SuperGrid

This article is about a technology concept using superconductivity. For current technologies for conventional long-distance transmission, see Super grid.

In the context of lossless power transmission, a supergrid with hydrogen is an idea for combining very long distance electric power transmission with liquid hydrogen distribution, to achieve superconductivity in the power lines. The hydrogen is both a distributed fuel and a cryogenic coolant for the power lines, rendering them superconducting. The concept's advocates describe it as being in a "visionary" stage, for which no new scientific breakthrough is required, but requires major technological innovations before it could progress to a practical system. A system for the United States is projected to require "several decades" before it could be fully implemented. High-voltage direct current (HVDC) lines have the capability of transmitting similar voltages, for example a 5 gigawatt HVDC system is being constructed along the southern provinces of China without the use of superconducting cables.

1.5% of the energy transmitted on the British AC Supergrid is lost (transformer, heating and capacitive losses), of which a little under two-thirds, or 1% on the British supergrid, represents "DC", resistive, heating type losses. With the use of superconductors, the capacitive and transformer losses, in the unlikely event the transmission lines were still overhead, AC lines, would remain the same. Overhead lines do not lend themselves at all well physically to the incorporation of cryogenic hydrogen piping, due to the likely weight of the transmission medium and the considerable brittleness of supercooled materials. It would probably be necessary for a supercooled hydrogen-carrying transmission line to be subterranean, and this in turn means that for such a cable, if it were of any distance (e.g. over 60 km), the power would have to be converted to DC and transmitted as such, since otherwise the capacitive losses would be too high. The power electronic losses in the AC/DC converter substations to convert the AC power at either end of the cryogenic cable to/from DC, if the transmission line(s) itself were DC, would also remain exactly the same as they would have been without the use of a superconducting transmission line - but the DC type resistive losses in the transmission lines would be rendered even smaller than at present. Even before comprehensive continental and (in the case of the proposed European Super Grid) intercontinental backbones of electrical transmission may be realized, such cables could be used to efficiently interconnect regional power grids of conventional design.

See also

• Superconducting cables
• High voltage direct current

External links

• SuperGrid Workshop at University of Illinois at Urbana-Champaign