Stepdown is to 240V for residential use in the US.  It is center-tapped to 

provide two 120V lines 180 deg out of phase with each other.  Is it 230V in 

NZ, or 460V center-tapped?



Incidentally, I've heard that the accidental electrocution rate in countries 

that use 230V for ordinary appliances (other than guzzlers like stoves, AC, 

water heaters, clothes dryers, etc) is significantly higher than in the US.



----Original Message Follows----

From: Robt Mann <[log in to unmask]>

Reply-To: Science for the People Discussion List              

<[log in to unmask]>

To: [log in to unmask]

Subject: Re: Pelosi calls for nuclear power to offset global warming

Date: Mon, 12 Feb 2007 21:21:39 +1200



>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 electricity.

>

>-- 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  ...



R





>

>________________________________

>

>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.



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