[ale] [OT][Way OT] Industrial Power Question

[Jim Kinney]

On Fri, Feb 6, 2009 at 11:27 AM, Thompson Freeman
<tfreeman at intel.digichem.net> wrote:
>
> My apologies to those who really don't want to see this.
> Unfortunately ALE is one place where I can consistently
> find intelligent technically informed people, so on the
> chance ...
>
> During the era of $4/gallon fuel, I got to blue sky
> thinking about solar power and transportation.
> Specifically, rail and/or light rail.
>
> If my back-of-the-envelop calculations are anywhere near
> correct, it is now technically feasible to run a rail
> transportation system (say like MARTA for instance)
> entirely from solar power collected from the right of way
> of the tracks and the roofs of the stations.
>
> I have recently seen a short article claiming a thermal
> solar conversion system is economically competitive with
> more traditional electric generation schemes.
>
> For the back of the envelope stuff...
>
> My understanding is that current solar collection runs
> about 1 watt/sq ft of collection area.

I am seeing 10W/sq ft on most current PV installations.

 To allow for clouds
> etc, take that to 0.5 watt/sq ft. Lets use a figure of 1
> horsepower=1kw, which is some 20% high, but keeps the
> number simple and turns on a light also. The Charlotte Lynx
> system runs vehicles of 780 rated horsepower,

Reasonable. The modern diesel/electric is 2200 HP. People haulers like
MARTA use bi-directional push-me/pull-me trains. So a "short train" (2
car) is likely around 800 HP (12-15 seconds to 50 mph thumnail
estimate). Let's call it 1kHP for easy round number and 1hp=1kw again
for easy.


 which means
> that MARTA may be up to a thousand?? In any event, 780x2000
> suggests Charlotte would need to dedicate 1.5 million sq ft
> of collection per running vehicle for full power usage.

And MARTA would need 200k sq ft/train car pair (1000hp/pair x 1000W/hp
= 1,000,000 W/train pair; divide by a 50% collection ratio of 5W/ft sq
= 200,000 ft sq.)

> Since the vehicles are under full power for only short
> periods of time that 1.5 million figure is probably a
> multiple of the required power needs, but I don't have the
> background to make the adjustment. In any event, that
> figure is approximately a strip 14 miles long by 20 ft
> wide, or the right of way available to one track of the
> Lynx line here.
>
> The question I have for the bright people here is "Can you
> refine these figures/guesses to something a little more
> defensible?"
>
> I probably should offer to purchase a round of virtual beer
> for the participants...
>
> Thanks for the use of bandwidth, and the opportunity to
> scratch a nagging itch.

I have always wondered why PV has not been mandated for rooftops. It
just keeps getting better and better.
The more that is in use, the more research that gets done to make it better.

<tinfoil beanie> of course Exxon, BP, Ford and GM are secretly
assassinating photovoltaic researchers worldwide..</tinfoil beanie>
>
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>



-- 
-- 
James P. Kinney III