The next clean energy source? Snow.

Researchers from UCLA invent a device that generates electricity from a rather unusual source.

The next clean energy source? Snow.
Photo credit: Bryce Evans on Unsplash
  • UCLA scientists have invented a cheap, flexible, and simple device called snow-TENG that generates electricity when it comes into contact with snow.
  • Scientists have known that snow carries an electrical charge for several decades, but this device is one of the first to capitalize on that effect.
  • The researchers believe that snow-TENG could be used in movement-tracking applications or as a simple weather station that requires no battery to operate.

The amount of effort that we spend digging up ancient plankton is starting to get more and more ridiculous. There's energy all around us that we can easily collect from the sun, wind, rivers, waves — and now from snow, too. Indeed, Maher El-Kady and Richard Kaner, two scientists from UCLA, recently published a paper in Nano Energy describing how they were able to construct a cheap, flexible, simple device — they call it the "snow-TENG" — that can generate electricity from falling snow.

How does it work?

snow-TENG is shown attached to the sole of a boot. In this use case, an individual walking across a snowy field could generate electricity for wearable devices or use snow-TENG to count their steps.

Abdelsalam Ahmed/UCLA

H2O is a polar molecule, meaning that one of its sides is negatively charged (specifically, the side with the oxygen atom) and the other is positively charged (the side with the two hydrogen atoms). When water molecules crystalize into snowflakes, they orient themselves such that the snowflake gets an overall charge. Friction, too, can confer an electrical charge to snowflakes.

The exact nature of the charge depends on the temperature: between −5°C and −10°C the charge tends to be positive, and between −15°C and −20°C the charge tends to be negative.

"Snow is already charged," said El-Kady in a UCLA statement, "so we thought, why not bring another material with the opposite charge and extract the charge to create electricity?" Materials like this are called triboelectric nanogenerators (or TENGs), named after the triboelectric effect, in which a material picks up the charge of another material through contact. For example, rubbing your hair on a balloon strips electrons off of your hair and onto the balloon, causing your positively charged hair to reach out towards the now-negatively charged balloon in pursuit of its stolen electrons — also known as static electricity.

"After testing a large number of materials including aluminum foils and Teflon, we found that silicone produces more charge than any other material," said El-Kady.

What can it be used for?

There are a significant number of potential applications for a device like this. It could, for instance, be attached to solar panels to provide energy when the sun is blocked by a snowstorm. It could be used to track the performance of cold-weather athletes, power small wearable devices, or a portable weather station. In addition, it could be coming to a neighborhood near you. "We believe our materials can be painted onto buildings to create electricity, and also provide protection against water and humidity," El-Kady told Popular Science.

One of the more impressive uses for snow-TENG is, of course, as a battery-free weather station. When particles of snow strike the device, it generates a variety of electrical signals that can be interpreted to determine the wind speed and direction in a snowstorm as well as the snowfall rate and accumulation.

Snow way

During the wintertime, up to a third of the planet becomes covered in snow, making devices like snow-TENG much more practical than they may initially sound. But, of course, one has to wonder how practical such a device will be in a future dominated by climate change. However, while many places will see less snow, climate change may actual increase snow fall in others, particularly in colder climates.

While free energy is always nice, it's important to stress that the snow-TENG is more of a proof of concept than a revolutionizing piece of new tech. During their tests, El-Kady and Kaner found that the device could output 0.2 milliwatts per square meter. As a comparison, a solar panel that's exactly one square meter could generate around 150 to 200 watts in good sunlight.

However, the device already works as a self-powered sensor of movement and weather, and the technology can likely be improved to generate more electricity. All told, snow-TENG demonstrates how much energy there is hiding in the background of our everyday environment.

This is what aliens would 'hear' if they flew by Earth

A Mercury-bound spacecraft's noisy flyby of our home planet.

Image source: sdecoret on Shutterstock/ESA/Big Think
Surprising Science
  • There is no sound in space, but if there was, this is what it might sound like passing by Earth.
  • A spacecraft bound for Mercury recorded data while swinging around our planet, and that data was converted into sound.
  • Yes, in space no one can hear you scream, but this is still some chill stuff.

First off, let's be clear what we mean by "hear" here. (Here, here!)

Sound, as we know it, requires air. What our ears capture is actually oscillating waves of fluctuating air pressure. Cilia, fibers in our ears, respond to these fluctuations by firing off corresponding clusters of tones at different pitches to our brains. This is what we perceive as sound.

All of which is to say, sound requires air, and space is notoriously void of that. So, in terms of human-perceivable sound, it's silent out there. Nonetheless, there can be cyclical events in space — such as oscillating values in streams of captured data — that can be mapped to pitches, and thus made audible.


Image source: European Space Agency

The European Space Agency's BepiColombo spacecraft took off from Kourou, French Guyana on October 20, 2019, on its way to Mercury. To reduce its speed for the proper trajectory to Mercury, BepiColombo executed a "gravity-assist flyby," slinging itself around the Earth before leaving home. Over the course of its 34-minute flyby, its two data recorders captured five data sets that Italy's National Institute for Astrophysics (INAF) enhanced and converted into sound waves.

Into and out of Earth's shadow

In April, BepiColombo began its closest approach to Earth, ranging from 256,393 kilometers (159,315 miles) to 129,488 kilometers (80,460 miles) away. The audio above starts as BepiColombo begins to sneak into the Earth's shadow facing away from the sun.

The data was captured by BepiColombo's Italian Spring Accelerometer (ISA) instrument. Says Carmelo Magnafico of the ISA team, "When the spacecraft enters the shadow and the force of the Sun disappears, we can hear a slight vibration. The solar panels, previously flexed by the Sun, then find a new balance. Upon exiting the shadow, we can hear the effect again."

In addition to making for some cool sounds, the phenomenon allowed the ISA team to confirm just how sensitive their instrument is. "This is an extraordinary situation," says Carmelo. "Since we started the cruise, we have only been in direct sunshine, so we did not have the possibility to check effectively whether our instrument is measuring the variations of the force of the sunlight."

When the craft arrives at Mercury, the ISA will be tasked with studying the planets gravity.

Magentosphere melody

The second clip is derived from data captured by BepiColombo's MPO-MAG magnetometer, AKA MERMAG, as the craft traveled through Earth's magnetosphere, the area surrounding the planet that's determined by the its magnetic field.

BepiColombo eventually entered the hellish mangentosheath, the region battered by cosmic plasma from the sun before the craft passed into the relatively peaceful magentopause that marks the transition between the magnetosphere and Earth's own magnetic field.

MERMAG will map Mercury's magnetosphere, as well as the magnetic state of the planet's interior. As a secondary objective, it will assess the interaction of the solar wind, Mercury's magnetic field, and the planet, analyzing the dynamics of the magnetosphere and its interaction with Mercury.

Recording session over, BepiColombo is now slipping through space silently with its arrival at Mercury planned for 2025.

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