Superconductors for Transporting Renewable Energy

My IEEE chapter hosted an interested talk from American Superconductor this week.

Superconductors are materials that when cooled to very low temperatures conduct electricity with very low resistance. Resistance turns electrical energy into heat.

One application for superconductors is transporting energy from renewable sources to populated areas. Most of the renewable energy in the US is in the desert or other sparsely populated areas. Another application is moving more modest amounts of power around densely populated areas where large power lines would be unsightly.

A 765kV power line made of superconductors costs the same per mile to install and maintain as a power line made of regular cables. The power capacity of a 765kV non-superconducting lines drops off at ranges over a couple hundred miles. Superconducting lines can be as long as you want. The only way to transmit power over long distances without superconductors is higher voltage power lines suspended from large towers.

Superconducting lines have the drawback of needing to be cooled all the way along the wire. If even one part of the wire is not refrigerated, the whole line is useless. Developers of superconducting equipment say redundant cables and cooling systems overcome this problem while keeping the cost similar to conventional power lines. If this is true, we could have an energy superhighway to move large amounts of energy around the country as needed without unsightly high-voltage power lines.

If someone invents and energy storage device that can be charged with electrical energy, can store energy with the same energy density as gasoline, and can discharge useful energy as fast as an internal combustion engine, such a device would be a killer app for superconductors. The energy could be generated by nuclear or a renewable source, transported, and used with no CO2 emissions. I am not predicting such a technology but something sort-of like it must be developed soon. The world is using oil faster than we can extract it, and there is no plan for how we’ll power our society going forward. If the right storage technologies are developed, superconductors could be a big component of the solution.