Koestner, you raise very logical questions. And as usual, the responses and citations provided by Jim (Jea48) are correct. The key to reconciling his comments and yours is that while AC current of course alternates direction, the transfer of energy that is intimately associated with that current is in one direction, from the source of that energy to whatever load it is connected to.
(In saying this, though, I’m putting aside reflection effects that occur at high frequencies, as I described earlier in relation to a digital cable. To at least a small degree reflection effects do in fact cause energy to be transferred in both directions, and to at least a small degree cause energy to be absorbed by the source of that energy, as well as by the load. And I’m also putting aside the fact that to the extent a load is capacitive or inductive, as opposed to being purely resistive, it cannot consume energy, although it can store it).
Regarding the underlying question, IMO the Audioquest statement on directionality Jim cited earlier amounts to the least implausible explanation of intrinsic wire directionality I have seen. It should be understood, though, that by its nature the noise effects that are referred to in that explanation will be highly system dependent and even location dependent. And as with many effects involving noise, it will not have much if any predictability. Also, as with many other explanations that are proferred for controversial audio effects, a basic problem is that this explanation doesn’t lend itself to being analyzed in a quantitative manner, that would provide a perspective on whether it does or does not have a reasonable possibility of being audibly significant in some or many systems. With further complication being added by the fact that it is extremely easy in audio to attribute perceived effects to the wrong variable, as illustrated by the example of a digital cable that I discussed earlier, and as illustrated more extensively in the recent thread on fuse directionality.
When it is not possible or practical to obtain a quantitative perspective on explanations that may be offered for a claimed effect, there is virtually no limit to the explanations that can be conjured up and asserted, rightly or wrongly.
In saying all of this, btw, I take no position on the possibility that wire may be intrinsically directional in some systems, to at least a small degree. (And I’m referring here to wire as used in cables, as opposed to the vastly shorter lengths that are used in fuses, whose alleged intrinsic directionality would be swamped by whatever directionality the vastly longer associated wiring may have). But personally I wouldn’t lose any sleep over it. And contrary to one of the comments Geoff made earlier, I certainly wouldn’t avoid the use of balanced cables on the basis of this possibility.
Regards,
-- Al