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Tapping Trees for Electricity?
dr_agonfly writes "Despite many skeptics, a Massachusetts company is getting investor interest in developing a process to tap electric power from trees. MagCap is looking to boost the current power from just under 2 volts to a more useful 12 volts with investor funding." From the article: "Jim Manwell, director of the University of Massachusetts Amherst's Renewable Energy Resource Laboratory, questioned the potential of MagCap's plans. 'I'm wildly skeptical,' he said. 'I would need to see proof before I believed it. It strikes me as pretty questionable for a number of reasons.'"
When you hook up two dissimilar electrodes through an electrolyte (which in this case is nicely packaged within a tree and the nearby ground), you get an electrochemical potential. In the case of copper and aluminum as your electrodes, the potential is about two volts.
An easy way to get 12 volts? Connect six tree-cells in series.
My guess is that iss no different from the classic lemon battery, just replacing the galvanized (zinc-coated) nail with an aluminum nail.
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From the article:Lagadonis said tests have generated 0.8 volts to 1.2 volts by driving an aluminum roofing nail half an inch into a tree attached to a copper water pipe driven 7 inches into the ground. But the electricity is useless because it's unstable and fluctuates.
Here's the answer: 13 aluminum roofing nails, 13 copper pipes, hooked up in series to an automotive voltage regulator and an ampmeter. If you get a fluctuation between 5-20 amps, take out the ampmeter and replace it with fuse and a cigarette lighter adapter, and plug in your iGo charger to charge your cell phone off of it.
SJW: a person who perceives an injustice, and while correcting it, commits a greater injustice.
When the nail completely corrodes, the tree will stop "producing electricity" and this company will have moved on to impressing investors with potato clocks.
An easy way to get 12 volts? Connect six tree-cells in series.
.01 milliamps, it's not going to power a whole lot. Unfortunately, the article doesn't mention amps or watts, and without at least 2 of the 3, there's not really much to say about the potential (pun sort of intended).
Precisely what I was going to say, and I'm sure anyone with a basic knowledge of electricity would say the same thing.
Of course, the real problem probably isn't the voltage so much as the wattage. 12 volts is great, but if it's at about
As Gregory Hines said in Running Scared about hitting the third rail on the subway, "it's not the volts that kill you, it's the amps". A taser hits with 50,000-150,000 volts. The reason you don't burn to a crisp when you get hit by one is the amps are so low.
You want to get the voltage to a usable level, but you also need enough amps to run whatever it is you want to run. Frankly, I doubt a tree can produce enough amps, at least without permanently damaging it, for any serious period of time. The act of being a battery will cause a chemical change in the tree which I have to think wouldn't be a healthy one. Since the tree is alive, it will probably repair the damage, but whether it can repair it fast enough to keep from dying is another question.
Needless to say, I have some serious doubts about this "technology".
He has indeed made a battery, and has made a cunning choice in using an aluminium nail because of its electrode potential. It works like this:
:v)
Copper(II) electrode potential: 0.337V
Aluminium electrode potential: -1.662V
(Source http://www.ami.ac.uk/courses/topics/0157_corr/)
String them together in a condictive electrolyte (tree sap & humic acid in the soil will do) to get a cell with 1.999V potential - magically matching his 2.0V
Of course, his aluminium nail is corroding and will need replacing - which is where the energy comes from.
You can't connect the trees in series to increase the voltage because they share a common ground.
Vik
First of all... Increasing voltage has a trivial, known solution. Starting with DC makes it a bit harder, but still a well-understood problem with a wide array of solutions to choose from. Since none of the sources of information on this company (and I looked into this one before it hit Slashdot) mention either wattage or ampereage, I have to suspect the real problem involves not volts, but watts. Yes, magically increasing voltage would increase watts via "W=V*A", but not if you do so via a voltage conversion rather than a "real" increase in output.
Second... An aluminum nail and a copper pipe, both embedded in a slightly corrosive fluid... Hmm, where have I heard something like this before? Oh yeah, the basic galvanic battery. Sorry MagCap, the Babylonians beat you to the punch on this one.
Finally... Do trees particularly like having a few thousand aluminum nails driven into them? Not making a flakey "tree rights" argument, but rather, does using tree sap as a battery electrolyte really count as sustainable, or will it just kill the tree? Not to mention that both aluminum and copper salts tend to have deleterious effects on many organisms native to this planet.
In summary - Listen to the skeptics on this one. I'll tolerate the zero-point folks before I'll let some MBA try to sell me a massively overblown version of the "potato clock".
Step 1: Cut down said tree
Step 2: Chop into firewood sized chunks
Step 3: Burn chunks obtained from (2)
Step 4: Harness heat from (3) boil water
Step 5: Use steam generated in (4) to turn steam turbine generator
Step 5: ???
Step 6: Electricity!!!
An Indian-American Hindu committed to non-violent thought/speech/action alarmed by the global explosion of radical Islam
Google for "potato battery", you'll find plenty like this.
;-)
I remember there was a story about some guys demoing their tiny microcontroller chip (or single-chip webserver, or something) running it off a "potato battery" to show how little power is required.
I guess I should start teaching physics to VCs, charging $300/hour -- will save them a lot in the long run...
Paul B.
Who ever told you that was wrong.
With special care, algae can produce 50 grams of oil per square meter per day.
But with more typical care, algae produces about 5 grams of oil per square meter per day.
Even using that typical figure, you could still produce the trillion gallons of oil needed annually with an area only slightly larger than the Great Sandy.
In other words, not only is there enough sun light hitting the earth, there's enough sunlight hitting in the earth in places were plants aren't currently growing.
According to the faq and press release on the home page for the company they do talk wattage. They essentially wire multiple taps into a capacitor circut that cleans the power a bit and ups the voltage by swapping the capcitors from parrallel for collection to series for pulsing when full.
They think they can scale the basic idea to 12 volts and 1 amp. So 12 watts of energy.
Interesting to note the faq clearly states this is not a galvanic reaction. And there is no destructive anode/electrode errosion. There seems to be no practical limit to the number of taps per tree (other than damaging the tree itself) and that the tree size dosn't make any difference. Also the power harnessed goes up during winter.
In the end it looks like it is tapping into a store of energy held universally in the ground by using the tree spike as a positive pole while the ground spike is the negative.
What I don't get is... this seems to mean it is something independent of the trees and it seems you could create an more efficient element for tapping the energy. All in all this sounds a lot like the old work of Tesla. He found that that the ground did indeed carry a charge along with the atmosphere. Heck lightning itself is indeed proof enough of the atmosphere... same for ground lightning with respects to the ground. So this isn't really all that crazy. Cloud based lightning is a difficult potential energy source to tap. However ground lightning should result from charge potentials in the gound. If you can find a way to tap that potential and release it in a measured manner you could then tap lightning as a basic source of energy. Since those potentials are driven by forces of nature it is essentially limitless.... though I suppose there is the potential to tap the energy at a higher rate than it is stored.
I don't ask you to be me. I only ask you not expect me to be you.
I'll do one better. The best rough estimate I could find of the power transferred from the Sun to the Earth was here (link). According to that we receive about 1.7x10^17 W from the Sun. Since Watts are Joules per second, we can do a little math and find that the energy total for a year comes to around 5.4x10^24 J/year. Now, the best estimate I could find for total worldwide energy consumption (link) puts us at around 5.418x10^20 J/year.
What does this mean? It means the Earth receives each year from the sun, approximately ten-thousand (10000) times the energy that we consume. What this in turn means is that the sum of our methods for capturing this energy and putting it to use needs only to achieve 0.1% efficiency.
If you're going to be proclaiming something as grandiose as the statement that the sun cannot possibly deliver enough energy to earth to meet our needs, then you really should have something better to back it up. Furthermore if you're talking about something at a global scale, you should analyze it at a global scale, not a unit scale.
GET THEM INSIDE THE VAULT!
The issue is a bit more complex. There is an atmospheric potential difference on objects relative to ground. That is, there is an electric field strength in the air that increases with height. I forgot if it's 200 volts per meter, or something like that. But you can demonstrate it with a wire suspended above ground and a high input resistance voltmeter. A tree is actually immersed in an EMF because of this. Being tall, there is a significant EMF difference between crown and roots. As the tree's inside cells contain water, it is a tall conductor (well, more like a resistor). Therefore there should be some division of the EMF depending on the place you tap the tree and measure to ground. You're not going to run motors from it, but the effect is real.
I don't know where you got that strange (and WRONG) idea from (sorry, I had to use your words!), but the total accumulation of solar energy on the surface of the earth at midday in the tropics without clouds is 1.4kw/m^2. Most places have an average midday solar exposure of a few hundred watts per square meter. It is not midday 24/7.
What else to cover. The price of solar cells isn't the only issue like you claim, as the overall cost is mostly efficiency*cost, so efficiency must be factored in, Also important is the nature of the fixture (for example concentrators), and cells aren't the only way to harness solar power. And oil companies actually lobby relatively little compared to the size of their industry, mostly for reduced environmental regulations and for better relations with other countries (yes, they're pro-pollution, but the big oil refiners and producers are actually somewhat antiwar because you can't pump oil when guerellas are sabotaging your fields and pipelines). Their main interaction with solar is actually positive - BP and Shell are some of the world's biggest investors in solar research. There's stating to be a movement to shift from being "oil companies" to being "fuel" or "energy" companies, not limiting themselves to one particular source.
The *special* hell.