Grid stability with three quarters renewables

04.02.2020

Keeping the mid-frequency of the grid stable at 50Hz is one of the core tasks of the transmission system operators (TSOs). In cooperation with the Regional Security Coordinators (RSCs), they operate the grid securely and keep it free of congestion. These tasks are becoming increasingly demanding due to the rising share of volatile renewable energies in the grid. Among the renewables, wind energy in quantitative terms plays the decisive role in Germany, and last weekend it was particularly windy – from the German coasts to the Alps – which led to a winter feed-in record for renewables: According to figures based on TSO data and provided by the renowned Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE), on 1 February 2020 renewable energies accounted for 74.8% of net public electricity generation in Germany. Together, the four German TSOs 50Hertz, Amprion, TenneT, and TransnetBW and TSCNET Services mastered the situation very well: The grid was stable at all times.

Fraunhofer ISE continuously publishes German generation and other energy data on the Institute’s Energy Charts website. Theoretically, renewable energies can by now only fully cover power generation in Germany on spring holidays such as Easter or at spring weekends, when power consumption is low and photovoltaics make a larger contribution to generation. The fact that on a winter’s day at the beginning of February renewable energies can already cover almost three-quarters of electricity generation is a good sign that the energy transition in Germany is on track – and the German TSOs and TSCNET Services play an important role in this.

Despite record wind energy feed-in in Germany, there were no problems with grid stability (picture: Karsten Würth)

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RSC future perspectives: integrate, cooperate, and digitise

31.01.2020

The annual conference “Future Power Grids” (“Zukünftige Stromnetze”) brings together key players from the German energy sector with a focus on power grids to facilitate a prolific exchange between politics, research and industry. This was once again the case this year when, under the auspices of the German Federal Ministry for Economic Affairs and Energy, energy experts met in the German capital of Berlin on 29 and 30 January. “Future Power Grids 2020” was technically chaired by Christian Schorn, Head of Asset Management and Operations at TSCNET shareholder TransnetBW, the transmission system operator (TSO) from the southwest of Germany.

Among the representatives of research institutions, ministries, authorities, NGOs and energy companies were Thomas Dederichs, head of energy policy at TSCNET shareholder and German TSO Amprion, and Maik Neubauer, one of the two managing directors of the Munich-based regional security coordinator (RSC) TSCNET Services. Mr. Dederichs spoke about the role of transmission grids in the further development of market design, while Mr. Neubauer, under the heading “The European Perspective – Integration of Renewables and Grid Security”, gave an overview of the history, services, tasks and challenges of European RSCs in general and TSCNET services in particular.

New Challenges for transmission infrastructures
Neubauer depicted the highly meshed European power transmission grid as one of the most complex critical infrastructures in the world and the function of the RSCs as an early warning system for the European TSOs to identify potential risks in the system. RSCs assess these risks continuously and in a coordinated manner and counteract potential congestions and power failures. The establishment of the RSCs was a reaction of the European Commission (EC) to a Europe-wide power outage in 2006 with under- and over-frequencies, which affected around 15 million people across Europe.

The increase in volatile renewable energies in the system further intensifies the need for the work of the RSCs. However, the tasks of the RSCs based on the third and fourth EC Clean Energy Package – e.g. security and risk analysis, capacity calculation, short term adequacy forecasts and longer-term outage planning coordination – depend on intensive cooperation between the European RSCs. The continuous collaboration of almost all European TSOs is essential, and the interests of the energy market and system security needs to be continuously balanced. In the long term, only the digitisation will be able to manage the increasing complexity of the grid. Neubauer points out the growing integration of OT (Operations technology) and IT (Information technology) layers and explicitly referred to the importance of artificial intelligence for congestions analysis and future network control and security.

Maik Neubauer presented RSC insights and future perspectives at the “Future Power Grids 2020” conference in Berlin (picture: Stefan Widua)

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> Visit conference website (html)

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TransnetBW promotes weather-dependent line operation

20.01.2020

The energy transition requires the transport of increased amounts of electricity and thus more efficient grid usage. TransnetBW, the transmission system operator (TSO) from the southwest of Germany, intends to take greater account of the fact that overhead lines have different maximum loads depending on the weather conditions. On a cool, windy day, for instance, considerably more electricity can be transported than on a hot, windless day. To make optimum use of this effect, the TSCNET shareholder is currently implementing a system that provides the necessary detailed information about the specific line capacity for improved network management.

The project, which the TSO is carrying out together with Energy & Meteo Systems GmbH, a provider of power predictions and virtual power plants, is called “Witterungsabhängiger Freileitungsbetrieb 3.0” (weather-dependent overhead line operation 3.0 – WAFB 3.0). Together, significant locations for the real-time monitoring of overhead lines in the TransnetBW control area were defined and weather stations and sensors are now being installed at 250 pylons and 48 substations to detect the weather-dependent transmission capacity of the respective lines. This will give TransnetBW much more accurate data on the utilisation of the grid to better avoid bottlenecks.

Alexander Hofmann, WAFB 3.0 project manager at TransnetBW, explains the approach: “Up to now, we have only considered the temperature at regional level for our grid operation. With WAFB 3.0, we record not only the temperature but also the wind on a small scale, which opens up much more options for our daily grid operation. Initially, the system helps us to check the forecast values used and to adjust them if necessary. From 2023 on, it will determine for each line individually and in real time which transmission capacities will be available when required.”

TransnetBW collects and utilises data on the weather-dependent transmission capacity of overhead lines (picture: analogicus)

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TransnetBW’s grid booster confirmed

22.12.2019

Power generation in Germany is changing rapidly in the course of the energy transition and increasingly large amounts of renewable electricity must be transmitted from the north and east to the south and west. If the generated electricity exceeds line capacities, the four German transmission system operators (TSOs) have to perform costly redispatch measures. The grid infrastructure clearly needs expansion, for which the four German transmission system operators (TSOs) have conceived the “Network Development Plan (NDP) 2030”, the 2019 version of which was published this spring. To minimise the need for grid extension and cut redispatch costs, the NDP includes innovations that could result from technological progress in the coming years. In addition to Power-to-X and monitoring systems, prototypes of so-called grid boosters are also considered.

TSCNET shareholder TransnetBW, the TSO from the southwest of Germany, plans a grid booster pilot at the Kupferzell substation near Schwäbisch-Hall in the German federal state of Baden-Württemberg. The concept includes a fast power source in the shape of a large battery at the end of a line section that is subject to frequent strain and overload, which applies to the Kupferzell grid node. The grid booster that is envisaged, one of three in the NDP, will have an output of 250MW. The booster battery can supply energy within a few seconds. In periods of high grid load, the booster is intended to relieve the system in case of disturbances until the bottleneck can be eliminated in a targeted manner by the system management.

The Federal Network Agency (Bundesnetzagentur), the competent authority, has now approved the booster plans of TransnetBW. With this confirmation by the agency, the project can enter the procedure for inclusion in the Federal Requirements Plan, the government list of essential projects for the sustainable energy future of Germany. TransnetBW considers the grid booster to be a great opportunity to design and operate the grid infrastructure efficiently in the long term and is investing a high multi-digit million-euro amount in this environmentally friendly storage technology.

The Federal Network Agency confirms the plans of TransnetBW for a grid booster at the Kupferzell grid node (illustration using a picture of TransnetBW)

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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)

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> 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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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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Central project management and office for SuedLink

24.09.2019

The SuedLink extra-high voltage line is not only the most important individual project of the energy transition in Germany, but also the largest underground cable project in the world: Around 700 kilometers of cable will be laid and around ten billion euros invested. By connecting the windy regions of northern Germany with the consumption centres in the industrially highly developed south, “power highways” such as SuedLink are indispensable for achieving Germany’s and Europe’s climate goals. SuedLink is implemented jointly by the two TSCNET shareholders TenneT, the Dutch-German transmission system operator (TSO), and TransnetBW, the TSO from southwest Germany.

In order to efficiently advance the further approval procedure and the subsequent construction of SuedLink, the two TSOs have commissioned the international technical service company Jacobs as central service provider. The aim is to coordinate and control the various tasks such as planning, approval, obtaining easements and construction under one roof. This makes SuedLink the first major project in Germany in which an external central service provider is involved. TenneT Managing Director Tim Meyerjürgens explains why the two partners decided on a model that has proven itself many times in such large-scale projects on the international market: “The schedule for implementation is challenging. At the same time, the expectations of politics and the public continue to rise. For this very reason, controlling and coordination play such an important role.”

The commissioning of Jacobs is accompanied by the opening of the central SüdLink office in Würzburg, Lower Franconia. Together with the central service provider, TransnetBW and TenneT will initially create 130 jobs there, the number of which will rise to 250 in the course of the project. To better incorporate regional knowledge into the planning process, further decentralised project offices are to follow along the route. Dr. Werner Götz, Chairman of the TransnetBW Executive Board, comments on the development: “By commissioning a central service provider and setting up a joint project facility in Würzburg, we have laid the foundations for the successful implementation of this major project.” The staff in Würzburg will include engineers, archaeologists, landscape planners, biologists, geologists, and project managers, all joining forces for Europe’s energy future.

TenneT and TransnetBW commission a central service provider for the implementation of SuedLink (picture: TenneT / Katja Schubert)

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> See TenneT press release, in German (html)
> See TransnetBW press release, in German (html)
> See TransnetBW press release on the office opening, in German (html)

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Reconstruction start at TransnetBW substation

18.09.2019

On September 18, TSCNET shareholder TransnetBW, one of the four German transmission system operators (TSOs), started the conversion of its substation in Schwörstadt with a symbolic cut of the spade. The construction site is located in the furthest southwest of the German federal state of Baden-Württemberg near the Swiss border. The upgrade provides the technical basis for connecting the substation to the 380kV extra-high voltage grid.

Dr. Werner Götz, Chairman of the TransnetBW Executive Board, referred at the groundbreaking ceremony to the steadily increasing share of renewables in the electricity mix, which confronts TSOs with maintaining voltage at a stable level despite the changing wind and weather conditions. “We are preparing the substation for the requirements of the energy transition and thus are also strengthening supply security in the Upper Rhine region.”

The reconstruction of the substation’s switchgear will be carried out in two stages, starting with the dismantling of the operations building and the switch panels of the existing 220kV switchgear. By 2021, the new 380kV switchgear will have been installed. The new device will initially be operated at 220kV before being connected to the 380kV grid in 2023. This implies that at the same time and section by section, the corresponding power lines will also be upgraded to 380kV.

TransnetBW starts conversion of the Schwörstadt substation (picture: TransnetBW; from left to right: Olaf Jungnitsch of GE Grid; Uli Glich, Project Manager Substations at TransnetBW; Christine Trautwein-Domschat, Mayor of Schwörstadt; Dr. Werner Götz, Chairman of the TransnetBW Executive Board; Thorsten Schwarz, Managing Director GE Grid; Bernd Jauch, Head of Technology, Projects and Portfolio Management at TransnetBW)

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TransnetBW order for “bnBm” gas power plant

20.08.2019

TSCNET Services shareholder TransnetBW, one of the four German transmission system operators (TSOs), has awarded Energie Baden-Württemberg AG (EnBW) the contract for the provision of a “special network equipment” (“besonderes netztechnisches Betriebsmittel”, bnBm). EnBW will construct and operate a gas turbine power plant with a capacity of 300MW at Marbach. The city is the birthplace of the poet Friedrich Schiller and is located about 20 kilometres north of Stuttgart on the Neckar River.

The special network equipment will not be available to the market, but will be used from 1 October 2022 as a “safety buffer” exclusively at the request of TransnetBW to ensure safety and reliability in the transmission grid. It thus serves as a further reserve for the safety and reliability of the electricity supply system.

“Behind us lies a demanding tendering procedure, because we had to procure a completely new product,” says Dr. Rainer Pflaum, Managing Director of TransnetBW. It was about access to a capacity that “helps to stabilise the power grid flexibly and reliably”. The new plant would be an important component for supply security in the region.

Together with the TSOs Amprion and TenneT, TransnetBW issued a call for tenders for the special grid technology equipment with a total volume of 1,200MW open to technology and Europe-wide at the end of June 2018. Altogether, the tenders cover four regions in southern Germany, each with a capacity of 300MW.

TransnetBW placed an order for the provision of a gas turbine power plant with a capacity of 300MW (picture: EnBW)

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TSO conditions for reserve capacity approved

05.08.2019

The four German transmission system operators (TSOs), the TSCNET shareholders 50Hertz, Amprion, TransnetBW and Tennet, the Dutch-German TSO, ensure the supply of electricity under all circumstances and thus hold reserve capacities as ultima ratio for unforeseeable and exceptional extreme situations on the electricity market. The reserve capacity is calculated at 2GW and the facilities to provide the capacity are determined every two years by the TSOs through a tendering procedure.

Last week, the Bundesnetzagentur (German Federal Network Agency) approved the new standard conditions for the reserve capacity which had been drafted by the TSOs. The standard conditions are the basis of the contractual relationship between the respective TSO and the operator providing the capacity. They are designed to be as transparent as possible and include, among other things, rules on the availability and use of the reserve system, remuneration or contractual penalties.

Due to the standard conditions, the potential participants in the tender procedure know the terms under which the reserve facilities must be operated and the legal consequences in case of failure of a plant. Now that the conditions have been approved, the tender for the first performance period can start as planned on 1 September 2019.

The German Federal Network Agency approved the TSO standard conditions for reserve capacity (picture: Bundesnetzagentur)

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