Posted by Neon John on December 8, 2008, 6:52 am
We're not discussing efficiency but capacity in this thread spur. Andy's
statement should have read "35% capacity factor".
The problem here is, I think, that this is cross-posted to both a US and UK
newgroup. Conditions are tremendously different in our two countries,
especially in the desert areas of the southwest and western parts of the US. I
am most assuredly NOT a wind advocate (need power? Plant a nuke.) but I do
regard the trade press as generally accurate, particularly where they quote a
journal paper that's been refereed.
The trade journals survive BECAUSE they provide utility execs useful and
accurate info. Given the high and fairly reliable wind conditions where wind
farms are planted in the US, I think that a 50% capacity factor is probably
accurate. From your description, Andy, it sounds like the UK thing is more a
publicity stunt than a serious attempt to generate power.
John De Armond
See my website for my current email address
http://www.johndearmond.com <-- best little blog on the net!
Tellico Plains, Occupied TN
What do you call 4 Blondes in an Abrams? Air Tank.
Posted by BigWallop on December 8, 2008, 7:45 am
Capacity is just another way of saying "May Produce" when it comes to
renewable energy design. To work out exactly what the capacity of a wind
generator farm is, depends mostly on whatever you compare it with. The
whole plant may have the capacity to supply electrical power to a small
city, but it won't supply a whole region with many cities. So what capacity
does it really have? It has the capacity to generate electrical power, but
to what extent?
If you mean that the position of the site to capture the most prevalent wind
conditions to the fullest, then you may get a capacity of all the turbines
to capture around 50% of the wind from the site. It depends on the reaction
of the turbines to turn the wind they have captured into a potential energy
So I'm confused on what is actually being meant by "Capacity" in this
Most wind farm sites in the UK can give figures from 62 to 79% Capacity for
possible wind conversion into potential energy. Anything less than a
capacity to turn 62% of the potential wind source into a potentially usable
power supply is not going be anywhere near efficient enough to supply the
grid with anything usable.
Posted by David Hansen on December 8, 2008, 2:10 pm
On Mon, 08 Dec 2008 07:45:12 GMT someone who may be "BigWallop"
The report which may be downloaded from
explains the terms.
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
Posted by Andy Champ on December 8, 2008, 9:33 pm
Efficiency of conversion (and for that matter, average load factor)
really aren't the issue for large scale wind farms. Denmark's running
at about 20% wind, and that causes trouble - you have to be able to cope
with the odd windless day. If we had a wind-based system that was 99%
reliable in terms of supplying the base load (not the interruptible
stuff - the aluminium smelters and so on can just shut down when the
wind doesn't blow) would you be happy? Remember that this would mean 24
hour power cuts 3 times a year. *I'd* be getting a backup system if it
did that, and imagine what 20 million private backup systems in the UK
would cost. (more for the US. And all similar to Neon John's. But
without being able to use scrap parts, 'cos we're all fighting over
those. And the price of lead shoots up. And lead pollution rises...)
p.s. Coal lovers - REMEMBER ABERFAN!
Posted by Tim Jackson on December 8, 2008, 10:43 pm
Andy Champ wrote:
There's a brand spanking new 65MW wind farm that I can see every time I
go out of my house, and it's been goldbricking for most of the last week
during the cold snap we just had.
I know the moors where it is built, I used to walk up there a lot and
I've never known it not to be windy. There is a little hillock out in
the middle about the height of the hubs, and even on the nicest summer
day it was an effort to remain standing when you got to the top.