[NCLUG] Re: "Green" power

[Yuri Csapo]

To contribute with a piece of trivia: there's a plant in my home town 
(São Paulo - Brazil) that does exactly that some of the time. It's used 
for several things including flood control and to keep water levels 
constant for hydroelectric generators downstream, but a large part of 
its night cycle is spent pumping water upstream so it can get to a 
steeper slope on the other side, increasing that particular river's 
generating potential. It is also sometimes used to generate electricity 
(because the pumps can act either as pumps or generators).

Yuri

S. Luke Jones wrote:
> On Sep 13, 2008, at 12:29 PM, danbob wrote:
>> Just as a point of order, Sean, the average utility grid losses as heat
>> in the USA are 9.5 percent, between the power plant and your electric
>> meter. So "almost 100% efficient" is not correct, and that 9.5% is
>> heating the great outdoors.
>> DAN FINK
> 
> 
> Do you know how much of that is due to "heating up the wires" at night 
> for lack of anything else to do with the power?
> 
> As I remember, many utilities offer power at negative cost for large 
> industries that can commit to using a lot of power at night. Another 
> solution is to use power to pump water upstream back up behind a dam 
> (treating a reservoir as a battery) (with attendant accelerated erosion 
> in the river downstream from the dam). This seems counterintuitive, but 
> is the result of generation in large plants like Rawhide that take two 
> weeks to spin up or down, but use in small appliances like air 
> conditioners, clothes driers, and ... energy-star computers that people 
> put to sleep when they're not in use.
> 
> Any discussion of electricity conservation is -- well, not meaningless, 
> but pretty shallow -- if it doesn't consider baseload generation and 
> time-of-day factors.
> 
> S. Luke Jones - slukejones at gmail.com
> 
> 
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-- 
Yuri Csapo
Academic Computing & Networking
Colorado School of Mines
CT-256
Phone:  (303) 273-3503
Fax:      (303) 273-3475
Email:   ycsapo at mines.edu

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