Wind energy is one of the most widely used renewable energy resources. Tens of thousands of turbines operate around the globe to generate pollution-free power. But as this transition to cleaner energy accelerates, one significant issue emerges. What will we do with giant wind turbine blades when they are no longer needed?
Learning About Wind Turbine Components
Today’s wind turbine blades are an incredible feat of engineering. They can grow to over 80 meters long and weigh several tons. They are manufactured with high-tech composite materials, such as fiberglass and epoxy or polyester resins. This combination of materials creates parts that are lightweight and incredibly strong so they can withstand the most challenging weather conditions for years to come.
Methods have been developed in the manufacture of carbon-fibre-reinforced composites for wind turbine blade fabrication that represent an important advancement in materials science. Fibreglass is considered the primary material for constructing the majority of the blade structure, while resin matrices bind the fibre together. In order to increase stiffness, engineers will also add additional layers such as carbon-fibre reinforcement; to reduce the overall weight, foam cores are incorporated; and to create a weather-resistant surface, gel coats are often used. All of these attributes create a very complex product capable of efficiently converting wind energy into usable energy while simultaneously maintaining the mechanical stability of the blade through cyclic loading due to bending, thermal cycling, ultraviolet exposure, and moisture ingress.
The same qualities that make these materials excellent for use in wind turbines also mean they can be virtually impossible to dispose of safely once destroyed. Thermoset resins, for example, have intermolecular bonds which cannot be released or broken as with thermoplastics. Therefore, the recycling of outdated turbine blades will require a very complex system.
Understanding the Size of the Issue
The wind energy sector in Europe has been the frontrunner in developing renewable energy; however, it is now facing its first challenge of blade disposal. Experts estimate a yearly disposal of approximately 25,000 tonnes of wind turbine blades by 2025; this number could increase to 52,000 tonnes annually by 2030. Countries with established wind markets, such as Germany, Spain and Denmark, are already addressing the issue of increased waste.
US wind farms that were built during the 1990s and early 2000s are nearing their end-of-life and present challenges for the future generation of power from the wind. In Asia, growing demand for wind energy will create similar issues within the next decade. The worldwide impact of this issue will require companies to manage hundreds of thousands of tonnes of composite materials.
Right now, it is possible to recycle 85 to 90 percent of a wind turbine’s parts using existing techniques. Steel towers can be melted and reshaped, copper wiring can be reused, and electronic parts can go through standard e-waste recycling systems. But the blades are a big issue. Most of the time, they are either buried in landfills or put in storage for years, which goes against the friendly reasons behind choosing wind energy in the first place.
New Methods to Recycle Wind Blades
The recycling sector is exploring different ways to handle old wind blades. Each method comes with its own set of benefits and issues to solve.
Mechanical Recycling is the most basic method. Machines like industrial shredders or diamond wire saws slice the blades into smaller parts. Next, they grind these pieces into various sizes of particles. These recycled materials can be used to make cement filler concrete aggregate, or support lower-quality composite items. This method is straightforward and already in use, but it reduces the value of the material instead of recovering it.
Pyrolysis Technology breaks down the resin matrix by applying heat in an environment without oxygen. This technique retrieves glass fibers in a intact state and changes the resin into oils and gases that can be used as fuel. The retrieved fibers, while not as strong as new ones still hold enough value to be used in making new composites. Some companies are expanding facilities made to handle wind turbine materials using pyrolysis.
Solvolysis Methods rely on chemical solutions to dissolve resin matrices but leave the fibers unharmed. These methods may include using high-pressure heated water organic solvents, or designed chemical mixes. This process provides the best quality fibers for reuse, but scaling it up for larger operations remains hard because of the high cost of recovering solvents and the complicated process involved.
The chemical recycling process converts fiber and resin back into their fundamental molecules. This allows for the manufacture of new materials comparable to the original products. Chemical recycling requires a significant energy expenditure and highly sophisticated technology; therefore, this method provides a comprehensive solution for recycling. Many chemical manufacturers and laboratories are making significant investments into the development of low-cost methods to chemically recycle composite wind turbine blades.
Wind-Sourced Electricity: The next step is to prepare for reusing end of life turbine materials. Companies and entrepreneurs are developing new ways to produce wind turbines that will perform better than current turbine designs; however, they also have a focus on the recyclability of their blades after they have been used in wind farms.
Currently, thermoplastics are being evaluated for this purpose. A unique feature of thermoplastics is their ability to be melted down and remolded into new products, making recycling easy. Some thermoplastic resins now exhibit mechanical performance features very similar to those of thermosets, as a result of improvements in manufacturing processes, but are still recyclable. As a result, commercial companies have begun developing wind turbine blades made of thermoplastic materials. However, the entire process related to manufacturing must still be addressed, as well as additional durability tests to determine long term durability.
Resins made from plants give another way to improve sustainability. These resins rely less on petroleum chemicals and might break down more when no longer in use. Natural fibers like flax or hemp could swap out fiberglass in certain parts of blades, enabling creation of bio-based composites for jobs that do not need as much structural strength.
Designing modular blades that break down into recyclable parts can bring big changes to wind blade recycling. If producers manage to build blades where materials come apart , it will make recycling much simpler and faster. Each part, like the outer shell, foam cores, and reinforcement pieces, can go into the right recycling process instead of being handled as one mixed unit.
New Uses for Old Blades: Not Just Recycling
Creative minds are finding ways to reuse old wind blades. Wind turbine blades are a great resource for engineers to create many new tools and structures. Blades provide a great deal of strength due to the way they are made and the way they are shaped in a curved manner, and engineers take that strength and use it to design and build pedestrian bridges. Blades have also been designed and formed into playground equipment, benches in parks, bus stop shelters, and outdoor furniture.
The business case for recycling wind turbine blades becomes more compelling as disposal costs increase and the market for recycled materials continues to grow. The disposal fees for large composite blades can easily reach into the thousands of dollars, making it a more cost-effective option for manufacturers to recycle.
Things to Think About: Economy and Environment
The economics of recycling wind turbine blades continue to improve as waste disposal costs increase and as more markets become available for the recycled raw material. Composite blades for wind turbines are typically several thousand dollars each to dispose of through a landfill, which increases the value proposition for the wind turbine industry to recycle their blades; In addition, more regulations within the European market, among other places, have and will continue to limit the amount of composite waste generated and sent to landfills, hence creating a compelling reason to create an efficient method for recycling blades.
However, the economics of recycling wind turbine blades continues to be affected by financial issues, such as the cost to transport the large blades to the recycling facility and processing the blades for the recovery of value-added raw material. For All Cost Components Associated with Transporting and Processing, Companies Will Need to Identify a Value-Based Alternative to Offset the Cost of Doing Business and That Will Allow Them to Pay a Price for the Recycled Raw Material. Companies Need to Develop Trust With the Turbine Manufacturers About the Quality of the Recycled Fibres and Composite Particles in Order to Develop Reliable Markets for These Recycled Raw Materials.
Environmental benefits go beyond the reduction of waste sent to landfills; the manufacture of new fibreglass products, which creates greenhouse gases, relies on fossil fuel-based energy to produce the fibre. By utilising recycled fibres and, in some cases, recovering energy by converting the Resin Content to energy, this can reduce both carbon emissions and natural gas usage while providing manufacturers with additional savings.
Moving Toward Circularity
To create real circularity in the wind energy sector, collaboration at every stage is crucial. Blade makers need to focus more on making recyclable designs a priority. Operators of wind farms require clear advice about how to handle decommissioned materials and the recycling choices available. Providers of recycling technologies must work on expanding their systems and bringing down costs.
Industry Collaboration: Standards and Certification for Recycled Composites
Companies within the wind turbine industry are collaborating more frequently than ever, with companies exchanging research results and effective methods of recycling composites for wind turbine blades. This changes the way that companies view recycled composites by establishing a set of standards to certify Recycled Composites. This increases confidence in the ability of Manufacturers to grow their businesses using certified Recycled Composites, as well as the ability of Governments to promote the benefits associated with the circular economy by implementing regulations and incentives to use recycled composites in their respective countries.
Advancements in technology and increased awareness will be critical factors in the future sustainability of wind energy as we continue to strive towards establishing a circular economy for wind turbines and their components.
