During a recent heatwave, the UK's electricity grid relied on European interconnectors for a fifth of its power, highlighting the critical role of cross-border energy links. However, political tensions, including potential French withdrawal from the EU's electricity system, pose a significant threat to future energy security.
Heatwave Highlights Interconnector Reliance
On Thursday, a low-wind "heat dome" day, 20% of the British grid's power came from the continent at 10am. Cables from France alone supplied 11% of demand, or 3.54 gigawatts, more than double the output from the UK's entire windfarm fleet at that time. This reliance is not new; the UK currently imports roughly a tenth of its electricity annually.
The economic appeal is clear: cross-border transfers boost security and can be cheaper, especially from France's nuclear-dominated system. On sunny, windy days, the flow reverses, with the UK exporting surplus renewable power.
Political Tensions and Grid Management
However, the politics of interconnectors have become messy. In June, the National Energy System Operator (Neso) cut off exports to the Netherlands at short notice during a frequency incident, prompting an investigation. In July, Neso ordered traders not to export via four interconnectors in the day-ahead market to ensure domestic supply.
Phil Hewitt, a director at energy market specialist Montel, warns: "The impact of Neso redispatching interconnectors close to real time can cause trouble, especially for smaller markets like Belgium and the Netherlands." In May, contractual limits were set to restrict late changes on six links with Belgium, Denmark, France, and the Netherlands to 300 megawatts per cable. Independent energy analyst Peter Atherton notes: "The UK is potentially seen as the weak link in the European system."
Future Threats: Norway and France
Deeper political tensions predate the summer. Norway, after a consumer backlash over higher prices, banned new interconnectors and scrapped a planned 1.4 gigawatt cable to Peterhead in Scotland in 2023. More significantly, if Marine Le Pen wins next year's presidential election, her National Rally party wants to pull France out of the EU's cross-border electricity system, which is closely integrated with the UK's.
Hewitt warns: "There would be price rises for UK consumers and questions for security of supply if the National Rally gets in in France and implements their policy." He adds: "Mainstream parties in Norway and Sweden are increasingly anti building more interconnectors – they're saying 'enough is enough'. If there is no more build-out and France says 'we're not going to send you any of our electricity', the position looks more dicey." While he calls it an "edge case", he acknowledges "political risk is there. Populism can cause trouble."
Medium-Term Prospects and Risks
In the medium to long term, the position should improve with new renewables and nuclear capacity, and Britain is expected to become a net exporter in the 2030s. However, in the shorter term, energy systems across Europe have become more complex, with decentralized renewables and extreme intraday price swings making balancing harder.
Atherton states the political reality: "It is a fundamental fact of democratic life that no country will export power if it means potential blackouts in its own cities. It would be electoral suicide, whatever contracts you have in place." For now, pan-European cooperation remains intact, but tensions are rising, and solar eclipses are easier to manage than Europe's cross-border electricity politics.
