Researchers at the Oak Ridge National Laboratory have developed a low-cost carbon fiber that could reduce the cost of wind turbine blades.
The fiber begins as a widely available raw material used in the textile industry which contains thick bundles of acrylic fibers. The material is heated, which converts any fiber in the material to carbon. The fibers are converted into planks using pultrusion, a process similar to extrusion, except that the material is pulled through a die rather than pushed through. This process creates carbon fibers with the strength and performance characteristics suitable for the manufacture of wind turbine blades. The process is also well suited to be scaled up to high volume production.
ORNL sent samples of its new fiber, composites made from it, and similar composites made from commercially available carbon fiber to Montana State University to compare their performance and measure their mechanical properties. The MSU team also included standard fiberglass composites in the study.
Researchers at the Sandia National Lab then took the vane mechanical properties and cost modeling results from ORNL, and used them to analyze a theoretical turbine blade model using the new carbon fibers in composites for the spar cap, the main structural support.
They found that the new fibrous material had 56% more compressive strength per dollar than commercially available carbon fiber, the industry benchmark. Typically, manufacturers compensate for lower compressive strength by using more material, which increases the cost and weight of the blade. The team estimates that the new material would reduce the material costs of a spar cap by around 40% compared to commercial carbon fibers.
The new fiber also reduced expected material costs compared to fiberglass for land-based turbines, thanks to its improved fatigue resistance and longer life. The cold turbine also be designed differently to achieve even more advantages in terms of costs and performance thanks to the new carbon fiber.
Turbine engineers know that carbon fiber blades weigh 25% less than traditional fiberglass blades, and carbon fiber blades can be longer than fiberglass ones and capture more energy in them. low wind locations. A switch to carbon fiber could also extend the life of the blade, as carbon fibers have greater resistance to fatigue.
Due to the high cost of carbon fiber composite blades, only one company uses them extensively in their blade design. But wind turbine blades are the largest one-piece composite structures in the world, and the wind industry could represent the largest market for carbon fiber materials by weight if a material that rivals in terms of cost. fiberglass reinforced composites were commercially available. The new carbon fiber could open the door for that to happen.
However, the wind power and carbon fiber industries do not currently overlap. The wind industry designs wind turbine blades using only commercially available materials, and carbon fiber manufacturers face a barrier to innovation due to the high investment costs associated with the introduction of ‘a new production line for the wind industry.