Natural Science Forum / Physics / General Physics / July 2008

I'd love to know how much wind energy America can provide without
disrupting meteorological flows.  Everybody thinks that wind is free, but
as physicists, we know that the wind coming out the back of the windmill
has lost kinetic energy equal to the electrical energy generated plus
dissipative losses in the electrical and mechanical systems.  

Nature needs wind to function properly, and just think how awful life would
be if you walked outside on a cool day in May and there were no breeze.  
But breezes are even more important in July.  I'm not saying that's what
will happen, but since the hallmark of The Green Movement is to analyze the
world as a closed system, using conservation equations, this is yet another
a green question worth examining.

I will always prefer rooftop solar cells, because otherwise that solar
radiation is just going directly to heat, and it's only function is to heat
an already overheating planet.  Recapturing that energy would help the
environment, not hurt it; it would be concentrated in cities, where energy
use is also concentrated, and it would boost the economy, by making jobs
for home contractors.  It would also help reduce the problem of urban heat
islands.  

Even central station solar power plants in the desert are harmful to the
environment, because the desert ecology is very delicate, and building
those things will destroy the ecology at the plant site.  Likewise, the
energy collected is proportional to the area covered by solar collectors,
and larger outputs would claim proportionately more ecologically sensitive
land.  GW power plants will have an enormous ecological impact.

Ocean wave power has the same problem as wind, which is that ocean waves
are critical to the functioning of their ecosystem.  The Japanese plan to
beam solar power from space can provide unlimited energy, but it will
contribute to the global heat budget by introducing energy that wouldn't
have arrived on earth in the first place.  I expect that would contribute
to global warming, although I can't way would be the ratio of trouble
caused by that to the trouble caused by CO2.  

That pretty much covers everything except nuclear, whose pollution problems
are worse than global warming, and fusion, which will probably never pan
out, if you believe Lidsky's 1985 MIT analysis.