Vattenfall picks HVDC for 1.8GW Norfolk projects

UK: Swedish developer Vattenfall will deploy high-voltage direct current (HVDC) cables at its Norfolk Vanguard and Norfolk Boreas projects, the company has announced.

Vattenfall's Norfolk Vanguard and Norfolk Boreas are planned to be 47 and 73 kilometres from the shore respectively

The company chose HVDC over high-voltage alternating current (HVAC) for the two 1.8GW wind farms off the east coast of England because it believes it will be cheaper and minimises the impact on the local environment, it said.

Vattenfall argued using HVDC would avoid the need for cable relay stations, use a narrower cable corridor (45 metres instead of 100 metres), and be quieter because it uses fewer components that emit low-frequency noise.

The company also stated that it believes HVDC will be "cost competitive in the early 2020s".

Using HVAC would have required relay stations near the village of Happisburgh, Vattenfall stated. This possibility had sparked opposition from residents, according to reports in regional newspaper the Eastern Daily Press.

But announcing the use of HVDC, Ruari Lean, Vattenfall’s project manager for Norfolk Vanguard, said "concerns raised by local people" had influenced the company’s decision.

The company said it had held a public consultation and received "direct feedback from nearly 800 individuals and organisations".

Lean added: "By backing HVDC technology, we will minimise the impact on people and the environment whilst keeping the cost of electricity down for the British consumer."

Vattenfall said it would submit final plans for its 1.8GW Norfolk Vanguard site to the UK’s Planning Inspectorate in June 2018.

The developer expects to receive government consent for the sites at the end of next year and to complete the project in the mid-2020s, it stated.

It added that the Norfolk Boreas wind farm, also 1.8GW, is "one year behind Vanguard in its development". 

A cable provider is yet to be named.

Gunnar Groebler, the head of Vattenfall’s wind business, said the company would work with HVDC cable and component manufacturers as well as platform manufacturers and civil construction companies.

The projects formed part of the UK's Round Three East Anglia offshore wind development zone. The area was being developed by Vattenfall in a joint venture with ScottishPower Renewables.

However, the two utilities ended their partnership in August 2015, electing to split the zone and develop projects separately.