Your questions

What is an interconnector?

An interconnector is a connection between the electricity transmission systems of different countries, in this case via submarine cables. An interconnector provides the opportunity to trade electricity with other countries, thus helping to ensure a safe, secure and affordable energy supply for Great Britain and Denmark.

What is a converter station?

A converter station converts electricity between Alternating Current (AC) and Direct Current (DC). AC is used in each country’s transmission systems, while DC is used for sending electricity along the submarine cable.

How big will the converter station be?  

The footprint of the overall converter will be approximately 4 hectares, comprising a range of buildings and outdoor equipment and access roads etc. with some buildings up to approximately 25 metres tall.  This ‘technical’ area excludes any land required for any drainage systems or landscaping / screening which will vary depending on the location. 

What is a substation?

A substation is a point of connection to an electricity network. It is where the voltage of electricity can be stepped up to flow into the national transmission system or stepped down to supply consumers.

Why DC?

Viking Link would connect two High Voltage AC electricity systems separated by the North Sea using High Voltage Direct Current (HVDC) 

HVDC allows efficient transportation of electricity over large distances and in particular for submarine applications. It is also highly controllable and brings operational benefits to both transmission systems.

Why is an interconnector required?

Energy security: By allowing Great Britain and Denmark to trade power, the Viking Link interconnector will increase security and diversify both countries’ electricity supply.

Electricity prices: Greater opportunities for Great Britain and Denmark to trade with wider European energy markets will contribute to downward pressure on wholesale electricity prices.

Supporting renewables: To meet international and domestic renewable and climate change targets, Great Britain and Denmark is generating more power from renewable sources, including offshore wind. By its nature, wind generation is intermittent and interconnectors provide an effective way to manage these fluctuations in supply and demand.

Why Denmark and Great Britain?

Denmark is part of the Nord Pool power market and has good links with Sweden, Germany and Norway. For Great Britain, connecting here will prove access to a well-developed, low cost market with prices set by a diversified energy mix from across Scandinavia and Northern Germany.

For the Danish electricity producers, an interconnector to Great Britain will give access to a high price market and thus increasing the value of intermittent wind generation.

Viking Link will give Denmark and Great Britain access to a broader energy mix, providing the countries with new opportunities to expand into other electricity markets. The market forces of supply and demand will result in lower prices in peak-consumption periods.

Wind generation outputs between the UK and Denmark show low correlation and periods of high production are unlikely to occur at the same time in both countries. Energy that is surplus to requirements will be easily transmitted through the interconnector to where the level of demand is higher. This will support the renewable energy markets in both countries, reduce the need to curtail generation during peaks in production and have a beneficial impact on market prices.

Why are you connecting at Bicker Fen substation in Great Britain?

National Grid Viking Link (NGVL), the company developing Viking Link, applied to National Grid Electricity Transmission (NGET) for a connection to the national electricity transmission network. NGET undertook a study of possible connection points and a number of different options were considered along the east of England. NGET, together with NGVL, identified Bicker Fen substation as the most appropriate connection point.

Details of all the options identified and the assessments are included in a Strategic Options Report produced by NGVL. You can find this report in the Project Documents section of the website. 

Why are you connecting at Revsing substation in Denmark?

The 400 kV substation in Revsing, located close to Vejen in Southern Jutland, has been selected as the preferred connection point for Viking Link on the Danish side. The decision was based on technical and socio economic criteria. 

Energinet.dk screened possible connection points for Viking Link in the Danish 400 kV transmission network. Five different substations were evaluated and the screening showed that a connection point in the substation Revsing would require the minimum of grid enhancements when compared with the other possible connection points. 

The Revsing substation has a very central location in the Danish transmission system with 400 kV connections north, south and west – and a planned connection eastwards by 2020. Furthermore, connecting at Revsing would have one of the shortest line lengths for both land and submarine cables. Finally there is space available in Revsing for the expansion required for Viking Link.

The final choice of connection point needs approval from the Danish authorities in accordance with Danish law. In the consent process Energinet.dk will consult the neighbours and other relevant stakeholders.

Who will pay for this?

The project is being developed jointly by National Grid and Energinet.dk. On 15 July, 2016 the project was successfully awarded funding through the Connecting Europe Facility (CEF). This award means Viking link’s final development costs will be co-funded by the EUROPEAN UNION. The construction costs will be separately funded by the two companies.