Way is paved for 400kV line in western Romania


For more than ten years, the completion of the 400kV Oradea-Békéscsaba overhead line in the far west of Romania has been prevented due to unresolved ownership issues regarding the section Oradea South-Nădab. Because of this, the line could only partially be put into operation, that is between the Romanian town Nădab and the Hungarian town Békéscsaba, near the Romanian-Hungarian border. Now the property situation has been clarified and the Romanian transmission system operator (TSO) and TSCNET shareholder Transelectrica was able to award the building contract for the missing section.

Transelectrica expects the construction work to be completed within twelve months. The commissioning of the last 72-kilometre section and thus the completion of the Oradea-Békéscsaba overhead line will contribute to the closure of the “400kV Ring” in the west of Romania. This project is a priority energy target for Romania, which will significantly improve the operational reliability of the national transmission system and security of electricity supply in the north-west of the country. The new Oradea-Békéscsaba line will also enable Transelectrica to eliminate congestions and thus save considerable costs for grid interventions. Finally, Romania’s interconnection capacity will be increased by 100MW in export and 300MW in import direction, which will not only contribute to compliance with EU regulations, but also make a sustainable contribution to the integration of the European electricity market.

Transelectrica has awarded the building contracts for the last section of the 400kV Oradea-Békéscsaba overhead line (picture of Oradea: Marculescu Eugen Iancu, Creative Commons)

> See Transelectrica press release, in Romanian (pdf, 191.kb)

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Swissgrid analyses supply disruption in Valais


On Friday, 17 July, the Swiss transmission system operator (TSO) Swissgrid carried out check-operations concerning the extension of the 220kV switchgear in the Chippis substation in the canton of Valais. At 4.23 p.m., the protection equipment of the 220kV grid node Creux de Chippis was accidentally tripped, causing the switchgear to lose voltage. As a result of the technical failure at Chippis, the switchgear of the substations in Stalden, Bitsch, and Mörel were also affected by the voltage drop, which led to a regional supply interruption in the distribution system.

The result was a one-hour power outage in a total of 60 municipalities with around 112,000 households as well as trade and industry in the Swiss Sierre district and the largest part of the Upper Valais. By 5.23 p.m., all affected switchgear and lines of the TSCNET shareholder were back in regular operation. Thanks to the good cooperation between Swissgrid and the five affected distribution system operators (DSOs) of the lower voltage levels, it was possible to gradually restore the electricity supply from 5 pm onwards. By 6.15p.m. almost all customers were back on power. Swissgrid immediately initiated a detailed investigation of the incident, which is currently in progress.

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

> See Swissgrid news release, in German (html)

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Worldwide unique equipment for TransnetBW substation


European transmission system operators (TSOs) respond to the increasing need for grid regulation – resulting from the growing share of volatile renewable energies and the proceeding shutdown of conventional power plants – with reactive power compensation measures, such as the installation of shunt reactors. Shunt reactors are absorbers of reactive power and support security of supply and system management by keeping the grid voltage within the specified range, especially during low load periods. They thus stabilise the power grids and increase the energy efficiency of the transmission system.

In the Stuttgart-Mühlhausen substation, TransnetBW, one of the four German TSOs, has commissioned a variable shunt reactor for reactive power compensation developed especially for the TSCNET shareholder. Up to now in the TransnetBW control area, shunt reactors have only been used in the 110kV grid. Compared to customary reactors, the new system provides a much more precise control of the grid voltage. The 360-tonne reactor has a control bandwidth of 50-250MVAr in 33 stages and a permanently permissible system voltage of 440kV. With these specifications, the Mühlhausen shunt reactor is not only a novelty for TransnetBW, but for the entire energy sector.

TransnetBW has commissioned a state-of-the-art shunt reactor in the Stuttgart-Mühlhausen substation (symbolic picture: Siemens)

> See TransnetBW press information, in German (html)

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Swissgrid responds to revised legislation


With the national “Energy Strategy 2050”, the Swiss electorate decided in 2017 to promote renewable energies. To extend the duration of the correlating support measures, create planning security for the energy market, and eventually achieve Switzerland’s climate policy goals, the Swiss Federal Council has developed a revision of the national Energy Act (“Energiegesetz”). The Swiss transmission system operator (TSO) Swissgrid appreciates that the Federal Council intends to create more incentives for the expansion of domestic renewable energies while at the same time ensuring long-term security of supply.

However, the TSCNET shareholder considers that the legal framework must also contribute to integrating renewable energies into the overall system. According to Swissgrid, this is the current situation in Switzerland: The combination of the absence of an electricity agreement with the EU, a significant increase in renewable energy with volatile generation, and the sluggish expansion of the grid affects the operation of the transmission system. Because even today, the grid expansion is not keeping pace with that of the renewables.

To meet the goals of the “Energy Strategy 2050”, it must first be ensured that approval procedures for grid projects are consistently optimised and accelerated. Secondly, innovative solutions for load management are needed to generate flexibility and provide frequency services to the transmission grid. The crowd balancing platform Equigy – a cooperation of Swissgrid, TSCNET shareholder TenneT, the Dutch-German TSO, and the Italian TSO Terna – is one example of such a solution. Thirdly, an electricity agreement between Switzerland and the EU is essential, since import and export capacity will make an important contribution to Switzerland’s supply security given the significant expansion of renewable energies. Finally, Swissgrid considers the non-discriminatory availability, quality, and transparency of data to be increasingly important for secure grid operation. This requires a legal basis for regulating data transfer between TSOs, distribution system operators (DSOs), storage and power plant operators, and other parties involved.

Swissgrid comments on the revision of the national Energy Act by the Swiss Federal Council (illustration based on a picture of Lac de Moiry in Valais, Fotoauge, Pixabay)

> See Swissgrid media release (html)
> Open Swissgrid position on Energy Act, in German (pdf, 212.6kb)

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Construction permit for Pradella-La Punt


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)

> See Swissgrid media release (html)

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Smart control of heat pumps – HeatFlex expands


Launched in the summer of 2018, the HeatFlex research project aims to exploit the potential for grid stabilisation that small and decentralised consumer devices can offer – if actively involved in the stabilising process. The founding project members are TSCNET shareholder TenneT, the Dutch-German transmission system operator (TSO), and the southern German distribution system operator (DSO) Bayernwerk Netz. Following the successful cooperation and positive test results, TenneT and Bayernwerk Netz are now expanding the project. The grid operators are pleased to welcome three new project partners: the DSO Regensburg Netz as well as the public utilities Stadtwerk Haßfurt and SWW Wunsiedel.

With HeatFlex, TenneT and Bayernwerk are jointly researching the most effective integration of decentralised devices – such as electric storage heaters, heat pumps, and water heaters – into grid balancing. These flexible capacities are intended to avoid cost-intensive interventions by the TSO in the case of future grid bottlenecks. Since November 2019, the project partners have already been implementing the first concrete measures based on HeatFlex results: The heat pumps and direct heating systems connected to Bayernwerk Netz are being intelligently controlled for bottleneck prevention. Decentralised heating systems are thus partially taking over the stabilising function of fossil plants. Using ripple control technology already in place, no additional investments are required.

The increase in partners should serve to make intelligent use of even more local flexibility and to investigate further controllable, decentralised consumption units and alternative applications. The ultimate aims of HeatFlex are cost savings, reduction of grid extension, and the acceleration of the energy transition without jeopardising system security. “The intelligent control of the smallest, decentralised electricity consumption units is a small but essential element,” explains TenneT Managing Director Tim Meyerjürgens, “because the many pieces of the puzzle together make up the overall picture of the energy transition”.

The research project HeatFlex is extended with three additional partners (picture: Stiebel Eltron)

> See TenneT press release, in German (html)

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Contracts for 525kV SuedLink cables


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)

> 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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High-voltage pylon of Swissgrid sabotaged


On the morning of Friday 26 June, motorists on the Lausanne-Geneva motorway near the municipality of Gland in the Swiss canton of Vaud noticed how a high-voltage pylon collapsed. The cantonal police of Vaud were alerted and immediately cordoned off the area around the scene. No persons were injured. TSCNET shareholder Swissgrid, the Swiss transmission system operator (TSO), disconnected and grounded the two 220kV lines affected by the collapse of the pylon, Banlieue Ouest-Foretaille and Crans-Romanel. Grid stability is guaranteed and there are no supply failures in the Swiss transmission system.

Initial findings indicate that the pylon was subject to an act of sabotage, probably with the help of explosives. On-site investigations have been carried out by the Vaud Cantonal Police and the Swiss Federal Office of Police (Fedpol) while a criminal investigation has been opened by the Office of the Attorney General of Switzerland.

A 220kV pylon of Swissgrid has collapsed after an act of sabotage (picture: Canton de Vaud)

> See Swissgrid news release, in German (html)
> See Media release of the Cantonal Police of Vaud, in French (html)

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ALEGrO: Civil engineering concluded


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)

> See Amprion press release, in German (html)

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Summer Outlook: Pandemic facilitates adequacy


Due to the corona crisis, system operation is challenging and uncertain in 2020, but as European transmission system operators (TSOs) have responded adequately and across borders to the changes in the electricity system, the European Network of Transmission System Operators for Electricity (ENTSO-E) does not see any substantial threat to continental security of supply in summer 2020. The annual ENTSO-E Summer (and Winter) Outlooks provide valuable information on where bottlenecks are most likely to occur or which are the main risks to the pan-European electricity transmission system. The 2020 edition does not identify any major adequacy risk in Europe. It is expected that the COVID-19 pandemic this summer will ease adequacy, although the high level of uncertainty makes it difficult to predict its impact.

Like previous editions, this year’s Summer Outlook is based on a comprehensive database, but this time relies on an improved assessment methodology consistent with the relevant EU regulation. It was published somewhat later than customary, as important updates on planned outages, particularly in France, were announced at the end of May. ENTSO-E conducted a special Europe-wide stress test with the new information. However, this stress test confirmed that the new information on planned outages did not entail any additional adequacy risk and that the results of the summer 2020 forecast are still valid.

As usual, ENTSO-E presents the Summer Outlook together with the Winter Review 2019/20. The winter 2019/20 was the warmest on record in Europe. Towards the end of the season, there were several winter storms that coincided with the beginning COVID-19 pandemic. In result, TSOs faced challenges in regulating voltage and handling unusual flow patterns when renewable generation was high, and demand was low. To deal with the situation, the TSOs relied on the markets and used the curtailment of renewable generation only as a last resort. Despite these exceptional circumstances, security of supply was not affected anywhere.

To provide a more in-depth insight into the results of the Summer Outlook 2020, ENTSO-E is organising a public webinar on 17 June from 12.00 to 13.00 CEST.

ENTSO-E has released the Summer Outlook 2020 and Winter Review 2019/20

> See ENTSO-E press release (html)
> Visit ENTSO-E seasonal outlook site with access to several documents (html)
> Open Summer Outlook 2020 (pdf, 5.97MB)
> Register for webinar (html)

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