Superconductors Are Near Room Temperature But UHV Lines are Better for the Grid

It has been over 30 years since the discovery of the first high-temperature superconductor. The first high-temperature superconductor was 30 degrees about absolute zero. There was a flurry of work and the critical temperature reached -135 Celsius (138 Kelvin). The progress on improving the temperature at which the materials could work stalled for decades.

There was a lot of effort to work with the materials which tended to be fragile and tricky to use.

There was still progress made on using them to do what was impossible without them. Magnets could be made far more powerful using them than without them. Magnets can be made three times or even four times stronger. This means more powerful particle accelerators. Some are trying to use the more powerful magnets for smaller nuclear fusion designs and reactors.

The dream of room temperature superconductors means that expensive refrigeration would not be needed for lossless energy and magnetic applications. Cooling to extreme temperatures is insanely expensive using helium. It is still expensive but more reasonable using nitrogen. The first high-temperature superconductors moved the situation from helium to nitrogen. A step better than nitrogen is regular refrigerators and cooling which are usually freon based. Room temperature means no refrigeration at all.

This new work could get to regular refrigerator temperatures using freon.

Arxiv – Superconductivity at 250 K in lanthanum hydride under high pressures

However, there is a catch. The material has to be at 1.7 million atmospheres of pressure.

This material tries to make the refrigeration problem better but needs to be squeezed between diamond anvils.

The hope would be that as we figure out the structure of what works under high pressure then the chemists can work at finding a different recipe that keeps the warm superconducting and gets rid of the high-pressure restriction.

Room temperature superconductors area way to get super technology. Super-efficient powerful magnets can make flying cars, better high-speed trains, nuclear fusion and other super technology.

Grids Can Be Built Without Energy Loss. Now. Not Decades From Now.

One major application that has been part of the room temperature superconducting dream is transmitting electricity without power loss.

Current electrical grids can lose up to half their energy because of power loss moving the electricity from power plant to your home.

Ultra-high voltage energy grids are needed for efficient power transmission across large distances. These are being deployed at continental scale by China. The highest voltages can transmit electricity 99.8% without energy loss over 100 miles of distance. They exist and being built over thousands of miles and can transmit the power of 200 nuclear reactors. How long until superconductors approach this scale? Would superconductor handling problems be worth the 0.2% or less of future UHV lines?

A 100 mile (160 km) power line at 765 kilovolt carrying 1000 MW of power can have losses of 1.1% to 0.5%. A 345-kilovolt line carrying the same load across the same distance has losses of 4.2%. China’s 1.1 megavolt line can have power losses that 10 to 20 times less than 345 kilovolt lines.

1.1 megavolt transformer

ABB helped create the 1.1 megavolt transformers and key equipment for world’s first 1,100 kilovolt (kV) project in China.

When fully operational the UHVDC link will be capable of transporting 12,000 megawatts of electricity over a distance of 3,000 km from the Xinjiang region in the Northwest, to Anhui province in eastern China. This vast amount of electricity is equivalent to twice the average annual power consumption of Switzerland.

Asia Super-grid

China’s State Grid company switched on its first million-volt alternating current line in 2009 and the world’s inaugural 800,000-volt direct current line in 2010. State Grid is now by far the world’s biggest builder of these lines. By the end of 2017, 21 ultra-high-voltage lines had been completed in the country, with four more under construction.

If the world wants to move energy around on a continental scale then ultra-high voltage grids are needed.

China’s high voltage grid will be nearly 23,000 miles long. It will be able to deliver about 150 gigawatts of electricity. This is roughly the output of 150 nuclear reactors.

At the end of 2017, China had invested least 400 billion yuan ($57 billion) into the projects. In September, China said it will sign off on 12 new ultra-high-voltage projects by the end of 2019.


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