Highways could one day transport electricity and hydrogen fuel, as well as enabling vehicles to travel at nearly 500 miles per hour, according to a new study. The setup would combine three green technologies into one piece of infrastructure, making each one financially more feasible.
The system is a twist on maglev transportation, in which cars containing superconducting material are suspended over a magnetic guideway. Maglev systems transport vehicles frictionlessly, but are very expensive.
Superconductors can also conduct electricity highly efficiently, without any loss of power along the way. But superconductor transmission lines are extremely costly because they only work at temperatures more than 100 degrees below zero.
Meanwhile hydrogen is a promising green fuel source, but it’s difficult to transport because it’s a gas at room temperature, and liquid hydrogen pipelines are expensive because of the cooling required.
In the new study, researchers propose flipping the conventional design of maglev systems upside down with magnetic vehicles suspended over a superconducting guideway, a setup they dub SClev.
This tweak enables the system to serve three functions, with a superconducting electricity transmission line cooled by a liquid hydrogen pipeline and a highway for levitated vehicles over top. “In order to have the electrical power transmission and storage capability, the superconductor has to be on the road, which led me to flip them,” says study team member Zhifeng Ren, a physicist at the University of Houston in Texas.
In turn, the combination of functions makes the cost more tenable, Ren and his collaborators argue in a paper published in the journal APL Energy.
The researchers built a miniature SClev system in which they ran a matchbox-car-sized magnetic vehicle along a superconducting guideway about three-quarters of a meter long. This enabled them to show that magnets can levitate above superconductors just as superconductors can levitate above magnets – a key technical requirement of the system that hadn’t been demonstrated before.
They used liquid nitrogen to cool the superconductor in their laboratory model for the sake of convenience, but say that liquid hydrogen in the eventual full-scale system would be even more effective because it would provide an even greater levitating force.
The researchers envision retrofitting current highways with the technology, so that it could be rolled out without further need to acquire land. People could drive on the system with passenger or freight vehicles equipped with dual motors (a specialized motor for the superconducting highway and a standard motor for navigating surface streets at either end), or magnetic platforms could be used to transport standard vehicles.
Vehicles could travel the highway at speeds of 500 to 800 kilometers (nearly 500 miles) per hour. That’s almost as fast as big commercial airplanes, and could replace much passenger air travel and airborne freight transport, the researchers predict – especially because if comes without the need to adhere to fixed schedules or the rest of the airport rigamarole.
The system represents a dramatic departure from current transportation and energy transport and storage methods, but Ren is bullish on its potential. “I do not see any big questions on the technology unanswered, but more on the financial support,” he says. “I hope to see either government or private investment to start a real project to demonstrate actual installation of the concept.”
Source: Vakaliuk O. et al. “A multifunctional highway system incorporating superconductor levitated vehicles and liquefied hydrogen.” APL Energy 2023.
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