By Sarah Lozanova, Renewable Energy Writer
The energy mix in the United States has shifted significantly in recent years. Wind and solar energy capacity has skyrocketed and continues on an upward trend. Wind energy generated 7% of the total electricity in the United States in 2019. Since 2008, the use of coal-fired power plants has declined, as the use of renewable energy and natural gas has increased. Wind energy is an excellent way to reduce carbon emissions, but what happens when the wind turbine blades wear out? Is there a looming waste disposal issue?
Looming Waste Management Issues
The design life of wind turbines is about 20 to 25 years. The longest wind turbine blade to date is 350 feet, almost the length of a football field. Although certain parts of wind turbines can be relatively easily recycled, others are not designed for recyclability. In particular, wind turbine blades present the biggest waste management challenge, but researchers from the National Renewable Energy Lab (NREL) in partnership with Arkema Inc. are making progress in this area.
Most wind turbine blades are currently constructed with composite material infused with a thermoset resin, which makes them highly durable to withstand storms and the elements. Unfortunately, thermoset plastics are almost impossible to recycle, so the blades do not have much scrap value and are not very appealing to recyclers. Therefore, many spent turbine blades are piling up in landfills, although some reinforced plastic blades are downcycled into cement products.
Promising Turbine Blade Research
The good news is that researchers have developed a blade out of thermoplastic resin (instead of thermoset resin) that is low-cost, lightweight, and seems to be recyclable. If the new blade also proves to be durable, this could be a gamechanger for the offshore and onshore wind industry. Lower costs also could help boost wind energy deployment, reducing the use of fossil fuels. A lightweight blade is easier to transport and uses less fuel. It also seems easier to recycle and uses less energy in the manufacturing process. These are all wins for the environment and the wind energy industry.
“With thermoset resin systems, it’s almost like when you fry an egg. You can’t reverse that,” said Derek Berry, a senior engineer at NREL in a press release. “But with a thermoplastic resin system, you can make a blade out of it. You heat it to a certain temperature, and it melts back down. You can get the liquid resin back and reuse that.” This means that the blades could be recycled instead of downcycled into lower-value goods.
So far, the thermoplastic resin blade durability looks promising. “The thermoplastic material absorbs more energy from loads on the blades due to the wind, which can reduce the wear and tear from these loads to the rest of the turbine system, which is a good thing,” said NREL researcher Robynne Murray.
Although the research looks promising, progress will be slow. Most wind farms being constructed today will be decommissioned in a few decades. The benefits of recyclable blades are still decades away at best. The decommissioning of wind farms and the associated environmental impact has largely been a blind spot for the industry. Hopefully, recent advances will help make wind power even greener. Despite the waste issue, wind power is still one of the most sustainable sources of energy.