A supergrid is a wide area transmission network that makes it possible to trade large volumes of electricity over long distances. In a lossless power transmission, a supergrid with hydrogen is an idea to combine the transmission of very long distance electric energy with the distribution of liquid hydrogen, to achieve superconductivity in the electric lines. Hydrogen is both a distributed fuel and a cryogenic refrigerant for the electrical lines, making them superconducting. Proponents of the concept describe it as a "visionary" stage, for which no new scientific breakthrough is required, but which requires great technological innovations before it can advance to a practical system. A system for the United States is projected to require "several decades" before it can be fully implemented.
A proposed design for a superconducting cable includes a superconducting bipolar DC line operating at ± 50 kV and 50 kA, transmitting around 2.5 GW for several hundred kilometers with zero resistance and almost no line loss. High voltage DC power lines (HVDC) have the ability to transmit similar powers, for example a 5 gigawatt HVDC system is being built along the southern provinces of China without the use of superconducting cables.
In the United States, a 4,000 kilometer-long Continental SuperGrid could carry between 40,000 and 80,000 MW in a tunnel shared with high-speed high-speed trains, which at low pressure would allow one-hour cross-continental journeys. The liquid hydrogen pipeline would store and supply hydrogen. 1.5% of the transmitted power in the British Supergrid AC (transformer, heating and capacitive losses), of which a little less than two thirds, or 1% of the British supergrid, is lost. ", Resistive and heating. With the use of superconductors, capacitor losses and transformers, in the unlikely event that the transmission lines were still overloaded, the AC lines would remain the same. The airlines do not lend themselves physically at all to the incorporation of cryogenic hydrogen pipes because of the likely weight of the transmission medium and the considerable fragility of the supercooled materials. It would probably be necessary for a super-cooled hydrogen-carrying transmission line to be underground, and this in turn means that for such a cable, if it were outside any distance (eg more than 60 km), the power would have to be converted In DC Y is transmitted as such, otherwise the capacitive losses would be too high. The electronic power losses in the AC / DC converter substations to convert the AC power at each end of the cryogenic cable to and from DC, if the transmission line itself were DC, would also remain exactly the same as those that would have been Without the use of a superconducting transmission line - but the DC type resistive losses on the transmission lines would become even smaller than at present.
Even before complete continental continental networks and (in the case of the proposed European electricity grid) can be made, such cables could be used to efficiently interconnect conventional regional electrical networks.