[ RadSafe ] BUT solar energy just doesn't cut it .....

[Maury]

Re: absence of comments on your earlier post -- I suspect that silence 
resulted in part because your findings and some of the inevitable 
conclusions are rather overwhelming when presented so starkly! My 
digestion is being sorely tested! <g>  Thank you for posing the problems 
rather clearly.
Best,
Maury&Dog

========================

On 10/5/2011 12:13 AM, Ted de Castro wrote:
> Or more precisely PROMPT solar energy gathered over a technologically 
> feasible area/volume.
>
> I posted a calculation here a few months ago that demonstrated the 
> enormity of utilizing enough solar energy just to replace fossil fuel 
> use in the US.  Doable but not easily.  All energy, whole world - I 
> doubt it.
> Realize however that ALL the energy we use is solar (or maybe stellar) 
> energy - in one way or another.  The difference is the time and area 
> over which it is integrated.
>
> Solar panels (PV) are prompt solar energy x collection efficiency 
> integrated over 0 time and the area of the panel.  Same for solar 
> thermal processes.
>
> Solar dissociation to produce hydrogen and integrate over a large area 
> and time for use in a short time and space - but how much area?
>
> Bio fuels are delayed solar energy integrated over the growing season 
> and the area of cultivation x collection efficiency.
>
> Wind energy is solar energy integrated over the area over which the 
> air is heated and the time it heats - times absorption efficiency of 
> course.
>
> Fossil fuel energy is integrated over an epoch or two and over the 
> area that the "donors" grew and fed in, times many efficiency factors.
>
> Hydro is of course solar energy integrated over the area of 
> evaporation and the time that process takes until condensation and 
> deposition.
>
> Wave energy is solar energy either by wind blowing or orbital mechanics.
>
> And of course nuclear is solar - or more likely stellar energy 
> integrated over billions of years and the volumes of the sun or stars 
> that produced the source material from cosmic hydrogen.
>
> So the issue is time and space - mostly space.  We are using the 
> energy in a shorter time and smaller space than the time and space it 
> was integrated over which when used up (or not used due to political 
> restrictions) will leave us only with prompt solar energy which we 
> will need to integrate over a LARGE area to supply our concentrated use.
>
> It was said here that more than enough solar energy falls on the earth 
> each day to meet our usage - but that is only true if we can intercept 
> and use all that shines on the entire surface.
>
> Looking at the calculations I did just to replace fossil consumption 
> with solar would use a massive amount of land and we don't really have 
> the technology to harvest much solar energy over the seas.  From those 
> calculations - the combination of solar energy and our technology to 
> use it just can't meet the need.
>
> I did not attempt a wind energy calculation as I couldn't come up with 
> determination of the area/time over which the solar energy is 
> integrated and harvested.  HOWEVER it is clear that even enormous wind 
> farms can intercept but a very small percentage of the total airflow - 
> in other words - the total solar energy imparted to the winds.
>
> Its just a back of the envelope calculation - that got no comments 
> here BTW - but its very clear that no form of short term integration 
> or small area collection or harvesting of solar energy can meet the need.
>
> IMHO
>
> Ted de Castro
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