From: Spike Jones (spike66@ibm.net)
Date: Wed Sep 06 2000 - 20:27:36 MDT
> > Eugene writes:
> > > Let's assume a 1 m^2 PV panel, with the average insolation of 0.5
> > > kW/m^2. Let's say the efficiency is 10%, so it generates 0.05 kW ...
> >
> > hal@finney.org wrote: No, 1000 times greater. 36500 hours * .05 kW =
> > 1825 kWH.
> > Spike Jones wrote: At 11 cents per kWh, ... over 200 bucks worth
> > of power. So now we just need the economies of scale to produce
> > m^2 panels for less than 200 clams. spike
>
> "Michael S. Lorrey" wrote: Assuming 365 days of 10 hours of sunlight for ten
> years is quite a stretch, Spike. Even in California.... ;)
Ja, I thought it a little optimistic too, but the 10% efficiency was
conservative enough to make up for it. We can do better than 10%.
We can do mid to high teens without even resorting to the high techy
multispectrum cells.
I will ask a friend who had a solar panel for several years and measured
the power collected, then get back with you on that.
Nowthen let us look again at the corn distilling experiment to get an idea
of how much energy we devour on a regular basis. We estimated 1400
liters of ethanol per hectare year. My detroit travels about 10,000 miles
a year, thats 16000 km and devours a gallon of petrol about every 14
miles, thats 3.87 liters every 22 km, and petrol is about 10% more potent
per unit volume than ethanol, so I figure thus:
(hectare-yr/1400 liter C2H6) * (1.1 liter eth/liter petrol) *
(3.87 liter petrol/ gal) * (gal petrol / 14 mile) * (10,000 mile / yr) =
about 2.2 hectares
2.2 hectares just to keep my detroit on the road, or about 5.4 acres for
of you who know how much an acre is. You may wish to plug into
the above formula your own fuel economy and distance per year.
Granted, growing corn and distilling the result is not the best way to
capture solar energy, but it does give one a feel for orders of magnitude.
When one hears some yahoo say: "Hey, if we put solar panels on our
cars, and let them charge during the day, we could run our cars on
electricity." After this exercise, we know that that person isnt even in
the right order of magnitude. Another way to look at it is this: if a
parking lot capable of comfortably holding about 600 cars were to
be dug up, planted in corn and the result distilled, the ethanol produced
could be used to power one of those 600, assuming it is an average
American guzzler driven an average amount.
That same area, covered with solar cells would be able to power
about 15 of those 600 cars. If the cars were all state of the art
electrics, the parking lot could power about 25 of em.
Conclusion: petrol is your friend. spike
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