Sustainability in Wind Turbine

Renewable Energy Plant Life And The Need For Recycling

Figure 1: Global wind turbine blade waste projection up to 2050

Wind power is one of the cornerstones in the quest to tackle the climate emergency. In 2030, wind power will cover 19.7–24.0 % of global electricity demand, a meeting between a fifth and a quarter of the world’s electricity needs. Although wind energy is clean and pollution-free, it faces the challenge of using turbine blade disposal and recycling.

Wind turbines usually have a service life of 20 years, and in the coming years, many wind plants will be decommissioned, creating huge amounts of composite waste. According to the University of Cambridge, 43 million tons of used blades will be used by 2050. Without proper management, they are likely to pile up in landfills.

Challenges in Wind Turbine Recycling

The following are the significant challenges faced by the wind turbine recycling industry:

• Classification of recyclable components and their identification: 85% of turbine components, including steel, copper wire, electronics, and gearing, can be recycled or reused. Fiberglass blades, however, are still challenging to recycle as wind turbine blades are usually made by bonding components with resins. So, dismantling wind turbine components without compromising the recycling process’ quality is one of the biggest challenges. Also, product disposal and specifications must be identified to industrialize the recycling process.
• Need for profitable recyclable technology: Most wind turbine composite waste is recycled using mechanical shredding. This simple process creates microplastic pollution. Recycling technology that can extract raw materials from the composite material turbine blades is needed to complete the recycling cycle of wind turbines.

Sustainable Wind Turbine Recycling Solutions

Two methods are used to address the wind turbine recycling issue. The first is the creation of entirely recyclable components through innovation in turbine blade production. The second includes innovations in recycling technology for used blades.

Advancements In Recyclable Materials For Turbine Blade Manufacturing

• Blade made with thermoplastic resin: LM Wind Power, as a part of the ZEBRA consortium, has developed a prototype of a 100% recyclable wind turbine blade with Elium® resin. Elium is a thermoplastic resin developed by Arkema that has recyclable properties. A chemical recycling process separates the fiber from the resin to recover new virgin resin and high-modulus glass.
• Blade made with Epoxy resin: RecyclableBlade of Siemens Gamesa is a recyclable blade made with Recyclable Epoxy Resin. The resin is developed with Aditya Birla Advanced Materials’s Recyclamine Technology. Recyclamine technology uses multiple unique Amine-based curing agents containing specifically engineered cleavage points at cross-linking sites to convert thermosetting epoxies into thermoplastics. This enables the recovery and reuse of reinforcing fiber and matrix material.

Innovative Recycling Technology

Numerous recycling techniques for composite materials include mechanical shredding, incineration, pyrolysis, and solvolysis. The following is the list of developments in wind turbine recycling technology:

Pyrolysis

The wind turbine blade can be recycled using a novel pyrolysis process developed by the University of Tennessee. In this process, organic composite components like resins or polymers are broken down with intense heat without oxygen and separated from the inorganic fiberglass reinforcement.  Also, the process converts organic products into raw hydrocarbon products like syngas and pyrolysis oil and recovers the composite fibers. Following are the latest developments in the pyrolysis technology:

• Carbon Rivers’ is using this pyrolysis process to recycle composite materials. Based on similar technology, Windfall Inc., a part of Carbon Rivers, is developing the first full-scale U.S.-based glass fiber recycling facility in Knoxville, Tennessee.
• R3FIBER process: R3FIBER is a green technology developed by bcircular to recycle wind turbine blades and other composites at the end of life. Moreover, it uses a pyrolysis process to recover composite fibers. The technology has been patented with patent No US11168261B2.

Solvolysis

The wind turbine blade can be recycled by dissolving binding resin to separate the fiber from the resin and recover new virgin resin and high-modulus glass.  The blade is immersed in a heated, mild acidic solution to separate the resin from the fiberglass, plastic, wood, and metals. Following are the latest advancements in solvolysis-based recycling:

• Chemical recycling: Elium® based composite components are recycled using an advanced method called chemical recycling, similar to solvolysis.
• CETEC’s novel technology: Vestas, in collaboration with chemical producer Olin, Danish Technological Institute (DTI), and Aarhus University, is working on similar technology to separate glass or carbon fiber from resin. This technology is developed with DreamWind, which consists of a two-step process. Firstly, thermoset composites are disassembled into fiber and epoxy. Secondly, through a novel chemcycling process, the epoxy is further broken up into base components similar to virgin materials. These materials are then reintroduced into the manufacturing of new turbine blades.

Shredding To Green Cement

The wind turbine blade is currently recycled using a shredding process to make green cement. The process recovers 90% of the weight of the blades. Additionally, 65% is in the form of green cement, and 28% is an alternative fuel. The following companies provide dismantling solutions for wind turbines:

• Veolia is using this process to recycle decommissioned blades of GE Renewable Energy. The DecomBlades innovation project has created product disposal specifications for recycling partners to industrialize blade disposal and recycle blade material easily. DecomBlades uses the most cost-effective processes, like mechanical shredding, cement co-processing, and pyrolysis, to recycle wind turbine blades.
• ROTH International has developed a range of signature cutting and separation technologies. These technologies provide hassle-free cutting of rotor blades and other composite objects without sparks, dust, or fragmentation.

Conclusion

Decommissioned wind plants will create huge composite waste in the future. To address this, a reliable and profitable recycling process is required to complete the wind turbine recycling chain. Pyrolysis and mechanical shredding are mature and profitable technologies currently used in wind turbine recycling. However, these methods are energy-intensive and cause micro-plastic pollution.

Solvolysis is an innovative approach to solving the wind turbine blade recycling problem by dissolving the binding resin of composite material to recover virgin fibers. Although it is in the initial stages of development, this process successfully recovers raw materials used in wind turbine blade manufacturing without significantly changing mechanical properties. It is the best process that completes the recycling cycle of composite material. So, it is recommended that composite material recycling companies and wind turbine recycling companies should focus their research on this process and deploy it on a larger scale to enhance its feasibility.