In 2035, the world is facing the consequences of climate change, and wind farms are powering the human enterprise. Valeria La Saponara, a polymer composites expert and professor in the UC Davis Department of Mechanical and Aerospace Engineering, is exploring the possibility of developing compostable and ecologically friendly wind turbine blades. Her team, consisting of co-principal investigator Michele Barbato in the Department of Civil and Environmental Engineering and a group of students and researchers in the Advanced Composites Research, Engineering and Science laboratory, is currently testing a prototype wind turbine blade made from bamboo and mycelium.
The Problem with Traditional Wind Turbine Blades
Wind energy is one of the fastest-growing sources of renewable energy worldwide, with California aiming to achieve carbon neutrality by 2045. China, which accounts for over half of global wind power, is planning to build a wind farm that can power 13 million homes by 2025 as it works towards its 2060 net-zero goal. However, the increasing use of wind energy also means that there is a need for a sustainable solution for the growing number of wind turbine blades bound for landfills.
Wind turbine blades are massive, with an average rotor diameter of 418 feet in the United States in 2021, making a single blade almost as big as a Boeing 747’s wingspan. These blades are designed to be resilient against harsh weather conditions, and they have a lifespan of approximately 20 years before they are retired or replaced. Most wind turbine blades are constructed from a composite structure of fiberglass/epoxy built on top of balsa wood, which provides stability and flexibility. Unfortunately, recycling options for these blades are limited, costly, and have additional carbon footprint impacts from transportation.
According to recent studies, over two million tons of decommissioned wind turbine blades are projected to end up in landfills in the United States alone by 2050. Globally, the mass of all the blades expected to be retired by 2050 may be as high as 43 million metric tons. The use of balsa wood is also causing devastating ecological impacts, leading to overlogging in the Ecuadorean Amazon rainforest and unchecked deforestation and societal harm to Indigenous communities in the region. Some manufacturers have been switching to PET plastics, adding to the millions of tons of PET waste in the environment.
The Solution: Compostable Wind Turbine Blades Made from Bamboo and Mycelium
Valeria La Saponara’s solution to wind blade pollution is to create a compostable wind turbine blade made from woven bamboo, mycelium, and biomass from agricultural waste in California’s Central Valley, replacing fiberglass and balsa wood. Mycelium is a highly versatile substance, and La Saponara’s lab has been researching ways to leverage it as a low-carbon emission, low-toxicity, compostable alternative to non-degradable materials like polyurethane and acrylic.
Creating a design for compostable wind turbine blades requires work from multiple disciplines. La Saponara’s team includes co-principal investigator Barbato, who will support structural development, and research engineer Shuhao Wan, who is a skilled bamboo artisan. Wan is testing different ways to weave the bamboo reeds. The team is also working on optimizing media for growing and attaching the mycelium layer, with the goal of incorporating post-consumer textile waste to grow mycelium using waste otherwise bound for landfills.
The team has already built a prototype wind turbine blade made from mycelium and bamboo, which will replace blades on a commercial 1-kilowatt turbine set up near the STEEL Lab, part of the Western Cooling Efficiency Center, away from central campus. La Saponara’s team will test the resilience of these blades to ensure they can withstand 85-mile-per-hour winds.
Once the team has the proof of concept for a 1-kilowatt turbine, they can begin working with companies for the commercialization of this concept for distributed energy applications. Wind turbine blades made from bamboo and mycelium could help in areas affected by natural disasters, where energy solutions are needed quickly and wind power can be paired up with solar panels.
Valeria La Saponara emphasizes that wind blade pollution is a pressing issue that needs to be addressed. “We want to have clean energy, but clean energy cannot pollute the environment, and it can’t cause deforestation,” she said. “If we’re doing clean energy, it’s not to deforest the Amazon rainforest. We want to be good citizens for everybody.” La Saponara’s team is working towards a sustainable solution to help the environment and future generations.
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