In response to comments by Dr. Byrne, Dave writes: "The cost in dollars,
IMO, is not as relevant as the energy cost to produce the PV panels (or
other renewable source)versus the output. If it takes more energy to produce
and install than is produced in its lifetime, it's a losing battle,
especially since the energy required for production probably comes from
fossil fuels. As an analogy, consider the use of ethanol to replace
petroleum. I understand that it works pretty well in Brazil, where most of
the work in producing sugar cane is done by inexpensive human labor. There
are many workers and relatively few drivers, so the production is relatively
energy efficient. In addition, it is easier to pay local help than to come
up with hard currency for importing oil. In contrast, ethanol in the States
is produced from corn, using large quantities of diesel fuel and little
human labor. Given the cost of labor, it would be much worse economically to
place many workers in the fields to cut down on the use of petroleum. But
this is energy inefficient. In fact, I think I recall reading that it takes
more energy to produce ethanol from corn than can be recovered by burning
it. There may be other reasons for using ethanol or gasohol, but it is not
energy efficiency in the States."
Dave hits the nail on the head: you can't argue with the laws of
thermodynamics (not only is there "no free lunch," you can't even break
even). It's not so much a balanced financial ledger but the energy balance
that must be considered. This is especially important when the discussion
turns to the use of hydrogen as fuel. The argument is often made by the
media that, with all the water in the world, hydrogen is an abundant fuel."
Separating the H from the O in H2O takes more energy than you get when you
combine the H and the O again to make water.
Getting back to generating portable fuels like ethanol, I suppose it would
be possible, rather than grow corn in North America for the production of
ethanol, one could use destructive distillation of wood to produce
hydrocarbons. This was used in WWII but, for obvious reasons, discarded
when oil flowed more freely again.
Chuck Vandergraaf
Pinawa, MB
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