Siemens Gamesa SG-14-222 turbine. (Siemens Gamesa)
George Harvey
The wind turbines that generate electricity for power grids are not small. In fact, they are gigantic. The largest have blades that are a good deal longer than a football field, including end zones. And, of course, they weigh quite a lot. They are supposed to last longer than twenty years, but they do fail earlier than that sometimes.
Wind turbine blades are not easy to design and build. They have to be as light as possible and somewhat flexible, but strong and stiff enough to hold up to the wind. Ideally, they have some built-in system for dealing with lightning. For most sites, they should be capable of being heated to prevent ice buildup. Usually, they are made with fiberglass and resin to provide for these needs, but there are additions ranging from carbon nanotubes for strength to copper wire for electrical conductivity.
The result of all of this is that wind turbine blades, which can be massive, have historically been difficult to recycle. Reusing them has been investigated, including such things as cutting them up to make such things as foot bridges and bicycle shelters. But a really good recycling system would need changes to the list of materials used to make them.
Siemens Gamesa, one of the world’s largest wind turbine manufacturers, has been putting a lot of effort into building new blades that are easier to recycle. Over a period of ten months, they developed a new type of recyclable blade. According to Marc Becker, CEO of the Siemens Gamesa Offshore Business Unit, they started the design project in September of 2021, and they actually began field testing at the Kaskasi wind project in the North Sea, north of Heligoland, in July of 2022.
The Kaskasi wind farm has 38 turbines and a nameplate capacity of 342 megawatts (MW). The turbines, each of 9 MW, are huge – far bigger than any normal, land-based wind turbine. The blades for the turbines at the Kaskasi wind farm are 81 meters long. That’s almost 265 feet, for each blade. Clearly, the length is one of the big reasons that a machine of this size would be so hard to put up on land – it’s hard to turn a corner with a 265-foot long trailer in tow.
The new blade technology was not used on all the turbines at the Kaskasi wind farm, but according to Siemens, a number of them do. Of course, the company will have to let them spin for some time to find out whether they are as good as they need to be, so the test will go on for a while.
The materials in the blades can be separated by a mild acid, but the components will not be recycled into new turbine blades when that is done. Instead, they will be made into other products, ranging from suitcases to the casings for flat-screen TVs. Siemens made it clear that all of the materials in the new blades can be recovered and reused, without any need to use other resources.
The blades are to be marketed under a RecycleBlades brand name. RecycleBlades will also be available for SG 14-222 DD and SG 14-236 DD turbines. These are the new 14-GW Siemens Gamesa turbines, which are among the largest on Earth. The blades for these turbines are 108 meters and 115 meters long respectively. A football field, with end zones, is just a bit less than 110 meters.
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