Robin Rigg, the offshore wind-farm
Aerial photo of the windfarm, with the substation and one of the service vessels just in view (my thanks to E.On for this image)
Note: this 'story' was written in 2011, when the wind-farm had been in action for a year. The pre- and post-construction marine survey is available here.
I have written more recently about the undersea picture, 'Seeing the sea-bed' as an illustrated post on my related blog www.solwayshorewalker.wordpress.com
We all have our own - often diametrically-opposed - opinions about wind-generated power and the turbines that produce it: but this is not a story about the pros and cons, rather it is a story about the place of the Robin Rigg offshore wind-farm and its social and human stories, in relation to the Solway Firth.
There's a small telescope on the windowsill of E.ON's main office, and on the clear but blustery day of my first visit, it gives a fine view of the wind-turbines rising elegantly from the sea. The morning sun is highlighting their pale columns and glinting on the shifting waves; the small red shape of the support vessel is just visible on the far side towards the Galloway shore; and a yacht is wallowing slowly up the Firth, goose-winged in front of the wind.
The 'Operations Facility'
E.ON's 'Operations Facility' for the Robin Rigg wind farm is at the Prince of Wales Docks in Workington and well-placed for the team to be able to look out across the sea and admire the objects of their efforts. The dockside building itself is two years old; only partly protected from the north-westerly winds by a low earth bank, it is light and spacious inside, its temperature controlled by an air-source heat-pump system. Sally Shenton, Robin Rigg's Site Manager, a cheerful woman in her forties who enthuses continuously about the project, takes me on a tour.
A bright office downstairs is where the Vestas technicians work; there are comfortable metal chairs, and desk space around two walls, with the usual monitors and keyboards. There are twelve technicians, but there is only one technician in the office today, and he explains that the Danish firm Vestas has the contract for supplying and maintaining the turbines. "The technicians are nearly all local now and are based here," Sally tells me, "but Vestas sends the occasional Dane."
We walk through into the Service Area, through the Mess Room with its cooking facilities and pale wooden tables, and Sally knocks on a door. " We'd better warn them!" she laughs: it's the Changing Area, but since there is no reply we carry on inside. It's empty apart from yellow waterproof jackets hanging on pegs; Sally opens another door into a small drying-room, where orange one-piece suits are crammed together on a rail, their boots dangling at different heights above the floor. These are what people wear when transfer onto the turbines, she explains; they can change into them when they're going out on the boat. I think the suits look uncomfortable with their thick, stiff, waterproof outer skins, and neoprene cuffs and neck seals, but they are elastic and apparently well-fitting inside. There are life-jackets, too, with Personal Locator beacons attached, and climbing helmets with head-lamps.
Then into the store-room, a large hall with a high curved roof and surprisingly warm despite its stark concrete block construction. Spares, tool-boxes and other kit are stacked around the walls, and several tall, blue, metal boxes, fronted with dials and displays, stand side by side - switch gear for the turbines, apparently.
There are blue plastic boxes, labelled simply with letters and numbers, stacked on shelves in the middle of the hall. These are the "bundle-boxes", collection boxes for kit that needs to go out for general maintenance. "For example, if a First Aid Kit is past its use-by date and no-one is working on the turbine, there's no point sending a boat out specially," Sally says. "So the next time someone goes out on a visit or has an urgent task, they take whatever's in the boxes - it saves time, it saves fuel, and it saves people's effort. You can tell we've just finished the annual service on the East part - those are the turbines with the letters A to E - because their bundle-boxes are mostly empty. We're just starting again on the West."
It's a long trip out to the wind-farm, especially on a choppy day, and the logistics of moving people and objects, some of them heavy, from heaving deck to ladder, could be pretty formidable.
"The trick with offshore wind is planning ahead and being organised. It's a half-hour boat trip out, you take half-an-hour getting people off the boat - and there's the same at the end of the day, getting them all off and into the boat and the trip back again. We aim never to forget things and to be extra-organised!"
"Some of our arrangements come from what has been done on other offshore sites, some we've worked out ourselves. For example ... there are 12 seats on the boat, and each person might have a couple of bags. Then there might be 15-20 orange lift-bags, so you can imagine the boat-deck gets crowded. The men were complaining, 'We always have to have a good old ratch around to find things we need'. " She shows me some rails on which are hooked coloured circular tags. "They came up with a simple scheme - fix the different coloured tags to the bags, according to which turbines they're needed on. It's not rocket-science, but it just helps by getting organised at the beginning."
Wind turbines: a tutorial
I had noticed, when I was looking through the telescope, that the blades of four of the turbines were stationary, and that the support vessel was pottering around their bases. "Two are off for foundation inspections, and two are off for top inspection," Sally says. There might be other reasons for breakdowns, although so far breakdowns have been relatively infrequent: "For example a sensor might fail - this happened fairly frequently early on - and if the motor doesn't get a signal it waits and then shuts down. Or the pump or the motor might have a problem. It's what they call a bath-tub curve -- you get more failures at the beginning when the system is new and running in, then they drop off to a low steady level - and then increase again near the end of the system's life as parts wear out."
I raise the question of the turbines "sinking into the sand", as recently reported in the local paper. Sally is exasperated: "They're not, nothing is sinking into the sand. It's an engineering problem that's industry-wide [in the offshore wind-turbine industry] and relates to the grouted connection at the base of the turbine. It is not affecting us in the short term but it is something we are needing to look at for the longer term. We're carrying out inspections to see how it relates to the conditions here."
Grout? This makes me think of bathroom tiles, and it's obvious that I need a tutorial in turbine structure, so we go back to her office and she draws me a diagram on the whiteboard with a red felt-pen.
First, a monopile is set into the sea-bed: at Robin Rigg, hammered in by the Resolution, the six-legged jack-up barge. Then a cylindrical transition piece (TP), with a flat top onto which the tower will be bolted, is set on top of that (the TP is "the yellow bit" with ladders and an outside tubular duct that holds the cables) and held in place with grout - this method of construction allows the TP's top to be adjusted so that it will be perfectly level. The main cylindrical part of the turbine is the tower, 80 metres high, with a ladder, the cable and a cage-like 'man-rider' system inside. At the very top is the structure that looks like a caravan, the nacelle, containing the mechanical parts, gears, generator, and a transformer that transforms the voltage to 33 KiloVolts. Additionally, there's a small mast at the back of the nacelle, supplying the information on wind direction that informs the aspect to which the tower should turn and best capture the wind.
The hub, to which the blades are attached, houses the hydraulics for the pitch of the blades, which can twist or feather as well as turn.
As for the blades themselves, they are smooth and light, made of a glass-fibre reinforced polyester; each is 44m long, making the total width, just short of 90 metres, "equivalent to the length of a football pitch", as Sally tells me. These figures wash over me: but just pause for a moment and imagine a circular football pitch, sweeping through the air, round and round, unceasing; nearly 6500 square metres 'captured' on each revolution .... Follow the tip of a blade, rotating at anything between 8-18 revolutions per minute and imagine the speed - an average of 170mph - at which it must be moving to draw the circumference of that circle.
The Solway's sea-bed
Elsewhere in these Shore Stories people have talked to me about the continual changes, both short-term and on a geological time-scale, in the sea-bed and margins of the Firth. Whenever man-made constructions are inserted in the Firth, from willow-hurdles and groynes, piers and harbour walls, to wind-turbines and proposed tidal barrages, the wind and water-currents cause the sea-bed to change and compensate, in ways both hoped-for and unexpected.
David Dobson, Director of Operations for the Inshore Fisheries and Conservation Authority, says of Robin Rigg, "For the fishing industry, let's say it hasn't proved any worse than expected. The Silloth fishermen feel that the bathymetry of the Solway has changed drastically. But it's too early to tell whether this will have an impact on brown shrimp catches." The fisheries' protection vessel, Solway Protector, has new sea-bed mapping instruments which are proving useful for looking at the changes. "There's no two ways about it - the Solway's extremely dynamic - and if you put something in the middle, like a mass of turbines, you're bound to get changes."
It's still early days, but it will be interesting to see how the feet of those 60 towers affect the Firth.
Electricity: what it's all about
The Robin Rigg turbines turn and generate power at wind speeds between 3 to 25 metres per second, but they shut down in a strong gale. Each turbine - Sally, of course, has given this tour many times and has all the numbers ready for instant recall - can generate 3MW, so that the whole windfarm will generate 180MW if all 60 turbines are working at full capacity. "Annually they will generate enough power for about 120,000 homes, equivalent to half of Cumbria. And we rarely have a turbine broken down for more than one day - though of course if they can't get out in the boat it might be longer." Her exasperation spills over again: "The press like to concentrate on the bad news, and to find something that's going wrong. I'd love to see the local paper with a headline 'Cumbria's Robin Rigg is the best- performing off-shore wind-farm'! We're currently Vestas' top-performing site, our turbines are working 98% of the time."
Ninety-eight percent, that is, of the time in which the wind is suitable.
A screen in Sally's office shows the day's target for generation as a green line, the predicted generation in purple, and the actual generation in red - there is a reasonably close fit. "Each day the wind brings different challenges - and variations on existing challenges," she says. On my second visit the indicator inside the front-door shows that Robin Rigg is generating only 76MW: many of the turbines have shut down because the offshore windspeed is more than 55mph. No wonder, then, that the service vessels are back in port having a "weather day".
The electricity generated is fed into the off-shore substation. Each of the substation's two platforms houses various modules that include switch gear, a standby diesel generator, and a big transformer that boosts each turbine's voltage from 33kV to 132 kV, ready to join the National Grid. "The higher voltage means that we have smaller losses as it comes ashore," Sally explains. An undersea cable brings the electricity ashore at Siddick beach, to a substation at the back of Seaton, and thence into the Grid via Electricity North-West's pylons that head South past Sellafield. In 2011, the Electricity Regulator Ofgem ruled that cabling and grid links for offshore windfarms must be owned and operated by an OFTO, an off-shore transmission operator.
The small Control Room is, for me, the most exciting part of the 'Operations Facility'. From its windows we can see the reality of the windfarm, but here on the bench beneath the window are two monitors, each showing bright white virtual turbines and the substations spaced in a bright blue sea.
Steve Johnson, Windfarm Engineer, starts to tell me about the data-monitoring, but suddenly one of the engineers out on the service vessel comes on the radio, asking for a system to be temporarily switched off, and Steve swings across the floor on his wheeled chair and busies himself at a keyboard, meanwhile talking on the radio.
We're in the way, and instead Sally hands me a cross-section of the cable which carries the electricity from the substations to the land. It's a piece of art as well as an elegant piece of engineering. When I admire it, she laughs and says that quite a few people have said they'd like to take it home.
Two rings of lead and steel armouring surround and protect the three copper cables which carry the current, and a small data-core, off-centre, carries the digitised data from the whole wind-farm. "There are 14 kilometres of cable," Sally tells me,"and it was laid in one piece, and is buried between one to four metres deep in the sea-bed."
There is a 50-metre protection zone around each turbine, and of the many screens of information being fed into the Control Room (there are also separate PCs for weather reports and sea-state), one is a chart of all the shipping in the Firth. Not only are large tankers and container ships coming to the Ports of Workington and Silloth, but there is all the fishing traffic, too, especially trawlers: hence the need for a protection zone and to bury the cable as deep as possible.
Steve now has the time to show me just how much we can find out onscreen about the distant turbines. Click on one of those bright white images and you can access diagrams of its different parts, and their current technical data: the wind speed, the direction the blades are facing, the angle of the blades and how fast they are turning, the power output, the temperature and pressure of hydraulic fluid ... There are layers upon layers of information. "Sometimes when faults are picked up onscreen they can even be fixed here, from the shore," Sally explains, "rather than by sending out a boat."
In 2011, on my first visit, Robin Rigg had two support vessels, Windcat, and the Solway Spirit which was named by the pupils of Ewanrigg School in Maryport. The Spirit has also helped in two yacht rescues - several of the eighteen or so people who work with the vessels are Lifeboat Volunteers.
Presumably they are not the ones who suffer from sea-sickness?
Sally tells me that, "In the early days when we were recruiting the team, there were a few people who pulled out because they hadn't kind of twigged it meant going out on a boat."
The windfarm provides forty to fifty permanent jobs, and Sally is clearly proud of the team and what they do. "We all come from a variety of backgrounds, that's probably why we're so successful as a team. Some people had some sort of power-generating background, either in gas or coal, or they came from Sellafield. There's even a car mechanic - there are all sorts. Most of us had never been near a windfarm in our life before this - we've learnt from the existing farms, and then built on what we knew. One of the engineers came here from building bases at the Antarctic, Steve Johnson in the Control Room was on nuclear submarines, he has a great understanding of marine stuff and the sea in general."
Sally herself moved here with her family three years ago. "I love it, everyone is so friendly." This is her twentieth year working with E.ON. "It's goldwatch time in September for me - I'll probably get a certificate or something!" she laughs." I love it! I started off in technology, then went into coal-generation, and gas-fired power-plants - I've always been in power-generation. It's so important to be able to provide something that's so essential in everyday life. I've got two daughters, and I'm really happy that I can look them in the eye and know I've done something to improve their future."
By coincidence, my visit is almost on the first anniversary of Robin Rigg's completion on April 20th 2010. Not long before that, the Robin Rigg team had to deal with an entirely unexpected natural disaster, the November 2009 floods. When Workington's Northside Bridge went down, "We lost all our data links and phone lines because the cables were on the bridge. It was a testing time for a very new team. But our divers helped to remove a lot of the débris from the harbour."
Robin Rigg is working in other ways to help the West Cumbrian and wider Solway community. Emma Steele, the Office Manager, joins us to talk about the Community Fund of £1 million over ten years, which E.ON has set up to be shared between Dumfries & Galloway's six community councils, and the Community Council Fund in Allerdale, Cumbria. "We work with the Solway Firth partnership, and sponsor their Tidelines magazine," she tells me, "and we've got our mobile E.ON Visitor Centre, which we send out to schools, and community events and shows like the Dumfries and Galloway show and the World Ocean Week at Rockcliffe, to explain about sustainable energy production."
Emma and Sally also tell me about the wildlife survey work that is being carried out. The IFCA's vessel, Solway Protector, is often used to help in surveys, and during the construction phase, birds were surveyed monthly by Steve Percival; the surveys of benthic and foreshore fauna were carried out by Dr Jane Lancaster, Senior Marine Ecologist at consultancy Natural Power; there were surveys for underwater noise; for the effect if any of the underwater cables on electroreceptive fish like the thornback rays; and surveys of migratory fish in Scottish rivers, and of marine mammals. All these data have recently been given to the Steering Group, comprising the Scottish Government, Scottish Natural Heritage, English Nature, the Scottish Environmental Protection Agency, and the Galloway Fisheries Trust, who oversee and monitor the data. (The report on the Year 1 data is now, in 2014, publicly available here .)
Later, the crew of Windcat told me they had been seeing a lot of big seals out by the towers, and often saw porpoises - but they hadn't seen any minke whales for quite a while and basking sharks were not yet around in the Solway, although were apparently off the Isle of Man. They have also seen an alien and a pink pig .... (And for that story, you'll need to read 'Robin Rigg's Service Vessels')
Text is copyright of Ann Lingard. June 2011, and 2015. (The text was subject to approval by E.On's press department)