Construction has started in Kent on the next phase of one of the world’s biggest ‘energy superhighways’. The £2.4bn interconnector known as NeuConnect will link Medway to Wilhelmshaven in Germany through two high voltage direct current (HVDC) cables, running 725km across the land and under the seabed.
The foundation works for the UK’s converter station began on the Isle of Grain this month. At the same time, National Grid has started building a new substation to connect NeuConnect to the British electricity network. In Germany, major construction commenced on 21 May, with a symbolic ground-breaking ceremony attended by UK and German ministers.
Once operational in 2028, NeuConnect will allow the each-way exchange of up to 1.4GW of renewable-generated electricity between Germany and Britain, helping to solve the ‘energy trilemma’ of affordability, security and sustainability.
Interconnectors in Britain
An interconnector is a cabling system that transmits surplus electricity from one location to another. Alternating current is taken from one country’s national grid, converted via a converter station to direct current (DC), and moved via undersea cables to a sister converter station on the other side of the sea. HVDC cables are used because DC is considerably more effective at transmitting energy over long distances, minimising energy loss.
The key benefit of an interconnector is that when renewables in one country generate an energy surplus, it can be sold to the connected country and transported via the interconnector. When the reverse is true, transmission can ‘flip’.
Such a mechanism allows excess volumes of electricity that would otherwise be wasted to be exported for use. The transmission also benefits consumers in the export market, whose electricity prices should reduce due to the increased supply.
National Grid currently maintains six operational interconnectors, two with France and one each with Belgium, Denmark, Norway and the Netherlands, with six more planned or under construction. (Northern Ireland and the Republic of Ireland have their own grid, although we do also have interconnector links to them.) In 2024, interconnectors are exchanging 7.8GW of power, or enough to supply 15% of the country’s energy requirements on any given day. (Though on the day I checked National Grid: Live, interconnectors were supplying around 20% of our energy requirements.)
Effective use of renewables
Initially, NeuConnect will allow Britain to take advantage of the excess renewable energy generated in Northern Germany, where wind turbines are frequently curtailed (paid to stop producing energy) due to production exceeding its grid’s capacity for use and storage. Through more efficient use of renewable energy, NeuConnect is projected to deliver a net reduction in carbon emissions of 13 MtCO2 over 25 years, the equivalent of planting more than 20 million trees.
While the UK is currently a net importer of energy via its interconnectors, projections suggest that by 2030 it will become a net exporter, aided by further wind farms and major solar developments such as Project Fortress near Faversham. Interconnectors like NeuConnect will then be key to transmitting that energy to Europe.
Energy security
Interconnectors are also a key pillar of energy security. They provide a level of resilience by sending the fluctuating power that is a feature of renewables to where it is needed, when it is needed. And any infrastructure that imports electricity generated by European partners’ renewables in turn reduces reliance on major fossil fuel producers, such as the Russian liquid natural gas (LNG) the EU has just sanctioned for the first time.
Interconnectors also help to offset energy security risks when other forms of power fail. In 2022, Britain temporarily become a net exporter to France via its existing interconnectors. French domestic production was suffering from more than a quarter of its nuclear power stations being closed for maintenance or due to problems with cooling systems.
Supply chain and sustainability challenges
Although NeuConnect’s project is on track, there are several challenges associated with delivering such significant infrastructure projects.
One is the supply chain. HVDC cabling manufacturers’ order books filled up in 2023 with numerous ‘mega tenders’ awarded worldwide, and a limited number of cable-laying ships are available at any one time. It appears to be good news for future interconnector projects, then, that an HVDC manufacturer is being supported by the Scottish government to build a £1.4bn factory in North Ayrshire.
Another challenge is the environmental impact. Despite the significant contribution of interconnectors to reaching Net Zero, undersea cables have been associated with potentially negative impacts on marine life through habitat disturbance or destruction during installation. Electromagnetic fields have also been alleged to impact the navigational capability of some fish and marine mammals during operation.
The NeuConnect project has undertaken environmental appraisals, which include mitigation measures for such disturbances. The appraisals indicate that, once mitigation measures are applied, effects on marine life are considered to be negligible to minor. Measures to be deployed include marine mammal mitigation plans (MMPS) to protect North Sea porpoises, dolphins and seals, and special arrangements to support the 24 species of birds along the Thames Estuary.
The future for interconnectors
Ultimately, though, NeuConnect should bring significant economic and environmental benefits to Germany and Britain. As well as the significant carbon reductions, the clean power generated will power up to 1.5 million homes across both countries over the life of the project. It is also expected to generate hundreds of jobs during construction in the clean energy sector.
The previous government’s target was to deliver 18GW of interconnector capacity by 2030, which would mean more than doubling current capacity. It remains to be seen what the next government will do to speed up the process of issuing consents for projects like NeuConnect, which, along with enhancements to battery storage, appear to be critical for Europe’s energy security, sustainability and affordability.
