The Story So Far
From a scientific perspective, this is all extremely sketchy. What the E-Cat purports to do is turn a little bit of input energy, plus hydrogen, into a huge amount of output energy (heat) using a nickel catalyst with only copper as a byproduct: somehow, hydrogen combines with nickel to create copper while giving off heat. So technically, it's not cold fusion, but a low energy nuclear reaction.
Some calculations of one test run showed an output of 30 kilowatt-hours after an initial input of only nine kilowatt-hours, and the final generator should produce energy at a rate of six to one. This isn't "free" energy — hydrogen is being used up. But only a tiny amount of hydrogen is used, relative to the amount of energy being produced, and there are no carbon or radioactive outputs at all.
At least, this is what we've all been told is going on. But nobody knows for sure, and this weekend will be the first independent verification of the power input and output of a one megawatt reactor based on E-Cat technology.