In article , Austin Shackles
writes
On or around Sun, 28 Dec 2003 19:02:49 +0000, John Beardmore
enlightened us thusly:

ISTR that there's a place in France where they have an 12-tonne flywheel (or
thereabouts) as a power storage device.

Commonly used in French phone exchanges I understand.


Not sure of details, nor of how you
get power out of it effectively.

Coils and magnets I expect.


There seem to be some indicators that power station size fuel cells may
be around in 10 years time, so the energy storage problem may get
solved.

fuel cells don't store power though.

No. See other message for mention of electrolysis.


They generate more efficiently from
fossil fuels than some conventional systems -

Doesn't help much if used like that though. One scenario is that you
strip hydrogen out of oil or gas, use the hydrogen in fuel cells and
burn the more carbon rich hydrocarbon in the usual way elsewhere.


The fuel cell concept is
supposed to generate at about 90% efficiency I think, maybe more these days.

Probably optimistic at the moment ?


The above, coupled with the growth in the output of WT plant suggests to
me that you may be very wrong indeed in about a decade.

I take it you don't mean Wireless Telegrpahy... Water Turbine I suppose.

Correct.


but none of the "intermittent" class of renewable generators will work
without truly big electricity storage.

Which is likely to be available by then.


And you've a problem from the outset
there, in that the distribution system (rightly) runs on AC, so you can't
use simple storage batteries without inverters, which are of course
inefficient.

Modern inverters can be surprisingly efficient and large. Some WTs
output to the grid via switch mode electronics which handles power
factor correction and safety protocols.

The 'electronics pack' on an Enercon E66 for example can be thought of
as an efficient 1.8MW power conditioning 3 phase inverter with an 11 or
33kV output depending on the line it's connected to.

With this sort of kit getting more common, I don't think grid connection
of energy stores is going to be a huge issue.


Actually, the pumped storage method isn't too silly, really,
but it tends to require a lot of space.

Yes, the hell of a lot !


Cheers, J/.
--
John Beardmore