Teen Shows How to Turn Noise into Sustainable Electricity

A seventeen year old's curiosity could change the future of energy production

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Climate change is scary, but it’s also fueling our species’ notorious innovation. We know now how destructive burning non-renewable fossil fuels and the resulting greenhouse gases are to our atmosphere, which spurs us to explore renewable energy sources instead.

After all, energy is everywhere — water, solar, wind, geothermal, hydroelectric — and there are boundless ways to harness it with new methods added constantly. In fact, it just so happens that a teenager in Louisiana hit upon a pretty fantastic sustainable energy option — converting sound vibrations into electric energy.

Current Standing

Global energy production comprises three components: transportation, heating, and electricity — but it’s the latter that we’ll be discussing today.

Currently, the world is overly reliant on non-renewable energy sources to generate electricity. In 2023, around 60 percent of global electricity was produced by fossil fuels. Coal was the most significant single contributor, at roughly 36 percent, followed by natural gas at 23 percent.

Regarding nuclear energy, the World Nuclear Association, which promotes global nuclear energy, recently reported that generating electricity accounts for over 40 percent of annual energy-related carbon dioxide — making the power sector the single largest source of planet-warming carbon dioxide worldwide.

Considering that our thirst for electric power is unlikely ever to be satisfied and the known dangers of burning fossil fuels, the only solution is to grow and expand our renewable energy sources. However, accredited scientists and researchers aren’t the only ones up for the task, as a relentlessly curious teenager shows.

The Curiosity

When she was fifteen, Gyeongyun Lily Min’s curiosity was sparked as she observed heat rising from her mother’s homemade compost. She wondered how the heat could be captured and converted into usable energy. Min told Ramsha Zubairi of Smithsonian Magazine:

“This led me to explore the principles of heat transfer and energy conversion through experiments with composting coffee grounds.”

A few months later, the teen’s spark of curiosity grew when she watched the 2001 Disney film Monsters, Inc. In it, children’s screams are harnessed and converted into energy. Cruelty aside, Min wondered if turning sound into usable energy could have real-life applications in our global transition to sustainable energy. She explained to Zubairi:

“This imaginative concept sparked my curiosity about the potential of converting sound into usable energy. I began to wonder if, in reality, we could harness the abundant noise in environments like sports arenas and use it to generate electricity.”

Min’s idea is fantastic, and lucky for us, the science behind such a feat already exists: the piezoelectric effect.

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The Piezoelectric Effect

Put simply, the piezoelectric effect, or piezoelectricity, is an electric charge produced by applied pressure.

Some materials produce large amounts of mechanical energy (the energy an object has when it’s in motion) as shocks or vibrations. This energy is usually wasted, but the piezoelectric effect allows us to harness it and convert it into electric energy.

One of the best examples of this process was accomplished from 2008 to 2009 at Tokyo’s busy Shibuya train station. The Shibuya Ward government and the Soundpower Corp created a 14 square-inch (90-square-cm) mat about an inch (2.5 cm) thick that produced electricity every time someone stepped on it. Then, they installed it outside the train station's main entrance.

The piezoelectric mat produced between 0.1 and 0.3 watts of electricity each second it was stepped on. That may not sound like much, but it adds up when the estimated 2.4 million people step on it while passing through the Shibuya station every day.

The mat's electricity powered a holiday light display on a nearby wall and an LED board that provided live updates on its electricity generation.

Beyond pedestrian commutes, experts have also proposed applying the piezoelectric effect to railways to supply electricity to train stations. However, Min’s curiosity took her in another direction.

Min’s Research

Now seventeen years old, Gyeongyun Lily Min is a senior at her high school in Louisiana. She’s continued following her curiosity about the piezoelectric effect by studying how she can apply it to sound all on her own. She told Zubairi,

“This idea led me to explore the feasibility of acoustic energy harvesting as a sustainable and innovative energy solution that could contribute to meeting global energy demands and reducing our reliance on fossil fuels.”

Min created a makeshift laboratory in her parents’ garage and spent months designing, conducting, tweaking, and repeating experiments for converting vibrations made by soundwaves in sports arenas into electrical energy. She described two reasons she chose to focus on sports arenas:

“I chose a sports arena as the suitable location for my project because it represents a unique environment where noise levels are consistently high due to the cheering crowds, announcements, and music.”

“Additionally, sports arenas are large, public spaces where implementing sustainable energy solutions could have a significant positive impact, making them an ideal candidate for exploring innovative energy harvesting techniques.”

Considering the American Academy of Audiology reports that sporting events are on par with car horns and concerts, Min may be on to something by producing noise levels that reach as high as 110 decibels.

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Experiment One

Min didn’t have access to a sports stadium for her experiments, so using foam board and plastic, she constructed a 22-inch by 12-inch (55 cm by 30 cm) model of a basketball stadium matching the official NBA court ratios to simulate the sound environment of a real one.

After studying sound pressure in relation to its origin position, Min identified the ideal locations in the model stadium for piezoelectric generators. Then, she played recordings of typical crowd noises in a sports arena at a scaled pressure level of 70 and 100 decibels, representing typical sound levels during a live event.

Throughout her experiments, Min designed three energy-harvesting models: front feed, Cassegrain, and gregorian. These models focused sound into her piezoelectric generators and improved their energy-capturing efficiency.

The Results

The voltage produced by Min’s energy-harvesting models demonstrated a significantly higher voltage output than standalone piezoelectric devices. She reported to Zubairi that,

“While a regular piezoelectric device might produce minimal voltage under similar conditions, the harvester models in the experiment produced up to several tens of millivolts, depending on the configuration and sound pressure level.”

She continued to explain that this enhancement indicates that the models that focused sound energy toward the piezoelectric materials played a "crucial role in increasing efficiency.”

Experiment Two

Despite her spirited scientific passion, Min is still a teenager with limited resources, which results in several obstacles. One of them is settling for sub-par piezoelectric material she ordered from Amazon. She told Zubairi:

“[The materials were] not as sensitive as needed for optimal energy harvesting. This limitation significantly impacted the efficiency and accuracy of my experiment.”

Rather than give up, Min adapted her experiment’s design and reevaluated her expectations for the resulting voltage output.

Results

Ultimately, Min’s experiment showed that piezoelectric devices produced relatively small amounts of electricity. She explained some specifics to Zubairi:

“For instance, the Cassegrain model produced an average of 44.90 millivolts at 100 decibels, while the front feed model yielded around 38.60 millivolts at 70 decibels.”

That output is admittedly relatively low, but when scaled to an event at an actual sports arena, there’s clearly potential — especially with better, more sensitive materials and a few tweaks to her design. Min said:

“The success of the experiment was evaluated based on the comparative voltage output between different models and setups, indicating that strategic deployment can enhance energy harvesting efficiency. If I had access to better materials, I believe I could significantly enhance the effectiveness and reliability of my energy harvesting research.”

Although Min is seventeen, her research and amateur study successfully demonstrated that piezoelectric devices placed in environments with high noise levels can generate electric energy.

Beyond sports arenas, this technology could have monumental potential to decrease our global dependency on fossil fuels when implemented on a large scale — which would result in reducing greenhouse gas emissions and weaken the effects of climate change.

Beyond Sports Arenas

A mechanical engineer at the University of Michigan and co-author of Piezoelectric Energy Harvesting, Daniel Inman, agrees it’s a plausible technology. He told Zubairi,

“There have been a number of studies on floor vibrations as a source of harvested energy, and this may be viable.”

That said, applying the method to sports stadiums isn’t without significant challenges and dozens to hundreds of variables to make Min’s idea work. These include things like measuring and calculating the vibrational energy of a crowd walking, stomping, or, in Taylor Swift’s case, dancing throughout the structure and the specific materials the arena is made from. Inman explained:

“The big challenge is that a reasonable amount of piezo material only has the ability to harvest microwatts of energy. There are many issues and factors in determining how much energy can be harvested in a given situation.

“This makes it impossible to make predictions about a given situation unless one knows all the factors, such as the density of the available ambient energy and its properties such as frequency, amplitude, etc. Bringing these systems to scale would require hundreds of such elements.”

Still, even if sports arenas don’t turn out to be the ideal environment for Min’s acoustic piezoelectric idea, there are plenty of others that would be, including the public transportation systems and railways I mentioned earlier. Piezoelectric technology could power at least some of their operations in these and other more amenable environments. Min explained how,

“In urban areas with heavy traffic, the constant noise from vehicles could be harnessed to generate electricity, contributing to the energy needs of city infrastructure. Manufacturing plants, which often have continuous machinery noise, could integrate piezoelectric devices to capture and convert these sound vibrations into electrical energy, thereby reducing their overall energy consumption and improving sustainability.”

You can’t help but be impressed by Gyeongyun Lily Min’s persistence and passion for science and innovation. If she’s already demonstrating how piezoelectric energy can be incorporated into urban planning as a sustainable energy source at seventeen, imagine what she’ll accomplish five or ten years from now if she continues following this curious path of hers.

Perspective Shift

Youth today get a lot of slack about their technology addictions, illiteracy, and, well, basically everything about them. Meanwhile, not enough attention is given to their (many) accomplishments. For instance, did you know Time’s 2024 Kid of the Year was Heman Bekele, a fourteen-year-old who invented a soap that prevents cancer?

Heman Bekele and Gyeongyun Lily Min are just two of many youths actively working to make the world a better and safer place for all life on Earth. Imagine a day when piezoelectric mats, tiles, and other devices are incorporated into urban planning, along with solar panels of all shapes and sizes. A day when we utilize our rivers’ currents and capture energy from the literal air. It’s possible. The technology exists.

But to achieve this, we must shift our focus to implementing renewable energy sources and methods on a larger, global scale and transition away from fossil fuels.

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Photo by Michael Lee on Unsplash