IEEE: About Wind Turbines

Mike O'Dell mo at
Fri Feb 5 12:31:14 CST 2010

it has nothing to do with sloppiness

wind and solar have problems with "dispatch reliability"
the wind doesn't blow the best way all the time
and clouds are equally difficult to predict a year in

after a wind farm or solar farm is in operation for a while,
the planning assumptions, developed from detailed monitoring
for an extended period before the farm gets built, are validated
with "real life", and those can be used to estimate the expected
output from the facility. but those are *estimates* based on
past history, and weather is notoriously unreliable.

until we have realistic grid-scale power storage ability, or
until wind and solar have enough geographic diversity to allow
large-scale averaging, and the transmission infrastructure is
sufficiently modernized to support significant transit traffic,
wind and solar cannot be used for "base load" distribution because
they cannot be relied upon to be there when required.
as a result, every megawatt of generation contracted with
wind or solar has to be backed-up with a contract for
dispatch-reliable generation (fossil or nuclear).

just last year, in the Texas Independent Operating Area
(larger than Texas but it is the majority of the area),
they were using a large wind farm in northwest Texas
to carry part of the daytime peak load. to the vast
surprise, a little dry line moved through, dropping the
wind speed to essentially zero in the space of two or
three minutes. suddenly the TIOA had a deficit of several
hundred megawatts and the impact was felt all the
way into Canada. the TIOA has rightly decided they have
to solve this problem before they can carry base load
generation with wind or solar.

progress is being made on grid-scale storage,
and plans are being developed for a new long-haul
transmission core to make it easier to move power
long distances. the current transmission infrastructure
was designed to be regional at most, within one power
company's regional footprint. moving power from
the sunny southwest to the dreary northeast is just
not realistic at the moment. new EHV transmission coupled
with a move to DC-based interties offer the possibility
of both building a new transmission core as well as making
the existing grid more stable by sectionalizing it.

it turns out large AC power grids and large dynamically-routed
data networks have the same fundamental problem: they are
both too large to be synchronous. the speed of light is just
too bloody slow. the solution in both cases is to break
the network into subnets small enough to be quite stable
and then interconnect those regional subnets with technology
which doesn't propagate instability. those are DC interties
in the electric power case and exterior routing protocols
in the packet network case.

the Europeans have been doing DC interties and DC transmission
for quite some time now and the technologies are relatively
mature, but the network planning and engineering required
to exploit them are not as well-developed or well-understood
over here. and utilities are not prone to spend money they
can't relate directly to bottom-line growth, so the incentives
may require a bit of tuning to produce the desired behavior.

but it is gonna happen - just not terribly quickly.


On 2/4/10 11:12 AM, Karl W4KRL wrote:
> Andre,
> There should be exact figures for how much wind-generated electricity was
> produced. Then we would not need to resort to rules of thumb to compare wind
> capacity to non-intermittent capacity. It is sad to see the degree of
> precision increase when applying approximate factors. Shame on the author!
> An interesting statistic that was missed is that US wind generation capacity
> was increased 40% in one year.
> 73 Karl W4KRL
> -----Original Message-----
> From: andre kesteloot [mailto:andre.kesteloot at]
> Sent: Wednesday, February 03, 2010 12:39 PM
> To: Tacos
> Subject: IEEE: About Wind Turbines
> New turbines amounting to almost 10 gigawatts were installed in the
> United States in 2009
> <
> Release.html>,
> bringing the country's total wind capacity to about 35 GW, according to
> data released by the American Wind Energy Association this week. Next
> week the Global Wind Energy Council, based in Brussels, is expected to
> release figures showing that wind installation worldwide almost equalled
> the booming growth rates seen in recent years, which have been around 28
> percent per annum.
> Putting its spin on the rather sensational 2009 news, the American wind
> association asserts
> <
> hts_of_2009.html>
> that additional U.S. wind capacity avoids or saves more than 60 million
> metric tons of annual carbon dioxide emissions, 200,000 tons of sulfur
> dioxide, 80,000 tons of nitrous oxide, and 20 billion tons of water. A
> spokesperson for the association claims, perhaps a little dubiously,
> that their numbers crunchers got these results whether the generation
> that wind is substituting for is taken to be the average national mix or
> the specific mix replaced by specific turbines.
> To keep things in perspective, recall that when wind (or solar) capacity
> is compared to baseload fossil or nuclear generation, it is normally
> divided by a factor of three, four or even five, to account for
> intermittancy. (The wind doesn't always blow and the sun doesn't always
> shine.) By that standard, the new wind capacity really is equivalent to
> no more than 3.3 GW of natural gas. But even by that reduced benchmark,
> it's the equal of three nuclear power plants--not a single one of which
> is getting built in the United States at present.
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"Of course it's hard!
If it was easy, we'd be buying it from somebody else!"

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