If the national grid were made of superconductors rather than metals, then the savings would be enormous - there would be no need to transform the electricity to a higher voltage (this lowers the current, which reduces energy loss to heat) and then back down again. Since there is no loss in electrical energy when superconductors carry electrical current, relatively narrow wires made of superconducting materials can be used to carry huge currents. 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".
Superconducting magnets are also more efficient in generating electricity than conventional copper wire generators - in fact, a superconducting generator about half the size of a copper wire generator is about 99% efficient; typical generators are around 50% efficient.
Recently, power utilities have also begun to use superconductor-based transformers and "fault limiters".
-An electrical current in a wire creates a magnetic field around a wire. The strength of the magnetic field increases as the current in the wire increases. Because superconductors are able to carry large currents without loss of energy, they are well suited for making strong electromagnets.
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.
Superconductors can perform a life-saving function 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 (MRI).
A Korean Superconductivity Group 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. With this technology, the body can be probed to certain depths without the need for the strong magnetic fields associated with MRI's.
Synchrotrons and Cyclotrons (Particle Colliders)
Particle Colliders are like very large running tracks that are used to accelerate particles to speeds approaching the speed of light before they are collided with one another or other atoms, usually to split them. Since they use magnetic field to cycle particles, a strong magnetic field can be provided by superconductors.
Fast Electronic Switches
Type II superconductors can be used to as very fast electronic switches (as they have no moving parts), due to the way in which a magnetic field can penetrate into the superconductor.
The Josephson junction is a super fast switching devise. Josephson junctions can perform switching functions such as switching voltages approximately ten times faster than ordinary semi conducting circuits. This is a distinct advantage in a computer, which depends on short, on-off electrical pulses. Since computer speed is dependent on the time required to transmit signal pulses the junction devices' exceptional switching speed make them ideal for use in super fast and much smaller computers.
The military is 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 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.
HTSC SQUIDS are being used by the US NAVY to detect mines and submarines.
The possible discovery of room temperature superconductors has the potential to bring superconducting devices into our every-day lives.