Homestead mailing list

[Clansgian AT wmconnect.com]

In a message dated 6/11/2006 7:41:02 AM Eastern Daylight Time, 
genegerue AT ruralize.com writes:


> Perhaps not with current transportation habits. Those habits will be 
> forced to change. Not enough pain yet.

Yes.  Yes.  That's exactly the point.  Most of the talk one hears is about 
what alternatives we are going to use to replace increasingly expensive 
petroleum.  What is needed is more talk on what lifestyle changes are needed, 
are 
inevitable, to drastically reduce energy consumption.  This concern eclipses 
all 
considerations of alternate fuels.  If we make those habit changes early 
enough, we'd have petroleum fuel to last for many decades.


> 
> Have you seen figures for how much transportation energy could 
> feasibly be produced by solar generated electricity?  
> 

It's the same sort of paradox.  Instead of getting too deeply into the power 
required for vehicular motion, consider that one square yard of direct 
sunlight contains a maximum potential of 833 watts.  It's physics, there just 
isn't 
any more there than is there.  One horsepower is 746 watts so let's say that 
if 
we had one square yard of solar collector in ideal circumstances and near 
100% efficiency, we could have at our disposal one hourspower of work.  

Let's suppose that we have a super efficient vehicle whose payload and 
vehicle weight are 1000 lbs and let's suppose it is going to travel almost 
entirely 
on level ground.  50 hp would be enough to get it about rather efficiently.  
Let's suppose 5 hours daily of ideal sunlight.  

With only two square yards of solar collector you could run the vehicle for 
one hour a day.   Sounds feasible.

But:

-Solar pannels are no where near 100% efficient.  The average now is around 
10% with the maximum (for pannels made of very expensive material) of 35%.
-There are very few places with 5 hours a day ideal sunlight for power 
generation.
-A 1000lb solar vehicle is unlikely, battery weight is high.
-50 hp for any time of reliable transportation is unlikely such as multiple 
passengers and cargo.
-etc etc same sort of negativism you've come to expect from me

To view it another way, using only one gallon of gasoline an hour is the same 
as using 39Kwh's of electricity.

I'm thinking that when you go to that much trouble to go from one place to 
another, you'd just choose to walk.   Or stay home.  Or hitch the horse.