Every year, thousands of tourists travel to the northwestern corner of Castellón, a province on Spain’s Mediterranean coast, to visit some of Europe’s oldest and most plentiful cave paintings, dating back to the Stone Age. With rich images depicting archers hunting stags, boars and bears, as well as other scenes, the caves are now a UNESCO World Heritage site and have survived for millennia thanks to the area’s hot and dry weather — the same conditions that lured the world’s largest maker of blades for wind turbines to the area.
LM Wind Power opened a factory 11 years ago amid olive groves in the broad valley below the caves, drawn by a climate that made it possible to store dozens of finished blades in huge, open-air lots and a location that made it easy to ship to nearby wind farms — some of the nation’s first.
José-Luís Grau, who has been running the LM Wind Power plant since the start, remembers the early days with a hint of nostalgia. A decade ago, workers here were making blades measuring 37.3 meters — about one-third the length of FC Barcelona’s Camp Nou field, but an easy distance compared to the 73.5-meter behemoths they make now. And the LM Wind Power team is now getting ready to help make the blades for the world’s most powerful offshore wind turbine, GE Renewable Energy’s Haliade-X. The 107-meter blades for this 12-megawatt turbine will be 2 meters longer than Camp Nou’s field, and LM Wind will manufacture them at a brand-new factory in Cherbourg, France.
Doubling the size of the blades — from 37.3 meters attached to 1.5 MW generators to 73.5-meter blades with 6 MW generators — enabled the team to build machines that can harvest four times as much energy. But the large size also brought outsize challenges.
For starters, the number of workers at the plant has doubled from 300 to over 600 in just two years. After undergoing five weeks of new-hire training, plus additional on-the-job learning, the hive is ready to start production.
Assembling each blade is a well-orchestrated affair that takes around two days and 100 people, with crews working round-the-clock shifts to keep up with demand. “Instead of working five days a week, we keep going through the weekend,” Grau says. “That means that we have to manage exponentially more complexity not only in terms of process, quality and safety but in terms of people as well.”
It’s an intense scene, and for good reason. The blades must be well-made because once they leave their idyllic birthplace, some will endure punishing gales whipping up over the North Sea and other extreme weather on land or out at sea. “Customers invest a lot in these blades, which are going to be installed in the sea 30 kilometers from the coast,” Grau says. “Problems are costly to fix. They need to trust us and our process that we will be able to deliver.”
From Liquid To Solid
The manufacturing process is an interesting hybrid of the latest digital technologies — the teams here, dressed from head to toe in white Tyvek suits, use robots and sensors to precisely monitor production — and manual labor. To grossly simplify, workers make the blades from a “sandwich” of fiberglass fabric and balsa wood. They lay out the material, which resembles a long white carpet, inside large blade forms that look like one-half of an enormous split peapod.
It takes a dedicated team, working in concert to lay down the materials and following a precise formula. They work closely with a team of inspectors, who make sure everything is in order before they pass the blade to the next group.
That team covers the blade with an airtight transparent foil and attaches a set of tubes that suck out the air and install a network of tubes that act as veins pumping in and evenly distributing several gallons of the molasseslike resin.
Maintaining a stable vacuum is crucial because it enables the right amount of resin to permeate the structure — too little could result in air bubbles in the blades, and too much could cause structural and mechanical problems. They use more than a dozen sensors per each half blade to monitor the conditions inside, including the pressure, temperature and vacuum levels, while another group of workers monitor closely from above.
After the resin cures, they remove the blade’s protective wrap using a crane. Then another team picks up the two halves using powerful vacuums attached to the crane, which is capable of holding up to 12 tons, and moves each one to a large “cradle” that looks like the skeleton of some prehistoric reptile.
Once the blade is in place, workers glue in a special piece for structural integrity, close the mold and stick the two halves together with more fiberglass and resin. During the process, they use precise lasers to make sure that the blade’s aerodynamic shape has the right curves.
Once set, the now unified blade is ready for post-molding. Part of this process includes adding a special coat of paint just for the leading edge of the blade, which can reach speeds of up to 300 kilometers per hour when it’s windy — faster than the takeoff speed of a Boeing 747. The coating protects the blade from dust particles and water droplets colliding with it at Category 5 hurricane wind speeds. Finally, workers add the flange and bolts at the root that allow the blade to be attached to the wind turbine’s rotor, and a special metallic strip at the tip that acts as a lightning rod.
The managers use sensors and data to monitor every production station and feed the information to software that allows workers to visualize individual steps on large monitors in the factory. This way, they can compare the production process with other LM Wind Power factories — in Denmark, where the company has its headquarters, but also in Poland, the U.S. and elsewhere in the world. “Every day we share the information with our quality and production teams and we have daily meetings where we try to figure out how to maximize output and reduce cycle time,” says Elena Díaz-Albo Fernádez, site engineering leader at the factory.
This obsession with data and analysis is at the root of what Díaz-Albo calls “continuous improvement.” The team even started experimenting with virtual reality, using an interactive overhead projector that will guide workers during assembly.
Another project involves attaching sensors to the blades and monitoring them in transport. “We want to make sure that they are not exposed to excessive vibrations before they are attached to the turbines,” says blade production manager Abel Mateu.
Which brings us to another crucial — and tricky — part of the process: transportation. Workers move as many as 10 finished blades per week to an outside storage lot, where another team hoists them onto specialized trailers using a pair of giant, crablike lifters. From there, trucks haul them to a port in Castellón de la Plana some 30 miles away.
These convoys are quite a sight. Two of them leave the plant every day, with each truck-and-trailer measuring a whopping 100 meters. Grau’s team spent 13 months working with state and local governments and the port authority to figure out how to move the first monster blade to port, removing lampposts and street signs, as well as paving paths across tight roundabouts. The first transport a few years ago took nearly five hours, but the logistics teams together with the driver are now able to make the trip in 70 minutes. The final destination for some of these blades will be Merkur, a 396 MW offshore wind farm in the North Sea of Germany that will use 66 GE Haliade 150-6MW wind turbines.
But Grau is already thinking about LM Wind Power’s next project — the 107-meter blades for GE’s Haliade-X 12 MW turbine. While his plant will help produce the prototypes, the blades will be too long to send down the road when production picks up. That’s why LM Wind Power started building a new factory in Cherbourg, right on the Atlantic coast. It’s set to open early next year.
When it comes to wind turbines, bigger is better. So that's why we made this enormous offshore wind turbine blade. http://invent.ge/2z55XBs
Posted by GE on Wednesday, December 20, 2017