Interconnectors: The Energy Superhighways Linking Britain to Europe
Undersea cables connecting the UK to European grids are fundamental for energy security, controlling costs, and supporting renewable energy integration.
Hidden beneath the seas surrounding Britain are some of Europe's most significant energy assets: high-voltage electricity cables, known as interconnectors, directly linking the UK to the power grids of neighboring countries. These systems are fundamental for energy security, controlling costs, and supporting renewable energy integration.
What Are Interconnectors?
Interconnectors are high-voltage direct current (HVDC) cables that transmit electricity between countries. The UK operates 10 interconnectors, delivering a combined capacity of over 9 gigawatts (GW)—enough to supply several large power stations.
Key Connections
| Interconnector | Country | Capacity | Operational Since | Notes |
|---|---|---|---|---|
| IFA | France | 2 GW | 1986 | Interconnexion France-Angleterre |
| IFA2 | France | 1 GW | 2021 | - |
| ElecLink | France | 1 GW | 2020 | Via Channel Tunnel |
| Nemo Link | Belgium | 1 GW | 2019 | - |
| BritNed | Netherlands | 1 GW | 2011 | - |
| East-West | Ireland | 500 MW | 2013 | To Republic of Ireland |
| Moyle | Ireland | 500 MW | 2002 | To Northern Ireland |
| Greenlink | Ireland | 500 MW | 2024 | - |
| North Sea Link | Norway | 1.4 GW | 2021 | World's longest (720 km) |
| Viking Link | Denmark | 1.4 GW | 2023 | - |
Why Interconnectors Matter
Cost Savings
Electricity can be imported when prices abroad are lower. According to National Grid ESO, in 2023 UK interconnector imports saved consumers approximately £1 billion.
Energy Security
Multiple international links reduce reliance on domestic sources and improve resilience if local supply is limited. Diversification of energy sources strengthens the UK's overall energy security.
Renewable Integration
The UK can export excess wind or solar when generation is high, or import hydropower and nuclear energy when needed. This flexibility supports the integration of variable renewable energy sources.
Grid Stability
Interconnectors help balance the system from second to second, supporting frequency management and reliable supply.
Lower Carbon
Imports of hydropower or nuclear can displace fossil fuel generation, reducing UK emissions and supporting net zero targets.
How They Work
Most interconnectors use HVDC technology, which optimizes energy transfer over long distances by:
- Minimizing losses over hundreds of kilometers
- Allowing precise control of power direction and magnitude
- Eliminating the need for grid-wide synchronization between different national systems
Converter Stations
Large converter stations at each end transform power from AC to DC and back, enabling seamless integration with local grids. These facilities contain some of the most powerful electrical equipment in the world.
How Interconnectors Operate
Patterns of power flow change throughout the day based on supply, demand, and price signals:
Daytime:
- Imports usually from France and Norway
- Nuclear and hydro provide baseload supply
Evening:
- Higher imports meet UK demand peaks
- System prices typically rise
Windy Nights:
- UK exports excess wind power to Europe
- Helps maintain grid balance during high renewable generation
Sunny/Windy Days:
- Exports rise when UK renewables are abundant
- Supports renewable energy economics
Real-Time Monitoring
For real-time updates on Britain's interconnector activity, including direction, scale, and usage of each cable, visit the GridMix dashboard, which uses live data from the Balancing Mechanism Reporting Service (BMRS). This dashboard is the most comprehensive public resource for visualizing Britain's energy interconnections in action.
Future Projects
Major expansions are planned to increase interconnector capacity:
Under Construction
Proposed
- NeuConnect (1.4 GW to Germany)
- MaresConnect (2 GW to Ireland)
- FAB Link (1.4 GW to France via Alderney)
- Additional Norway links
Total capacity could rise above 18 GW by 2030, expanding trade opportunities and grid resilience.
Challenges and Considerations
Grid Dependency
Some experts warn about dependence on imports, but a wide network of connections provides diverse sources, improving overall security. Analysis by the National Infrastructure Commission examines the balance between interconnection and domestic generation.
Brexit Impacts
While the UK is no longer in EU energy trading arrangements, interconnector access remains open through negotiated mechanisms. Physical infrastructure continues to operate as designed.
Environmental Impacts
Laying cables disturbs marine environments, but environmental studies indicate limited long-term effects when best practices are followed.
Investment Balance
Both interconnectors and domestic generation are critical for energy stability and future growth. The optimal mix depends on economic, technical, and strategic factors.
Technology Evolution
Grid technology is advancing with several innovations:
Multi-Terminal HVDC
Multi-terminal systems allow multi-point connection "webs" instead of simple point-to-point links, enabling more flexible power routing.
Offshore Hubs
Artificial islands could connect multiple wind farms and nations, creating integrated offshore energy networks. Projects like the North Sea Wind Power Hub explore this concept.
Voltage Source Converters (VSC)
VSC technology supports better integration with weak grids and offshore wind, providing enhanced controllability and grid support functions.
Economic Impact
Interconnectors involve significant private investment:
- Construction costs: £1-3 million per MW of capacity
- Investment horizon: Returns come over decades through market price differences between connected countries
- Capacity markets: Interconnectors can participate in UK capacity market auctions
The Bigger Picture
Britain's interconnectors are a key part of Europe's vision for a connected electricity "supergrid," making it possible to transfer renewable energy wherever it's needed most. By leveraging these energy superhighways, the UK can access cheaper, cleaner power and play a vital role in the continent's transition to net zero.
Interconnectors enable:
- Sharing of renewable energy across borders
- Improved utilization of generation assets
- Enhanced system resilience and security
- Cost savings through market integration
- Support for decarbonization goals
Explore Real-Time Data
For a real-time view of electricity trade and interconnector flows, explore the GridMix dashboard powered by BMRS—a window into Britain's role in an interconnected energy future.
<br/> <br/> <br/>References
National Grid ESO (2024). Interconnectors. Available at: https://www.nationalgrideso.com/industry-information/balancing-services/interconnectors
Elexon (2024). Balancing Mechanism Reporting Service (BMRS). Available at: https://www.bmreports.com/
UK Government (2022). Energy Security Strategy. Department for Business, Energy & Industrial Strategy. Available at: https://www.gov.uk/government/publications/energy-security-strategy
Climate Change Committee (2020). The Sixth Carbon Budget: The UK's path to Net Zero. Available at: https://www.theccc.org.uk/publication/sixth-carbon-budget/
ENTSO-E (2024). HVDC Technology and Interconnections. European Network of Transmission System Operators for Electricity. Available at: https://www.entsoe.eu/about/inside-entsoe/wgs/cim/hvdc/
National Infrastructure Commission (2023). Energy Infrastructure Assessment. Available at: https://nic.org.uk/studies-reports/energy/
UK Government (2020). UK-EU Trade and Cooperation Agreement - Energy. Available at: https://www.gov.uk/government/publications/uk-eu-trade-and-cooperation-agreement-energy
North Sea Wind Power Hub (2024). Project Overview. Available at: https://northseawindpowerhub.eu/
EMR Delivery Body (2024). UK Capacity Market. Available at: https://www.emrdeliverybody.com/CM/Home.aspx
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