Interconnectors’ role in transitioning to net zero

Our Future of Interconnectors innovation project is investigating the opportunities and challenges that an increase in interconnectors presents to operating the electricity system as we transition towards our net zero target. 

What are interconnectors?

Interconnectors are high-voltage cables that run under the sea, underground or via overhead cabling that connect the electricity systems of neighbouring countries to one another. Interconnectors allow excess power on the system to be traded and shared between countries. By sharing excess power, we can ensure renewable energy isn’t wasted, and constraint payments are minimised.

For example, when weather conditions mean supplies from UK wind farms and solar are lower, we can draw on carbon-free sources of electricity through the interconnectors. On windy or very sunny days in Britain, excess renewable energy can be sent via an interconnector to neighbouring countries. By connecting Great Britain to broader and more diverse sources of energy, interconnectors can help overcome operability issues, which lowers costs to consumers.

How do we use interconnectors?

Great Britain’s electricity network is linked to networks in several other countries including France, Norway, Netherlands, Belgium, and Ireland via interconnectors that allow electricity to be traded and shared. 

These interconnectors have a total capacity of 8.4GW and more are being built, potentially adding 16GW more capacity by 2035. Interconnectors will play an important role in the import and export of electricity to help us manage the peaks and troughs in our renewable energy generation, but we want to learn more about the technical and commercial impact of increasing the number of interconnectors on the network. 

The future of interconnectors

To explore these opportunities and challenges, we’ve carried out a 12-month project looking at the impact interconnectors have on adequacy (security of supply), flexibility (balancing the system) and ancillary services that enable us to transport electricity around the grid in a stable, efficient and safe way.

Working alongside consultants from AFRY, we started looking at what’s on the system now, current market arrangements, the wider European energy landscape and how Brexit has impacted electricity trading. We also carried out some modelling, using the four Future Energy Scenarios as a baseline, to see how the role of interconnectors might change in 2025, 2030 and 2035. 

Our modelling data found that interconnectors will remain an important source of energy into GB in periods of highest need, and imports into GB are mostly expected to grow in absolute terms during periods of system stress. 

Interconnector flows will remain dynamic with more variety of renewable generation, and periods of spare capacity will grow to provide greater flexibility to the system. 

An increase in interconnectors can deliver consumer savings as they adjust their position in real-time from day-ahead scheduling rather than the ESO accepting repositioning bids from generators to balance the system, which incurs costs to consumers. 

We also explored the impact of potential sensitivities and found that in a zonal market, redispatch volumes are expected to drop as grid constraints are already, to some degree, being accounted for in the market scheduling. The pricing signals implemented by a zonal market would incentivise flows to be aligned between day-ahead and real-time, reducing the need for additional actions.

The decarbonisation ambition of different countries is also becoming increasingly interdependent. When we import electricity using interconnectors, around half the time (scenario/year dependant), the marginal plant is not in GB and is often a thermal generator in continental Europe.

Our learnings and next steps

This project is improving our knowledge and understanding of interconnectors and how they can be used in the future to establish a more stable network as we move to zero carbon operations. 

The next steps for the project will be the further and deeper analysis of these potential solutions. We’re undertaking a prioritisation exercise of key issues to ensure resources are initially allocated to the areas that require strategic focus. Then we’ll be engaging with key stakeholders and broader industry to develop solutions to improve the effectiveness of cross-border flows in a net zero future.

If you wish to keep updated with this project, we are producing a roadmap outlining a practical approach to implement the solutions identified from industry engagement.

Get in touch

Visit our website or contact us at [email protected] to learn more about our innovation projects and priorities.