IEEE: About Wind Turbines

Mike O'Dell mo at
Fri Feb 5 13:02:37 CST 2010

the chinese are indeed developing mfg capability for
wind turbines and they have suffered mightily doing so.
Suzlon has had repeated catastrophic failures due to
the complexity and rigors of the gearboxes, which is
the single largest source of failure in large 3-blade turbines.
Suzlon's design uses 3 smaller generators instead of one
large one, but that dramatically complicates the gearbox
even if it simplifies generator design challenges.

Vestus and GE Wind are currently the largest suppliers of turbines for
US and European development projects.

the biggest push by China has been in polycrystalline
solar cells. they have developed massive infrastructure
for making solar-grade silicon and then producing sells
of respectable efficiency at very competitive prices.

but in both cases, the capabilities are manufacturing,
not technology development, and both areas require massive
technology development if the LCOE (Levelized Cost of Energy)
is to become competitive with fossil fuel combustion without
massive subsidies.

one big target is the so-called "direct-drive" wind turbine,
where the generator is driven directly by the turbine rotor
without a gearbox in the middle. essentially all such designs
generate variable-frequency AC which is then bulk-rectified
and then converted with a line-synchronous inverter to make
60Hz. the concept is incredibly attractive on the white board.
execution is non-trivial - the alternator design alone is
a huge task.

the Japanese currently hold the record for non-Hydro grid-scale
power storage. Tokyo Electric worked for years and several bilion
dollars to develop a liquid-sodium/liquid-sulphur battery that
can supply a megawatt for 7 hours (including inverter losses).
a 7MWH module is about 40 feet long, 10 feet wide, and 15 feet
high, and tips the scales at about 200 tons. the cells operate
at 300C, btw.  TEC needs these because the vast majority of their
base-load generation is nuclear, and nuclear plants are not
very flexibile. they are expensive, so running them flat-out
is most efficient in terms of kilowatts per yen of depreciation,
and nuclear plants have such a huge thermal mass, they don't
throttle up or down in less than multiple hours. as a result,
the sodium-sulfur batteries let them deal with the diurnal
cycles and peaks with less over-capacity.

several US utilities have ordered a sodium-sulfur battery for
the purpose of exploring how they could use grid-scale storage
in their networks, but i doubt seriously anyone in the US
will try to deploy them - they want a technology which won't
make people instantly crazy when they hear a few thousand
pounds of liquid sodium will be located down the street at
the neighborhood substation. and there is more appropriate
technology is being developed in the US.

so while China's manufacturing ability is not to be
underestimated, it's also a long, long way from the
last reel of the movie.


On 2/4/10 4:14 PM, andre kesteloot wrote:
> 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!
> indeed
>> An interesting statistic that was missed is that US wind generation
>> capacity
>> was increased 40% in one year.
> also the news today that the Chinese are already able to produce that
> kind of equipment at 40% less than we do.
> Are we going to miss the boat, once again ?
> 73
> André
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