🚀 go-pugleaf

John DeFiore wrote:
>
> James Salsman <jsalsman@bovik.org> wrote: 
>>
>> For terrestrial collectors, I revise from about five square 
>> kilometers to about 100,000 (based on the up-to-date efficiency 
>> and weather factors from other posters.)  That's a square 
>> 200 miles on each side, or about 1/20th the area of Saudi Arabia, 
>> or 2/5th of Nevada.  Again, that's to serve the electrical power 
>> needs of everyone on the planet, and it's all solid state, 
>> zero-emission renewable (at least for the next 3 billion years)
>> technology.
>
> Perhaps, but Mr. Waltz is correct when he points out that it takes more
> energy to make a solar cell, using current technology, than it can
> return in it's entire life.  Also, the cells do not last forever.  They
> are degraded by the UV exposure, weather, oxygen, etc.  The cost to
> fabricate and maintain a 1000 square kilometer expanse of solar cells
> would be prohibitive, let alone 100,000.  Granted that improvements in
> technology may eventually let the solar cell produce a net energy gain
> in it's lifetime, but still, let's be practical.

Agreed.

What is the efficiency factor of mechanical (non-PV) solar 
collector arrays and their associated turbine systems?

The 100,000 km^2 figure is based on a 20% duty cycle of 15% efficient 
collectors, and I'd like to figure the area required for turbine-based 
generation systems.

Sincerely,
:James Salsman