BSC Insights: Interconnector flows in and out of Great Britain

Great Britain is connected to the rest of Europe through five interconnectors with a combined capacity of 5,000MW. So far this year 9.2% of Great Britain’s energy demand has been met by energy from the interconnectors. In this Elexon Insight, one of our Market Advisors, Emma Tribe describes how much electricity flows on the interconnectors.
^{Published: October 2019}

Interconnector capacity

There are five different countries that are currently connected to Great Britain’s electricity network through undersea interconnectors.

The graph below shows the current capacity of those interconnectors. The largest capacity interconnector being the one that links Great Britain with France and allows the transfer of up to 2,000MW.

The interconnector status filter on the right hand side of the graph can be used to show the interconnectors that are planned to go live in the next few years.

GB interconnector capacity by country

The four planned interconnectors that are currently under construction will add an additional 4,800MW of capacity and create new links to Denmark and Norway.

Currently there is only one interconnector per country, however the planned interconnectors will add an additional two links to France leading to a combined capacity of 4,000MW.

The graph below compares how much energy could theoretically have been transferred over the interconnector if they were always operating at full capacity, against how much energy was actually transferred. The graph shows the volumes of energy in the period 1 January 2014 to 30 September 2019, but the date range can be altered using the slider at the right of the graph.

GB interconnector metered volumes compared to potential capacity

BritNed, which is the interconnector joining Great Britain with the Netherlands, had the highest percentage of potential capacity transferred (84.7%). The two Irish interconnectors have both transferred less than 50% of their potential capacity.

Technical issues on the different interconnectors and the networks they are connected to have meant that they were unable to operate at full capacity for the entire period.

Direction of flow for electricity transferred

Since 2014 the majority (87.8%) of electricity transferred by interconnector has been imported into Great Britain.

The pie chart below shows the ratio of electricity imported to and exported from Great Britain to different countries since 2014.

You can change the date range of the graphs and filter by country using the date slider and country filter on the right hand side of the graph.

GB import vs export

Great Britain is a net importer of electricity from continental Europe over the interconnectors. The ratio of flow over the interconnectors is:

• 98.8% of electricity imported from Belgium
• 98.1% of electricity imported from Netherlands
• 94.2% of electricity imported from France.

However, 63.4% of electricity on the Northern Ireland interconnector was exported out of Great Britain and 57.7% of electricity on the Republic of Ireland interconnector was exported to Ireland.

Volume of electricity transferred

The graph below compares the volume of electricity transferred over the interconnector by year.

Metered interconnector flows

We don’t yet have a full year of data for 2019 and the data shown is from 1 January 2019 to 30 September 2019.

So far this year, Great Britain has imported 18.7TWh and exported 2.6TWh. The total volume of energy transferred was highest in 2014 when 23.1TWh was imported and 3.7TWh was exported.

The graph below shows the electricity imported over the interconnectors as a percentage of Great Britain’s electricity demand.

Interconnector imports as percentage of GB demand

The electricity imported over interconnectors in 2019 so far met 9.2% of Great Britain’s electricity demand. 2019, while not a full year yet, has the highest percentage of demand met by interconnector imports since 2014.

French electricity imports have met 4.4% of demand in Great Britain in 2019 so far and imports from Netherlands met 2.3% of demand.

Interconnector flows after Brexit

Interconnectors play an important role in the supply mix for GB. Generally electricity on the links has flowed into GB as our wholesale electricity prices have tended to be higher than on the continent. It is not expected that these fundamentals will change in either Brexit scenario (deal, or no-deal).

More data on interconnector flows

Elexon publishes close to real time data on the volume of electricity transferred over the interconnectors on our Balancing Mechanism Reporting Service.