At the end of 2016, there were 321,320 wind turbines spinning across the globe. As the wind energy industry matures, one trend is clear: Wind turbines are getting larger and taller, and have greater electricity generation capacity. There are now 8-megawatt wind turbines in operation that are 720 feet tall, have 260-foot blades and can power about 3,000 U.S. households. This means fewer turbines can generate more power than the wind turbines of yesteryear. As wind turbines age, it’s important to recycle them to maximize the environmental benefits of wind energy.
Wind turbines are designed to last 20 to 25 years. Denmark, Germany and California installed the first generation of modern wind farms in the 1980s and will be at the forefront of dismantling aging equipment, recycling it and likely repowering wind farms with fewer, more-efficient turbines. As the world’s fleet of wind farms ages, decommissioning and recycling materials will become an increasingly common issue that needs to be addressed. What challenges will we face?
Are Wind Turbines Recyclable?
Industrial-scale wind turbines are largely recyclable and contain primarily steel and copper. These materials are widely recyclable but decommissioning wind farms might be more costly than the construction phase. Let’s take a closer look at all the recyclable components of the wind turbine, including its foundation, tower, and components of the gearbox and generator.
- The turbine foundation must secure these mammoth structures to the ground and entails creating a solid base for these huge machines. Constructing the San Roman Wind Farm involved excavating the site to a depth of nearly 10 feet, building a reinforcing cage with 68.5 tons of steel, pouring 18,000 cubic feet of cement, and then backfilling the base.
- Most wind turbines have tubular steel towers that are assembled in 65- to 100-foot segments to make it easier to manufacture and transport. The towers are a conical shape for greater strength (wider at the base), requiring less steel. Open lattice towers that use less steel have largely been phased out due to long-term structural issues and problems with birds nesting on the towers (boosting fatality rates).
- The gearbox is located between the turbine blades and the generator and its function is to help transfer the power from the rotation of the relatively slow wind turbine blades to the speed-hungry generator. Gearboxes can be a weak link in the wind turbine because they are noisy and prone to failure. Most of the components in the gearbox are recyclable.
- The generator converts the mechanical energy from the spinning blades into electricity and contains rare-earth magnets. Although many parts of the generator are recyclable, the implications of recycling rare-earth elements have not been well studied.
Turbine Blades Present a Problem
Turbine blades are lighter, longer and more aerodynamic than the blades of yesteryear for better performance, but they are not well designed for durability and recyclability. Some of the blades of the largest new wind turbines are 288 feet long, creating a large-scale waste reduction issue. Unfortunately, blades are made of a reinforced composite glass or carbon material and create a recycling dilemma. Unlike other wind turbine components, they do not have good scrap value, making them less appealing to recyclers.
Currently, many wind turbine blades end up in landfills, yet some reinforced plastic wind turbine blades have been downcycled into cement products. Other more creative projects have repurposed wind turbine blades to make playground equipment and outdoor seating. There is also research underway to more effectively recycle turbines into higher-value goods.
Most wind farms are planned at least five years in the future, and even longer for offshore wind projects. This means that the wind energy projects that are being planned today will be decommissioned and recycled in 25 to 40 years. Because of the long time horizon, this presents some difficulties that many wind turbine blade manufacturers are starting to address.
Unfortunately, decommissioning and recycling wind turbines has been identified as a blind spot in the wind energy industry when considering the total environmental impact of wind energy. Many studies have focused primarily on the manufacture and operation of wind farms and not the decommissioning phase. Many older wind turbines have been recommissioned and sold in Eastern Europe and North Africa, prolonging the useful life of the equipment. Although some thought has been given to restoring the wind farm site, in many cases this isn’t necessary for a long time. As wind turbines need to be replaced, some sites are retooling with newer technology instead of decommissioning projects completely.
As wind energy technology advances, wind energy is becoming more cost competitive and efficient. Despite some of the issues with wind turbine recycling, wind energy remains one of the greenest sources of electricity. Wind energy saves water, carbon emissions, natural resources, and is cost-competitive with electricity from fossil fuels in many areas.
Feature photo courtesy of Shutterstock