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Nothing. A well-made solar panel will last 40 years (there are some 40 year old solar panels still operating fine) and will probably last over 70 years: https://us.sunpower.com/sites/...

Neither feathers nor kittens would have been my first choice for generating electrical power to charge batteries. My guess is that the weight of feathers and/or kittens needed to provide a megawatt of electrical power would probably be more than the same power generated by solar arrays, but I'd be very interested in hearing the results of your experiment showing the contrary.

Seems you cut out all of my part of the post , but here we are. So I'll drop some comments that aren't specifically related to you.

Anyhow, the US military is very capable of setting up mini-cities as need be. They can even do so-called alternative powering schemes. Like Solar https://us.sunpower.com/blog/2... wind - http://www.decentralized-energ... .

They aren't going to set up a big system like the examples shown for PR, but that's where Tesla's PowerWalls really fit the bill. And they can be charged by equally deliverable PV panels.

The remarks by some Slashdotters have been concerning, especially for a site frequented by people presumably tech-savvy. A company does something humanitarian, and Slashdotters don't seem to think the military can deliver it, that it won't work once its there because they can't deliver solar cells, which is kinda weird because they have to believe that something can't be delivered and can be at the same time.

More concerning to me is that our presumed smart people seem to think alternative energy is still in the early 1960's. Too expensive, batteries too little storage capacity, wind power just a toy. All things that have long since been untrue.

Hell, in my area, we have installed enough wind power that they can feather back during off-peak times. It's freaky to see a site starting up and stopping as needed. In fact, wind has made the transition to mainstream energy as far as most around here ae concerned.

Puerto Rico will make good use of these PowerWalls, and Tesla will reap a lot of goodwill and publicity - but Jesus on a pogo stick, it takes a mind like a bag full of warts to hate a humanitarian effort like that.

These "lots" of energy you are talking about are not nearly enough for a modern smartphone.
Even if you would make use of the electromagnetic radiation coming from a nuclear fusion reactor, and position your phone optimally, a harvesting panel the size of a smartphone would barely be able to gain 1W.

I think you missed the joke because when around a couples of hundreds THz, said nuclear fusion reactor emitting the electromagnetic radiation is called the sun.

So we're more speaking about 3W range. (3.5W for 12x12cm)

Still not enough to fully power a modern smartphone monster with both CPU and GPU on full gear.
But solar charging is actually really a thing.

http://www.solarcity.com/resid...
http://us.sunpower.com/homes/h...

A number of places do leases where you are cash-positive day-1. But if you use no power and live super-far north, it's probably not available for you. Look up solar leases.

Looks like you can get 20.4% panels on the market: http://us.sunpower.com/cs/Satellite?blobcol=urldata&blobheadername1=Content-Type&blobheadername2=Content-Disposition&blobheadervalue1=application%2Fpdf&blobheadervalue2=inline%3B+filename%3Dsp_E20_327_320_ds_en_ltr_MC4Comp_504860B.pdf&blobkey=id&blobtable=MungoBlobs&blobwhere=1300286769491&ssbinary=true

So 3.5 * 160 * 0.204 = 114.24 KWh per day, not counting waste getting it to and from the battery and your direct power drains.

True, but the Stirling engine is actually in the process of revolutionizing the way we refrigerate as well as new ways to extract significant power from heat sources. Just to let you know Stirling isn't as impractical as it at first seems.

It is important, though, to keep in mind what the parent says, and that sometimes theories and applications don't quite match up.

See the book "The NExt Great Thing", a pretty good book, was written in 1994 about a company that was working on this back then, and still works on Stirling engines.

http://www.sunpower.com/enthusiast/tngt.html

BTW, Stirling engines make great heat pumps (aka, air conditioners) for certain situations.

Guys, it's a thermoacoustic Stirling. Stirling engines can do a variety of things. You can supply heat, and they will supply motion (usually a reciprocating motion, which works nicely when connected with a linear alternator). Or, you can supply motion (reciprocating), and they will move heat (i.e. usually cooling something). Sunpower has been making cryocoolers based on them for years. And yes, they even played with a module which would attach to a CPU and supercool it.

Hit Google and look for information on Stirling engines. Then, reduce the number of moving parts. Instead of a power piston and a displacer, they use sound waves as the displacer and the speaker as the power piston.

There are already companies at work trying to commercialize this technology. The guys at Purdue are re-inventing the wheel. Check the first link about thermoacousting Stirling engines, and you'll see they've been working on this for some time.

A fun read still in print is Mark Shelton's The Next Great Thing -- a 1989 account, in a tone reminiscent of "The Soul of a New Machine," telling of the attempt by an Ohio company to develop a Stirling engine for use in solar power conversion.

The company still exists and sells a 1KW engine -- but as a $46K "prototype," not a production model.

A fun read still in print is Mark Shelton's The Next Great Thing -- a 1989 account, in a tone reminiscent of "The Soul of a New Machine," telling of the attempt by an Ohio company to develop a Stirling engine for use in solar power conversion.

The company still exists and sells a 1KW engine -- but as a $46K "prototype," not a production model.