[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: A Republican!!!!!! (was Re: OT: sponge burning!)

On Tue, Feb 27, 2007 at 10:31:18AM -0500, hendrik@topoi.pooq.com wrote:
> The hope is that large, well-engineered, monitored power plants can 
> produce energy in a cleaner way than small, internal-combustion engines.
> Whether this is true is a matter of fact -- doesn anyone know the 
> relevant facts here?  (Not to mention the energy losses in the 
> transmission of energy from the power plant to the wheels, of course)

well, the current "consensus" is that yes, centralised power
generation is easier to clean up. And each time you upgrade the
generation source, all the electric cars on the road automatically get
cleaner. That only makes sense. The transmission loss is significant
(something in my head says 10% on average, but I don't know where that
came from). The biggest issue is the infrastructure. Massive numbers
of new power plants and significant increases in the transmission
infrastructure. There was a recent "discussion" (very reminiscent of
this one) on slashdot where some folks ran the numbers on an electric
car battery that could recharge in a few minutes. That's great until
you realise that you have to dump a couple (?) hundred kwh into the
thing in just a few minutes. That works out to a couple thousand kwh
capacity per plugin apparatus. Put several of those into a "recharging
station" and you're looking at some serious electrical
infrastructure. Being able to serve up say 8 cars at a time with a 5
minutes of recharge and a 150 kwh capacity battery rig per car means
you need 14,400 kwh capacity in that station. Don't know how accurate
my numbers are but I think it adequately illustrates the problem. A
typical house in the US has 200kw service, so you'd need the power
service of 72 houses to put up 1 recharging station. 

Other option include "swapping" batteries at the station. That's all
fine as it means you get in and out of the station in just a few
minutes with a conventional battery rig. but still, you have the same
charging problem -- in order to serve 8 cars every 5 minutes or so,
you are still moving the same amount of power out of the station, but
now you also have to store all those batteries while they go through
their 6 hours recharge.

Obviously that kind of change can't happen overnight. Its an ugly
problem, no matter how you cut it.


Attachment: signature.asc
Description: Digital signature

Reply to: