[ RadSafe ] BUT solar energy just doesn't cut it .....
maurysis at peoplepc.com
Wed Oct 5 00:36:34 CDT 2011
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
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
> 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
> 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.
> Ted de Castro
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