This won't be cheap, easy or quick but it's an exceedingly interesting idea.

Cryogenic, superconducting conduits could be connected into a "SuperGrid" that would simultaneously deliver electrical power and hydrogen fuel. . .

A five-gigawatt Super-Cable is certainly technically feasible. Its scale would rival the 3.1-gigawatt Pacific Intertie, an existing 500-kilovolt DC overhead line that moves power between northern Oregon and southern California. Just four Super-Cables would provide sufficient capacity to transmit all the power generated by the giant Three Gorges Dam hydroelectric facility in China.

Because a Super-Cable would use hydrogen as its cryogenic coolant, it would transport energy in chemical as well as electrical form. Next-generation nuclear plants can produce either electricity or hydrogen with almost equal thermal efficiency. So the operators of nuclear clusters could continually adjust the proportions of electricity and "hydricity" that they pump into the Super-Grid to keep up with the electricity demand while maintaining a flow of hydrogen sufficient to keep the wires superconducting.

The ability to choose among alternative forms of power and to store electricity in chemical form opens up a world of possibilities. The Super-Grid could dramatically reduce fuel costs for electric- and hydrogen-powered hybrid vehicles, for example.

About 10% of the electricity generated is dissipated in transmission loss through conventional cable. It generates heat which degrades the wires, making them sag and age, and are limited in the amount of power they can transmit without blowing their insulation off. We are bumping up agsinst the limits of that technology, and it inhibits us from exploiting some power generation design options.

No major scientific advances are needed to begin building the SuperGrid, and the electric utility industry has already shown its interest in the concept by funding a SuperGrid project at EPRI which will explore the numerous engineering challenges that integrating Super-Cables into the existing power grid will pose. The largest of these is what to do if a Super-Cable fails.

The grid today remains secure even when a single device, such as a high-voltage transmission line, fails. When a line sags into a tree, for example, circuit breakers open to isolate the line from the grid, and the power that was flowing on the wire almost instantaneously shifts to other lines. But we do not yet have a circuit-breaker design that can cut off the extraordinary current that would flow over a Super-Cable. That technology will have to evolve. Grid managers may need to develop novel techniques for dealing with the substantial disturbance that loss of such a huge amount of power would cause on the conventional grid. A break in a SuperCable would collapse the surrounding magnetic field, creating a brief but intense voltage spike at the cut point. The cables will need insulation strong enough to contain this spike.

Safely transporting large amounts of hydrogen within the Super-Cable poses another challenge. The petrochemical industry and space programs have extensive experience pumping hydrogen, both gaseous and liquid, over kilometer-scale pipelines. The increasing use of liquefied natural gas will reinforce that technology base further. The explosive potential (energy content per unit mass) of hydrogen is about twice that of the methane in natural gas. But hydrogen leaks more easily and can ignite at lower oxygen concentrations, so the hydrogen distribution and storage infrastructure will need to be airtight. Work on hydrogen tanks for vehicles has already produced coatings that can withstand pressures up to 700 kilograms per square centimeter.

Probably the best way to secure Super-Cables is to run them through tunnels deep underground. Burial could significantly reduce public and political opposition to the construction of new lines.

Not easy, not cheap. This may still be at the SF stage.