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Where there’s tech, there’s magnets. The strong magnets that generate their own magnetic field,
AKA permanent magnets, aren’t only on your fridge. They’re in multiple places _inside_ your fridge,
and in your cell phone, headphones, and hard disk drive, too. Permanent magnets are also a
critical resource for renewables, because the generators in some wind turbines and
motors in electric vehicles rely on them to run. This is far from ideal, though. Most permanent
magnets are made of what we call rare-earth metals, and these elements are difficult to mine,
expensive, and not widely recycled. Processing rare earths creates radioactive waste. Plus,
the vast majority — over 90% ⁠— ⁠are sourced from China alone, creating supply risks. As a result,
the elements most crucial to clean energy are ironically the most unsustainable.
But what if we could avoid using them altogether … and potentially make a better
electric motor? With his design for a permanent magnet-free electric motor,
a Floridian high school student has just shown us how. Another company is using
cloud computing to try to improve electric motor performance. There’s
some exciting advances being made when it comes to electric motors,
but how much of a difference can they make? I’m Matt Ferrell … welcome to Undecided.
In his own words, 17-year-old Robert Sansone of Fort Pierce, Florida has “a natural interest
in electric motors.” While researching electric vehicles one day, he learned about the negative
environmental impacts of the rare-earth elements used in the permanent magnet motors that power
them.This sparked his interest in developing an alternative type of motor without rare earths.
But first, what are these rare-earth elements, and why are they so problematic? Well, 17 elements of
the periodic table are considered rare-earth elements or rare-earth metals, AKA REEs. To
clarify, rare earths aren’t really “rare” in terms of crustal abundance so much as rarely found in
quantities large enough to justify mining.However, we’re surrounded by rare earths every day. These
elements are highly conductive to electricity and used in a huge number of technologies,
from fighter jets to fiber optic cables. Glass and ceramics are another primary application, and they
represented about 10% of the end-use distribution of rare earths in the United States in 2021.
Rare earths are used extensively in the automobile industry, whether in the catalytic
converters of cars or the rechargeable batteries of hybrid vehicles. Some act as stabilizers in
the process of turning oil into gasoline. And when it comes to permanent magnets, neodymium
and dysprosium in particular are vital. In fact, according to the United States Geological Survey,
neodymium-iron-boron magnets are the most powerful we’ve got. These magnets can withstand
temperatures as high as 230 C, and they’re especially advantageous in clean energy tech
because they allow gearboxes to be eliminated in wind turbines and electric cars. To put the use
of neodymium into perspective, a single 1 MW wind turbine needs about 700 kg of it for the
turbine’s magnet-based generator to function. As the demand for rare earths continues to
skyrocket, their concentration in the hands of a few suppliers is becoming more and more
of a concern. The CEO of USA Rare Earth, estimated in a 2021 interview
that the United States would need to produce around 20 to 25 times more rare earths than
it already does to lessen our near-total reliance on China between now and 2050.
However, rare earths production is a costly, difficult process that has serious consequences.
Rare-earth metals never occur as free elements, but instead as mixtures in ores. They have to be
purified to be used, and the process of separating rare earths can involve thousands of steps and
massive amounts of harsh chemicals. This is made even more complicated by the fact that all rare
earths require different chemical techniques for refining.Also, the ores and minerals that rare
earths are primarily sourced from naturally contain uranium and thorium. This means that
producing rare earths creates a significant amount of toxic and radioactive wastes.
To make matters worse, products containing rare earths (like smartphones, monitors,
and LEDs) are usually dumped into the trash, not recycled.Attempting to salvage valuable
metals from this e-waste can be extremely dangerous to human health anyway because
consumer electronics typically contain harmful substances like lead and mercury.
All these factors translate into the priciness of rare earths. Some elements, like neodymium and
gallium, go for hundreds of dollars per kilogram. Others, like hafnium and germanium, will run you
_thousands_ of dollars per kilogram. Meanwhile, copper hovers at about 8 bucks per kilogram.
So, despite their usefulness, rare-earth elements complicate our relationship to
renewable energy. If the permanent magnets that set EVs in motion come at such a high cost,
then what are our other options? When Sansone continued his research to answer this question,
he discovered that synchronous reluctance motors don’t use permanent magnets. The
thing is, synchronous reluctance motors don’t provide nearly as much efficiency or torque,
so they normally wouldn’t work in an EV. Motivated by the opportunity to
use this research as a project for school, Sansone began a yearlong quest to fix that.
But before we get into what this ingenious high schooler did, I’d like to thank Surfshark for
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to Surfshark and to all of you for supporting the channel. Now back to Sansone’s discovery..
To understand what Sansone eventually accomplished, let’s lay out what an
electric motor is and where permanent magnets come in. Electric motors are everywhere:
if an object moves, chances are an electric motor is driving it. That’s why it’s no surprise that
electric motors are responsible for 43% to 46% of the world’s electricity consumption.
An electric motor works by converting electricity into mechanical energy. When an electric current
flows through a coil within a magnetic field, a force is generated that in turn
produces torque.Torque is what causes an object to rotate about an axis, and when
torque is applied to a motor, it spins.This rotation is then transferred from parts like
gears to whatever needs to move, like a fan’s blade, a car’s wheels, or your vacuum cleaner.
The core of an electric motor is its electromagnet. It takes the form of a
metal loop called an _armature_, which, once connected to a current, essentially becomes a
big flat magnet. Like any other kind of magnet, it has a north pole and a south pole. These can
be flipped by reversing the polarity, which really just means some control electronics are swapping
which wires are charged to the positive and negative ends of the battery. In a direct
current or DC motor, curved north and south pole magnets on opposite sides of the armature make
up a stator, or static permanent magnet. The armature will spin to align with the
stator’s magnetic poles, but when we reverse the polarity, it continues spinning to align to
the new north on the opposite side. Reversing the polarity back and forth causes magnet to
keep spinning as it tries to stay aligned, which in turn creates mechanical energy.
DC motors have been in use since the mid-1800s, but alternating current or induction motors are
preferred in 70% of industries.In DC motors, flip-flopping the polarity of the inner rotor
causes it to spin. In an AC motor, made famous by everyone’s favorite scientist, Nikola Tesla,
power is sent to paired coils positioned along the stator to produce a magnetic field in the rotor,
which is affectionately referred to as a _squirrel cage_.These coils are charged in a rotating
phase sequence, essentially creating a swiftly rotating magnetic field. The magnetized rotor
then spins as it tries to “catch up” to the field flowing around the stator. This can be measured
as the saliency ratio, which is how efficiently a rotor aligns with the applied magnetic field
before the coils change their charge.
Enter Sansone, who zeroed in on synchronous reluctance motors (syncronous reluctance motor)
which create an exploitable difference in magnetic reluctance.
Magnetic reluctance is equivalent to magnetic resistance. Metals with high magnetic
reluctance move more as they try to resist a magnetic field. Per Sansone’s description,
maximizing the difference between the low magnetic reluctance of the steel rotor and
the high magnetic reluctance of the slots cut into it increases the motor’s saliency
ratio. Higher saliency means higher torque. Still, neither the torque nor efficiency of
synchronous reluctance motors, or syncronous reluctance motors, are currently enough for
EVs. Therefore, Sansone’s goal was to improve upon these relative weaknesses in hopes of designing a
syncronous reluctance motor that could compete with permanent magnet ones. Then, by switching
to these motors, we could theoretically make EVs both much more sustainable and cheaper.
Armed with a 3D printer, steel, and copper, Sansone spent a year optimizing his concept for
a novel syncronous reluctance motor.Over the course of building 15 prototypes,
Sansone developed his motor without air gaps, instead incorporating another magnetic field in
their place. This one tweak gave the exploitable resistance and saliency ratio of the motor a big
boost, producing 39% more torque and operating 31% more efficiently at 300 revolutions per minute.
The efficiency jumped to 37% when the motor ran at 750 RPM, but any higher and Sansone’s
3D-printed plastic parts would overheat. One prototype actually melted on his desk.
Fortunately, this loss was not in vain. In May, Sansone received first prize at the Regeneron
International Science and Engineering Fair for his syncronous reluctance motor,
heading home with $75,000 for his efforts. He hasn’t stopped, either: as of October,
he was still working on the 16th iteration of his motor, with plans for version 17 underway.
We can only say so much about the viability of Sansone's design for two reasons. For one thing,
he intends on patenting his syncronous reluctance motor, so he hasn’t shared specifics about how it
works. And as Sansone points out himself, a Tesla motor can reach 18,000 RPM. It simply
isn’t possible for him to test the relative power of his heat-sensitive prototypes with
the resources he has.In any case, Sansone’s story is an impressive show of what’s possible.
Synchronous reluctance motors are an upcoming potential pathway to addressing the sustainability
issues caused by rare earths. _Switched_ reluctance motors, however, are already
in motion. Like syncronous reluctance motors, switched reluctance motors, or SRMs, sidestep
magnets entirely. They both start with the same letters and lack permanent magnets, so it’s a
little confusing, but they work differently. On a superficial level, SRMs function similarly
to three-phase induction motors, a type of AC motor.
An SRM works by wrapping magnetic steel in copper, with
a similarly magnetic steel and copper-coil rotor. That might not sound like it makes a difference,
but it does. The magnetic forces exerted on the iron in a SRM’s rotor can be up to 10
times greater than the magnetic forces on the current-carrying conductors.
that on some significant drawbacks, including how loud they are. Though SRMs are powerful,
they’re not very efficient. They aren’t as smooth as three-phase induction motors. They vibrate,
and they display more severe torque ripple, or variations in torque as the shaft rotates.And
managing the charged steel components also requires more advanced control and monitoring
methods than other types of electric motors. With all these issues in mind, Turntide
Technologies is attempting to tackle our need to reduce energy consumption through its Smart Motor
System. Using SRM technology, the company’s system is made up of a motor, its controller, and the
cloud. The system collects data from the different parts of the motor to determine the ideal
motor speed, and stores analytics for both the controller and the user in the cloud. The idea is
to ensure the motor operates at optimum efficiency at all times so that no power is wasted.
That’s a big deal considering the sheer number of electric motors running at any given time.
According Turntide CEO Ryan Morris, if we were to replace the motors in every building on earth
with smart motors, we could reduce global carbon emissions by 2.3 gigatons a year,
or what he calls the equivalent of growing seven more Amazon rainforests.That’s a bold claim,
and one you should take with a giant grain of salt, but the smart motors’
performance in the HVAC system case studies available on Turntide’s website is promising.
In one pilot program, Canadian real estate company Ivanhoé Cambridge retrofitted the HVAC systems in
two malls with Turntide’s smart motors. These locations saw 38% and 35% in energy savings and
79% and 64% decreases in motor energy usage, respectively.The British retail chain Wilko
similarly tested 800 motors across 400 stores. The company saw 40% in energy savings alongside
an additional 20% in savings when coupled with building automation.Overall, when used in HVAC
systems, Turntide’s smart motors promise to pay for themselves in less than three years.
Sansone’s synchronous reluctance motor and Turntide’s switched reluctance motor are
great examples of “when there’s a will, there’s a way.” And in Sansone’s case, it gives me a lot
of hope for the future of budding engineers out there. Even as we face the destructive effects of
manufacturing permanent magnets, we have pathways ahead of us to help fix that problem. Rare-earth
elements might be ubiquitous in the clean energy sector at the moment, but may not have to be.
So are you still undecided? Do you think electric motor innovations like these will make a big
difference for the future of EVs and renewables? Jump into the comments and let me know.
And be sure to check out my follow up podcast Still TBD where we'll be discussing some of your feedback.
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