From: steinly@topaz.ucsc.edu (Steinn Sigurdsson)
Newsgroups: sci.environment,sci.physics,sci.energy
Subject: Re: ZERO Nuclear impact (was: Is car pooling for real? etc)
Date: 23 Jul 92 00:14:33 GMT
	<1992Jul21.232009.1209@nmt.edu> <STEINLY.92Jul22143340@topaz.ucsc.edu>
	<1992Jul22.221159.19297@vexcel.com>
Organization: Lick Observatory/UCO
NNTP-Posting-Host: topaz.ucsc.edu
In-reply-to: dean@vexcel.com's message of 22 Jul 92 22:11:59 GMT

In article <1992Jul22.221159.19297@vexcel.com> dean@vexcel.com (dean alaska) writes:


   In article <STEINLY.92Jul22143340@topaz.ucsc.edu> steinly@topaz.ucsc.edu (Steinn Sigurdsson) writes:
   >In article <1992Jul21.232009.1209@nmt.edu> houle@nmt.edu (Paul Houle) writes:
   >
   >Paul, please go calculate the extractable wind energy, comapre it with
   >demand, and contemplate potential climatic effects if a significant
   >fraction were actually extracted. Wind is going to a marginal
   >contributor unless demand plummets.

   Wind power could be the dominant energy supply in the upper plains and if
   the grid has the capacity to distribute it, the power could be a 
   non-trivial (10's of %) part of the U.S. energy supply.

US concumption is about 10TW of which 3TW is grid,
mean wind speed is about 6 m/s - if you have a 1km
turbine, assuming wind power can be regenerated by solar
heating on a time scale of 10**5 seconds, you need an
area of 2d16 cm**2 to get 1TW. That's 1000miles square,
100% extraction. What do you think the climate impact
would be, even if it could be done?

   >This is dubious. I refer you to Physics Today from early 1992,
   >the problem is the comparisons used to make that claim (I assume
   >you're referring to the "the Japanese and Germans use much less
   >energy - and look we can marginally decrease our household
   >consumption...") usually fail to take climate and population
   >distribution into account.

   Studies of possible electricity savings for the U.S. based on studies
   of currently used versus currently available technology in the U.S. range from
   about 75% on the liberal side (from RMI) to 44% on the lower (from the EPRI).
   The 44% figure is the maximum _MTP_ figure which assumes full
   utilization of the best existing technology.  

I'm puzzled, is the study for all uses or for domestic uses only?
Are metal foundries and transport really that far from thermodynamic
limits? Don't forget household only accounts for 1/3 of energy
consumption, - or does this presume the US does not refine its
ore and continues to export heavy industry?
	The EPRI studies I've seen quote the 20-30% easy
efficiency, and that does not factor in the energy to do 
the change, simply the new consumption rate if you magically
replace all old inefficient devices.
	Again I ask, does the study include the energy
that is requried to fabricate the new efficient devices,
in energy efficiency, assuming finite lifetime it is not
worthwhile to replace all old inefficient equipment immediately,
refining Al and moulding glass are high energy activities.


   >If people would look beyond arbitary "sustainable" labels and
   >realistically assess what the options are - rather than jerking their
   >knees and becoming phobic, then there might be stable long term
   >energy sources available.

   If people understood the true state of efficiency and sustainable
   technologies, they might stop calling others knee jerks.

 no. "nuclear" jerks knees.

*  Steinn Sigurdsson   			Lick Observatory      	*
* steinly@helios.ucsc.edu		"standard disclaimer"  	*
*  Some people think they're really clever			*
*  Smash your head against the wall            Specials, 1979	* 
Xref: sparky sci.environment:9811 sci.geo.meteorology:2537 sci.skeptic:13096