Military radars will have to be built in north Norfolk because of a huge offshore wind farm.

Eastern Daily Press: Trimingham Radar Station.PHOTO: ANTONY KELLYTrimingham Radar Station.PHOTO: ANTONY KELLY (Image: © ARCHANT NORFOLK 2011)

Up to 200 turbines 350 metres high could be put up by energy firm Vattenfall 50km off the north-east Norfolk coast.

But the Vanguard wind farm will harm the ability of the Ministry of Defence radar station at Trimingham to operate.

The MoD warned in December 2017 that the turbines would have a 'significant and detrimental affect' on Remote Radar Head Trimingham.

It said the turbines would appear as targets to its radar and aircraft could disappear from radar screens.

But Swedish firm Vattenfall and it and the MoD had now agreed on steps to mitigate the impact.

In a letter on January 25 to the Planning Inspectorate, which is expected to decide Vattenfall's application this year, the MoD said the mitigation 'will entail the applicant providing separate radar(s) located to provide infill coverage to the air defence radar at Trimingham.'

But it did not provide any details as to how big the new radar installations could be, how many there would be or where and when they would be built.

Vattenfall said those details were commercially confidential.

Ruari Lean, from Vattenfall, said: 'All relevant parties agree a constructive dialogue relating to aviation and radar safeguarding is underway and that a mitigation proposal recently submitted by Vattenfall has been accepted by the MoD.'

The Vanguard farm will create cleaner energy for hundreds of thousands of homes, but it has drawn protests from groups across the county.

To connect the farm to the National Grid a huge cable trench 45 metres wide and around 60km long will be cut from Happisburgh on the coast to Necton where new substations will be built.

A second farm called Boreas is also planned by Vattenfall near the Vanguard farm.

When up and running in the mid-2020s, Vanguard's 1.8GW capacity will produce enough power a year to meet the equivalent electricity demand of 1.3 million UK households, Vattenfall said.

Meanwhile a third huge wind farm called Hornsea Three is planned off the north Norfolk coast by Danish firm Orsted.

That will see a second cable corridor cut from Weybourne to Swardeston.

•Flashback to 2011

In 2011 this newspaper reported that a new American-built piece of kit would mean Trimingham radar station would not be impacted by wind farms.

The station, also known as the golf ball, was reported to be getting a 'turbine friendly' radar.

At that time the MoD feared Trimingham would be harmed by new wind farms in the Greater Wash area.

But the new piece of kit opened up the area to more applications without the MoD objecting.

However since then wind farms have got bigger and the new turbines Vattenfall wants to build at its Vanguard farm are 350 metres high.

The size of the farm would also impact civil aircraft with air traffic controller NATS raising an objection.

But to mitigate against that planes are expected to be diverted around the wind farm airspace, NATS wrote in January to the Planning Inspectorate.

Vattenfall said it was still in discussion with NATS.