General Electric (GE) and
the U.S. DOE have agreed to discontinue work and close
the 100MVA HTS generator program by March 2006. The
decision was reached after the recent completion of the
preliminary design review, which examined all aspects of
the HTS rotor, the refrigeration system, the excitation
system, and the conventional stator, and was based on
uncertainty over the costs, the benefits, and the
technological viability of the generator. The program
began in 2002, and the total amount spent on the project
(as reported in 2004) was $26.7M, with GE contributing
$14.4M (54%), and the DOE contributing $12.3M (46%).
>>more available inside
2002
500MVA Generator Better Suited to Market
GE had anticipated HTS
generators to provide customer benefits such as: a 0.35
to 0.55% efficiency gain, improved reliability from the
near complete absence of thermal cycling on the rotor,
and the potential capability for generator uprating/retrofitting.
While 100MVA is a technologically appropriate class of
machine for the development, it is too small to be a
cost-effective product because the efficiency benefit is
not sufficiently great, nor are such generators of that
class necessarily online often enough to recoup the
added cost of the technology.
>>more available inside
2002
Large Generators a Strain for BSCCO
A 100MVA generator operating
at 20% overspeed (4320rpm) would put a load of 8000g on
the HTS coils. For generators greater than 200MVA, the
load would surpass 10,000g, requiring a two-fold
increase in strain capacity, to at least 0.4%, and more
probably 0.5%. Fogarty commented: “The challenge of
working with a conductor under these conditions is the
equivalent of trying to stack 1000 sport utility
vehicles on top of a 1m by 4m glass table. If the glass
cracks, you lose.”
>>more available inside
2002
Hurdles Include Wire and Refrigeration Cost
GE’s warm iron rotor HTS
generator concept was reportedly designed to minimize
the length of HTS wire needed for a large generator, as
well as the volume of material that must be at cooled to
cryogenic temperatures. Nonetheless, the cost to
incorporate HTS technology into a generator was higher
than initially expected. “Wire costs alone were higher
than the entire cost of a conventional rotor, with no
allowance for the rotor shaft or refrigeration,” said
Fogarty.
>>more available inside
2002
Requirements for HTS Wire Underscored
Challenges aside, GE
speculated that 2G HTS wire might one day address a
number of the technical issues encountered. GE pointed
out what it termed some positive trends in 2G wire
development, including increasing Je, the introduction
of copper-plated stabilizers, and higher tensile
capability. The company stated that high compressive
strain capability tends to be where 2G is most
vulnerable.
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Additional topics covered in the story include:
500MVA
Generator Better Suited to Market - Large Generators a
Strain for BSCCO -
Hurdles Include Wire and Refrigeration Cost -
Requirements for HTS Wire Underscored
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NEW!
OP-ED: Philip Sargent writes,
"Capital Costs May Make YBCO Coated Conductors
Cost-Prohibitive"
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