# Physics You’ve Never Heard Of Provides Power From Waves

“In the future, we’ll be generating a significant fraction of our electricity from harnessing the waves!” People have been saying this for decades, and wave-generated electricity is not a significant fraction of an ant’s poop. It’d be fantastic if this could change.

If you believe the owners of Oscilla Power, the main failing of traditional wave-power generators is that they’ve got too many moving parts. Literally. Metal mechanical parts and their seals and so on are beaten down by sun and salt and surf over time, so it’s expensive to maintain most of the generator designs, and they’re just not worth it.

Oscilla’s generator, on the other hand, has basically no moving parts because it’s based on magnetostriction, or rather on inverse magnetostriction, the Villari effect. Which brings us to the physics.

Magnetostriction is the property that magnetic materials can shrink or expand just a little bit when put in a magnetic field. The Villari effect (which sounds much cooler than “inverse magnetostriction”) is the opposite: magnetic materials get more or less magnetic when they’re squeezed.

So to make a generator, you put two permanent magnets on either end, and wind coils around magnetostrictive metal bars that are inside the field of the permanent magnets. Squeeze and stretch the bars repeatedly and the net magnetic field inside the coils changes, and you’re generating electricity. Who knew?

Right now, according to The Economist Magazine’s writeup on Oscilla, the price per watt isn’t quite competitive with other renewable energy sources, but it’s looking close. With some more research, maybe we’ll be getting some of our renewable energy from squeezing ferrous bars.

And while we’re on the topic, check out this recent article on magnets, and how they work.

## 37 thoughts on “Physics You’ve Never Heard Of Provides Power From Waves”

1. rj says:

No, a shake light just directly uses a moving magnet to induce a current in the windings, just like a DC generator.

This is something far more subtle: by compressing a magnetostrictive material, the µ of that material changes, changing the magnitude of the B field relative to the H field, and that is what induces current in the windings.

… at least, if I understood what they said correctly.

1. Dias says:

Moving parts are just a waste of energy.

2. scuffles says:

I wouldn’t say no moving parts.
If I’m getting the just of it they are still technically moving but where the shake lights rely on the range of motion these rely more on the force of the motion. If I was to guess I would say that they are deforming ever so slightly that you aren’t going to be able to detect it with the naked eye.

1. marks47 says:

I’ve heard a couple times that this concept is one of the most common “science thesis” at the Naval Academy

2. Bill Jackson says:

It might be robust, but it will not ever be efficicent

1. RandyKC says:

Maybe we just haven’t found the right magnetostrictive material yet.

2. With “unlimited” sources of alternative energy, efficiency is not a direct concern. Overall cost per watt (including install and maintenance) is the key factor.

3. flamesholder says:

Robust and borderline efficient is good for sensors, where the cost of delivering the energy would kill the idea. But, can it be applied to non-marine applications also? I don’t see any obstacles.

1. static says:

AFAIK the cost of delivering the energy from the power plant to the market has never been an issue about the means of generating the electrical power. The controversial coal fired powerplant in near Holcomb that was built to burn coal imported from Montana despite not atop the Hugaton gas field its a short pipeline from it. Recent upgrade included delivering power to other States, I can’t recall the cost of that delivery being an issue.

1. jeff teller says:

upgrading transmission networks is a major impediment to the development of large scale power plants all over the world….

3. UnderSampled says:

Why not just use a Piezoelectric material — one that get more or less electrically polar when they’re squeezed?

1. Truth says:

High voltage but tiny current, so very low power generation overall. e.g. 48V DC 12mA from a 60mm by 30mm single crystal PZT. And since the frequency of a wave is low, the average power generated would be extremely low.

1. We’re talking maritime applications here. How would a 1 ton crystal perform?

1. Sparhawk817 says:

they also break down more over time, think about how often you have to buy bbq lighters because they stop getting spark.

1. John says:

BBQ lighters usually fail from problems in the spring mechanism or the electrodes getting corroded.

2. I think they’re also difficult to manufacture in large-sizes (i.e. 1 ton would have to be many, many, many smaller elements) and I’m not sure if the piezoelectric effect scales well.

3. Truth says:

Even that single PZT crystal would have an internal resistance of about 150 ohms, scale it up and the internal resistance would scale up as well.

And the logistics of growing a 1 one ton single crystal without it failing under its own weight would be complex, maybe it is something that could be grown in the low gravity of space. Extreme temperatures (>1350C ) and extreme durations would probably be involved. Scaling up is not necessarily something that would be easy.

I’m not sure of the exact process involved for single crystal PZT, but I would assume that it is something similar to growing quartz crystals and that can go badly wrong – https://www.youtube.com/watch?v=uo7H_ILs1qc

1. Truth says:

Anyhow Lead may be common enough on the earth’s surface, I’m not so sure about zirconate (zirconium.) and (titanium).

4. Cliff says:

Fluid Karma!

5. Cliff says:

Now, to be serious, this sounds like just the thing for an extended Titan rover (floater?).

6. Drone says:

One thing that is not mentioned is how the stress on the generator material eventually leads to failure.

This has been beaten to death already. It has some special (very limited) applications. Yet someone is throwing more hard-earned taxpayer money at it. Next, they’ll be connecting the “Batterizer” to it. This article should have been posted on Turkey Day.

1. static says:

Please spare use the “Yet someone is throwing more hard-earned taxpayer money at it” rant while you are using the internet. In saying ” It has some special (very limited) applications” you are t speaking wave use wave to generate electrical power or using the inverse magnetostrictive effect is use to produce power . In the event you are speaking of the latter please tell use what you know of that. With due respect to Elliot, you read as you know more about that than, Elliot has success in finding additional information.

1. Drone says:

What the heck are you going on about? And who is Eliot?

7. static says:

So this produces wild AC just like the Wind turbines just installed a few miles away from me? As understand it those wind turbines produce wild AC as well. That wild AC is rectified into to DC. That DC is used by inverters to create the AC that’s sent to the grid. That’s how a representative from Bussmann characterized it in an engineering TV interview with a Bussmann rep. explaining how Bussmann protection products are used in that industry. Unless the wild AC can be effectively sent far onshore to get away from the corrosive sea conditions, there’s a lot of circuitry to be protected by a harsh environment. Although that wouldn’t be any different than any other wave power technology. Off shore wind turbines need means to protect the circuitry as well. In that environment would the ferrous current generating components be be subject to hydrogen embritlement? Hell if this works it could be an alternate means to harness the wind to create electrical, although it would involve moving parts. However this has moving parts as well. the stretching and relaxing of the cables that anchor it and the their attachment points.

1. Greenaum says:

People live close to the beach, submarine cables come ashore there. Protecting electronics from sea-shore weather’s a solved problem. Just run some cable to a box a few metres inland from the beach.

8. andrewjhull says:

I hate to state the obvious, but anything that converts wave power to energy must by its very nature involve moving parts. This method stresses a magnetic material, most methods rotate a magnet.
The key to this particular project appears to be in this statement.

“Oscilla Power’s iMEC™ technology platform enables low cost alloys to behave like best-in-class magnetostrictive materials. We are transforming a previously cost-prohibitive energy conversion technology into cost-effective, highly scalable energy generation systems.”

This is the part of the puzzle I would like to know more about.

1. +1 The Navy has been working with nonrestrictive for nearly 100 years. It is how they produce high power SONAR. It is in no way efficient at producing signals from compression waves. I have certainly heard of the physics, but what these people claim needs some outside verification.

I wish they would quit dicking around with the alternative blight on the landscape and get serious about nuclear. The fantastic Columbia Gorge in Washington State is now an eye sore of giant white towers and (not moving) propeller blades. They sit in sight of the big dams that are always dumping excess water. The wind farms are required by renewable energy rules that do not consider hydro to be renewable. The wind farms don’t run because the power isn’t needed. And if it was, you can’t run the dam turbines and the wind farms at the same time despite the hefty grid in that region. How can you take this seriously? Anyone want to buy some Carbon Credits?

P.S. If you don’t know the system on the Columbia River, the Grand Coulee isn’t the dam, it is a a big coulee at a higher elevation. During seasons of excess water and power the dam pumps to the coulee and creates a huge lake. If water flow runs low, water is drawn from the coulee for power and/or salmon. It is a storage battery, and nobody needs the incredible ugly wind farms, which are spreading like a noxious weed even to landmarks like Steptoe Butte. Someone is making a LOT of money off this. Enough money to make it worth declaring hydro power as not qualifying for renewable energy quotas. This ocean wave power movement is the same. It doesn’t have to make economic, environmental, energy, or engineering sense. It has to move lots of money to the right people.

Creeping across the landscape. This exact region already has the lowest cost electricity (due to hydro) in the U.S, at 5 cents a kW/h or less in commercial quantity. Yet, the wind farms MUST be built! Progress! http://www.investorvillage.com/smbd.asp?mb=4143&mn=226155&pt=msg&mid=11666937

1. nonrestricive –> magnetostrictive (what a strange typo).

9. Dax says:

–“He calculates that the cost of producing electricity from them will be around ten cents a kilowatt hour. That compares with 16 cents a kilowatt hour for offshore wind farms and six cents for the onshore variety.”–

The white elephant in the room is the fact that about 4/5th of all the energy consumption in the world is not electricity, but heat, and for heat production the fossil fuels are much cheaper than electricity. Gas, coal and oil basically come in at 1-3 cents a kWh which is an order of magnitude cheaper than ANY renewable power source when you look at unsubsidized prices.

The five cents you pay for energy at the coal powerplant already contains profit for the company who sold the coal, transported the coal, owns the plant, taxes etc. and then the 12 cents or whatever you pay at your own meter then contains the cost of transmission and profit and tax…

Our societies are built on the point that the actual energy input cost – sans profit – about a cent per kWh. Increasing the input cost 10x is simply unsustainable because it means we would have to take our spending on energy from today’s 5-8% of GDP to something around 33-48% of GDP assuming we increase our economic activity to compensate (which means using more energy).

If we don’t, we will end up spending 50-80% of our energy in just producing energy with a corresponding reduction in every other activity such as social infrastructure, which makes it practically impossible to sustain because reducing our other spending reduces our social complexity to a level where we can’t maintain advanced technology. We go back to middle ages.

1. Marvin says:

Heat pumps can go some way into making up the difference. My house was probably designed in the 60’s and it’s very difficult to insulate. I get the feeling that people didn’t think oil and gas would ever be expensive. I think we need more efficient homes.

1. More like the easy to use and install insulation of today did not exist. A 60’s house has blown spun glass and spun glass matting if you are lucky and single pane windows. Nobody had an affordable tech to make dual pane with sealed argon. Plus, fuel was not considered cheap it was a considerable part of a family budget in northern areas. Basically, and surprising only to Bernie Sanders, earnings were closely linked to fuel costs.

1. Law says:

People like B. Sanders are dangerous to the economy in more ways than hurting energy production with unneeded regulations and restrictions. Redistribution of wealth when controlled by a small group usually leads to the end of production of wealth. One B.S. example is “free” higher education for all, which would lead to more waste and corruption. Another B.S. is expanding social security further leading to more debt. No, social security is not a Ponzi scheme, it is worse. Ponzi schemes are voluntary, social security is not. Ponzi schemes don’t put a whole nation in massive economy sinking debt, social security can. B.S. is dangerous.

1. His free education will work easily as long as the faculty work for free, and the grounds crew and the utilities and maintenance are free. Plus the materials and permits for the construction of the buildings need to be free, and the construction contractor has to sign a contract to construct for free. Students can provide all the janitorial services for free. Hmmm. Apparently it requires an entire free economy! It takes a (free) village. But we can make a living doing each other’s laundry. Sander’s danger is he is a True Believer and quite sincere, basic arithmetic be damned! I wonder how he is on conspiracies to hide 100mpg carburetors and Tesla free energy secrets? He also thinks people with \$billions in net assets actually have billions of dollars – really wacky yet with massive dedicated followers of his Scrooge McDuck monetary ideas. (Maybe the Sultan of Brunei and Vlad Putin have \$billions in gold, but he can’t tax them).

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