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Discussion page for OS:Human Hair Solar Panel by Milan Karki.

• 
  Featured: Solar > Photovoltaics >
  Nepalese teen claims cheap solar panel using human hair - Milan Karki, 18, of rural Nepal, believes he has found the solution to the developing world's energy needs, saying hair (due to Melanin) is easy to use as a conductor, in place of expensive silicon. The £23 solar panel produces 18 Watts. Electrical engineers call it a hoax. (PESWiki; Sept. 10, 2009) (Comment)
  

Comments

The following comments were posted at the Daily Mail, unless otherwise noted.

Complete Bunk

On Sept. 11, 2009, Bill of Auckland, New Zealand, wrote (Daily Mail; UK):

You cannot solder hair. It singes and shrivels at much lower temperatures than the melting point of solder (typically 180 to 190 degrees C).

Hair is not conductive. The resistivity (the ability of something to conduct electricity) of hair has been tested. It was found to have a resistivity of 6 x 10^6 ohm-cm, in other words 6,000,000 ohms per cubic centimeter (ohms is the unit of resistance). By comparison pure water has a resistivity of 2.5*10^5 ohm-cm. Silicon has a resitivity of 6.4*1-0^2 ohm-cm ot 640 ohms per cubic centimeter. Copper has a resistivity of 1.72*10^-8 ohm-cm or 0.00000017 ohms per cubic cm.

Also the CFL bulb he is holding is a 230V device, that being the mains voltage in India. So this is complete bunk.

Surface Area Doesn't Compute

On Sept. 10, 2009, Jack of Scottsdale, AZ wrote (Daily Mail; UK):

The more surface area a collector exposes to direct sunlight the more power it can theoretically extract. As one person noted even assuming 100% efficiency at 1000Watts per sq. meter possible from sun there isn't enough surface area in the "hair" collector to generate 18Watts of power as the hairs are in what appears to be a lattice of individually peg-mounted hairs. If however the hair covered the entire surface area of the panel (guessing ~0.3sq meters) it could at least have a theoretical capability of producing that much power. I see no evidence of taped-down hair.

A Scam

On Sept. 9, 2009, Craig Hyatt, NC, USA, wrote (Daily Mail; UK):

He is a liar. He has hidden a commercially available 9V/18W solar panel behind the translucent backing. Just google "solar 9V 18W" and you'll find them for sale.

Can't Make Electricity from Hair

On Sept. 9, 2009, Robert Downe, Stoke On Trent, USA, wrote (Daily Mail; UK):

This is absolute rubbish!! You cannot possibly make elctricity from hair. As an electronic engineer I can assure you that this story is absolute nis-information.

Hoax

On Sept. 9, 2009, Crispin, Boston, Mass., USA, wrote (Daily Mail; UK):

I vote with those who consider this a hoax, and a cynical one.

A hoax because
--the amount of surface area of hair presented to the sun is negligible
--the topology makes no sense - why should a single hair be strung across a whole row of terminals that appear to be attached to the same plate?
--the irregular layout of the terminals has to be just to make it look breadboardy and/or third-worldy - a scientific kid wouldn't do that
--the reporter is technically unsophisticated at best, equating volts to watts to energy, etc.

And cynical because it plays on all the idealistic heartstrings about third world poor boy inspired by Edison and Hawking...

Some Science in Melanin as Semi-conductor

On Sept. 9, 2009, Adelle, of Canberra Australia, wrote (Daily Mail; UK):

There is some science behind using melanin as a semi conductor, but I am skeptical.

Hair like most organic material is not a great conductor or even semi conductor and the man made organic semi conductors are doped in the same way that silicon is doped.

I have high doubts about unadulterated human hair somehow producing free electrons when hit by light that then produces enough of a current that can run a device.

As mentioned by some of the commentators as well, the amount of surface of area exposed to the light is very small.

A good general global average for power from solar irradiation is 1k watt per meter squared. The claim is they can produce 18 watts, they would need to cover an area of .018 meters squared to collect that much power from the sun at 100% efficiency. This would mean they need 180 hairs (1 meter long) or 360 hairs (1/2 a meter long) or 740 hairs (25cms long) based on hair diameter of 100um.

See also

• OS:Human Hair Solar Panel by Milan Karki

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