TenneT to invest up to €5bn p.a. for the energy transition

31.07.2020

The Dutch-German transmission system operator (TSO) TenneT has just published its first-half 2020 report. Needless to say, the second quarter of 2020 was characterised by the corona pandemic and the extensive measures taken to ensure a safe and healthy working environment, but despite this, the TSO has made significant progress in developing the transmission grid onshore and offshore and in integrating growing amounts of renewable electricity. At the same time, TenneT has maintained a high level of supply security of 99.99% for 42m end consumers in Germany and the Netherlands.

As Europe’s first cross-border TSO, TenneT promotes the European market integration. The TSCNET shareholder increasingly benefits from its binational integrated approach to grid planning, management, and operation. Manon van Beek, TenneT’s CEO, comments: “Sharing best practices and lessons learned between our German and Dutch operations is paying off more and more in terms of an integrated approach to offshore and onshore grid expansion, better grid utilisation due to European innovations and cross-border energy system planning.”

TenneT currently operates 14 offshore grid connections, twelve in the German and two in the Dutch North Sea. The twelfth offshore grid connection in Germany, BorWin 3, was handed over to TenneT in the first half of 2020. In Dutch waters, the Borssele Alpha grid connection recently transmitted offshore wind power for the first time and the Borssele Beta grid connection has now been commissioned well ahead of schedule. While in the offshore sector experience from the German market is used for the Dutch, the situation is the other way round when it comes to underground cabling. Here, expertise from the Dutch Randstadt project is applied for the DC connections SuedLink and SuedOstLink. These two largest projects of TenneT, which are being entirely installed underground, will be essential for the transmission of wind energy from northern to southern Germany.

Such efforts require huge investments – facilitated by solid financial results: The underlying operating result (EBIT) increased to €414m in the first half of 2020. During the same period, investments in the German and Dutch high and extra-high voltage grids also increased by approximately 30% compared to the first half of 2019, but will do so much more in the future. TenneT expects a further rise in the annual investment volume to €4 to 5bn in the next years. Otto Jager, CFO of TenneT, explains: “We are going to connect growing amounts of renewable electricity to the grid while facilitating the development of a borderless European electricity market. In light of future equity funding needs, the ongoing talks with the German government about a possible equity participation, next to the Dutch State, are welcomed by TenneT.”

TenneT presents Half-year Report 2020 (picture: TenneT)

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Construction permit for Pradella-La Punt

13.07.2020

As the extra-high voltage line in the Swiss Engadine between Pradella and La Punt constitutes a bottleneck in the Swiss and pan-European transmission system, the Swiss transmission system operator (TSO) Swissgrid has long aimed to increase its transmission capacity to 2 x 380kV. This will improve import capacity and security of supply in the canton of Graubünden and facilitate the transport of Engadine hydropower. The project is part of the “Strategic Grid 2025”, Swissgrid’s ambitious modernisation and expansion plan.

The Swiss Federal Inspectorate for Heavy Current Installations (Eidgenössisches Starkstrominspektorat-ESTI) now has approved the reinforcement and new construction of pylons between Pradella and La Punt. Swissgrid has already refurbished the pylon foundations in the past two years, so that work can commence soon. Approximately 3500 tonnes of steel will be needed to upgrade the around 50-kilometre-long overhead line. The construction will be carried out in two sections and is expected to be completed by the end of 2022.

To reduce the overall environmental impact in the region, Swissgrid is supporting a local grid operator in replacing a 60kV overhead line with a 110kV underground cable. As a result, 1100 pylons will be disappearing from the landscape.

Swissgrid can start with the 2 x 380kV upgrade of the Pradella-La Punt line (picture: Swissgrid)

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Contracts for 525kV SuedLink cables

29.06.2020

SuedLink is evolving in major steps this year. The DC line – realised jointly by the two TSCNET shareholders TenneT, the Dutch-German transmission system operator (TSO), and TransnetBW, the TSO from southwest Germany – is the largest and probably most important single project of the energy transition in Germany. With around 700 kilometres of underground cable to be laid and an investment of around €10bn, SuedLink will connect the windy regions of northern Germany with the centres of consumption in the industrially highly developed south and west. In February 2020, the Federal Network Agency (Bundesnetzagentur) initiated the plan approval procedure for the first SuedLink sections, in May the orders for the regional planning offices were placed and now TenneT and TransnetBW have awarded the contracts for the plastic-insulated 525kV underground cables – in parallel with the ongoing approval procedures.

NKT and Prysmian PowerLink have eventually been selected as providers for the SuedLink cables, with a total order value of approximately €2bn. The contract comprises design, manufacture, supply, laying of the underground cables, further installation work, and the final high-voltage testing of the cable system. Both companies have demonstrated their expertise in numerous international connection projects on and offshore, and both have proven the quality of their cables in extensive prequalification tests with several cable manufacturers in a multi-year test phase. They were also commissioned for the German affiliate project, SuedostLink, by the two TSOs 50Hertz and TenneT.

TenneT and TransnetBW chose plastic-insulated underground DC cables with a voltage level of 525kV because they transmit more power compared to a 320kV solution and only require half as many cables. Less transmission loss and less civil engineering work translate into both, financial benefits for the TSOs and minimal environmental impact. TenneT Managing Director Tim Meyerjürgens comments: “In the future, SuedLink will form the backbone of the energy transition in Germany. With the commissioning of the DC ground cables, we are now moving from the planning stage to the realisation of this important power link.” Dr. Werner Götz, Chairman of the TransnetBW Executive Board, adds: “We are very happy to be able to apply this innovative and environmentally benign technology for SuedLink.”

TenneT and TransnetBW awarded the contracts for the 525kV DC underground cables for the SuedLink power highway (picture: TenneT)

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> See TenneT press release (html)
> See TenneT press release, in German (html)
> See TransnetBW press release (html)
> See TransnetBW press release, in German (html)

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ALEGrO: Civil engineering concluded

26.06.2020

The cable laying work for the “Aachen Liège Electricity Grid Overlay” (ALEGrO) started in October 2018. The DC interconnector with a transmission capacity of 1,000MW will be the first direct link between the Belgian and German electricity grids and is being implemented as a joint venture by TSCNET shareholder Amprion, one of the four German transmission system operators (TSOs), and the Belgian TSO Elia. The European Project of Common Interest (PCI) provides much needed grid capacities for cross-border electricity flows and at the same time strengthens supply security in the Aachen-Cologne region in Germany and in the Belgian Liège Province. The entire binational power bridge is being realised with underground cabling exclusively.

After twenty months of construction, Amprion now has concluded the civil engineering work on the 41-kilometre-long German section of ALEGrO between the substation in Niederzier and the border to Belgium. “We have reached an important milestone even ahead of schedule,” explains Rainer Millinghaus, Head of Cable Civil Engineering at Amprion. Most of the underground cables have already been drawn into the conduits and only in some sections this still needs to be done. The converter construction site in Niederzier is also making great strides. Here, the DC from the underground cable will be converted into AC to allow connection to the German grid.

The challenging project required different types of cable installation. About 75 percent of the line was built in conventional open construction. However, obstacles like roads or railway tracks were passed with trenchless embedding techniques like horizontal thrust boring or pipe jacking. Also, a modified flush drilling method was used for the first time, which will be beneficial for Amprion in further cable projects, too. Besides these technical aspects, the implementation of ALEGrO is also state-of-the-art in terms of environmental protection: Careful handling of the soil and its hydrologic balance is ensured until the entire installation is completed. An independent soil expert accompanies the construction and recultivation, and there is also an ecological supervision.

Amprion has finished the civil engineering works for the ALEGrO interconnector (picture of Rainer Millinghaus and Theo Heitkamp from ARGE Amprion ALEGrO Aachen welding the last sleeve joint of the conduit system: Amprion)

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Work begins on the final section of Nant de Drance

15.06.2020

The Nant de Drance pumped storage power plant in the Swiss canton of Valais is being commissioned successively in sections since 2019. The plant has a capacity of 900MW, making it one of the most powerful pumped storage plants in Europe – when it is fully operational in 2021, it will be able to generate close to 2.5bn KWh a year. TSCNET shareholder Swissgrid, the Swiss transmission system operator (TSO), is responsible for connecting the power plant to the extra-high voltage grid and for to transmitting the hydropower to the urban areas of Switzerland.

Swissgrid is implementing the 380kV connection in three sections, two of which were already commissioned at the end of November 2018: the 6.5km underground cable line connecting the Nant de Drance power plant to the Châtelard substation via the plant’s access tunnel, and the 12.5km overhead line between the Châtelard and La Bâtiaz substations. The last section – from La Bâtiaz to the connecting point to the Chamoson-Romanel overhead line in Le Verney – crosses the Rhône valley over a length of 1.3km. An underground variant for this section was finally approved in January 2020 by the Federal Inspectorate for Heavy Current Installations (“Eidgenössisches Starkstrominspektorat”, ESTI). It provides for a tunnel with a diameter of around 2.5m and a depth of 12 to 20m to be drilled between different groundwater levels. This is the second underground extra-high voltage line built by Swissgrid, but the first to extend at great depth for more than one kilometre.

Preparations for construction work on the two sites in Le Verney and La Bâtiaz have been underway since mid-May. Excavation of the shafts at Le Verney will commence in mid-June. In August, the mini tunnel boring machine will be installed on the main construction site in Le Verney. Tunnel driving will take about eight months and start in September 2020 at the same time as the excavation of the shafts in La Bâtiaz. After around two years of work, the third section is scheduled to be commissioned, until which time a provisional solution has been found: In 2019, the voltage of one of the two overhead lines La Bâtiaz – Le Rosel was increased to 380kV.

Swissgrid is starting construction of the final section of the connection of Nant de Drance to the national 380kV grid (picture: Nant de Drance SA)

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SuedLink: Regional planning offices take up work

10.06.2020

With around 700 kilometres of underground cables to be laid and around €10b to be invested, the SuedLink 525kV line is the largest and probably the most important individual project of the energy transition in Germany. By connecting the windy regions of northern Germany with the consumption centres in the industrially highly developed south and west, “power highways” such as SuedLink are indispensable for achieving Germany’s and Europe’s climate goals. SuedLink is realised jointly by the two TSCNET shareholders TenneT, the Dutch-German transmission system operator (TSO), and TransnetBW, the TSO from southwest Germany.

SuedLink has just taken the next big step: After the Federal Network Agency (Bundesnetzagentur) initiated the plan approval procedure for the first sections in February 2020, the two TSOs have now awarded the contracts for the regional planning offices, which are responsible for the detailed planning of the underground DC connection. These offices, some of which have already been involved in the previous SuedLink planning, take care of all operational tasks – initially in the context of the approval procedure, and later also in the supervision of construction. This includes, among other things, route mapping, construction logistics, environmental planning, and awarding of contracts for civil engineering work. On special topics such as soil investigations, they cooperate with local companies.

The overall project was divided into nine planning sections for the award of contracts. After an extensive bidding competition, a total of four companies were awarded the contract for the three northern sections under the responsibility of TenneT and the six southern sections under the responsibility of TransnetBW. TenneT Managing Director Tim Meyerjürgens explains: “The offices are now preparing the detailed planning for the routing and are taking a very close look at the conditions on site.” This will help the TSOs to accurately develop appropriate routing proposals. Dr. Werner Götz, Chairman of the TransnetBW Executive Board, adds that, due to their local presence, the offices can optimally consider the regional conditions for the detailed planning. “They are intended to discuss the proposals together with the project developers in a close dialogue with the owners and land managers concerned and to review their advice when preparing the approval documents.”

TenneT and TransnetBW awarded the contracts for regional planning offices for the SuedLink power highway (picture: TenneT)

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Foundation laid for DolWin6 converter

28.05.2020

With a dozen operating offshore connection systems for wind farms in the German North Sea totalling a transmission capacity of 7.132GW, the Dutch-German transmission system operator (TSO) TenneT has already in 2019 exceeded the German government’s expansion target for offshore wind energy capacity for 2020 by more than half a million GW. A further 900MW will be provided by DolWin6, like the predecessor projects DolWin3 and BorWin3 a high-voltage direct current (HVDC) connection. The DolWin kappa offshore platform in the Wadden Sea near the island of Norderney will convert the three-phase wind current into DC for transmission via a 45 kilometre submarine cable to the East Frisian mainland and from the landing point via an underground cable, also around 45 kilometres long, to the TenneT site in Emden/East.

Here, the TSCNET shareholder is constructing the DolWin6 onshore converter station and a substation on 23,500m² to reconvert the DC into three-phase current for feeding into the onshore extra-high voltage grid. A significant milestone for DolWin6 was reached on 27 May: The laying of the foundation at the converter construction site was celebrated in Emden/East by embedding a time capsule with coins, a regional daily newspaper, and construction plans into the foundation stone. Due to the Covid-19 pandemic, the event was only celebrated with the most important project managers from TenneT and the plant constructor Siemens.

Concrete preparations for DolWin6 began in the summer of 2017 and 2018 with horizontal drilling on Norderney. In September 2019, the foundation work commenced in Emden/East. Work on the DolWin kappa offshore platform at a dockyard in Cádiz/Andalusia also started in mid-2019 and the DolWin6 cable laying will follow from summer this year. The completion of the HVDC offshore connection is scheduled for 2023.

TenneT celebrated the laying of the foundation stone for the DolWin6 converter in Emden/East (picture: TenneT)

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380kV line Beznau-Birr commissioned ahead of schedule

25.05.2020

The upgrading of the existing 220kV line between Beznau in the canton of Aargau and Mettlen in the canton of Lucerne to 380kV is a key component of the “Strategic Grid 2025“, the national expansion plan for the transmission infrastructure of the Swiss transmission system operator (TSO) Swissgrid. The voltage increase ensures energy distribution and supply security in the Zurich metropolitan area, Central Switzerland, and the Swiss Central Plateau. The TSCNET shareholder has now put the first section between Beznau and Birr in Aargau into operation, one year earlier than planned.

This stretch was partly installed underground, namely across the so-called Gäbihübel near Bözberg/Riniken about halfway between Beznau and Birr. The cable laying at the Gäbihübel is the first time that part of an extra-high voltage line in Switzerland has been implemented using underground cables. Twelve cables with a weight of 30 tonnes each were installed in the conduit blocks in the summer of 2019. This was followed by the completion of the overhead line section. To connect overhead lines and underground cables, special structures were erected at both ends of the approximately 1.3-kilometre-long underground section. After a construction period of around two years, the Swissgrid control centre connected the new 380kV line to the transmission grid on 19 May 2020. The reasons for the early completion were Swissgrid’s successful project and implementation planning as well as the rather warm and dry weather.

Swissgrid is providing scientific support for the construction, commissioning, and further operation of the underground cable. Investigations are carried out, for example, on the thermal behaviour of the cable conductors depending on the current load, the temperature variation in the soil above the conduit block and in the surroundings, and the biodiversity in the soil. In May, work began on dismantling the old 220kV overhead line and restoration of the pylon sites to their original condition. The deconstruction work is expected to last until the end of 2020.

Swissgrid has put into operation the 380kV line Beznau-Birr, the first Swiss extra-high voltage line partially laid underground (picture: Swissgrid)

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Amprion invests €1bn in 525kV cables for A-Nord

12.05.2020

The DC transmission line A-Nord represents the northern part of Corridor A, which is one of the main axes of the German energy transition. The 300-kilometre line from the port city of Emden at the Dollart Bay to Osterath in the Lower Rhine region is being implemented by TSCNET shareholder Amprion, one of the four German transmission system operators (TSOs). With a capacity of 2GW, A-Nord will transport wind power from the North Sea to the centres of consumption in the Rhineland and Ruhr district. The southern part of Corridor A is the Ultranet line, which is being implemented jointly by Amprion and further TSCNET shareholder TransnetBW.

Like other large-scale German DC interconnection projects that are essential to the country’s low-carbon energy future, A-Nord will be realised via underground cabling. The transmission capacity of 2GW will be achieved by 525kV cables whose efficiency significantly reduces the environmental impact but requires a special insulation material and highly competent suppliers. After extensive technical tests, Amprion has now contracted the underground cables for A-Nord. The specialist companies Prysmian Powerlink and Sumitomo Electric Industries are each supplying one cable system for A-Nord. The manufacturers will produce the systems concurrently with the construction of the line, scheduled to start in 2023.

Dr Hans-Jürgen Brick, CEO of Amprion, comments in view of the challenges to achieve a sustainable energy future: “It is essential that the grid expansion continues to progress swiftly.” Dr Klaus Kleinekorte, the TSO’s CTO, adds: “With this assignment, Amprion once again demonstrates that we are a driving force for innovative developments.”

Amprion has awarded contracts for the 525kV underground cables for the A-Nord power highway (picture: Amprion / Lutz Kampert)

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525kV cables for SuedOstLink

05.05.2020

The SuedOstLink is one of the major German DC interconnection projects that are essential to Germany’s low-carbon energy future by transporting green electricity generated in the north and east of the country – mainly wind power – to the centres of consumption in the south and west. Like the other so-called “Stromautobahnen” (power highways), SuedOstLink is primarily implemented via underground cabling. Its realisation is a joint effort of the two TSCNET shareholders 50Hertz, the transmission system operator (TSO) from northeast Germany, and TenneT, the Dutch-German TSO.

The European Project of Common Interest (PCI) now has reached an important landmark with the award of the contract for around 1000 kilometres of underground cables, the definitive centrepiece of SuedOstLink. The technology to be used for this is a global novelty: plastic-insulated underground cables for a voltage of 525kV. With these cables, the SuedOstLink connection will have a transmission capacity of 2GW. The higher capacity requires fewer cables to transmit the same power. The routing can therefore be designed narrower and the necessary civil engineering work is decreased. This significantly reduces the impact on the public and the environment.

The contracts were assigned to NKT for the northern part of the project in the 50Hertz control area and to Prysmian PowerLink for the section under TenneT’s responsibility. Both companies are internationally represented in numerous connection projects on- and offshore and both have proven the quality of their cables in extensive prequalification tests. The contracts include design, manufacture, delivery, laying of the underground cables, further installation work and the final high-voltage testing of the cable system. SuedOstLink is currently in the planning approval process. It should be completed by the end of 2025.

Dr Frank Golletz, Technical Director at 50Hertz, expects the cables to be laid from 2022 and describes the contract award as “a good signal for the SuedOstLink joint venture project as well as for the energy transition across Germany and Europe”. Tim Meyerjürgens, Managing Director of TenneT, adds: “We will use the innovative, plastic-insulated 525kV underground cables for the first time worldwide and will thus set new standards in technology and the reduction of environmental impact.”

50Hertz and TenneT have assigned the orders for the 525kV underground cables for SuedOstLink (picture: NKT)

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