Wooden floors rotted by fungi generate electricity when walked on | Hacker News Reader

Wooden floors rotted by fungi generate electricity when walked on

newscientist.com

101 pointsBluestein59 comments

This seems like it's constrained to produce a trivial amount of energy. There is no way it's a practical source of power to reduce carbon emissions. Let's say we drop an 80kg person onto this floor and they deform it half a centimeter. That's 9.80 N/kg * 80 kg * .5 cm = 3.92 joules. A AA battery has 14,000 joules in it, which means you'd have to do that 3,571 times generate the equivalent energy.

The paper's abstract gives 0.87 volts * 13.3 nA = 1.15E-8 joules per second. That's not exactly going to make a dent in our power grid.

One paper I found [2] says you could get about 5J per step from walking on level ground, but that's still the same order of magnitude as my initial estimate and nowhere near a practical power generation technology.

[1]: https://www.baldengineer.com/9v-battery-energy-density.html

[2]: https://www.tandfonline.com/doi/full/10.1080/23311916.2016.1...

All of these "clever" energy recovery schemes are inherently stupid, because you'd almost always be better off just making the original system more efficient rather than recovering some negligible fraction of its losses.

Maybe the innovation is designing devices that require orders of magnitude less energy, and then meeting in the middle with low output energy sources like solar panels, etc.

At that point, we just make less batteries and solar panels and call it a day. An order of magnitude less energy consumption means we basically already have the necessary renewables and nuclear installed as is, job done.

You’re not wrong, but I think your point is missing the most interesting aspect of the article. Which is fair, I don’t think this article was written very well. The thing that stands out to me the most is the realization that mycelial networks generate electricity at all, just from applied pressure.

The article stated that this is the piezoelectric effect, which by definition is a very minuscule amount of electricity. I can’t imagine anyone is seriously considering this effect could be tapped reduce carbon emissions. They suggested if more buildings were constructed from wood that might reduce carbon, but it’s sort of a tangent to what should have been the headliner if you ask me :)

The fact that the fungus is generating an electric charge, albeit very small seems incredible to me! Add it to the list of incredible things fungus and mushrooms are capable of, and the important role they play in our environment. Is no surprise the show ‘Star Trek Discovery’ chose a ‘mycelial network’ as the ships basis for teleporting around the universe.

I got the impression, both from this article and the original (here: https://advances.sciencemag.org/content/7/11/eabd9138) that the electricity wasn't generated by the fungus, but instead the increased compressibility of the wood after being rotted enhanced its pre-existing piezoelectric properties. The original article does mention "mitigation of climate change" as a possible application, by the way.

I heard that squeezing "possibly related to climate change" somewhere in academic work increases chances of getting grant money nowadays, could it be it's the only reason why this phrase is there in this case?

Oh dang, Yeah I think you’re right! Maybe I got to excited for the fungus part from my own bias, maybe I’ve been watching to much Star Trek haha :)

So it’s the resulting structure of the wood, not the mycelium itself. Thanks for setting me straight.

It’s a little unclear how, or what types of devices could be powered by this, but they would be very low power. The biggest is mitigation to climate change come from selecting wood as the primary building material, versus steel which produces a lot of greenhouse gas.

Interesting, cellulose is not conductive, the molecular changes must be subtle.

It's not gonna power your fridge, but it could make a cool rotten floor sensor!

> There is no way it's a practical source of power to reduce carbon emissions.

Even if it were, the fungi probably release a couple more orders of magnitude more CO2 than saved by this generation mechanism.

Common fallacy is anything "natural" is a carbon reduction. Not always true. A biker on a meat-based diet releases more CO2 per kilometer than a Prius. [1]

[1] http://www.keith.seas.harvard.edu/blog/climate-impacts-of-bi...

The energy 'created' (transformed) is still generated by the human by effectively burning carbohydrates/fats/etc. Might as well create a tiny alternator, spin it by hand and be done with. Alternatively, attach magnets/coils to gym equipment and there you go. If you continue further, no need for springs and weights at all - make all gym equipment with NdFeB and copper instead - 'free' energy.

The idea of generating energy from people is actually kind of interesting because it's something that we already do at the gym. We have all these weights and machines to have people expend as much energy as they can, but don't capture it.

Now I'm sure the amount of energy expended at a gym is fairly trivial, but if we can attach a $5 generator to every exercise bike, rowing machine, stair machine, etc. it could potentially be profitable.

Lots of gym equipment has screens and stuff powered by the human.

Sure, a black and white LCD screen only uses under a watt, but it saves the equipment having a battery or power cable.

LCD uses significantly less than a watt unless they have a backlight as well. What takes the most of the energy is the microprocessor.

You could build large towers out of this material that sway in the wind like trees and generate electricity.

Yeah, but you could also build a windmill.

Not in the exact same spot as a usable building. Not a big one anyway. I guess it could conceivably be more effective to just put a vertical windmill on the roof.

Make structures out of it lol. Its rotten balsa. Also the amount electricity is still too small to use.

Perpapbs a pressure sensor or some kind strain gauge is more applicable.

This is a pretty fun idea to think about. Does the energy from the animal that walks on the wood cost the animal extra energy or does the energy come from the efficiency loss from walking (whatever that means?)?

Presumably the energy that would normally go into deforming the wood is converted to electricity. The wood would spring back less or be less warm or make less sound, etc.

It's also possible that the wood deforms more requiring the walker to expend more energy.

I think it's an interesting thought experiment. How would we measure it?

work= energy = force x distance (integrated if force is variable).

Stick a load cell on a linear slide, measure accordingly.

Drop a ball, slow-mo camera to measure bounce, mic to measure sound, infrared to measure heat....BUT the energy amounts were talking about are very small.

>cost the animal extra energy

short version: yes

It seems like this would be easier to apply in measuring stresses in wood beams and building parts than it would be to apply in generating electricity.

> The amount of electricity generated is still very small, just 0.85 volts

That's numberwang! We like those decimals, NewScientist.

>That's numberwang

Lol. BRB, going to go watch Youtube.

you do know you can measure energy in electron volts. Using the standard volts would need to have current given and time to transform to energy, though.

Why do fungi generate electricity after deformation?

Or asked differently, what information is encoded in that electrical pulse? Presumably, evolutionarily, fungi developed transmitting information via mycelium to other connected fungi. But why are fungi letting connected fungi know, “hey, I got stepped on!” ?

If someone steps on your foot, the nerves in your foot conduct an electrical signal to your brain for interpretation as pressure, pain, etc. Plants use external chemical signals for similar signaling. Presumably this is similar.

Right, but the point of the pain is to remind conscious me to pull my foot away. But fungi (afaik) aren’t conscious, nor can move, so what’s the evolutionary advantage to this signaling?

It may signal where to invest more effort into decomposing the material (if the pressure degrades the material) or where it wouldn't be a good idea to put effort into sprouting to reproduce (wouldn't make sense to put your reproductive organs in harm's way).

Alternatively, where it _would_ be a good idea to produce spores if you want to hitch a ride on some passing foot traffic.

We don't know. Interestingly enough, mushrooms also double their yield after a single high-voltage shock.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5029503/

I am kind of partial to the pan-psychic notion of all plants and animals who are living having something that could resemble consciousness or at least an experience of existing. It may not resemble the part of our consciousness that forms words and likes to project an ego into the world but perhaps the experiences we have while dreaming or non-verbally perceiving. I suspect that the experience of being a mycelium would be very alien to anything we can easily imagine. But this whole concept is best explored in science-fiction for now.

The idea that fungi would have rudimentary communication pathways isn't really that insane. That doesn't necessarily make it true, but it always strikes me as odd when people talk about plants, fungi and other non-animal life as if it wasn't life at all.

The Xenofungus from the video game Alpha Centauri comes to mind.

Depends on your definition of conscious, I suppose. Fungi can definitely move, just not via locomotion - fungi expand through mycelial networks and reproduction.

Who knows what the specific function is, maybe specific species are sensitive to the specific pressure of another species required for reproduction. In the plant example, they often use chemical signaling to repel predators (and note that plants are also "not conscious", and most are way less mobile than fungi).

From reading the article, I get the sense that the piezoelectric effect in the wood itself is what is generating the electricity. So I think the role of the fungi is just to weaken the wood so that it's soft enough to compress more easily.

Would connecting several together then still produce more current? Because I'd assume that all the pieces of infected wood would have to be moving at the same time to generate friction.

> "Moreover, we were able to significantly increase the maximum output current (≈ 205 nA) by connecting 30 wood sponges in parallel to each other, making a demonstrator suitable for wooden tables or floors." which is at 0.69V

But what elements of cellulose and lignin would allow the flow of electrons ?

There need not be any evolutionary advantage to this particular property of mycelium, as long as its structure provides other evolutionary benefits. Such as a medium to transmit nutrients. In other words, it could be just a side-effect of something useful.

Would be interesting for powering IoT devices.

One thing that surprised me recently was the electricity released by tearing and pulling off tape. I was trying to make some direct exposures onto photographic paper inside a camera obscura. Inside the very dark room I could see bursts static electricity every time I tore off a bit of tape. And when I went to remove some double sided tape from the back of photo paper, it also lit up, hopefully not leaving some strips on my exposure. Not really related to fungi, but maybe about as curiously surprising.

Wasn't there an indication it emits energetic particles?

https://wattsupwiththat.com/2008/10/22/scotch-tape-emits-x-r...

For what its worth they did make the tape based xray florescence machines, I saw them on applied science https://www.youtube.com/watch?v=KdfHVcU8U7U

So Minecraft already predicted this.

How does it work at the molecular level?

Can it be synthesised and manufactured at scale? If so, for what net energy loss/gain over the lifecycle of the material, and at what cost?

Yes, and we use them to make annoying buzzers in all modern electronics [0]! The article mentions some attempts at using the effect practically.

[0] https://en.wikipedia.org/wiki/Piezoelectricity

Isn't Piezoelectricity fundamentally static electricity? Like, instead of being generated on the surfaces of materials it's generated internally?

Seems like you could use this to make a fancy button that doesn't need phantom power. Neat!

I'm thinking of something like the PS3 on-switch, but using wood and not needing a constant low-voltage power supply to work.

A lot of folks are poo-pooing this, and maybe rightfully so, but you have to admit this is pretty damn cool. Besides the narrow-framed application it's interesting that it was even discovered.

The article says this rotted wood could be used as a building material but isn't the very rotting that makes the piezoelectric effect more efficient also counterproductive to strong building materials?

Layers of subflooring don't all need to be structural, but they do need to tolerate heavy foot traffic, plus occasional heavy items rolling on dollys. The more give it has, the more it has to be able to return to its original state, which rotted wood isnt usually great at.

for the actual paper https://sci-hub.se/10.1021/acsnano.0c05493

"Moreover, we were able to significantly increase the maximum output current (≈ 205 nA) by connecting 30 wood sponges in parallel to each other, making a demonstrator suitable for wooden tables or floors." which is at 0.69V

so to get 1A, you will need 150000 (though I doubt it would scale like that) all being stepped on actively. So as a power source? seems unlikely. As a sensor, sure.

cool tech.

I don't think a balsa wood floor is gonna handle more than one or two salsa dances, no more.

I suppose you'd have to put some kind of hard flooring material over it?

If there's a harder surface over it, it'll spread out the pressure over a larger area, meaning the wood as a whole would compress slightly. Not a bad idea.

scratch, scratch, scratch

And then the cat began to spark and exploded...

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