Why Wind Power Won't Make Power Flow
Sun Sep 30, 2007 at 08:14:58 PM PDT
[From the point of view of Aussie nuclear vs wind discussion on Nuclear Australia. This applies, everywhere, however. It's why wind cannot be a substitute for base load power--David Walters]
Critics of nuclear energy sometimes point to Germany's planned nuclear
phase-out policy as an example of the industry's limited future. Let
us put aside the very credible discussions regarding the possibility
of that policy being reversed for a moment and turn the tables.
How are German renewables performing?
As reported in the Herald Sun, Terry McCrann digs into the performance
record of one of the largest wind powered systems in Europe.
Germany's E.ON Netz operates the grid which has one of the biggest
'feed-in' wind power sources in Europe. Each year it produces a
WindReport. The latest makes interesting, sober, reading.
Germany has 18,300MW (megawatts) of installed wind capacity --
close to half Australia's total installed electricity generation
capacity, about double Victoria's.
E.ON Netz draws on 7600MW of that.
In the precise German way, it tells us that maximum feed-in was
6234MW at 9am on 15/12/05.
Sound great? Except when you read the minimum feed in, at 12.15pm
on 27/05/05. Just 8MW. And no, I'm not missing a nought or two.
Some 7600MW of installed capacity delivered just 8MW. When the
wind don't blow, the electricity don't flow.
On average across the year, the 7600 MW of installed wind capacity
produced 1327MW. That's an operational level of 18 per cent of
capacity. In rational terms, it's insanity.
Indeed as E.ON Netz notes, installed wind capacity went up 12 per
cent in the year but actual wind power fed in to the grid went up just
1.5 per cent. Because of lower "wind availability".
The way you 'solve' this is that 'traditional' power stations with
capacities equal to 90 per cent of the installed wind power capacity
must be permanently on line to guarantee power supply.
So not only do you have to install six to seven times as much wind
capacity as the output you will actually get, but you also have to
build 'shadow' coal/gas/nuclear(?) as well.
That's one power station for the cost of 12 or so.
Did I say insanity? Unless you can build big enough batteries to
store the power generated when the wind does blow.
Funny I should say that. E.ON has actually pioneered exactly such
a battery. It's the size of four shipping containers, uses
'undisclosed' chemicals and can produce all of 1MW for four hours.
See this link for projected vs. actual performance for any day (just
select via the calendar on the right side of the page). Interested
that they seem to always exceed the projection, but fall WELL short of
the 7,600 MWe capacity. The 18% number looks about right from my
perusal.
As much as I hate to be baited into nuclear vs. renewable discussions,
the data bears careful digestion. Just as I've said from the
beginning, when you objectify and quantify the discussion and base it
on demonstrated performance - the picture becomes MUCH more clear.
I've learned something though. In my previous back-of-the-envelope
calculations, I was crediting wind with a 30% capacity factor. Seeing
the 18% above, I guess I should pull that number back a bit.
