>Sorry, but your figures are wrong.  Total transmission and 
>distribution losses from a nuclear plant or any other plant are 
>about 7% in the US, and conservation contributes to a 100% reduction 
>in emissions immediately from the marginal units generating 
>-- Rich Rosen

Rich is correct: the figures from Caffrey are wrong.  But what the 
true figures may be is not easy to find out.  As an inventor of solar 
water heaters I have asked Amory Lovins' 'Rocky Mt Inst' for figures 
but the task seems beyond them.

Some stages of loss in electric  grids:

1  Power station alternator thru switchyard onto grid

2  Long-distance EHV transmission 200kV, 400kV or more

3  Substation stepdown (in NZ typically to 11kV) at 'city gates'

4  Local stepdown to 230V in NZ, 110V in USA

5  Local reticulation at this 'retail' voltage

6  Losses between the retail meter on the front of my house and the 
3kW element in my HW cyl (which is on only 15 - 30 min to top up 
after even quite a cloudy winter's day with my SWH gives me ca. 80 
litre tepid water).

	(1) and some other little-mentioned losses (esp in nuclear 
stations) are of interest, but not for the present purpose of 
comparing SWH against grid elec'y for HW.
	What we want is 2, and {3 + 4 + 5 + 6}.
	We gather (2) loses around 10 - 11% of annual energy in NZ; 
Poms claim as low as 3%.  Is the USA avg for losses in just the EHV 
transmission as low as 7%?
	My suspicion is that {3 + 4 + 5} may be considerably larger.
	Transmission losses from nukes are marginally larger in that 
they haven't been allowed within a few dozen mi of any big city i.e 
centre of consumption.  Some big fuel-fired generators are closer 
than that to main load centres.  On the other hand, some are very 
remote e.g Four Corners coal-monster  ...


>From: Science for the People Discussion List on behalf of Mitchel Cohen
>Sent: Fri 2/9/2007 5:59 PM
>To: [log in to unmask]
>Subject: Pelosi calls for nuclear power to offset global warming
>From: Andy Caffrey <[log in to unmask]>
>My fellow Earthlings,
>You lose 80% of the energy generated by nukes in the transmission to
>the end use.
>You can get a 50% reduction in emissions almost immediately with conservation.