POWER March 2012 - 14

5. A freezing current. A 10-kV high-temperature superconductor
cable made by Nexans will replace a 1-kilometer high-voltage cable
in Essen, Germany. At temperatures of around -200C (-392F), with
cooling provided by liquid nitrogen, the concentric superconducting
cable is transformed into an almost perfect electrical conductor able
to transport at least 100 times more electricity than copper. Despite
the cooling jacket, the compact design of the superconductor means
that it can transport five times the electricity as a similarly sized copper
cable with much lower electrical losses. Courtesy: Nexans
Cable cryostat
Liquid nitrogen
return
Dialectric
Liquid
nitrogen inlet
6. An advanced series. Mitsubishi Heavy Industries shipped its
first commercial J-Series gas turbine, the M501J, to Himeji Unit 2 in
Hyogo prefecture, Japan last December. Courtesy: MHI
Phase L1
Phase L2
Neutral conductor
Phase L3
That cable was manufactured by Paris-based Nexans using wire
produced by American Superconductor Corp. A handful of projects
have been tested since then, including a 300-m cable with fault
current limiting functionality installed under Manhattan. Known
as Project Hydra, Con Edison and wire-maker Southwire plan to
use that technology to connect two Con Edison substations in
late 2014 with a 170-m-long cable.
Asked why superconductor technology development has been limited
to smaller scales, Nexans said that though production processes
have improved, " superconducting wires are only now available in sufficient
lengths and quantities. " But " experts anticipate that these
innovative cables will soon be in a position to compete with copper
solutions in energy-intensive applications, " the company added.
One suitable use for the technology is in city networks. According
to Nexans, the " AmpaCity " project, scheduled for operation in
Essen by 2013, could " herald a whole new dimension in the restructuring
of inner-city networks. " The project follows a study by
KIT that found superconducting cables are the only " reasonable "
alternative to high-voltage cables in city networks. Although copper
medium-voltage cables could also be used in inner-city areas
to transmit power, the cost efficiency of this solution would be
cancelled out by the much higher ohmic loss, the study says.
After successful completion of a two-year field test, the project
could make it possible to install 10-kV superconducting links in
large sections of the Essen distribution network, Nexans claims. In
addition to greater efficiency and lower operating and maintenance
costs, a key benefit would be to reduce land use because numerous
110/10-kV transformer stations would no longer be needed.
Backed by the energy research arm of Germany's Federal
Ministry of Economics and Technology, total project costs are
approximately €13.5 million ($17 .7 million), including a government-funded
€6 million ($7.9 million).
MHI Ships First Commercial
J-Series Turbine
The first unit of Mitsubishi Heavy Industries' (MHI's) muchwatched
J-Series gas turbine, a technology MHI has been testing
for a year, was shipped this December from its Takasago Ma14
chinery
Works in Hyogo Prefecture, Japan, for commercial use at
Himeji Unit 2, also in Hyogo, owned by Kansai Electric Power Co.
(Figure 6). Though it touts its M501J turbine as having achieved
the " the world's highest efficiency and power generation capacity
in a system of this type, " MHI continues to grapple for share in a
highly competitive gas turbine market with industrial giants like
Siemens, GE, and Alstom.
MHI says the 60-hertz M501J is its most advanced gas turbine,
having reached an inlet temperature of 1,600C (2,912F)-100
degrees higher than the 1,500C-class G-Series. The M501J gas
turbine has also achieved a rated power output near 320 MW (ISO
basis) and 460 MW in gas turbine combined cycle (GTCC) power
generation applications. And it has a confirmed gross thermal
efficiency exceeding 60%- " the world's highest level in GTCC applications, "
MHI claims. (See " The T-Point Plant: The Ultimate
Validation Test " in our June 2011 issue.)
The 486.5-MW unit delivered to Himeji 2 plus five others will
become core components of GTCC plants with a cumulative capacity
of 2,919 MW. The units are slated to go online between
October 2013 and 2015.
The J-Series faces off with Siemens' SGT6-8000H gas turbine,
which was launched in June 2011. Siemens has called the 50-Hz
version of that turbine (SGT5-8000H), rated at 375 MW, the " largest
and most powerful in the world. " (See " Top Plant: Irsching 4
Combined Cycle Power Plant " in the September 2011 issue for more
information on the performance of this first 50-Hz installation.)
Six 60-Hz units are expected to be dispatched to Florida Power
& Light's Riviera Beach and Cape Canaveral Next Generation Clean
Energy Centers in Florida this year. Siemens has also received
orders from South Korea to build a turnkey single-shaft 60-Hz
combined cycle power plant by 2013.
Spain Inaugurates Two More Parabolic
Trough Units
Two identical 50-MW parabolic trough plants with thermal storage
in Cadiz, in the south of Spain, began operating this January.
The Valle 1 and Valle 2 projects (Figure 7) built by Torresol
Energy-a joint venture between Abu Dhabi-based Masdar and
Spanish engineering and construction firm SENER-are capable
of generating 160 GWh per year, producing power for up to 7.5
hours per day, even when there is no solar radiation.
Construction of the plants, which required 4,500 workers, began
in December 2009. SENER, which led the engineering, prowww.powermag.com
POWER
| March 2012
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POWER March 2012

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