Clean Energy Runs on Magnets

With all the talk about the battery boom, I thought it’d be worth a mention that it’s not just lithium that’s powering clean tech: it’s also neodymium and dysprosium.  These are the most important elements in the permanent magnet market.

Magnets? But how are those related to clean energy?

As a rule of thumb, any time you hear or read “electric motor” or “electric generator”, you should be thinking “contains magnets”. Permanent magnets are one of the best ways we have for converting back-and-forth between mechanical and electrical energy because once you’ve created an aligned magnet, you get to use its magnetic field in perpetuity: you don’t have to “recharge” a permanent magnet like you do a battery, and it doesn’t have ongoing energy costs like an electromagnet or combustion motor.

Because of this, magnets enable turbines to convert flowing wind and water to usable electricity, and use that clean energy to spin electric motors in cars, AC units and other applications.  Since we also need hard disks made of magnetic materials to store the data and software that’s critical to grid and energy management, it’s no stretch to make the argument that magnets are at the core of clean energy.

So let’s take a look at just how critical magnets are to the clean tech and renewable energy markets:

Energy Generation

SBC Energy Institute

Wind Power:

There are ~500 kg of permanent magnets for every MW produced by the newer, more efficient wind turbines.  That’s 2.75 tons of magnets per 5 MW turbine being installed today. There are also plans to double and quadruple⁵ the generation capacities for future onshore and offshore turbines, respectively, which would likewise increase magnetic material consumption.

Tidal Power:

There are a few different types of tidal power with varying degrees of real-world testing and market potential, but most still rely on spinning turbines (as with classic hydropower), which power magnet-containing electric generators.  Since the technology and market is still relatively nascent (though there are several projects in various stages of completion⁷), there is limited per-unit and market data for  magnetic material use.  If you know of any, please let me know!

Transportation

Hybrid and Electric Cars/Trucks:

A typical electric car uses ~0.7 kg of permanent magnets in its motor (with the notable exception of Tesla’s AC induction motors). While that doesn’t sound like much, especially compared to wind turbines, the total market size is formidable: it is estimated that 7,000 tons of rare-earth magnets were used in 2015 for this industry, and that is expected to rise to 17,000 tons by 2020.⁶

Electric Bikes:

Here, I’m just going to quote Steve Constantinides’ article⁶ because this market was surprising even to me and he sums it up very well:

This is a stealth application – one that grew rapidly without much notice, at least in the west, until it was a large market.  In 2009, the China market for EBs (electric bikes) was 20 million units.  The major market is currently China and Southeast Asia, but India’s market is growing and global production in 2018 is forecast to be 60 million units.  Magnet consumption per bike is highly variable ranging from motor assisted pedaled bicycles to high-power sport bikes competing with conventional motorcycles.  Magnet   usage in 2015 was 6,000 tons and is expected to rise to more than 15,000 tons annually by 2018.

Buildings/Efficiency

HVAC:

Traditional air conditioning units can have 3-4 electric motors within them.  As I mentioned above, every time you see “electric motor” or “electric generator”, you should be thinking “probably contains magnets”.  Based on Constantinides’ and Arnold Magnetic’s estimates,⁶ the proportion of the permanent magnet market going toward HVAC units is only a little behind that of hybrid/electric vehicles.  Furthermore, HVAC systems might get a whole lot more efficient if even more magnets are used as discussed below.

Refrigeration:

There is a big potential for magnetic refrigeration that takes advantage of the magnetocaloric effect.  Franco et al. summarize the advantages really well in a 2012 review paper:

Magnetic refrigeration is […] more energetically efficient than the process based on the compression/expansion of gases (magnetic refrigerator prototypes can achieve 60% of ideal (Carnot) efficiency, whereas the best commercial conventional refrigerator units can reach only 40%). Moreover, as no refrigerant gases are required for magnetic refrigeration, there is no concern about ozone depletion or greenhouse effect, which contributes further to its environmental friendliness.

Or put it another way: it’s potentially a 50% improvement in efficiency over existing technology.  GE, which has been pursuing this technology, reports that they have already achieved a ~20% improvement [see video: https://youtu.be/WlKKKMTA7XM].  That number is going to go up as the technology matures, and HVAC and refrigeration applications will get even more magnets!

I think this is a really exciting market with lots of potential.

Magnetic Couples/Drives:

There are many places in industry (mining, traditional power generation, water/wastewater) where big motors are used to turn fans, pumps and conveyors.  These big motors use lots of energy, so running them at peak efficiency is hugely important to the bottom line.

These motors have optimal run speeds for their most efficient operation.  Deviating from that optimal speed, which happens frequently if the fan/pump/conveyor needs to slow down or speed up, costs energy and harms equipment life.  However, if it’s possible to can keep that motor humming at its optimal speed while still slowing down the load to where it needs to be, operation costs stay low and equipment life is extended.

This is achievable with magnetic couples that put a physical air gap between the motor and drive (and if this air gap is adjustable, it is possible to gain speed control as well).  These magnetic couples and drives are (as the name would imply) big magnet users, but can result in up to 70% in energy savings.

Energy Storage

University of Oregon

Flywheels:

A flywheel is essentially a mechanical (rather than electrochemical) battery: you can spin a large heavy rotor that has a lot of inertia when you have extra energy, and then recover that energy by spinning the rotor down later. Magnets are used both in the electric motor/generator that spins the load up and down, and also as a way to reduce friction on the load through magnetic bearings.

However, flywheels have never quite taken hold as an energy storage option that is scalable and economical, so I’m mostly including them here for the sake of completion.  If someone cracks the code for a feasible/scalable flywheel, you can be sure it’ll be magnet intensive.

Magnets and Clean Tech go Hand in Hand

So while solar and batteries are (rightfully) getting a lot of attention in the clean tech world, don’t forget what’s at the heart of most of the rest of the technologies that are part of this sector. Magnets made the data revolution possible.  They might just make the energy revolution possible, too.

Luke G. Marshall Ph.D.  is a researcher at Northeastern University in Boston, MA, exploring synthesis and processed methods for the creation of novel and sustainable magnetic materials. A graduate of Whitman College and the University of Texas at Austin with a doctorate in Materials Science & Engineering, Luke’s passions are energy and clean technology with a focus on business solutions for transitioning cutting-edge science from the lab bench to the real world.  Follow him on LinkedIn (https://linkedin.com/in/lukegmarshall) and on Twitter @lukegmarshall.

References:

1. Stringer, G. and Ritchie, M. “Battery Boom Heats Lithium Gains as Outback Mining Stocks Soar.” Bloomberg Business, 17 Feb., 2016. Retrieved from http://www.bloomberg.com/news/articles/2016-02-17/battery-boom-heats-lithium-gains-as-outback-mining-stocks-soar (Accessed: 29 Feb., 2016).
2. Marshall, L. G. “Permanent Magnets: Why We’re Looking for New Materials.” LinkedIn, 12 May, 2015. Retrieved from https://www.linkedin.com/pulse/permanent-magnets-why-were-looking-new-materials-luke-marshall (Accessed: 29 Feb., 2016).
3. GTM Editors. “Grid Edge 20: The Top Companies Disrupting the US Electric Market.” Greentech Media, 23 Apr., 2015. Retrieved from http://www.greentechmedia.com/articles/read/Grid-Edge-20-The-Top-Companies-Disrupting-The-U.S.-Electric-Market (Accessed: 29 Feb., 2016).
4. Trabish, H. K., “‘The future grid’: How one DOE program is pushing the boundaries of aggregated DERs.” Utility Drive, 4 Feb. 2016. Retrieved from http://www.utilitydive.com/news/the-future-grid-how-one-doe-program-is-pushing-the-boundaries-of-aggrega/413023/ (Accessed: 29 Feb., 2016).
5. “Leading the Energy Transition: Wind Power.” Wind Power SBC. SBC Energy Institute, May 2013. Retrieved from https://www.sbc.slb.com/SBCInstitute/Publications/Wind.aspx (Accessed: 29 Feb., 2016)
6. Constantinides, S. “Permanent Magnets in a Changing World Market.” Magnetics Magazine, 14 Feb. 2016. Retrieved from http://www.magneticsmagazine.com/main/articles/permanent-magnets-in-a-changing-world-market/ (Accessed: 29 Feb., 2016).
7. “Tidal power.” Wikipedia. Retrieved from https://en.wikipedia.org/wiki/Tidal_power (Accessed: 29 Feb., 2016)
8. Campbell, P. “Performance and Cost Assessment for Motors Using Alternative Rare Earth-Free Magnets.” Magnetics Magazine, Jan. 2013. Retrieved from http://www.magneticsmagazine.com/conferences/wp-content/uploads/2013/01/Dr.PeterCampbell.pdf (Accessed: 29 Feb., 2016).
9. Franco, V., Blazquez, J. S., Ingale, B., and Conde, A. “The Magnetocaloric Effect and Magnetic Refrigeration Near Room Temperature: Materials and Models.” Annual Review of Materials Research. 42 305-342 (2012).
10. Bothum, G. “Energy Storage: Why is Energy Storage Important?”Energy Storage. University of Oregon. Retrieved from http://zebu.uoregon.edu/disted/ph162/l8.html (Accessed: 29 Feb., 2016).
11. Nelder, C. “Turn Up the Juice: New Flywheel Raises Hopes for Energy Storage Breakthrough.” Scientific American, 10 Apr., 2013. Retrieved from http://www.scientificamerican.com/article/new-flywheel-design/ (Accessed: 29 Feb., 2016).