Wind turbine blades get a sustainable upgrade

The average wind turbine generates enough electricity in 46 minutes to power a home in the United States for an entire month, according to the United States Geological Survey. And with more than 70,800 turbines scattered throughout the country, wind power has now surpassed hydroelectric power as the largest producer of renewable energy.

With a $2 million grant from the Department of Energy, researchers from Virginia Tech are pioneering processes to make this sustainable energy source even more sustainable. The grant is part of a $72 million initiative to innovate manufacturing processes for wind technologies and create sustainable solutions for harnessing wind energy. The research team at Virginia Tech will be using new methods of additive manufacturing, computational design, and a recyclable, high strength thermoplastic material.

Chris Williams, the L.S. Randolph Professor in the Department of Mechanical Engineering, is leading the project along with Associate Professor Michael Bortner of the Department of Chemical Engineering. They will be joined by postdoctoral researcher Joseph Kubalak and graduate student researchers from mechanical engineering, chemical engineering, and the Macromolecules Innovation Institute. The project will use Virginia Tech’s Stability Wind Tunnel to evaluate the printed turbine blades with help from Research Associate Professor Aurelien Borgoltz and Research Assistant Professor Nanyaporn Intaratep of the Kevin T. Crofton Department of Aerospace and Ocean Engineering.

“Although the energy generated by wind turbines is green, the materials they are made of are not recyclable, create a tremendous amount of waste, and blade manufacturing is quite arduous,” said Williams. “Our proposed project is looking to dramatically reduce waste, completely eliminate all hazardous materials, and enable 3D printing of a completely recyclable wind turbine.”

To accomplish this, Williams, the director of the Design, Research, and Education for Additive Manufacturing Systems (DREAMS) Laboratory, said the project requires the convergence of three key innovations:

• Robotically printing large objects using new technology created in the DREAMS lab 
• Utilizing unique design optimization techniques to enhance how the materials are printed in the most strong and efficient way possible
• Employing a novel polymer composite material, provided by Bortner and his team, that is completely recyclable, but has the properties of commonly known glass fiber reinforced composites 

Environmental improvements for the future

Currently, wind turbine blades are made at off-site production facilities using large molds that require long lead times. Once those blades are fabricated, they then take a long and costly journey to their often remote destination by way of semi-truck. According to Utility Drive, it can take up to 10 loads and a year of planning to relocate these roughly 200-foot energy generators. The team’s new printing technology could one day provide a means to produce large turbine blades near the installation site, thus removing the challenges in their transport.

“There is a huge emphasis right now across the world for renewable energy resources and implementation of renewable resources,” said Bortner, associate director of the Macromolecules Innovation Institute. “With my focus on the materials research side coupled with Chris Williams’ work on the process side for additive manufacturing, we’re able to collaborate and solve these complex problems and transition them into full-scale wind turbine blade components.”

When it comes to designing wind turbine blades, the materials used in construction play a critical role in overall performance and durability. This is increasingly crucial as wind turbine blades grow in size to harness more energy. While current blades are made out of some recyclable materials, they are not exclusively recyclable. This new process will eliminate the use of hazardous materials in manufacturing, making them reusable. 

“We have a novel material design that, when processed through 3D printing, not only produces the properties that are traditionally used to make up wind turbine blades, but are also wholly recyclable,” said Bortner. “So if the blades get damaged or reach their end of life, we can break them down, reprocess them, and 3D print them again into new blades.”

“Over the last few years, we’ve seen energy costs skyrocket,” said Bortner. “We need to start to identify more practical ways to harness renewable energy resources and ways to do so that are less expensive. By identifying technologies to reduce energy costs, that cost savings will eventually trickle down to the average consumer.”

This process is made possible through the team's new innovations in 3D printing, which allow large objects even bigger than the printer itself, such as wind turbine blades, to be printed on the spot.

Collaboration across disciplines

A project the size of a wind turbine blade could benefit from some helping hands. Luckily, the research team is collaborating with multiple groups in the wind energy industry to make the project a success.

Working with the National Renewable Energy Laboratory (NREL) and TPI Composites is a critical step toward the end goal of producing wind turbine blades on-site at wind farms throughout the United States. Virginia Tech’s Stability Wind Tunnel will take aeroacoustic measurements of the printed wind turbine blades using the wind tunnel on campus.

“Collaboration with industries gives us access to world class expertise in wind turbine blade designing, manufacturing, testing, and characterization,” said Williams. “NREL and TPI Composites are helping us explore how our research could be translated into their facilities and will help evaluate and test our materials and our optimized robotic printing toolpaths on their large robotic additive manufacturing platforms. The goal is to make sure that the interdisciplinary expertise we are bringing together has industrial relevance.”  

For Williams, collaboration across so many disciplines was natural to enable the creation of new technologies and materials.

“This project speaks to the core strengths of Virginia Tech,” said Williams. “We are bringing together interdisciplinary expertise in a collaboration that is unique to this university. Our work with national labs and industry partners adds contextual expertise and a guiding path toward industrial relevance and future technology transition. It’s all in the name of advancing sustainability, which aligns perfectly with Virginia Tech’s vision to be a leader in climate action in service to our community, the commonwealth, and the world.”