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From the blowing wind to the shining sun, energy is all around us.
And humans have an almost insatiable demand for it, so scientists and engineers
are always on the lookout for sustainable ways to provide the energy we need.
And, sure, with tools like solar panels, wind turbines, and geothermal wells,
they’ve already found some great alternatives to fossil fuels.
But then there are the other ideas. The alternative alternatives, if you will.
Some could be the next big thing; others might be as kooky as they are clever.
Here are six of the weirdest ways to harvest the energy around us.
Unless you’re standing next to a nuclear reactor or something,
the biggest source of energy near you right now might be, well, you.
Just sitting around, an average adult male human gives off heat
at a rate of about ninety Joules per second, which is to say, ninety watts.
That’s quite a lot of energy just going out into the world as wasted heat,
so some people are trying to put it to work.
The easiest way might be to just repurpose that heat,
like they’ve done at the Stockholm Central train station.
Around a quarter-million people pass through it every day,
generating a lot of heat as they wait for their train.
The station’s ventilation system captures that heat by using it to warm water,
which then gets piped into nearby buildings to help heat them in the winter.
At maximum capacity, those office buildings
can cut their heating bills by 25%, which is no small savings.
But what if you want to put your own body heat to work
without living in Stockholm or wrapping yourself in pipes?
Thermoelectricity might be for you.
First discovered in 1821, thermoelectricity is a property of certain materials.
Basically, when there's a difference in temperature across these materials,
it can generate an electric current.
Traditionally, this was a very inefficient process,
but modern materials science has made significant improvements.
Most thermoelectrics today are semiconductors,
like the materials used to make computer chips.
Take bismuth telluride. It’s a room-temperature semiconductor that,
when combined with antimony, produces a thermoelectric used for refrigeration.
It might sound complicated, but working with thermoelectrics can actually be really simple.
In 2013, for example, a high school student
used thermoelectric tiles to create a self-powered flashlight.
Just grab it by the handle and your hand’s body heat
creates enough electricity to light up the LED inside, no batteries needed.
NASA scientists are studying thermoelectrics for use inside astronauts’ spacesuits.
And, in 2017, researchers described using them to create medical implants
that can be powered by the patient’s own body heat,
like devices to help with regenerative therapies for bone tissue,
or brain stimulation for motion disorders.
For many alternative energy proposals,
a major obstacle is the need to build lots of infrastructure at massive costs.
But there’s one kind of human infrastructure
that’s already virtually everywhere on Earth: radio waves.
From your favorite radio station to the WiFi router on your desk
and the cell tower down the block, radio waves are already everywhere we are.
And as a form of electromagnetic radiation,
every radio wave carries energy that we can snatch right out of the air.
Engineers in the twentieth century developed special antennas,
called rectennas, that can convert these waves into electricity.
In the sixties, they were experimenting with using microwaves
to beam power from place to place, and the rectenna was a big part of that.
That never really panned out. But it does demonstrate that,
unlike the wireless charging technology that might be built into your phone,
rectennas work at large distances from the transmitter.
That said, the tradeoff for being able to gather this kind of power
from basically anywhere is that you don’t get a lot of it.
Like really not a lot;
we’re talking power measured in microwatts or even tenths of microwatts.
That’s not enough to charge your phone,
but it could be enough to power tiny sensors.
The goal here is to inject technological “smarts” into basically everything around you.
For example, diagnostic pills that noninvasively beam medical data out of your stomach,
or walls that can “intelligently” reflect and redirect signals so your wifi is always in range.
Which is weirdly close to that old saying about “if walls could talk,”
but it’s pretty cool that it might soon be possible.
Not all possible energy sources have potential applications
as important as wireless medical data.
But that doesn’t mean they can’t just be plain fun.
The human body is an amazing tool for converting chemical energy,
like, you know, potatoes, into the mechanical energy of motion.
But, since every action has an equal and opposite reaction,
only some energy in each step goes into pushing you along.
The rest is spent trying to push the Earth back,
where it’s effectively lost, unless we can capture it!
One way to do that is through piezoelectricity, a property of some crystals in which
they acquire an electric charge when compressed,
transforming mechanical energy into electrical energy.
Sure, that might sound like pseudoscience, but it was actually discovered in 1880
by future Nobel Laureate Pierre Curie and his brother Jacques.
Even if you haven't heard of them,
you've probably heard of Pierre's wife Marie Curie. Talk about a power couple.
Piezoelectricity works because the crystal structure of some materials is not symmetrical.
When you compress one of these crystals,
the molecules physically stretch or are squeezed,
moving the positive and negative sides together or apart.
And with positive charge on one side and negative charge on the other,
the crystal can now conduct an electric current!
So, to capture the energy lost by walking,
engineers just need to place piezoelectric materials underneath everywhere we walk.
Which sounds, ya know, expensive.
But there are some places where we step more often than others, like dance floors!
In 2008, this idea was put to the test by a pair of nightclubs located in London and Rotterdam
and I remember it because I wrote about it in my blog, EcoGeek.
By creating a piezoelectric dance floor, the clubs could capture the energy of dancing
and put it to use by running the lights and powering the air conditioning.
Each dancer creates up to twenty watts of power, which isn’t a lot on its own.
But add together more than a thousand people on the dance floor
and now you’re really talking!
This idea has also been tested at larger scale on a highway in the Netherlands,
where it could produce enough power to sustain traffic sensors
without the need for solar panels.
It might also make sense in other places with high traffic,
like subway platforms and busy sidewalks.
So the next time you feel a little extra spring in your step,
it might just be all the power you’re leaving behind!
If there’s one thing humans do more than anything else, it’s talk.
When you talk, your vocal folds create vibrations in the air that propagate outwards;
and remember: where there is motion, there is energy.
As a kid, you might have put this vibrational energy to work transmitting sound
if you ever tied a string to two cups to make a simple telephone.
The idea might be simple, but during World War II, it was used in a big way.
By the end of the war, naval officers could communicate between the decks of a ship,
or even across an island, using nothing but voice-powered telephones.
A sailor talked into the device, a special generator
would convert the vibrations from their voice into enough electricity
to send the message up to sixteen kilometers over telephone wires.
And while we obviously have more advanced communications equipment today,
these voice-powered telephones can still be found
on US Navy ships for use in emergency situations.
But even if you never set foot on a ship, sound power might be in your future.
In 2012, researchers at the Queen Mary University of London
experimented with tiny generators that could power a pacemaker
based on nothing but the sound of your heartbeat.
For use outside the body, there’s also the phenomenon of triboelectricity,
which is basically a fancy term for static electricity.
Triboelectric nanogenerators work when two different materials repeatedly collide
or rub against one another, exchange electrical charge, and generate a current.
And in 2015, researchers published a way to power these tiny generators with sound vibration.
Their experimental system could generate
up to one hundred twenty-one milliwatts per square meter of material.
That’s obviously not a ton of power, but these nanogenerators have been
successfully adapted for tasks like air filtration in noisy urban environments.
Wind power is one of the oldest forms of energy generation,
but even here there’s room for new ideas.
Over the last twenty years, electricity generated from wind power
has grown from virtually nothing to nearly ten percent of all US power.
But wind turbines are big, expensive things to build,
which limits where they can be placed and how they’re built.
That’s got some energy investors considering the use of giant kites to create power instead.
Funding from companies like Shell and Google
is supporting research into kite-powered generators that,
while less powerful than wind turbines, might also be cheaper.
The idea is to fly one or more kites several hundred meters above the ground,
where the wind blows with more force and greater consistency.
It’s called crosswind kite power
because the kites spend most of their time flying perpendicular to the wind.
One project under construction in the UK will use a pair of kites
flying in a figure-eight pattern to produce up to five hundred kilowatts of electricity.
And theoretical studies suggest improved designs
may be able to create up to tens of megawatts in the future.
That’s probably at least a little more than you were getting
when your sweet butterfly kite took to the skies as a kid.
Alright, we’ve got one wacky source of power left
and it’s maybe the most remarkable of all: creating electricity literally out of thin air.
Well, kind of—the power comes from the moisture the air has absorbed.
One of the most promising approaches,
developed in 2020 at the University of Massachusetts Amherst, is nicknamed Air-gen.
The device is made up of a seven-micron-thick film of nanowires
derived from protein, of all things, connected to electrodes.
When this combination is exposed to humidity in the ambient air,
the film absorbs molecules of water, and a moisture gradient forms.
Some of the water molecules will be ionized, or electrically charged,
so that moisture gradient creates a gradient of charged particles.
Those charges flow, creating a current.
In lab experiments, the Air-gen could sustain a consistent level of power
for around twenty hours before needing a few hours of rest.
And that performance remained steady for the duration of more than two months of testing.
One promising application of this technology
would be helping keep your smartwatch or cell phone charged
without ever having to plug it in.
And incorporated into paint,
it could potentially also help your walls generate electricity to power your home.
At least, if you live in a fairly humid place.
What is it with energy researchers and walls?
If this all seems kind of miraculous, that’s just the power of modern engineering.
As researchers gain control over more materials at smaller scales,
they’re discovering the kinds of properties we could only dream of in the past.
Of course, just because all these forms of power are possible,
doesn’t mean that they will prove to be practical.
But they do reveal how much energy is around us literally all the time.
If we can find a way to harvest even a bit of it,
we’ll be on our way to a more sustainable future.
If you’ve enjoyed this helping of quirky engineering,
you might like to keep learning with an engineering course from Brilliant.
In keeping with the theme, there’s even a course on Solar Energy,
which will teach you everything about how we capture energy from the sun.
And there are tons more courses, not just in engineering, but in basic science,
computer science, and math. Just all kinds of ways to learn something new.
If you’re interested, you can go to Brilliant.org/scishow to learn more.
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So thank you for your support!
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