Wireless Electricity by Brian Kearney

(Larry starts the story)

I brought up the idea of wireless electricity on the 10 miler a couple of times. The consensus was that it's not possible, or impractical at best.

While we were poo-pooing the idea, someone else was developing it.

http://money.cnn.com/magazines/business2/business2_archive/2007/04/01/8403349/index.htm

(by Brian)

I remember reading about this a while ago but then forgot all about it.

What I read likened it to the RFID chips that time us in races. Instead of picking up small amounts of electromagnetic radiation which power a transmitter which broadcasts its id number (which the chip does) they use the power to drive a battery charger. What they really figured out was how to pick up enough of the power to trickle charge small batteries.

They lose 30% of the energy, so it will take 43% more energy to charge your battery than plugging it in like we do now (100/70 since you need to reach 100% charge but you're only getting 70% of what you used to get or looked at another way 100 is 70% of 143). That's fantastic for devices, which really need it such as implanted medical devices, but not so good for convenience devices such as cell phones (can anyone say greenhouse gas emissions from all the extra electricity generated?).

If you want to do something really incredible, but not get FCC approval for your device, figure out how to charge the battery off all the stray radio and TV signals bouncing around already.... that's 'free' energy, but will decrease the quality of the over the air TV signals, a small price to pay. Or wait for the new generation of batteries coming out. The problem with rechargeable batteries is that it takes more energy to charge them up than you get in return, a function of the chemical reaction going on that creates the electricity. The ultimate rechargeable battery is the capacitor, which will return nearly 100% of the energy it takes to charge it. The problem was that no one could make a capacitor that held enough charge in the size of a battery... very short life batteries. Until someone recently figured out that if you attached millions of little carbon nanotubes to the surface of your capacitor plates you could multiply the capacitance many times over.

They're working on the production issues now... batteries will be coming out in a few years. Plug in your rechargeable battery and it will recharge in a few seconds but last a normal amount of time.... and capacitors don't lose the ability to take charge over time like other rechargeables do.

Brian

You're not magically creating energy here; you're using energy someone else expended that is otherwise going to waste...

Speaking of cars.... the new battery technology could do amazing things for cars. Right now approximately 90% of your car's energy consumption goes to accelerating the car up to speed (about 6% is lost to drag, etc) and about 4% goes to moving you where you want to go. Regenerative braking in hybrids captures some of the energy while slowing down, and uses that energy to accelerate you back to speed, but the energy capture isn't efficient due to battery technology. With the capacitor battery the energy capture during braking will be highly efficient so the acceleration back up to speed will be more efficient since it will require less net new energy.... and this can apply to most types of transport, cars, busses, trucks, trains, (hmmm airplanes? That will take some doing). Actually Japan has 3 hybrid locomotive engines it's testing now to see if it should take them system wide.

Brian