Combined Grid Solution inaugurated

20.10.2020

On 20 October, the world’s first hybrid offshore interconnector was ceremoniously put into operation: the Danish-German Combined Grid Solution (CGS). This interconnector in the Baltic Sea links the transmission grids of two countries via national offshore wind farm grid connections. For this purpose, two submarine cables with a length of merely 25 kilometres and a capacity of approx. 200MW each were laid between the offshore transformer platforms of the German wind farm Baltic 2 and the Kriegers Flak wind farm in the Danish part of the Baltic Sea, which is currently under construction. The CGS – a joint project of TSCNET shareholder 50Hertz, one of the four German transmission system operators (TSOs), and TSCNET customer Energinet, the TSO from Denmark – thus not only connects the platforms with each other but also the existing onshore connections of the wind farms. This allows the transmission of offshore wind power to Denmark or Germany and also cross-border electricity trading.

The official opening ceremony, which took place on site in the German capital of Berlin as well as digitally, was attended by Peter Altmaier, German Federal Minister for Economic Affairs and Energy, Dan Jørgensen, the Danish Minister for Climate, Energy and Utilities, as well as Kadri Simson, EU Commissioner for Energy. With their appearance, these high-ranking political representatives acknowledged the CGS as a technical innovation with model character for future offshore power grids. The hybrid nature of CGS is that it is the first electricity interconnector between two countries, that not only provides capacity for electricity trading, but also transports offshore wind energy onshore – in both directions. The costs of the binational EU-funded project amount to around €300m.

A technical obstacle had to be solved in the realisation of CGS: Because the transmission grids in eastern Denmark and Germany do not operate synchronously, it was necessary to install a back-to-back converter at the 50Hertz substation in Bentwisch near the port city of Rostock in the federal state of Mecklenburg-Western Pomerania. The device converts the incoming AC into DC and immediately back. Only in this way is it possible for electricity to flow smoothly from Denmark to Germany and vice versa. But CGS has not only hardware but also software components. The central digital control unit of the system is the Master Controller for Interconnector Operation (MIO), located in the 50Hertz control centre near Berlin. The MIO balances market requirements with offshore electricity production, which depends on wind conditions in the Baltic Sea. Its main function is to ensure optimum use of the CGS while preventing any overload of the line and the operating facilities in the substation.

Stefan Kapferer, CEO of 50Hertz, commented at the inauguration: “With this project, 50Hertz and Energinet are pioneering the efficient integration of offshore wind farms into the cross-border European electricity market. It offers us several effective options to balance the frequency and voltage of our transmission grids at all times, to deal with the integration of renewable energy sources with more flexibility and to increase the stability of the overall system.” Thomas Egebo, CEO of Energinet, added: “The CGS is not only a very important milestone in reaching Denmark’s ambitious goal of a 100 percent green power system in 2030. The groundbreaking project also delivers an important building block for decarbonising the rest of the society.”

The Danish-German Combined Grid Solution has been ceremoniously put into operation (illustration uses photos of 50Hertz, one of which shows Minister Altmeier)

Linkup
> See 50Hertz press release (html)
> See Energinet news release (html)
> Watch CGS inauguration film (YouTube)

See article on single page

Onshore converter for the Combined Grid Solution

31.01.2020

The Danish-German Combined Grid Solution (CGS) in the Baltic Sea is the world’s first offshore interconnector to use national grid connections of offshore wind farms to link the transmission systems of two countries. For this purpose, submarine cables were laid between the offshore transformer stations of the German wind farm Baltic 2 and the Kriegers Flak wind farm in the Danish part of the Baltic Sea. The CGS is a joint project of TSCNET shareholder 50Hertz, one of the four German transmission system operators (TSOs), and TSCNET customer Energinet, the TSO from Denmark.

The Bentwisch substation near the Baltic port city of Rostock houses the German onshore converters for the CGS. Here 50Hertz has installed a double converter system including a back-to-back converter. This is essential for balancing the asynchronous transmission systems of Germany and Eastern Denmark: The AC from the Nordic synchronous area is converted into DC and directly back into AC, now adapted to the European synchronous area.

50Hertz has now successively energised and commissioned all converter components in Bentwisch. The new equipment and further extensions of the substation had to be individually synchronised with the control technology in a series of individual testing and commissioning steps. The operational readiness of the double converter system in Bentwisch marks another important milestone on the way to the commissioning of the entire CGS.

The German onshore converter for the Danish-German offshore interconnector Combined Grid Solution has been commissioned by 50Hertz (picture: Jan Pauls / 50Hertz)

Linkup
> See 50Hertz project news (html)

See article on single page

RGI Award for the Combined Grid Solution

24.05.2019

On 23 May, during the Energy Infrastructure Forum in Copenhagen, Denmark, the Renewables Grid Initiative (RGI) presented the “Good Practice of the Year” awards to the 2019 winners. RGI, an association of non-governmental organisations and transmission system operators (TSOs) from all over Europe, annually awards the “Good Practice of the Year” upon recommendation of a jury of experts since 2012. This year’s award in the category “Technological Innovation & System Integration” goes to the “Combined Grid Solution” (CGS), the world’s first hybrid interconnector by the two TSCNET shareholders 50Hertz, one of the four German TSOs, and Energinet, the TSO from Denmark.

The CGS is the first Danish-German offshore interconnector for which submarine cables have been laid between the offshore substations of the German wind farm Baltic 2 and the wind farm Kriegers Flak in the Danish part of the Baltic Sea. The renewable energy generated by the wind turbines has priority and can flow into both interconnected countries if needed. Free capacity can be used to exchange electricity between the Danish and German markets. The jury acclaimed the potential of the CGS “to be enormously consequential for the development of the North Sea and Baltic Sea resources, and its ambition of approaching 100% utilisation of the offshore grid assets”.

Elke Kwapis, Senior Project Manager Offshore at 50Hertz, acknowledged “the collaborative manner amongst all project team members from 50Hertz and Energinet” and commented: “The CGS is the first offshore hybrid interconnector that allows integrating high shares of renewables and at the same time maximising the use of existing infrastructure for offshore wind grid connection.” Per Obbekær, project manager at Energinet, stressed the climate-specific impact of the CGS and the acute need for action: “We need to push all the known technologies and constantly focus on being innovative in our approach to new technologies in order for us to reach our climate goals cross borders.”

By the way, this is not the first time that 50Hertz has received the prize. In 2017, the TSO was awarded in the category “Communication & Participation” for the “DialogMobil”, an information van that functions as a kind of mobile citizen’s office.

The Combined Grid Solution project of 50Hertz and Energinet receives the “Good Practice of the Year Award” from the RGI (picture: RGI)

Linkup
> See 50Hertz press release (html)
> See RGI press release (html)

See article on single page

50Hertz plans to invest some €3.4bn

26.02.2019

Northeast Germany – and thus the control area of TSCNET shareholder 50Hertz, one of the four German transmission system operators (TSOs) – continues to be a pioneer in the integration of renewable energies in Central Europe. For the second year in a row, renewables accounted for more than half of electricity consumption, and once more a new record was set with a regenerative share of 56.5% (2017: 53.4%). The installed capacity of renewables rose to 32.9GW, which is why Boris Schucht, CEO of 50Hertz, had every reason to express his contentment with this development during the 50Hertz balance sheet press conference on 26 February 2019 in the German capital of Berlin: “We are proud that with this record share of renewables, we can contribute to a successful energy transition.” Since this share will increase continuously in the 50Hertz control area, the federal growth target of 65% for 2030 can be achieved as early as 2021.

At the same time, the costs for congestion management, mainly caused by redispatch, fell significantly last year, by an impressive €100m to around €105m. This is due in particular to the effect of the extra-high voltage line “Südwest-Kuppelleitung” (aka “Thuringian Power Bridge”) and two now fully operational phase-shifting transformers (PSTs) on the borders with Poland and the Czech Republic respectively. But also in the future, the expansion of the transmission infrastructure must keep pace with that of the renewables. 50Hertz is taking this into account with exceptionally high investments in the transformation of the energy system. These are facilitated by the TSO’s excellent operating results. Over the past five years, 50Hertz has already invested over €3bn in the grid (€492m in 2018). By 2023, 50Hertz plans to spend a further €3.4bn (€420m in 2019).

Among the outstanding infrastructure projects are the “Ostwind 1” offshore connection, which has been in trial operation since last year, and the “Combined Grid Solution”, a Danish-German interconnector in the Baltic Sea that links the German “Baltic 2” wind farm with the Danish “Kriegers Flak” farm and will be connected to the grid in 2019. The supra-regional DC project “SuedOstLink” is making significant progress, too, as the federal sector planning is underway and the European tender for the underground cables has been launched. 50Hertz CTO Dr. Frank Golletz, who will take over the function of Boris Schucht as interim CEO from 1 March 2019, announced the continuation of the TSO’s ambitious investment program. Golletz also pointed out that the political and regulatory framework must be optimised and made innovation-friendly to realise the energy transition.

50Hertz presents excellent results for 2018 and announces further sustainable investments in its transmission grid (illustration using pictures of 50Hertz)

Linkup
> See 50Hertz press release (html)
> Open press conference presentation, in German (pdf, 4.09MB)

See article on single page

Successful test for the Combined Grid Solution

09.11.2018

The Combined Grid Solution is a joint offshore connection project by the two TSCNET shareholders 50Hertz, one of the four German Transmission System Operators (TSOs), and the Danish TSO Energinet. The binational interconnector in the Baltic Sea will integrate the electricity systems of Denmark and Germany by linking the German wind farm Baltic 2 to the Danish wind farm Kriegers Flak. The utilisation of grid connections from offshore wind farms to couple the transmission grids of two countries is nothing less than a world premiere.

The laying of the two submarine cables “150kV-line KFE-BaZ 155“ and “150kV-line KFE-BaZ 156“ was completed at the beginning of July and the two TSOs have now successfully conducted 24-hour testing of both cables. Around noon on 6 November and in the afternoon thereafter, the two cables were energised one after the other up to the disconnector on the offshore substation OSS KFE and now are ready to transport electricity. Sebastian Wagner, Sub-Project Manager Sea cables at 50Hertz, and Energinet’s Project Manager Daniel Johan Brøndum jointly declared: “Everyone in the team worked closely together and delivered to-the-point. We are very happy and celebrate this success together.”

The submarine cables for the Danish-German offshore interconnector Combined Grid Solution of 50Hertz and Energinet were successfully tested (illustration based on pictures of 50Hertz / Sebastian Wagner)

Linkup
> See 50Hertz project news (html)
> See Energinet project news (html)

See article on single page

Combined Grid Solution: submarine cable installed

06.07.2018

In early May, all of the three offshore platforms for the planned Danish wind farm Kriegers Flak in the Baltic Sea were successfully installed. One of them will not only collect wind power, but also function as linking point for the Combined Grid Solution, the first Danish-German offshore interconnector. The Combined Grid Solution is a joint venture of two TSCNET shareholders, 50Hertz, one of the four German Transmission System Operators (TSOs), and the Danish TSO Energinet.

Just two months later, 50Hertz announces that the next significant step for the project has been taken. The Combined Grid Solution will integrate the electricity systems of Denmark and Germany by linking the German wind farm Baltic 2 with 25 kilometres of submarine cables to Kriegers Flak. Now both cables of the interconnector have been laid out completely. The Baltic 2 platform was the starting point for the cable laying, and on 5 July, the Kriegers Flak platform was reached.

Elke Kwapis, project manager at 50Hertz, acknowledges the good cooperation with Energinet in this process and states: “These are great news. In the business everybody knows how complex the installation of submarine cables can become.” Especially in this case, it was even more challenging than usual, because the Baltic 2 platform was constantly in operation during the cable laying.

The submarine cables for the Danish-German offshore interconnector Combined Grid Solution of the TSOs 50Hertz and Energinet have been laid out. Picture: Screenshot taken from video “Combined Grid Solution (CGS) by 50Hertz and Energinet“ (50Hertz, YouTube)

Linkup
> See 50Hertz press release (html)

See article on single page

CGS onshore transformers on site

03.06.2018

The Bentwisch substation near the city of Rostock in Mecklenburg-West Pomerania is the future onshore converter station for the Combined Grid Solution, the first Danish-German offshore interconnector. The project is a joint venture of two TSCNET shareholders: 50Hertz, one of the four German Transmission System Operators (TSOs), and Energinet, the Danish TSO. The Combined Grid solution integrates the electricity markets of Denmark and Germany by linking the Danish Kriegers Flak wind farm with its German counterpart, Baltic 2. Now another significant step for the interconnector has been taken, as two transformers have been supplied to Bentwisch.

In combination with a double converter system, the large-scale equipment is essential for balancing the asynchronous transmission systems of Germany and Denmark. The transformers were transported from Rostock harbour to the substation per heavy-duty road transport. The second arrived in Bentwisch on the night of 29 to 30 May, and the first three weeks before. “We have thus reached another milestone on the way to commissioning the Combined Grid Solution. The transformers are the most important technical components for the back-to-back system on site,” comments Martin Henschel, specialist engineer at the 50Hertz Northern Regional Centre.

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

Picture: visavis Filmproduktion GmbH

See article on single page

Platforms for Combined Grid Solution installed

08.05.2018

The installation of all three offshore platforms for the planned Danish wind farm Kriegers Flak in the Baltic Sea has successfully been completed on 7 May. A special heavy duty crane vessel was needed as the platforms weigh 800, 1,500 and 1,800 tonnes, respectively. The platforms will not only collect the electricity from Kriegers Flak, but one of them will also be used for the Combined Grid Solution, the first Danish-German offshore interconnetor, which is a joint venture of the two TSCNET shareholders 50Hertz, one of the four German Transmission System Operators (TSOs), and Energinet, the Danish TSO.

The Combined Grid Solution will link Kriegers Flak to the German wind farm Baltic 2 and thus integrate the electricity systems of Denmark and Germany. According to Jens Christian Hygebjerg, project manager at Energinet, the platform installation was the “most costly risk” of the whole project. “It is therefore a great relief to see all three platforms in their rightful place.” The platforms are scheduled to be put into operation in October 2018, but only after an intensive phase of further assembly work and a series of tests under real-life conditions.

> See 50Hertz press release (html)
> See Energinet press release (html)

Picture: Jakob Fynsk / Energinet

See article on single page

Transformer for Combined Grid Solution

06.04.2018

At the Hollandia shipyard in Krimpen aan den IJssel in the Dutch province of South Holland, the next step has been taken for the Combined Grid Solution, the first Danish-German offshore connection in the Baltic Sea: A 450MVA transformer was placed on the Kriegers Flak Extension offshore platform. The interconnector is a joint venture by the two TSCNET shareholders 50Hertz, one of the four German Transmission System Operators (TSOs), and Energinet, the Danish TSO.

By linking two offshore wind farms, the German Baltic 2 and the planned Danish Kriegers Flak, the Combined Grid Solution will integrate the electricity systems of both respective countries. The transformer is necessary to balance the different voltage levels of the Danish and German offshore wind farms. After the complete assembly of the transformer, the entire platform topside will be shipped to Kriegers Flak at the end of April. Here, it will be installed on the gravity foundation, which has been erected in February of this year on the floor of the Danish Baltic Sea.

> See 50Hertz press release (html)

Picture: Dieter Böhm / 50Hertz

See article on single page

Kriegers Flak platform foundations installed

27.02.2018

The TSCNET shareholders Energinet, the Danish Transmission System Operator (TSO), and 50Hertz, one of the four German TSOs, are jointly creating the first Danish-German offshore connection in the Baltic Sea, the so-called Combined Grid Solution. For the first time, offshore wind farms will be used for integrating the electricity systems of two countries. The high capacity interconnector will link the German wind farm Baltic 2 with the planned Danish wind farm Kriegers Flak. It is funded by the European Union as a Project of Common Interest.

To collect the wind power from Kriegers Flak, two transformer platforms are needed, of which the larger one will also be used for the Combined Grid Solution. The gravity foundations for these platforms have now been successfully installed in the Baltic Sea at a distance of 8 kilometers from each other. The installation time was about ten hours each. The barge had to be partly subsided below water level, so that the foundations could be unloaded with a special crane vessel. Subsequently, they were lowered to the sea floor. The installation of the platform topsides is scheduled for May 2018.

> See 50Hertz press release (html)

Picture: 50Hertz

See article on single page