the suply of wind and solar energy.

The station was built as part of the grid reinforcement for the growing amount of sustainably generated energy in the north of the Netherlands which requires an increase in transmission capacity. Other measures of the TSCNET shareholder include a 380kV connection between the Eemshaven (Oudeschip) high-voltage substation and Vierverlaten near Groningen as well as the extension of the Vierverlaten substation. This new 380kV “power highway” will replace the existing 220kV line. Until it is put into operation – scheduled for 2023 – TenneT will commission a provisional 380kV substation in Eemshaven (Oostpolder) in October 2020.

TenneT has put into operation the new substation Eemshaven for the supply of green electricity (picture: TenneT)

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More power for the digital hub Frankfurt Rhine-Main

24.08.2020

The world’s largest and best-known data centres are mostly situated in the United States, but compared to its size, Germany is a significant IT location as well. And no other German location is as important for the Internet as the Hessian metropolis of Frankfurt. Germany’s digital hub is one of the largest Internet nodes in the world, resulting in enormous energy requirements that are constantly rising. Consequently, the government of the federal state of Hesse wants to increase the locally available electricity capacity by around 50% within seven years, which poses considerable challenges for the Dutch-German transmission system operator (TSO) TenneT, whose control area includes Hesse.

Together with the two regional distribution system operators (DSOs) Avacon and Mainova, the TSCNET shareholder will thus expand transmission lines and substations at the major feed-in points. The grid operators will jointly invest around €750m in a sustainable energy supply for the economic and financial centre that is the Rhine-Main metropolitan region. Tim Meyerjürgens, COO of TenneT, comments on the ambitious plans: “By expanding and modernising the electricity infrastructure in the Rhine-Main area, we are securing the electricity supply and laying the foundation for the further sustainable development of this central economic and financial hub in Germany and Europe.”

Together with two regional DSOs, TenneT is investing €750m in grid expansion measures in the Frankfurt Rhine-Main region (picture: TenneT; from left to right: Marten Bunnemann, CEO Avacon; Tarek Al-Wazir, Hessian Minister of Economics, Energy, Transport and Housing; Dr. Constantin Alsheimer, CEO Mainova; Tim Meyerjürgens)

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