Here's one way you could charge electric cars in the future. A South Korean city is testing electric buses that get their charge from cables buried underneath the road.
The cables create magnetic fields that a device on the underside of the buses converts into electricity. (In principle, they're like enormous versions of the induction power that charges toothbrushes and smartphones wirelessly.) The charging works both while the buses are driving and when they're sitting still.
Right now, there are two of the buses and they run back and forth along a central city route that's about seven miles long, or 15 miles round-trip. The Gumi government plans to add 10 more so-called OLEV (Online Electric Vehicle) buses by 2015, according to the Korea Advanced Institute of Science and Technology. Electrical engineers at the institute developed OLEVs.
Other specs from the institute include that the electromagnetic field that the cables create is weak enough to be safe for pedestrians, according to the institute. The cables also switch on only when they detect that OLEV buses are passing over. Five percent to 15 percent of a roadway needs to have cables in it for the buses to run.
Before deploying the buses, engineers tested the wireless charging on institute campus shuttles and in trams at an amusement park in Seoul.
In 10 years they will have all their buses, trains and cars like that. At least that is not polluting the air even more.
LIFE IS TOO SHORT.
How much energy is wasted as compared to plug-in? That waste directly translates to more pollution if the energy is derived from conventional power plants.
Since the induction cables only turn on when they sense the bus, I would assume the actual waste is fairly low. The big loss of electricity here is likely to be the efficiency in the conversion.
South Korea gets ~65% of their electricity via "thermal" generation which includes all fossil fuel burning (nat gas, coal, oil). Since large scale thermal plants are more efficient than individual cars, I'm inclined to believe that this would contribute to a net lowering of pollution, but without firm numbers it's impossible to say.
Okay, I did a little poking around the internet looking for numbers.
Fossil fuel power plants are ~35% efficient (other sources can be up to 90% [hydroelectric]).
Utah State University has an induction bus that is 90% efficient at transferring energy.
Electric engines are 50-90% efficient.
Gasoline engines are ~25% efficient.
Obviously this is far from enough info to endorse of condemn the technology. As this technology is developed further it can only get better.
Conversion loss is exactly what I was referring to.
I'm not sure about some of these claims.
The source article claims that the field generated is 62.5 mG (milliGauss). That's pretty amazing. The earth's magnetic field ( the one that moves compass needles) comes in at about 600 mG. Just doesn't seem to ring true.
As for the efficiency of conversion, I'd think that they'd be lucky to get 70% with this system.
And when you're comparing electric power, you also have to add in the losses through the electric grid from the source.
Not saying that this is a bad idea -- I'd just like to have a few more facts.
Wonder about the efficiency of a streetcar powered by overhead wires.
What about the dangers, what if someone with a peacemaker gets into contact with it or any electronic device - if it has metal, wires, coils in it - it will convert that magnetic field o electricity.
I second 'lifestream's concerns. A metal framed baby buggy would induce some scary currents!
I do wonder why you couldn't have a short stretch of overhead power lines with a roof-top pantograph that automatically aligns with it as you approach a stop.
From a practical and operational point of view:
Are the cables installed city-wide? When a bus has to detour (which happens every day in a busy city), it won't be able to if the entire area doesn't have the cables installed.
To address the health concerns, if they are using the same tech as in chargers, then there is a communication protocol that has to be established before charging takes place.
Without knowing all the details of their system, the article does say charging. This would mean that they would have batteries on board. I would think that the buses still have a direct plug in for charging at the garage.
This systems appears to be starting point for a sensible and completely all electric vehicle roadway. It makes sense and I am all for it!
Wrong! An electric motor has to include the entire path of power generation. In this case it also has to include battery loss. An electric powered bus won't have the theoretical power conversion that is much better than a normal diesel engine.
Direct transfer of energy to trains is simple, tested and somewhat safe. Using this technology is not an improvement. Just neat or cool but not fully safe.
Nice post. I like the way you start and then conclude your thoughts. Thanks for this information .I really appreciate your work, keep it up
This city bus sounds to be interesting and exciting. I would like to mention that I like to read such posts that relate to bus or bus services.
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This is instructional blog as I got to know about the city bus that is now rolling and progressing. The development of the bus should always be there.