Stanford University designs high efficiency wireless charging system
Just yesterday we wrote about inductive charging systems for residential use. Then we found an article reporting on a Stanford University research project with the potential of creating an electric highway. This electric highway could be developed with the intent of charging electric vehicles (EVs) as they drive. While this may sound appealing to early adopters of EVs, we have serious doubts that such a system will be developed in a big way anytime in our lifetimes.
First let’s take a look at the system. According to the conclusion reached in the study, the system has a maximum potential energy transfer efficiency of 97% based on distance between source and receiver coils. That’s a good thing. The illustration above is taken from this YouTube video. As can be seen, electric coils must be placed in the roadway in order to transmit power from the grid to the vehicle. This, in itself, is the single biggest obstacle to this system ever being developed on a grand scale. According to one of the study authors, electrical engineering associate professor Shanhui Fan, “Large-scale deployment would involve revamping the entire highway system.” According to the U.S. Department of Transportation, the Interstate Highway System is currently about 47,000 miles long. In our view, placing large electric coils in the ground every ten feet or so for 47,000 miles is not likely to happen anytime soon, if ever.
Secondly, one must look at the cost factor. How would the infrastructure be paid for, and then when installed how would consumers be charged for the use of the system? Electric vehicles will not likely ever make up the entirety of the vehicle population, just as sedans and coupes and trucks and SUVs all share the roads today. One possibility could be the development of private toll roads offered up for public use. Such systems are currently in place in California and other states around the country. These toll roads could be designed for EV charging and establish different toll rates for electric and gasoline vehicles. Based on this premise, one might see where such a system could develop in high EV use communities.
An early experiment involving a different type of electric highway, the Automated Highway System (AHS), was undertaken in San Diego in 1997. The AHS was designed with sensors that would communicate with vehicles driving by so that they could “platoon” together in order to optimize time efficiency and fuel efficiency. This was supposed to be the highway of the “near future” but as early as 2007 the Federal Highway System has written about the seven major obstacles of developing such a system.
Grand changes, such as the idea of driving cars powered by electricity instead of gasoline, inspire grand ideas. Not all of them will work out, but they in turn may spark a thought in another direction that does work out. When General Motors presented the EV1 in 1996 it was a grand change in an industry that was more accustomed to glacial progress. It was a change that the United States and the world were not quite ready for. The world is a different place in 2012 and the idea of the electric vehicle has now been taken much more seriously by automobile manufacturers around the globe. We will continue to see research into wireless highways and inductive residential chargers for our EVs. We will also see research into new battery technologies and alternative forms of energy storage. Who said that it had to be a lithium ion battery that provided the power in an electric car? Who’s to say that the power storage must be in the form of a battery at all? As more and more brilliant minds analyze the questions, the answers will likely surprise us all as the EV continues its march into our homes.