On 3/18/2011 3:22 AM, Just Wondering wrote:
....

1. Wind power is dependent on the wind. There are very few locations
with a dependable wind source. And there's not enough wind power
available, even if used 100%, to make much of a dent in a nation's
energy needs.

....

I've posted the capacity factor records for the Gray County (KS) wind
farm previously...

For the eight years of operation, the average monthly capacity factor
has only been 40% in one of the prime locations for wind generation in
the US (western High Plains region). Months during the diurnal cycle of
early winter and late summer are generally 30% and less; even the
highest in early spring have only hit 50% in one of eight years.

Han recently asked if that weren't owing to other factors than wind
availability such as dispatch so I recently did a correlation w/ the
monthly average wind speeds and no month was below 0.8 w/ the overall at
0.90 even on such a coarse basis as monthly averages.

It can thus be concluded that on average it takes 2.5X the installed
capacity to generate a given level of power from wind and that that
factor goes even higher for significant fractions of the year (and
there's a smaller daily diurnal period as wind speed generally falls at
night as solar heating goes away). This causes two effects, neither of
which is conducive to saving much if at all economically and mitigates
the positive benefits from diversion. First, the low fuel density means
a high cost/output as well as a huge over-capacity required to make up
for at least some of the variability in supply. Second, for a reliable
grid there has to be standby generation for most, if not all, of this
capacity and this has exacerbated the rush to build natural gas-fired
co-gen units as the cheapest/quickest way to get that done. That's a
_terrible_ short term use of natural gas, btw, that will undoubtedly
come to haunt in the (not so distant) future as heating costs continue
to rise...

All in all, free fuel ain't so free after all...

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