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The Yamanashi MLX01 MagLev
train.
Uses for Superconductors
Magnetic-levitation
is an application where superconductors perform extremely well. Transport
vehicles such as trains can be made to "float" on strong
superconducting magnets, virtually eliminating friction between the train and its tracks.
Not only would conventional electromagnets waste much of the electrical energy as heat,
they would have to be physically much larger than superconducting magnets.
A landmark for the commercial use of MAGLEV technology occurred in 1990
when it gained the status of a nationally-funded project in Japan. The
Minister of Transport authorized construction of the
Yamanashi
Maglev Test Line which opened on April 3, 1997.
In April 2015, the MLX01 test vehicle (shown above)
attained an incredible speed of 374 mph (603 kph).
Although the technology has now been proven, the wider
use of MAGLEV vehicles has been constrained by political and environmental concerns (strong
magnetic fields can create a bio-hazard).
The world's first MAGLEV train to be adopted into commercial service,
a shuttle in Birmingham, England, shut down in 1997 after operating for 11 years.
A Sino-German maglev is currently operating over a 30-km course at Pudong International Airport in Shanghai, China.
Click this link for a website that lists
other uses for MAGLEV.
MRI of a human skull.
An
area where superconductors can perform a life-saving function is in the field of biomagnetism.
Doctors need a non-invasive
means of determining what's going on inside the human body.
By impinging a strong superconductor-derived magnetic field into the body, hydrogen atoms that
exist in the body's water and fat molecules are forced to accept energy
from the magnetic field. They then release this energy at a frequency that
can be detected and displayed graphically by a computer. Magnetic Resonance Imaging (MRI)
was actually discovered in the mid 1940's. But, the first MRI exam on a human being
was not performed until July 3, 1977. And, it took almost five hours to produce one image!
Today's faster computers process the data in much less time.
A tutorial is available on MRI at
this link.
The Korean Superconductivity Group within KRISS
has carried biomagnetic technology a step further with the development of
a double-relaxation oscillation SQUID (Superconducting QUantum Interference Device) for use in
Magnetoencephalography. SQUID's are capable of sensing
a change in a magnetic field over a billion times weaker than the force that moves the needle on a compass (compass: 5e-5T, SQUID: e-14T.).
With this technology, the body can be probed to certain depths without the need for the strong magnetic fields associated with MRI's.
Probably the one event, more than any other, that has been responsible
for putting "superconductors" into the American lexicon was the
Superconducting Super-Collider project planned for construction in Ellis
county, Texas. Though Congress cancelled the multi-billion dollar effort
in 1993, the concept of such a large, high-energy collider would never
have been viable without superconductors. High-energy particle research
hinges on being able to accelerate sub-atomic particles to nearly the speed
of light. Superconductor magnets make this possible. CERN, a consortium of several
European nations, is doing something similar with its
Large Hadron Collider (LHC) recently inaugurated along the Franco-Swiss border.
Other related web sites worth visiting include the proton-antiproton collider page at
Fermilab. This was the first facility to
use superconducting magnets. Get information on the electron-proton collider HERA
at the German lab pages of DESY.
And Brookhaven National Laboratory features a page dedicated to its
RHIC heavy-ion collider.
Electric generators made with superconducting wire are far more efficient
than conventional generators wound with copper wire. In fact, their
efficiency is above 99% and their size about half that of conventional generators.
These facts make them very lucrative ventures for power utilities. General
Electric has estimated the potential worldwide market for superconducting generators
in the next decade at around $20-30 billion dollars. Late in 2002 GE Power Systems received $12.3 million
in funding from the U.S. Department of Energy to move high-temperature superconducting
generator technology toward full commercialization. To read the latest news on superconducting
generators click Here.
Other commercial power projects in the works that employ superconductor
technology include energy storage to enhance power stability. American
Superconductor Corp. received an order from Alliant Energy in late March 2000
to install a Distributed Superconducting Magnetic Energy Storage System (D-SMES)
in Wisconsin. Just one of these 6 D-SMES units has a power reserve of over 3 million watts,
which can be retrieved whenever there is a need to stabilize line voltage during a
disturbance in the power grid. AMSC has also installed more than 22 of its D-VAR systems to provide
instantaneous reactive power support.
The General Atomics/Intermagnetics General superconducting
Fault Current Controller, employing HTS superconductors.
Recently, power utilities have also begun
to use superconductor-based transformers and "fault limiters". The Swiss-Swedish company ABB
was the first to connect a superconducting transformer to a utility power network in March of 1997. ABB also recently announced the development of a
6.4MVA (mega-volt-ampere) fault current limiter - the most powerful in the world. This new generation of HTS superconducting fault
limiters is being called upon due to their ability to respond in just thousandths of a second to
limit tens of thousands of amperes of current. Advanced Ceramics Limited
is another of several companies that makes BSCCO type fault limiters. Intermagnetics General
recently completed tests on its largest (15kv class) power-utility-size fault limiter
at a Southern California Edison (SCE) substation near Norwalk, California. And, both the US and Japan have plans to
replace underground copper power cables with superconducting BSCCO cable-in-conduit cooled with
liquid nitrogen. (See photo below.) By doing this, more current can be routed through existing cable tunnels.
In one instance 250 pounds of superconducting wire replaced 18,000 pounds of vintage
copper wire, making it over 7000% more space-efficient.
An idealized application for superconductors
is to employ them in the transmission of commercial power to cities.
However, due to the high cost and impracticality of cooling miles
of superconducting wire to cryogenic temperatures, this has only happened with short
"test runs".
In May of 2001 some 150,000 residents of Copenhagen, Denmark,
began receiving their electricity through HTS (high-temperature superconducting) material.
That cable was only 30 meters long, but proved adequate for testing purposes.
In the summer of 2001 Pirelli
completed installation of three 400-foot HTS cables for Detroit Edison at the Frisbie Substation capable of delivering 100 million
watts of power. This marked the first time commercial power has been delivered to customers of a US power utility through
superconducting wire. Intermagnetics General has announced that its IGC-SuperPower subsidiary has joined with BOC and
Sumitomo Electric in a $26 million project to install an underground,
HTS power cable in Albany, New York,
in Niagara Mohawk Power Corporation's power grid.
Sumitomo Electric's DI-BSCCO cable was employed in the
first in-grid power cable demonstration project sponsored by the U.S. Department of Energy
and New York Energy Research & Development Authority. After connecting to the grid
successfully on July 2006, the DI-BSCCO cable has been supplying power to
approximately 70,000 households without any problems. Currently the longest run of superconductive power cable
was made in the AmpaCity project near Essen,
Germany, in May 2014. That cable was a kilometer in length.
The National Science Foundation, along
with NASA and DARPA and various universities, are currently researching
"petaflop" computers. A petaflop is a thousand-trillion floating point operations per second.
Currently the fastest in the world is the Summit (OLCF-4) Supercomputer, capable of 200 petaflops per second.
It has been conjectured that devices on the order of 50 nanometers in size along with unconventional switching mechanisms,
such as the Josephson junctions associated with superconductors, will be necessary to achieve
the next level of processing speeds. These Josephson junctions
are incorporated into field-effect transistors which then
become part of the logic circuits within the processors. Recently it was demonstrated at the Weizmann Institute in Israel that the tiny magnetic
fields that penetrate Type 2 superconductors can be used for storing and retrieving digital information. It is, however, not a foregone conclusion that computers
of the future will be built around superconducting devices. Competing technologies, such
as quantum (DELTT) transistors, high-density
molecule-scale processors , and DNA-based processing
also have the potential to achieve petaflop benchmarks.
In the electronics industry, ultra-high-performance
filters are now being built. Since superconducting wire has
near zero resistance, even at high frequencies,
many more filter stages can be employed to achive a desired frequency response. This translates into an ability to pass
desired frequencies and block undesirable frequencies in high-congestion rf (radio frequency) applications such as cellular telephone systems.
ISCO International
and Superconductor Technologies are companies
currently offering such filters.
Superconductors have also found widespread
applications in the military. HTSC SQUIDS
are being used by the U.S. NAVY to detect mines and submarines. And, significantly smaller motors
are being built for NAVY ships using superconducting wire and "tape". In mid-July,
2001, American Superconductor unveiled a 5000-horsepower motor made with superconducting wire (below).
An even larger 36.5MW HTS ship propulsion motor was delivered to the U.S. Navy in late 2006.
The newest application for HTS wire is in the degaussing of naval vessels.
American Superconductor has announced the development of a superconducting
degaussing cable. Degaussing of a ship's hull eliminates residual magnetic fields which might otherwise
give away a ship's presence. In addition to reduced power requirements, HTS degaussing cable offers reduced size and weight.
The military is also looking at using superconductive
tape as a means of reducing the length of very low frequency antennas employed
on submarines. Normally, the lower the frequency, the longer an antenna must be.
However, inserting a coil of wire ahead of the antenna will make it function as if it were
much longer. Unfortunately, this loading coil also increases system losses by adding the resistance
in the coil's wire. Using superconductive materials can significantly reduce losses in this coil.
The Electronic Materials and Devices Research Group at
University of Birmingham (UK) is credited with creating the first superconducting
microwave antenna. Applications engineers suggest that superconducting carbon nanotubes might be an ideal
nano-antenna for high-gigahertz and terahertz frequencies, once a method of achieving zero
"on tube" contact resistance is perfected.
The most ignominious military use of superconductors may come with the deployment
of "E-bombs". These are devices that make use of strong, superconductor-derived magnetic fields
to create a fast, high-intensity electro-magnetic pulse (EMP) to disable an enemy's electronic
equipment. Such a device saw its first use in wartime in March 2003 when US Forces attacked
an Iraqi broadcast facility.
A photo of Comet 73P/Schwassmann-Wachmann 3, in the act of disintegrating
,
taken with the European Space Agency S-CAM.
Among emerging technologies are a stabilizing
momentum wheel (gyroscope) for
earth-orbiting satellites that employs the "flux-pinning" properties of imperfect
superconductors to reduce friction to near zero. Superconducting x-ray detectors
and ultra-fast, superconducting light detectors are being developed due to their inherent ability to detect
extremely weak amounts of energy. Already Scientists at the European Space Agency (ESA) have developed what's being called the S-Cam,
an optical camera of phenomenal sensitivity (see above photo). And, superconductors may even play a role in Internet communications soon. In late
February, 2000, Irvine Sensors Corporation received a $1 million contract to research and develop
a superconducting digital router for high-speed data communications up to 160 Ghz.
Since Internet traffic is increasing exponentially, superconductor technology may be called upon
to meet this super need.
According to GMInsights.COM the superconductor market will witness a 17% growth over the projected timespan. Low-temperature superconductors
are expected to continue to play a dominant role in well-established fields such as
MRI and scientific research, with high-temperature superconductors enabling newer applications.
The above graph gives a rough breakdown of the various markets
in which superconductors are expected to make a contribution through 2024.
All of this is, of course, contingent upon a
linear growth rate. Should new superconductors with higher transition temperatures
be discovered, growth and development in this exciting field could explode
virtually overnight.
Another impetus to the wider use of superconductors is
political in nature. The reduction of green-house gas (GHG) emissions has becoming a
topical issue due to the Kyoto Protocol which requires the European Union (EU) to reduce
its emissions by 8%. Physicists in Finland have calculated that the
EU could reduce carbon dioxide emissions by up to 53 million tons if
high-temperature superconductors were used in power plants.
The future melding of superconductors into
our daily lives will also depend to a great degree on advancements in the field
of cryogenic cooling. New, high-efficiency magnetocaloric-effect compounds such
as gadolinium-silicon-germanium
are expected to enter the marketplace soon. Such
materials should make possible compact, refrigeration units to facilitate additional
HTS applications. Stay tuned !