"Wes" wrote in message
...
"Ed Huntress" wrote:


"Wes" wrote in message
...

Do you need something precise, with documentation, etc.? If so, there are
lots of studies, using different methods of measurement. Search on "wind
power embedded energy," wind power embodied energy," or "wind power life
cycle analysis."

I just need to get a rough idea if windmills are net energy plus and what
the span is.


I did this a few years ago. At that time photovoltaic was showing a
worst-case payback of around 24 years, while wind power showed a payback
in
6 months or even less.

Just grabbing one from a Google search, without checking it for accuracy,
here's something that shows how it's calculated and some specific numbers.
There are better studies that you can find, I'm su

www.rogerhelmer.com/sustainability.pdf

I googled a bit and didn't find something better yet. That one gave me a
good enough idea
of inputs and how long to recover them.

Near the end where they break down financial payback was an added plus,
saved me another
question. However, my googling shows estimated life of about 20 years
for these
machines. About the time the project recovers the expendature it needs
major renovation.

Of course getting longer life than estimates could happen and the designs
are going to
improve over time as a body of experience is collected.

At least now I have something in my head to detect if someone is trying to
run some bs on
me.


While googling I ran into this chart:
https://eed.llnl.gov/flow/images/LLN...y_Chart300.jpg showing energy
inputs and where
they go. Notice how much waste is in electrical distribution.

Yeah, it sounds like distribution is the problem that's holding up a lot of
possibilities. Somebody has to solve that (not to make big improvements in
efficiency, necessarily, but just to make it possible to transmit power over
long distances in the US -- politics and regulation are big impediments) or
wind and large-scale solar are going nowhere. Not that I ever expect them to
be a dominant source of power, but they could be significant.


https://eed.llnl.gov/flow/ The section of the site were this came from
looks like it has
some interesting reading material.

I notice that there assumptions for next few decades have coal as an
energy source. I
guess they didn't get the memo.

Wes

I'm looking forward to seeing if my prediction made 20 years ago comes to
pass. I predicted then that more nuclear fission was inevitable, that it
would eventually dominate our electricity generation, with wind and/or solar
being mostly of local application in a few areas. My heart sunk when Three
Mile Island put the final nail in fission's coffin for at least a
generation. I hope I live long enough to see something happen.

--
Ed Huntress