Tuesday, February 2, 2021

Onboard an offshore wind turbine

From The Telegraph by Andrew English

Where will the power for our electric cars come from?
We visit the Teesside windfarm to explore clean energy generation at first hand

Boris Johnson was in ebullient mood last October when he promised the Conservative Party conference that within 10 years offshore wind farms would generate enough electricity to power every UK home.
“Your kettle, your washing machine, your cooker, your heating, your plug-in electric vehicle – the whole lot of them will get their juice cleanly and without guilt from the breezes that blow around these islands,” he said, rehashing a Tory pledge to increase offshore wind capacity to 40 gigawatts by 2030 and promising the creation of 2,000 construction jobs, the support of 60,000 more, and that Britain would become “the world leader in clean wind energy”.

With current offshore wind capacity amounting to about 10 gigawatts, a subsequent study by Oxford-based consultants Aurora Energy Research reckons this pledge would cost £50 billion and involve a new offshore wind turbine being installed every day for the next decade.

So, was this a far-sighted future or just plain-old Boris bluster?
I thought about this without conclusion as I banged along in a chilly one-metre North Sea swell on the Windcat crew transfer vessel steaming south-east from Hartlepool’s historic docks to EDF’s Teesside offshore wind farm.
 Teeside Wind Farm in the GeoGarage platform (UKHO map)

Background – and some controversy

This 62-megawatt, 27-turbine facility was constructed between 2011 and 2012 and commissioned in July 2013.
Within sight of the imposing 12th century church of St Hilda’s on Hartlepool headland, it was north-east England’s first large-scale wind farm.

EDF's Teesside windfarm is so close to Redcar that it is variously described as offshore and onshore CREDIT: Andrew English

The nautical chart shows the 3.9 square-mile, three-row site of 27 sits on a shallow 10- to 16-metre sea bed of sandy gravel and shells about one mile off Coatham Sands, Redcar, just south of the dredged main shipping channel into the River Tees.

While crab- and lobster-pot fishing is still allowed in the farm, trawling isn’t because of the danger to cables, which didn’t best please local inshore fishermen, who pointed to a lack of research on effects on marine life of the rock “cable-armouring”, which creates underwater reefs.
Indeed, the Crown Estates, which leases the seabed, has just committed £25 million towards a five-year Offshore Wind Evidence and Change Programme, aimed at gathering evidence about how to protect and restore the seabed in the face of the unprecedented offshore wind bonanza.

Similarly, there have been issues with wind turbine blades killing seabirds on their feeding grounds such as the Hornsey site.

In addition, there’s a well-mannered standoff between the Royal Yachting Association (RYA) and some wind turbine operators – although not EDF.
The RYA is petitioning not to have total exclusion zones around wind farms as some operators would like.
With a minimum 22-metre blade height off the water at the highest of tides, most yachts can negotiate a wind farm and there have been no recorded incidents involving wind turbines and pleasure craft in UK waters.
The 27-turbine site is far from new; construction began in 2011 and it was commissioned in 2013 CREDIT: Andrew English

Yet, as an RYA source told Yachting Monthly magazine this year, some operators “are nibbling at the edges”.
As an aside, I found it extraordinary that the seafaring rules on radio procedure, identification lighting and identification for a vessel of limited manoeuvrability are generally observed in the breach in the wind industry.

Teesside is an EDF structure, but the “balance-of-plant” infrastructure contract was awarded to Dutch specialist Van Oord, with marine engineering specialist SeaRoc as principal contractor and Siemens as turbine supplier and operator of the farm for five years until EDF took over.
Wind turbines explained

These Siemens SWT 2.3 units are the Ford Focus of the wind turbine world, with the 93 model most suited to efficient generation in moderate wind conditions.
Prevailing winds at Teesside are south-west offshore and the farm starts to generate power from wind speeds of about 9mph (Force 3 in the Beaufort Scale, a gentle breeze), with their peak 2,300-kilowatt generation in wind speeds between 25mph (Force 6, strong breeze) to about 56mph (Force 10, storm).

Above that the blades are feathered so they don’t drive and the whole rotor assembly is braked to a halt – they should survive winds speeds of up to 123mph.
When they are spinning merrily (or “turning and burning”, as technician Richard Wardle puts it), the entire farm is capable of powering up to 40,000 homes (lately reassessed to 56,000) in the nearby Redcar, Marske and Saltburn areas.

The industry has settled on three-bladed rotors as the best compromise of power generation, cost, turbine speed and noise.
At Teesside each glass-reinforced plastic (GRP) rotor is 93 metres long and sweeps an area of 6,800m2.
Their maximum speed is 16 revolutions per minute, at which point the blade tips are travelling at 174.5mph.

Each of the three glass-reinforced plastic (GRP) rotors is 93 metres in length and sweeps an area of 6,800m2.
The turbines are designed to withstand wind speeds of up to 123mph
CREDIT: Andrew English

While Siemens is currently building direct-drive turbines, this turbine has a Winergy three-stage planetary gearbox, with an overall ratio of 1:91.
It takes primary drive up to about 1,500rpm and through the sacrificial drive coupling and into the 690-volt four-pole generator which delivers AC current at the grid frequency of 50 Hertz.

That current is increased to 33kV onboard the turbine, then the electrons are flowed back to land via twin undersea cables to the substation at Warrenby, where two huge transformers step up the voltage to 66kV for more efficient introduction to the National Grid.

Facing into the wind

The UK is well served with wind compared with the rest of Europe, but winds blow hardest and longest in the spring and at night.
To face the wind, Teesside’s turbines are controlled with a motorised yaw plate driving the entire nacelle assembly around according to the readings from the wind speed and direction weather station on the back.
English aboard the turbine's nacelle, which opens to permit maintenance
CREDIT: Joe Collins

Except it’s not that simple, since the readings are affected by the turbine blades and those of neighbouring turbines, which create their own propwash.
Pointing into the wind might not always be the most efficient and there’s software to adjust the direction accordingly.
In fact, there’s even turbulence between wind farms themselves and, in a few cases, one wind farm has had to pay compensation to another for wind turbulence.

You can find Teesside’s “load factor” figures on the Renewable Energy Foundation website, which shows it as middling in terms of its actual-against-theoretical maximum generation productivity.

James Wilson, EDF’s area manager, winces at the average figure of just over 35 per cent (the highest is a Scottish pilot project at 54.8 per cent), but says that’s mainly to do with the site’s location and its intermittent offshore winds.

What Wilson should be (and is) proud of, though, is Teesside’s operational efficiency, which for an older field is exemplary and as much to do with his team of crack technicians and engineers as it is the ease of access to the site.

Serious about safety: a week of training and induction

You’ll not find many reports from inside one of these remarkable machines; news reports tend to be filmed from dry land.
The reason for this became clear when I first enquired of EDF, the only company willing to hear me out and one that we’ve had a good relationship with over the years, about going aboard.
Long way up - and down.
English begins his ascent to the business end above
CREDIT: Joe Jackson

One of the reasons that the global offshore wind business has such a good safety record is that everyone who goes on a turbine has to have a minimum standard of fitness, a comprehensive medical and six days of intensive training in fire safety, sea survival, manual handling, first aid and working at height.

In spite of the fact that I’m a qualified yacht skipper, a former long-line fisherman, a strong swimmer and the heaviest thing I’m carrying is my Nikon, I was no exception.
I can report that the sea-survival training in the eight-degree water of a London reservoir was adequately bracing, although tutor George Buist at MCL training was very reassuring.

“Just about every turbine I’ve been on has been a very safe and professional place to work,” he said as he dragged me out; as a former blade-repair technician, he knows of what he speaks.
The wind turbine gold rush

“A journey inside the whale; you will see such things,” said John Constable, director of the Renewable Energy Foundation (REF) charity.
Constable is one of those trying to keep the hype over the offshore wind bounty in check, but it’s difficult not to feel excited – there’s a gold rush into offshore wind at present.

In June Bloomberg was reporting on an offshore wind investment bonanza, with $35 billion invested in the first half of the year including Vattenfall’s $3.9 billion Netherlands array and SSE’s $3.8 billion array planned for the Firth of Forth.
UK investment in the first six months was up to $5.7bn, more than 3.5 times greater than the total investment in early 2019.
The head of the turbine unit is rotated for maximum efficiency according to data from its own weather station
CREDIT: Andrew English

Even the young people on the MCL safety course were betting their future on wind energy in the same way young people have been at the sharp end of extractive industries throughout the ages.
It’s a tough life but, like mining or the oil rigs used to be, it can be lucrative.

In the relatively shallow waters of the Teesside Bay, turbine construction consisted of driving a 5.5-metre diameter steel monopile, weighing around 500 tonnes, 35 metres into the sea bed from a jack-up vessel and then gently lowering a 300-tonne yellow transition section on top.
These two sections provided the foundation for the 80-metre tower with an 82-tonne nacelle containing the gearbox, the rotor and blades, the sacrificial drive and the generator.
Finally onboard

The evening before going aboard I went to Redcar Sands to see the turbines, spinning like ghostly vedettes in the chill Westerly, their warning lights coruscating in the dusk.
The nearest ones are absurdly close by the beach and at various times Teesside has been termed offshore and at others onshore.

The morning brings brighter weather and while modern health and safety can sap the joy from any job, even trussed in steel toe-capped boots, warming fleeces, climbing gloves, safety goggles, helmet, a neoprene immersion suit and a safety harness hung with clattering work-positioning and fall-arrest systems, plus my camera bag, it’s hard not to enjoy the 20-minute transfer, seeing a seal and loads of black-headed gulls in winter plumage.
You have to climb from sea level to the lower platform (up the yellow bit, for those of us not of a technical disposition).
From there it's a rickety lift for the remaining 80 metres to the top CREDIT: EDF

Team leader Joe Collins has responsibility for taking control of the turbine as we approach, but the day’s paperwork and risk assessments have to be immaculate before the controller in EDF’s onshore base hands over the turbine into his capable hands.

There some clever machinery being developed for turbine access and egress, but here it consists of a tall, sea-swept vertical steel ladder, which you step on to while skipper Malcolm Kirton revs the Windcat’s twin Volvo turbodiesel engines and drives the bow into a couple of J-shaped tubes.

He has to decide if the transfer is safe, then his crewman and then I have a right of veto, although since Collins, Wardle and lead technician Joe Jackson have already swarmed up like a troop of monkeys (an animal close to the hearts of Hartlepool residents), it would be churlish to refuse.

So, I stand at the bow, clip on to the fall-arrest line and make the big step.
I don’t mind admitting that this moment (statistically the riskiest in the wind-turbine business) fair sparks up the old ticker and I almost leave finger indentations in the yellow steel rungs.
Coming back down is even worse.
Weighed down by an immersion suit and comprehensive safety equipment, English arrives at the lower platform
CREDIT: Joe Jackson

Thankfully EDF hasn’t laid out the red carpet; there’s no fresh paint, or top brass, I’m just part of the crew and the day’s jobs of replacing the galvanic anode plates in the monopile and lubricating the yaw plate gear are going ahead as planned.
Hands-on approach

The size of these turbines changes according to your point of view; up close they are enormous.
With ladders, height, high-voltage electricity and the sea, there are a lot of ways to get hurt (lightning is one of the biggest risk elements) so safety isn’t just a meaningless mantra.

The team have a close-knit camaraderie, which surpasses the pecking order and each member takes care of each other; Jackson asks me to check his harness and vice versa.
Ladders require complicated fall-arrest bracketry to be attached, which frustrates cold fingers.
“Take your time,” says Jackson gently.

The tower has a clanky, echoing quality as I climb the short ladder runs, while my gear graunches against steel.
We then cram into a two-person aluminium lift (what luxury), which clatters and grumbles up the remaining 80 metres to the yaw plate.
A brief climb to the top and I’m amazed to find the whole nacelle top has opened up like a gently lubricated Bond villain’s lair.
The turbine's nacelle opened ready for maintenance, showing the Winergy three-stage planetary gearbox in the centre
CREDIT: Andrew English

I stand up on the slightly greasy generator, feeling the whole tower swaying underfoot and marvel at the view of the windfarm and Redcar beyond.
It’s an irony that while the Teesside British Steel plant has closed at a time when steel is in high demand for newer and bigger windfarms, the turbine’s air-cooling systems are no longer coated in carbon-black emissions from the plant.
And there, in the distance, is the Hartlepool advanced gas nuclear reactor, which is also owned and run by EDF.

It’s a changeable day and pretty soon it’s raining and you can feel the chill to your bones; small wonder they try to pack the bigger maintenance jobs into the summer, like last year’s gearbox change.

Offshore wind is big, complicated and expensive engineering, and with the Hornsea and Dogger Bank and other big offshore wind farms under development, it’s increasing in all these aspects.

Government and green groups keep telling us that offshore wind is getting cheaper, but there’s evidence that if anything it’s getting more expensive as plant gets old and firms juggle capital against operational expenditure.

Last year's gearbox change required the use of a jack-up ship and took five days to complete

Most wind farms are calculated to have a 25-year life, after which most Crown Estates contracts demand the site is cleared and made good.
In that time, like all machinery, the turbines need looking after and can go wrong – and that maintenance cycle is complicated by the unquantifiable stresses imposed by salt water, high winds and UV radiation.

Giant automatic lubrication drums and careful design means a wind turbine should be able to look after itself for six months between essential maintenance.
But after eight years turning and burning, Teesside’s turbines are ageing and sometimes need replacement parts, which is entirely in line with the few studies that have been done on reliability.

“It’s mainly motors and pumps,” says Wardle.
“Things that are running 24/7; they take the strain.”

But while the Teesside turbines have required no blade replacements, last year’s transmission change, while well planned and executed, took five days of intensive work with a jack-up ship.
Time for a reviving tea within the nacelle atop the turbine once the job is finished
CREDIT: Andrew English

You can be sure that EDF will have done some pretty fancy calculations before taking over Operations and Maintenance (O&M) of Teesside from Siemens.
And one of the inputs to those calculations will have been the Government’s subsidies to renewable power generation, comprising: Feed-In tariffs; the Renewable Obligation; and Contracts for Difference, the last two aimed at larger generators.

Teesside, for example, received 369,772 Renewable Obligation Certificates in the 12-month period between 2018 and 2019, which are worth a lot of money.
Everything is complicated in this business and the financing is no exception.
The latest report from the Office for Budgetary Responsibility states that last year renewable subsidies amounted to about £8 billion and its figures project a total subsidy rising every year to £11.3 billion in 2025/26.

Gareth Jackson is Teesside’s head of O&M and pays moving tribute to his team, adding: “It’s good to be doing a good job and it makes it extra special to be doing a bit for the environment.”

And there lies the rub.
Offshore wind is doing its bit for the environment, but over-claiming its contribution is as short-sighted and idiotic as discounting it.
Harvesting the wind was never going to be free, or particularly easy.
To claim it is rashly ignores the amazing engineering design and the skills and bravery of the engineers and technicians who build and look after them.

We thank everyone at EDF’s Teesside farm for their kindness and generosity in allowing us on board.
Inside the hollow steel shaft that supports the entire windmill assembly
CREDIT: Andrew English

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