Induction highways and roads?

[Bread and Circus]

Is it feasible to have segments of roads/highways w/ electrical wires threaded into them so that electrical vehicles could be "charged" via induction as they drive over them? I could see where this might be helpful to extend electric vehicle range and decentralize the charging process. I could also see where this would be helpful along long stretches of desert highway as you could passively charge cars and trucks via solar linked to the induction system.

This is total pie in the sky wondering out loud. I've never heard much of this idea, so I'm just asking what the E/E DU folks think.
D

[beyurslf]

1. Would the roads have electric charge running through them then?

What if you had a flat and had to step out of the car? Would it be like the 3rd rail in the subway? Zap! and you're toast.

[Bread and Circus]

4. The electrical current would be embedded and not exposed. That's why electrical

charge would be transferred by induction. The electricity would be in the road, the magnet would be in the vehicle.

[beyurslf]

14. Sounds like a very interesting idea.

[madrchsod]

2. nice idea but it would not work in the real world

[Bread and Circus]

5. why not?

[biscotti]

3. Also, how would you do road maintenance and repair.

Might get very tricky.

[Bread and Circus]

8. wires would be embedding in the road but segments would be compartmentalized

so that repair of one segment wouldn't affect another. Also, it would be discontinuous. Not every road would have it. Also, it wouldn't be the sole source of power for the vehicle but rather an "assist" to extend range.

[MineralMan]

6. Not very practical, and maintenance would be a bitch.

A better idea is charging facilities in every parking lot and parking ramp. Homes, too, of course. Swipe your credit card and charge up, pretty much wherever you go.

[Xithras]

7. It works. There have been tests done on the idea before.

The problem tends to be in the practical implementatation. Everything from road cracking (different expansion rates for conductive and road surface materials in freezing/hot temperatures) to maintaining uniform induction levels over long distances have been brought up as problems. Plus, it's an extremely expensive option. Plus plus, it wastes electricity by using it even when no vehicles are being charged. Plus plus plus, the introduction of high energy magnetic fields under a roadway is bad news for people iPods...and their pacemakers.

[Bread and Circus]

9. One thing is that we've never had widespread electric cars before, that might change

in 2012+ and beyond. Maybe at that time, there will be incentive to do something to passively assist vehicles.

I don't quite understand the argument that electricity would be wasted if no cars are on the road. If no cars are on the road, there would be no load on the system and a sensor could easily cut power. Also, alot of wind corridor and desert highways could be passively powered by roadside turbines and solar farms.

Just powering Highway 5 in California from SF to LA would be an interesting experiment.

Obviously, until there's a huge electrical fleet, there'd be no use.

[Xithras]

10. IIRC, it's mostly loss in the transformers

Admittedly, it's been several years since I read anything on this, but the problem has to to with both the required power AND the distance over which it has to be transferred. Induction words reasonnably well at very short range, but in a vehicle you're going to have 6-10 inches between the vehicle and road surface, and at least 4 additional inches between the road surface and the induction coils. To make the experiment worthwhile, they also had to make sure that the vehicle was receiving a fairly large amount of power from the grid. The result? Several kilovolts of power running under the roadway, stepped up with transformers. Transformers burn power even when there's no load on them, which is why all those wall warts around our houses should be unplugged when we're not using them.

By the way, the people who did this experiment had a slightly different solution, and one that would work better if it could be implemented. Instead of electrifying the entire roadway, they simply wanted to add "charging lanes" to the roadway every 10 miles or so. Their idea was that people could drive their electric cars in normal lanes, and when the battery started getting low they'd simply jump into the next charging lane for a top-off.

It just wasn't very practical.

[Bread and Circus]

12. Very interesting information. Thanks. I hadn't imagine the induction would

be the sole source of power but rather just an adjunct of power that would extend range (kind of like your "charging lane" idea).

I thank you for the detailed info.

Construction costs aside, energy loss isn't an issue of the road was just being passively powered by roadside solar.

But at any rate, I'm sure you are right. It was just an idea that popped into my head.

[lumberjack_jeff]

11. For the forseeable future, liquid fuels will power interstate travel.

That said, most travel is not 50+ mile trips.

[kestrel91316]

13. Magnets in the vehicles are going to increase drag/rolling resistance

or whatever it's called, so gas mileage would go down. That, plus the construction costs of implementing this, probably make for an untenable EROEI.

[hunter]

15. Here's a picture I took on a very busy U.S. highway...

That's just rebar you see, now imagine embedded power lines...

I figure with declining oil extraction, rising seas and climate change many Americans will be fortunate if they don't starve, and even that will require some extrodinary efforts.

[tinrobot]

16. What about overhead lines?

Kind of like the streetcars in San Francisco?

You could string the lines on long stretches of interstate between cities.

Within cities, create special EV lanes, similar to car pool lanes.

[Bread and Circus]

17. Not sure of that, but that's obvious proof that you can power vehicles via electric cable

I was just trying to get the lines out of the sky and get them in the road. Induction was just a means of transferring power.

I lived in SF for 4 years. Loved it. Loved the the electric buses. Ocassionally one of the contacts would come off the line. However, electric lines overhead are really unattractive and claustrophobic to me.

Also, I don't think a continue system of any kind is feasible and so the induction system I wonder about would be segmented as opposed to "tracked". People have to be able to get onto it and off it at will.

But electric buses in SF seem to work really well and are in essence proof that a powered grid can move large vehicles and lots of people. However, I have no idea of the efficiency of the SF system.