Offshore wind turbines are so good at wrecking radar defence systems, they look like active enemy espionage.
Wind turbines standing on columns 100-150m or more above sea level, with the tips of their 50-80m blades clocking 350 kph play havoc with radar systems, giving false images and distorting real ones. The result is unnecessary danger for pilots dependent upon accurate weather reports, and air traffic guidance, both essential for safe takeoffs and landings.
In a number of States, the US military has obtained legislation to prevent the construction of wind turbines anywhere near their airfields and training grounds.
Now Britain’s Ministry of Defence has finally read the memo, as Gareth Corfield reports.
How wind turbines are blinding the RAF’s vital North Sea radars
The Telegraph
Gareth Corfield
3 November 2023
Britain’s race to net zero risks blinding crucial radars protecting the UK from incursions over the North Sea amid fears that Russia will launch a campaign of sabotage.
Offshore wind farms blades interfere with radar signals and there are concerns that plans for a significant expansion of turbines in the North Sea by the end of the decade will cause problems for the Royal Air Force (RAF).
The Ministry of Defence has spent £18m over the past three years trying to stop wind farm blades from scrambling radar readings, the Telegraph can reveal.
However, none of this public spending has, so far, yielded a concrete solution to the problem.
Dangers in the North Sea are more than theoretical: a “ghost fleet” of Russian ships were spotted mapping communication and power cables in the area earlier this year, sparking fears that the Kremlin is preparing for a campaign of sabotage.
With ministers hoping to build another 35 gigawatts (GWs) of offshore wind capacity over the next seven years, national security must now compete with energy security.
Defence sources say the problem lies in how wind turbine blades reflect the electromagnetic pulses used by RAF radars to detect aircraft.
These so-called “primary radar” pulses are reflected by aeroplanes, sending a signal back to aerials housed in giant ‘golf ball’ domes around the UK’s coastline that register their position.
However, metal turbine blades also reflect radar pulses, generating false returns that can flood operators’ screens with nonsense information.
A serving RAF officer explains: “If you have three blades on one turbine, that’s three false reflections. Imagine you then put up 10 or 20 turbines.”
One existing wind farm off Scotland, known as Moray West, comprises 60 turbines. A future development, the Morven wind farm south-east of Aberdeen, plans to include up to 192 turbines stretching across more than 20 miles.
Rob Ward, an analyst with radar maker Lockheed Martin, which supplies the RAF’s air defence equipment, says the move towards bigger turbines and shafts in recent years has created the problem.
“When they were the height of Big Ben it was never a problem. Now they’re the height of the Shard.”
North Sea turbines can span up to 80 metres (262ft) each, with the tallest rising more than 200 metres (656ft) from the sea’s surface.
Former RAF Tornado instructor Tim Davies recalls using offshore turbines to hide from ‘enemy’ fighter jets during training exercises.
“We used to fly into wind farms and rapidly change direction, knowing that their radar would struggle to see us,” he says.
So far, efforts to fix the radar reflection problem have been slow. The government’s Defence And Security Accelerator (DASA) has been running a special wind farm mitigation project since 2019.
A Government whitepaper from the DASA project’s outset explains that a ministerial target for getting a slew of new wind farms online by the end of 2025 “drives a very compressed procurement timeline with associated greater risk”.
The pressure of finding a solution has eased somewhat in recent months, after the failure of the Government’s recent offshore wind farm auction to attract any bids. Companies said the electricity price offered by the Government was too low.
However, the Government has maintained its target of reaching 50GWs of offshore wind power capacity by 2030 and there is speculation that Chancellor Jeremy Hunt will signal support for the industry in his upcoming Autumn Statement.
Industry figures are nervous of talking about how security issues could potentially slow approvals of new wind farms.
A Ministry of Defence spokesman said: “We have robust multi-layered systems that detect and deter potential threats to the UK. Our network of air defence radars is only one layer of that protection.
The Telegraph
STOP THESE THINGS 
I cannot see why Russia would try to sabotage the UK when the politicians and bureaucrats are doing that as rapidly as possible.
The problem with wind turbines near airports is that the radars are “frog’s eye” radar: They only see moving things, so mountains and buildings and trees don’t appear on the air traffic controllers’ screens. But turbine blades do appear.
There is an enormous and quite old wind farm stretching down the east side of San Gorgonio Pass in southern California toward Palm Springs. Several of my friends who are private pilots refuse to fly into the Palm Springs airport. Another friend who lives near Palm Springs and travels a lot refuses to use the Palm Springs airport. She prefers to drive two hours to use the Los Angeles International airport. Now California wants to put floating turbines at sea.