Vattenfall to use HVDC technology for UK offshore wind projects

This article is part of a daily series of IPP articles. If you want to know more about the latest power generation projects globally visit our IPP Today section. You can receive them by email on a daily basis.

Vattenfall has announced plans to deploy High Voltage Direct Current (HVDC) cable technology to connect two planned 1.8 GW offshore wind farms, Norfolk Vanguard and Norfolk Boreas, to the UK National Grid. If approved, the wind farms will be located around 47km and 73km from the coast of Norfolk, on the east coast of England, respectively.

The plans were disclosed in the Interim Consultation Report, which was compiled following eight exhibitions in Norfolk and direct feedback from nearly 800 individuals and organisations.

Vattenfall believes that HVDC will soon be cost competitive with High Voltage Alternating Current (HVAC) technology, citing lower losses of transmitted electricity, fewer cables connecting the wind farms to the grid and innovation leading to lower cost on and offshore substations and associated equipment, as the main factors.

The report details that Vattenfall intends to install a 45m wide onshore cable corridor running from landfall near Happisburgh to a substation near Necton, 60km away. The use of HVDC transmission connections which will avoid the need to construct cable relay stations and will significantly reduce the size of the cable corridor - Vattenfall originally used a 100m corridor in line with HVAC requirements. The substation near Necton will be quieter than the HVAC alternative as it will incorporate fewer low-frequency noise emitting components and acoustic insulation.

Thus, HVDC technology will have less of an impact on the environment and local people where onshore infrastructure is located, in comparison to HVAC.

Vattenfall will submit final plans for Norfolk Vanguard to the Planning Inspectorate in June 2018. It is expected to receive approval from the UK Government at the end of 2019 and if permitted, commercial operations will commence in mid-2020s. The 1.8 GW wind farm will produce enough fossil-free power every year to meet the equivalent annual electricity demand of 1.3 million UK households, almost 5% of UK household demand.

Norfolk Boreas, also 1.8GW, is following Norfolk Vanguard in the planning process.