A vision

[Dylan]

I was driven to start finding more out more about electronics by the following vision that I had, while thinking about a sci-fi story I am working on:<p>You know that simple low-power lemon battery? Well, the question I asked myself was: what if, out of laziness, you never picked the lemon from the tree, before turning it into a battery? <p>That line of thinking ended in the following sci-fi picture:
There is a field of lemon-trees, and all the lemons are batteries. Spread out among the field are "kennels". That's where the little robots are recharged. Of course the robots, from time to time pick up anodes and cathodes from the rotting mass of lemons on the ground, and place them into the fresher lemons on the trees.

[jwax]

Methinks you have the wrong forum, Dylan.

[fsdenis]

Dylan:<p>Growing fields of batteries, automatically maintained by robots. The robots get their energy from the crop. Is there a "farmer" who harvest's the surplus for sale?<p>How much electricity CAN you get from a lemon, anyway. Or a lemon orchard?<p>Fascinating story.<p>As a boy, I was much influenced by science fiction into a technical career. I love my physics. I love my engineering. I love my crafts. I am truly grateful to the sci fi artists that came before you for this inspiration to do high-tech. I still love science fiction.<p>I wish you the best of luck in your writing and hope that ,when you have finished your lemon story, you will consider selling me a copy.<p>P.S. Energy farming is now well begun almost worldwide with windmill farms and photovoltaic farms rapidly coming into existence. <p>Your idea of direct electricity generation from living biologicals seems to fit, if ways can be found to do it. Robots are also coming and might make some approaches feasable, similar to your lemon farm.<p>How much energy CAN be extracted from a living lemon over its career? Are you actually attempting to measure this? Having any luck?<p>[ October 30, 2004: Message edited by: windmiller ]<p>[ October 30, 2004: Message edited by: windmiller ]</p>

[josmith]

The answer is "not enough to be worthwhile".
I did ontime hear of a plan for a seven mile diameter patch of forest with a powrplant in the middle and an automatic harvester/planter spoke protruding from it. The spoke would make one revoluton every few years giving the powerplant a continuous source of fuel.Bio based solar power!
There were no numbers to indicate how much power could be derived from such an arrangement.

[L. Daniel Rosa]

The problem with the lemon battery is that the juice is the electrolyte, nothing more. The electrodes (anode and cathode) get consumed in the reaction and must be refined and rebuilt (taking energy) to use again. Now growing fruit for the sugar to fuel a bacterial battery sounds plausible.<p>I like the radius cropper thing. I saw an article on the Kalle gasifier that may find use here. It is tempermental on a small scale, but takes combustible fuel (read: wood chips) that could be provided by brush and small trees. Use it to run an engine driving a generator. May be difficult to get it self sustaining.

[Chris Smith]

Or burn the wood/Product to make steam to drive the turbine to produce electricity?

[Dean Huster]

Little robots tending things unattended. Have you seen the Bruce Dern sci-fi film, Silent Running? It was the first thing I thought of when I saw the original idea here and well-worth renting at your video store. Made around 1971 or so as I recall, so it'll not be in the "New Release" section.<p>Why lemon trees? Have the robots tend cattle, collect the poop, make methane, churn out the megawatts, breed the sources, etc.<p>How about hamsters? Breed the little buggers, connect their little exercise wheels to little alternators, collect the poop for more methane (make a deal with the cattle robots), etc.<p>Or ants! They're industrious little critters and you won't upset the tree huggers so much if you abuse them (or the lemons, for that matter). Train ants to peddle nano-gens.<p>Actually, Silent Running was the real subject of my reply. The other was just clutter that was packed in the brain somewhere. It's good to put the trash out sometimes.<p>Dean

[John Brown]

It's not the lemons that provide the energy, it's the dissimilar metal electrodes. The lemon, potato or even saliva just act as the electrolyte.
Sorry, just noticed that this observation has already been made.<p>[ November 01, 2004: Message edited by: John Brown ]</p>

[paulrevelcet]

Dylan, I think that is a wonderful concept, and it's not so much the practicality of how much power you can get form a lemon, but the beautiful visuals that on could set up from having little black robots harvest bright yellow lemons in a very non robotic setting, while it would be more practical to use solar power, using the lemons would be the source of the struggle for the little lemon bots.<p>In the real world not a very good idea, but in the world of scifi and fantasy, it makes all the sense in the world, great idea for a book and a movie, can't wait read it!!!

[haklesup]

Substitute human bodies for the lemons and you have "The Matrix"<p>Lemons are a bit weak for earth but.... Assuming your robot planet has plenty of elemental copper and other metals lying around on the ground (as it must have to spawn robots as a life form) then the Lemon trees would supply the "precious electrolyte" needed for survival and propagation of their race. Furthermore, on such a metal rich world, the lemon trees are likly to uptake enough metal to form conductors which would simplify life for the robots collecting power from them.<p>If you like that, try this real headline from today:<p>Green, Leafy Spinach May Soon Power More Than Popeye's Biceps: For the first time, MIT researchers have incorporated a plant's ability to convert sunlight to energy into a solid-state electronic "spinach sandwich" device that may one day power laptops and cell phones ...<p>[ November 01, 2004: Message edited by: haklesup ]</p>

[jollyrgr]

This "Lemon Battery" thing would never work. It would be like having a battery factory that ran on the batteries it made and had power to make extra batteries to sell. It just does not work! It violates the laws of thermodynamics!<p>Everything from cars, computers, electronics, the lowest life forms to human beings run on a form of nuclear power. This power is formed by the fusion of hydrogen atoms into helium atoms. This takes place, give or take a mile or two, 93 million miles away in the sun. The sun drives chemical reactions (photosynthesis) in plants to take water (hydrogen and oxygen) and carbon dioxide (CO2 in the air, carbon in the soil) and form hydrocarbons. Millions of years ago a substance started forming (crude oil) made up of the decayed plant and animal material. Oil is nothing more than a complex mixture of hydrocarbon chains from which we derive substances such as gasoline. Other such carbons are formed (coal). In other suns billions of years ago hydrogen fused into helium, helium was the fused into heavier elements and so on. Even uranium was fused in the heart of some sun billions of years ago.<p>So all our power plants, automobiles, even our very existence is based on "solar nuclear power". Using lemons as a power source is just an extremely inefficient form of solar power. It takes a large, somewhat weak acid and uses it to decompose metal strips into "rust" and forces electrons out in the process that we use for a so called battery. This can be done much easier using an acid such as sulfuric acid, H2SO4. It is also reversible, as shown in a car battery. You cannot recharge the lemon easily. And the months needed to grow lemons far outweighs the useful life span of a lemon on the tree.<p>[ November 01, 2004: Message edited by: Jolly Roger ]</p>

[jwax]

Way more power available from hot air.
Happy election day.

[paulrevelcet]

Yes, but maybe the little robots are very efficient and only need tiny amounts of power to run, they live or exist in a warm climate to where they all ways have fresh lemons, and by the time the little lemon bots evolved into there present form, they had solved the whole dissimilar metals problem and had chose the lemon for there power sorce because they had a distant memory of there creator who used to plug them into his outlet on his work bench, that just so happened to look like a lemon because his granddaughter made him a outlet cover in art class, you see, like people, these little robots didnt all ways do things that made perfect sense, they sometimes done things based on vague emotions that compelled them to do things they didnt understand, because we all know, when life hands you lemons you make an external power source powered by lemon juice.

[Enzo]

Go for it Dylan.<p>The lemons don't violate the laws of thermodynamics unless they are in a closed system somewhere out in space. Sure the lemons are actually running off the sun. So the robots use them for power. As long as the sun shines and the soil has nutrients for the trees, it can work. I don't recall the premise mentioning a closed system, so there is no perpetual motion implications.<p>For a good story there has to be some challenge. Either to the robots if they are the heroes or to the spacefarers who come upon the lemon planet. How about the lemon trees have been bred for super strong acid content to make better batteries? Then the robots have to be careful not to get any on them or face disolving. Of ccourse the first spacefarer who tries to eat one faces dire results. Star Trek used that idea.<p>Or maybe something threatens the lemon crop - say that volcanic eruption over there creating a nuclear-type winter. Then the robots have to come up with an alternative. or maybe the settlers trade with them. or teach them to grow cold weather crops or yams.<p>Or maybe the robots grow in number to the point they can't grow enough lemons and have to grow oranges or grapefruit. (Yes, I know the soil and sun can only produce so much stuff regardless of package size, but this is fiction.)<p>Or every lemon-robots worst nightmare - fruitflies. Worse yet, robot fruitflies.<p>Or maybe the robots want to explore the cosmos, but can't because they can't grow trees without the sun, until one day they discover the Duracell.<p>Maybe a Time Machine approach so the lemon loving robots live on the surface and potato robots live under the earth. The Lemonoi and the SPudniks. The underground dwelling SPudniks make vodka and every so often they come to the surface to steal the Lemonoi lemons so they can have vodka with a twist.

[dyarker]

Please scroll back up and reread L. Daniel Rosa, John Brown and Jolly Roger. The lemons are NOT the power. The power comes from dissimilar metal reactions which destroy the electrodes. Recovery of the metals from rotten lemons takes MUCH more energy than produced. Digging, refining new metal takes MUCH more energy than produced.<p>What do you do when there are no lemons? Lemons are a seasonal crop at any location. Year-round availability is due to imports from different locations.