Teenager invents £23 solar panel that could be solution to developing world’s energy needs … made from human hair

Color me skeptical. The story, of course, is very skimpy on the science, but let’s look at this. The claim of “9 V (18 W)” is really hard to believe, because P=IV means 2 A of current flowing through the hair, though that will be divided up. Still, the diameter of a hair is thinner than AWG 32 wire (at about 200 microns), which has a current limit of less than 0.1 A for power transmission, and that’s for a good conductor. Hair? Not so much. The pictures show a grid of interconnected hair, which doesn’t have all that much area, so capturing any more than a small fraction of the few hundred W/m^2 of insolation is not in the cards. A 20 x 20 grid at less than 0.2mm per hair is just a few square mm of hair — it can only get you a fraction of a Watt.

Question: why don’t we have our hair generating electricity like this while it’s attached to our heads?

At best, somebody dropped a prefix representing several orders of magnitude somewhere. At worst it’s a scam.