Well, he just has build there a simple galvanic cell with his food can and some copper and other metal rods, so it is giving him a galvanic voltage of about 1 to 1.5 Volts and the current only scales to the surface area of these materials...
Then he uses some kind of a Jule Thief circuit to power a few LED Chains from the High Voltage output spikes of the Joule Thief... so nothing extraordinary... As this "lemon battery" type does not put out much current and corrodes pretty fast, this is NO free energy at all...
Sorry, but I analyzed the video in Slow motion and that´s just it...
BTW, I am running the overunity.com forum and are myself heavily involved in battery and supercap research in this moment... not wanting to bragg, but that is the thing this boy just presented with a lot of Media hype...
Anyway, good luck to him... maybe he can scale it up some more by using his own selfmade supercaps, which is not hard to do... Only needs the right carbon materials and electrolytes... Just go to Youtube and have a look at Robert Murray Smith and Cayrex2 channels, they are the best experts on new Supercap designs in this moment. Regards, Stefan.