Civil Engineering Reference
In-Depth Information
FIGURE 10-26
Superconducting energy storage schematic.
The superconducting energy storage has several advantages over other
technologies:
•
the round trip efficiency of the charge-discharge cycle is high at
95 percent. This is higher than that attainable by any other tech-
nology.
•
much longer life, up to about 30 years.
•
the charge and discharge times can be extremely short, making it
attractive for supplying large power for a short time if needed.
•
has no moving parts in the main system, except in the refrigeration
components.
In the superconducting energy storage system, the main cost is to keep
the coil below the critical superconducting temperature. Until now the nio-
bium-titanium alloy has been extensively used, which has the critical tem-
perature of about 9°K. This requires liquid helium as coolant at around 4°K.
The 1986 discovery of high temperature superconductors has accelerated the
industry interest in this technology. Three types of high temperature super-
conducting materials are available now, all made from bismuth or yttrium-
cuprate compounds. These superconductors have the critical temperature
around 100°K. Therefore, they can be cooled by liquid nitrogen, which needs
orders of magnitude less refrigeration power. As a result, numerous pro-
