Matthew,
My bad. Thanks for clarifying "better". I should have specified "much less expensive". To my surprise (thank you), it turns out Direct Current travels "better" (as in "much less energy loss") if you use high voltage or low amperage. Just how high and low is the big question.
I should have realized the AC/DC wars a century ago were limited by technology, not physics. Now DC transmission (at 500KV, 2GW, 40KM (4K amps!) and 3% energy loss) is "better" over long un-interrupted distances (under the English Channel, in this case). Better cost, better efficiency, though still not better reliability (hence the 4 link redundancy).
"Costs of high voltage DC transmission" at:
http://en.wikipedia
Thanks again,
Mark Stafford
--- In electricboats@
>
> Angela wrote:
> > Great responses to the AC/DC dilemma. Add to the mix: AC travels better, so the higher the current and/or the longer the wires, the more likely AC will be more efficient.
>
> That's not strictly true either. Now that high power electronics can
> cope with powers in the megawatt region, long distance high voltage DC
> power lines are now being built and are desirable - they have lower
> losses than their AC equivalents.
>
> We have AC distribution simply because the humble transformer is such a
> reliable and efficient item. Until high power electronics became
> available, building a high voltage DC line was difficult. High voltage
> DC was difficult to make and difficult to turn back into a useful lower
> voltage. Modern advances in power electronics have altered the picture.
>
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