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

[Thompson Freeman]

On 02/06/2009 12:10:00 PM, Jim Kinney wrote:
> 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.

I was working from memory. That said, 10W/sq ft sounds  
reasonable.
> 
>  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.

Ok, making the correction puts Charlotte &/or Atlanta in  
the 150,000 - 200,000 sq ft range of collectors per  
operating unit. Which is more better doable.

> 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>

You can take the tinfoil beanie off on this one. Exxon et  
al are not going to really push solar because solar doesn't  
show up even as a rounding error on their business models.  
The bosses are charged with making their 10% profit without  
a whole lot of risk. Risky profit is going to take a much  
higher level of profit to be worthwhile, and most solar  
schemes that I've heard of are going to take 10 years to  
turn their profit. Not exactly a deal maker. Plus a huge  
percentage of our population really really wants to show  
off with a SUV...