Energy Sources of Nanomachines

From the basic laws of physics we know that when work is done, energy is transferred. When you lift something up you are converting potential chemical energy which you acquire from into kinetic energy.

It has been stated by Drexler (see previous sections of this page) that nanomachines we build will be capable of self replication and precise manipulation. These tasks will require a great deal of energy on this scale.

A message on the Transhumanist Mailing List addresses the problem of providing sufficient energy to nanomachins:

in response to this message:

Transhuman Mailing ListAndre writes:> Secondly, nanomachines will still require energy to power them. The amount> varies drastically depending on the atoms involved and how you rearrange> them, but are always considerable simply because of the number of atoms> involved. Suppose you wanted to break Cardon-Dioxide (CO2) into carbon and> oxygen. (A plausible example as Carbon is major building block in anything> organic) It would take 393,500 joules, or about enough to energy to boil> four cups of water, to break apart a single Carbon-Dioxide atom. True,> that's not a lot, but that's only one atom.WHAT?! I don't think this is true, aren't you referring to the energyneeded to break apart one mole (~10^23) molecules? (Quick check in mychemistry book). Yes, this is the enthalpy of formation for one mole. As Dennet said, there is nothing I like less than a bad argument for aview that I otherwise agree with. Energy is an issue for nanotech, butthe amounts of energy needed aren't astronomical. The problem isinstead of getting the nanodevices to utilize it in a efficient way,and how to get rid of the waste heat.> Even on a smaller scale, power is still an issue. Classical motors, either> electric or combustion, cannot be constructed small enough so converting> energy into work is problem. Finding a way to deliver energy, even> assuming it can easily be converted to work, to millions of individual> nanomachines may also prove challenging. Does anyone know of any theories> in these areas?I would suggest looking at biology. The cell is filled with molecularmotors, and they work quite well. Energy is provided by ATP moleculesdiffusing through the cytoplasm, and their hydrolysis powers themotors (be they linear style motors like myosin, dynein and kinesin orrotating motors/generators like f-ATPase). This form of distributionworks nicely for distributed, slightly sloppy systems. The moremachinelike Drexler designs would need a more ordered form of energy;Merkle has suggested powering them with ultrasound (there are a fewdesigns on his website).Nanomachines might be limited, but their applications are likely muchwider than the microscopic scale.

One of the most popular theories for providing energy for nanomachines is through photosynthesis, a process already implemented by nature. Nanomachines could absorb energy in the form of particles from the sun, converting them into electrical energy and storing them in a battery. If groups of machines are next to each other and some are not in sunlight, the exposed machines could link up with the unexposed to transfer and share energy. With the current efficiency of converting sunlight into energy it would not be feasible to power nanomachines, but Drexler proposes on www.foresight.org that nanotechnology will drastically improve the efficiency of artificial photosynthesis.

Another popular theory for powering nanomachines is placing nanomachines in a chemical solution composed such that the solution has enough chemical potential energy that the nanomachines could convert it into electrical energy. This reduces the versatility of the nanomachines but is probably easier than building photosynthesizing nanomachines.

main