Talk-Polywell.org

Like the moving beltways in Heinlein's novel, The Roads Must Roll , this is a bad idea:

Wireless power could revolutionize highway transportation, researchers say

A charge-as-you-drive system would overcome these limitations. "What makes this concept exciting is that you could potentially drive for an unlimited amount of time without having to recharge," said APL study co-author Richard Sassoon, the managing director of the Stanford Global Climate and Energy Project (GCEP), which funded the research.

..."drive for an unlimited amount of time without having to recharge". Until you run out of State-approved, embedded recharge coils, that is.

Or forget to pay your library fine:

<BEEEEEP> <SCREEEEECH>
ATTENTION CITIZEN THX1138.
Your vehicle is now disabled pending resolution of State Case 41127-A1559.
Exit your vehicle now and wait for hoverbot transport to the nearest Administration Center.

Nah, just pull out the magnifying transmitters.

DeltaV wrote: Or forget to pay your library fine

Or stick pay tolls on those roads?

Uhm, so your car does not stop when you run out of gas? You get your gasoline for free?
Cars using this system would certainly have a battery pack that allows them to continue driving even in places where the system is not installed.
The way I understand it, it is meant as a range extender for EVs.

The car would need batteries good for a few miles off the grid. If only the primary coils adjacent to a car's secondary are active, and the system can track which car is over a given primary, the system could decline to energize for a car without a paid up account. The car will hopefully have enough independent range to reach the next safe spot to pull off. But from the big brother angle that means the ability to track where cars go, unless they go on independent power and turn off any transponder.

Why not use a somple RFID- chip in the car that confirms that you have paid for the use of the grid. Only then the coils underneath your car will activate. Or, if that was to costly (because every coil would have to be controled individually, or in small clusters), some sort of chip in your car that uses a prepaid code. If the code that you have on the chip in the car does not receive a matching signal from the road, you cant charge.
Of course there would always be attempts at tampering with these things and to manipulate the car into charging without a chip. But these things could be checked for.

Why not simply make these road segments accessible only thru toll booths?

Why not simply make these road segments accessible only thru toll booths?

Because gasoline powered cars might want to drive on them as well, as would maybe battery powered ones. I think people would only want to use them, when they have to, because the range of their own battery would not be sufficient.

This system is one of a handful that are all looking for press and business, and this is a pretty pressed-up version. Most likely such systems would not be installed first in highways. There are plenty of other places to start, like parking lots. If afterward EV's and wireless charging catch on, one MIGHT see them installed in things like highways, since you can install toll booths at all the entrances. It's a very long time after that you're installing in every street, and one expects we'd have installed bountiful and relatively cheap generation by then. Charging people isn't such a big deal if they're not using more than a dollar a day in energy.

I have to say though, the cost of installing coils under thousands of miles of highway seems to me to make it unlikely, even under some sort of mandate. I'd think such a thing would cost into the tens of trillions--no way to afford it.

I had this idea ten years ago. Lets just do a sanity check. The problem with their design is the car will only be over any one coil for but a fraction of the driving time. If the car is humming along using 10kW of power, and the coils only cover 10% of the road, then during each pass they have to transfer at 100kW. Lets just ignore the problem of inducing large currents in the car itself and say it works at 100% efficiency. For reference, your standard house pole transformer is rated only to around 10kW. Now lets suppose the load is not very high traffic, which means it could be pulsed. But now you are talking about capacitor banks or large switches rated for 100kW. Every one of these things would have to be a mini-substation. Not to mention how one would fit all that on the car side.

<BEEEEEP> <WHOOOOOOOOOSH>
ATTENTION CITIZEN THX1138.
Your hoverbot transport to the Administration Center has arrived.
Remain still during the grappling operation to avoid personal injury.

When fusion-powered VTOL aircraft are outlawed, only outlaws will have fusion-powered VTOL aircraft.

kcdodd wrote: ... Lets just do a sanity check. The problem with their design is the car will only be over any one coil for but a fraction of the driving time. If the car is humming along using 10kW of power, and the coils only cover 10% of the road, then during each pass they have to transfer at 100kW.

Why do you think that the car has to be "over" the coil? Resonant Xfer is pretty loose that way. The coils don't have to be aligned to pass significant power, do they?