525kV technology for Germany’s “power highways”

04.12.2019

SuedLink, SuedOstLink and A-Nord are large-scale DC connection projects that are essential for Germany’s low-carbon energy future, since these so-called “Stromautobahnen” (power highways) will transport green electricity generated in the north and east of the country to the consumption centres in the south and west. The three power lines will be implemented predominantly via underground cabling and are collaborative efforts of the four German transmission system operators (TSOs). TenneT and TransnetBW cooperate on SuedLink, 50Hertz and TenneT join forces on SuedOstLink and A-Nord is carried out by Amprion. Together with Ultranet, a joint project with TransnetBW, A-Nord forms the Korridor A.

The four TSCNET shareholders intend to install innovative plastic-insulated DC cables with a voltage level of 525kV in these projects. So far, 320kV cables have been used for comparable DC connections in Germany. As a matter of fact, it will be the first use of 525kV underground cables worldwide, which underlines the pilot character of the three high-performance connections. The decision by the TSOs was preceded by an extensive test phase on the technical suitability of the 525kV cables. The pre-qualification tests according to international standards of the Council on Large Electric Systems (CIGRE) were successful and proved that the 525kV cables are reliable and safe.

A higher voltage level of the cables translates into more transmission capacity. This has two possible effects for the planned DC lines, assuming technical feasibility for the entire system: On the one hand, more electricity can be transmitted in a certain corridor with the same number of cables. On the other hand, fewer cables are required to transmit the same power compared to 320kV cable systems. This allows the routing to be designed narrower, which reduces excavation work and environmental impact.

The four German TSOs opt for innovative 525kV solution for power highways with underground cabling (picture: TenneT)

Linkup
> See 50Hertz press release, in German (html)
> See Amprion press release, in German (html)
> See TransnetBW press release, in German (html)

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Swift progress for new 50Hertz overhead line

29.11.2019

This May, TSCNET shareholder 50Hertz, one of the four German transmission system operators (TSOs), started the construction of the first section of the 380kV Perleberg-Wolmirstedt overhead line. The new line will connect the Perleberg substation in Brandenburg with the Wolmirstedt substation in Saxony-Anhalt over a distance of 106km and replace the existing 220kV line from the 1950s. This grid extension is intended to ensure that the increasing quantities of regionally generated electricity from renewable sources are also available to consumers in southern and western Germany.

The first construction phase with 87 pylons and a length of 37km stretches between the substations Stendal West and Wolmirstedt. Construction work is progressing rapidly. More than half of the pylons have now been erected and some masts have already been fitted with power cables. Construction should be completed by mid-March next year.

50Hertz has already erected 48 pylons of the Perleberg-Wolmirstedt overhead line (picture of the substation Wolmirstedt: Otto-von-Guericke-Universität Magdeburg)

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> See 50Hertz press release, in German (html)

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ENTSO-E’s MAF 2019 is out now

23.11.2019

The European Network of Transmission System Operators for Electricity (ENTSO-E) has released the new 2019 edition of the Midterm Adequacy Forecast (MAF). In this context, “adequacy” refers to the balance between electricity generation and demand and the forecast is based on a comprehensive mathematical analysis of future pan-European supply security over the period up to 2021 and 2025. The MAF examines not only the interdependencies of supply and demand, but also of storage, climatic conditions, and interconnection capacity. This year, the data granularity and quality were further improved, in particular, with information on thermal generation, an improved hydrological database and a new calculation methodology for demand time series.

The results of MAF 2019 show a low risk for adequacy. However, the MAF also underlines the increasingly important role of cross-border cooperation between transmission system operators (TSOs) in promoting adequacy throughout the interconnected pan-European electricity system. As in the previous issue, MAF 2019 includes a low carbon scenario that considers the impact of the decommissioning of coal-fired plants by 2025. Here the results for some market areas directly or indirectly affected show increased risks. Sources of flexibility such as demand side patterns, storage, interconnections and enhanced and smarter integration of renewable and distributed energy sources are thus required.

The MAF is part of the broader 10-year Network Development Plan (TYNDP), which assesses system needs up to 2040. The results of MAF 2019 will be open to public consultation until 13 January 2020. In addition, ENTSO-E will organise a public webinar on 4 December to discuss the MAF results.

ENTSO-E has released the MAF 2019 (picture: ENTSO-E)

Linkup
> See ENTSO-E press release (html)
> Visit MAF 2019 website with access to appendices and data sets (html)
> Open executive summary of MAF 2019 (pdf, 1.29MB)
> Access to public consultation (html)
> Register for the webinar (html)

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Kick-off for new Weinviertel Line

19.11.2019

The Weinviertel Line (“Weinviertelleitung”) in Lower Austria is in operation for more than 70 years. An elementary component of the grid of TSCNET shareholder APG, the Austrian transmission system operator (TSO), the 220kV line is now in considerable need of rehabilitation. Apart from that, the routing of the existing line does not meet the requirements of the future energy system characterised by decentralised generation of the renewables. The Weinviertel Line reconstruction is therefore essential for the implementation of the Austrian energy and climate strategy “#mission2030”, which sets the national goal of covering 100% of electricity consumption with renewable energies by 2030.

The new 380kV Weinviertel Line will run from Seyring near Vienna to the substation in Neusiedl an der Zaya in the north-eastern Weinviertel. Here in Neusiedl, the ground-breaking ceremony for the new construction has now taken place. To the benefit of the environment and local residents, the new Weinviertel line requires 53 pylons less than the old one. “This is because we can dismantle the first eleven kilometres of the old line without replacement, as we will connect the new line with an existing line and feed it in there,” explained Gerhard Christiner and Thomas Karall, CTO and CFO of APG respectively. The investment costs for the new line amount to 200m euros.

Christiane Teschl-Hofmeister, a member of the Lower Austrian state government who attended the ceremony, commented: “With the new APG Weinviertel Line, Lower Austria will have an efficient and future-oriented grid connection for renewable energies from the region. The APG Weinviertel Line thus makes an important contribution to the Lower Austrian Climate and Energy Roadmap 2030.”

APG has started construction of the new Weinviertel Line (picture: APG; from left to right: Franz Mittermayer from Austrian energy company EVN, Thomas Karall, Christiane Teschl-Hofmeister and Gerhard Christiner)

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> See APG press release, in German (html)

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First pylon of new East Bavarian Ring erected

16.11.2019

The Ostbayernring (East Bavarian Ring) is an existing power line operated by the Dutch-German transmission system operator (TSO) TenneT, that stretches about 185km from the Upper Franconian town of Redwitz via Mechlenreuth and Etzenricht to Schwandorf in the Upper Palatinate. After the shutdown of Northeast Bavarian nuclear and conventional power plants, the Ostbayernring primarily transports renewable energies. On several days of the year, more energy is generated by wind turbines and photovoltaic plants in the regions along the East Bavarian Ring than is needed locally. Due to the resulting increase in the amount of renewable energy fed into the grid, the East Bavarian Ring regularly reaches its capacity limits.

To ensure the security of supply and the reliability of the grid and to prevent grid failures for the entire region of Upper Franconia and Upper Palatinate, the transmission capacities of the East Bavarian Ring need to be significantly improved. A replacement construction for the East Bavarian Ring was therefore included in the German Federal Requirements Plan and the urgency of the project for the energy market was legally determined. The new line is being constructed along the existing route, extending the current 380/220kV systems to two 380kV systems.

In the course of the construction of the new East Bavarian Ring and the related grid reinforcement, the Redwitz, Mechlenreuth, Etzenricht and Schwandorf substations of the TSCNET shareholder are also being upgraded. Now the first pylon of the new Ostbayerring has been erected on the site of the Etzenricht substation. TenneT has captured the construction on film in order to give a well-founded impression of the erection process.

The first pylon of the new East Bavarian Ring of TenneT has been erected (picture: TenneT / screenshot taken from TenneT-video “TenneT Ostbayernring: Der Projektleiter stellt sich vor”, YouTube)

Linkup
> See TenneT tweet, in German (html)
> Watch video of the pylon construction (YouTube)

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GIS with Clean Air technology for Daxlanden

14.11.2019

In present-day gas-insulated high-voltage systems, sulfur hexafluoride (SF6) is commonly used as insulating gas. It has excellent electrical and chemical properties, but also a strong greenhouse effect. For reasons of climate protection, TransnetBW, one of the four German transmission system operators (TSOs), focuses on eco-efficient technical concepts. In November last year, the TSCNET shareholder launched a pilot project at its substation in Obermooweiler, northeast of Lake Constance, with the world’s first gas-insulated switchgear (GIS) at extra-high voltage level using a climate-friendly alternative gas technology.

TransnetBW has now commissioned the new construction of the switchgear for the 380kV substation in Daxlanden near Karlsruhe, where the existing open-air facility will be replaced by two new GIS. Here, the TSO has opted for the so-called Clean Air technology, which exclusively uses processed air as an insulating medium instead of SF6. This significantly reduces the greenhouse effect of the entire switchgear system. The new GIS facilities will be built and commissioned gradually over the next few years and the existing open-air installation will be dismantled during ongoing operation.

The Daxlanden substation is an important network node in TransnetBW’s transmission grid and the central link between two grid construction projects from the German national Grid Development Plan for electricity (NEP), which contains essential grid extension projects to realise the energy transition. “A successful energy transition requires an efficient and future-proof transmission grid,” explains Dr. Werner Götz, Chairman of the TransnetBW Executive Board. “The more we are pleased to be able to make an additional contribution to the environment and climate protection by using the innovative Clean Air technology in Daxlanden.”

TransnetBW will build two GIS with Clean Air technology in the substation Daxlanden (computer simulation of the reconstructed Daxlanden substation: TransnetBW)

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> See TransnetBW press release, in German (html)

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PROMOTioN for a North Sea transmission grid

08.11.2019

“PROgress on Meshed HVDC Offshore Transmission Networks” is a very precise project description but also a bit lengthy. In contrast, the dynamic acronym “PROMOTioN” refers quite well to the ambitions that the consortium members contribute to the research project. General goal of PROMOTioN is the further development of innovative technologies relevant for the deployment of meshed offshore HVDC nets. The more specific objective is to improve cooperation between grid operators and major suppliers of technical architecture and interoperable technologies to accelerate offshore HVDC grid development. PROMOTioN is the largest energy project funded under the EU Horizon 2020 programme, with a consortium of 33 partners from 11 countries, including the two TSCNET shareholders Energinet, the Danish transmission system operator (TSO), and TenneT, the Dutch-German TSO.

A report by PROMOTioN has just been published (“Regulatory and financing principles for a meshed HVDC offshore grid”) summarising the principal findings for the design of a legal, regulatory and financial framework for cross-border HVDC offshore connections. The report provides recommendations for policy-makers and other stakeholders for overcoming regulatory and financial obstacles to the realisation of a North Sea transmission system. The key conclusion of the report and of the whole project is that the North Sea riparian states need to establish a harmonised legal and economic framework to fully exploit the potential of a meshed offshore grid in the North Sea.

A distinction is made between short-term and long-term recommendations, each of which is presented very concisely. Short term recommendations include the improvement of governance and regulation of the internal market for (offshore) electricity, optimisation of innovation financing, support for early communication of all parties involved and the formalisation of cross-border cost allocation (CBCA) as a binding contract. The latter aspect is regarded as one of the most important pillars in the economic framework. The most significant long-term recommendation is that EU member states, third countries and the EU should consider adopting a North Sea Treaty containing the objectives and principles of the offshore grid.

Tim Meyerjürgens, COO at TenneT, comments on the PROMOTioN project: “The development of a cross-border HVDC grid is one of the most promising opportunities for a sustainable energy future in Europe. TenneT is cooperating closely with other TSOs to develop the idea of a meshed and efficient offshore grid in the North Sea, which requires the creation of a common regulatory framework. PROMOTioN’s research shows the way to make this happen.”

The PROMOTioN project provides a framework for cross-border HVDC offshore connections (picture: TenneT)

Linkup
> See TenneT press release (html)
> Visit PROMOTioN website (html)
> Open PROMOTioN report (pdf, 2MB)

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TenneT quadruples capacity across the Elbe

29.10.2019

A new Elbe crossing between the German federal states of Schleswig-Holstein and Lower Saxony for the transport of green electricity from North to South Germany has been completed. Tim Meyerjürgens, COO of the Dutch-German transmission system operator (TSO) TenneT, together with the State Secretaries Andreas Feicht and Enak Ferlemann, the Energy Ministers Olaf Lies (Lower Saxony) and Jan Philipp Albrecht (Schleswig-Holstein), has commissioned the new power line between the substations Hamburg/Nord (near Norderstedt/Schleswig-Holstein) and Dollern (Lower Saxony).

The new 380kV line of the TSCNET shareholder consists of four sections and is a replacement of existing lines with predominantly lower voltage levels to meet the requirements of the energy transition. A total of 110 masts were built or modified and 37 temporary masts were erected on several sections of the line. Almost all of them have now been dismantled. The installation of new conductor ropes at “Elbe Crossing 2” which has the highest pylons in Europe with a height of 227 meters, was also part of this demanding grid expansion project.

Tim Meyerjürgens explained on the occasion of the commissioning: “The extension of the 45-kilometre-long power line is an important component of the energy transition. This also includes the optimisation of the ‘Elbe Crossing 2’, the main artery in the three-phase transmission grid between Schleswig-Holstein and Lower Saxony, which serves as a bridge between the two largest wind power states in Germany.” With these reconstruction measures, Tennet has quadrupled the available capacity for the transmission of wind power in this area to 9.6 GW. The transit capacity between Denmark and Germany will also be increased, which is why the new connection is of central importance not only for the energy transition in Germany, but also at European level.

Picture: TenneT

TenneT has put new power line across the Elbe into operation (picture: TenneT; from left to right: TenneT COO Tim Meyerjürgens; Olaf Lies, Lower Saxony Minister for the Environment, Energy, Construction and Climate Protection; Jan Philipp Albrecht, Schleswig-Holstein Minister of Energy, Agriculture, the Environment, Nature and Digitalisation; Parliamentary State Secretary Enak Ferlemann; Andreas Feicht, State Secretary at the Federal Ministry for Economic Affairs and Energy)

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> See TenneT press release, in German (html)

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Construction start of DolWin 6 converter station

24.10.2019

The so-called DolWin wind farm cluster in the southwestern part of the German Bight is an important component of Germany’s future regenerative energy supply. TSCNET shareholder TenneT, the Dutch-German transmission system operator (TSO), is responsible for transferring the DolWin energy ashore. The DolWin1 and 2 onshore connections are in operation since 2015 and 2016 respectively, and DolWin 3 is ready for feed-in since September 2018. The other ongoing projects, DolWin 5 and 6, are also making good progress.

DolWin6 is a 900MW DC connection with a length of 90km. The associated offshore platform to convert the three-phase current generated by the wind farms into DC is DolWin kappa. Half of the 90km distance is covered by submarine cables and the other half by underground cables to transport the electricity from the landing site in Hilgenriedersiel to the TenneT facilities in Emden in the Lower Saxony region of East Frisia.

On the grounds of the Emden/Ost substation, the TSO is building a converter station and a transformer station to convert the DC back into three-phase current and feed it into the onshore grid. The first construction phase of the DolWin6 onshore converter station has now begun with the foundation work. In the next 6 months, 1000 piles with a length of up to 24 meters will be drilled into the ground to create a stable foundation for the station.

TenneT begins construction of the DolWin6 onshore converter station (pictures: TenneT)

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> See TenneT Tweet, in German (html)

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€215m for green connection capacity

11.10.2019

The Dutch-German transmission system operator (TSO) TenneT plans to invest a further €215m to connect two GW of green electricity from solar and wind farms in the north of the Netherlands to the grid. The infrastructural measures include the construction of two new 380/110kV high-voltage substations in the provinces of Groningen and Drenthe. In addition, the TSCNET shareholder intends to provide extra capacity at nine existing 110kV substations in the northern Netherlands.

One GW corresponds roughly to the output of 3.5 million solar modules or 200 wind turbines. The additional capacity planned by the TSO is therefore considerable, but according to Ben Voorhorst, COO of the TSO, as many solar and wind farm transmission requests as possible should be complied with. Already now TenneT operates projects in the northern Netherlands with a volume of more than €1bn. This level of investment is now being further increased, with the TSO focusing strongly on the sustainability and efficiency of the investments. “The better the capacity expansions of electricity grids are actually utilised, the better the consumer’s money is spent,” explains Voorhorst.

TenneT invests €215m in the connection of renewable energies in the northern Netherlands (picture: TenneT)

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> See TenneT press release (html)

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