Crazy thought... can energy be transfered wirelessly? Has this ever been done?

Question

I was plugging in my laptop when I had this thought. I'm not sure if t's been done. And if it hasn't I doubt that it's possible. But we can transfer data wirelessly... it's different... but still...

When I say energy, I mean electricity.

Try to think about it in a commercial use.

Answer 1

Hmm ... thinking out loud, and combining some of the great comments from other answers:

The problem to solve is safety ... getting that amount of energy to the appliance and *only* to the appliance.

Most radio transmission technology (from radio transmitters, to the wireless router my laptop is using at this moment to communicate with the Internet), uses undirectionally broadcast radiation. The transmitter just broadcasts electromagnetic radiation in all directions, and the reciever picks it up. It is safe because this radiation is at such low power, and at non-hazardous frequencies. This low energy is further dissipated by the fact that it is broadcasting in all directions, which makes the inverse-square law apply. For these reasons, the energy transmitted by such radiation is insufficient to power even a small appliance, much less something like a laptop, although it is sufficient to transfer information (great amounts of it).

Something like the remote control for your TV is more directional. This uses infrared radiation (although still at very low power) but with a somewhat directional transmitter and receiver ... which is why you have to point the remote *at* the TV to make it work. However, this is still a fairly wide beam.

So, if the radiation were sent as a very narrow beam ... i.e. a laser ... directly from the transmitter to the reciever, then loss of energy to the inverse-square law could be eliminated.

The first problem would be for the transmitter to be able to locate the exact location of the reciever in order to beam a laser directly at it. I would suppose that magnets similar to CRT technology could be used for aiming ... so transmitters would look something like a small CRTs sitting somewhere in the room. When first turned on, some signal would start the transmitter scanning the room with a low-powered laser to pinpoint the exact location of the receiver.

The second (and much more important) problem is safety. With enough energy to power an appliance like a laptop, such a laser would be extremely dangerous. Even if the energy requirements of the appliance (laptop) were reduced considerably, such a laser would heat burn things in a short amount of time, and would cause irreperable blindness if it were to hit someone in the eyes.

So perhaps the technology would consist of a high-power laser accompanied by a low-power "guide beam". The low-power guide beam would be responsible for (1) pinpointing the exact direction of the receiver, so that the transmitter could hit it perfectly (e.g. if the appliance were moving, like a laptop in the room); and (2) interrupting the high-beam laser *immediately* if the low-beam guide laser gets broken by some intervening object, or otherwise loses the location of the receiver. (There would also be some heat dissipation problems as well, but these would get reduced as the laser technology improved, and the power requirements dropped.)

HOWEVER, I would not want to be one of the first people testing that "laptop", and a high-power laser pointing at my "lap." :-)

Answer 2

Not so crazy. Tesla proposed blanketing New York in a high voltage electric field (produced from a Tesla coil). In order to use the energy, simply orient an appliance towards the Tesla coils, and you get a voltage differential. This is how fluorescent lights work, by the way. Well, that didn't really work out and Edison proposed the more practical 60Hz AC over wires, and the rest is history.

High energy lasers are a wireless energy transmission medium. Of course, like microwave, it's all line-of-sight. It has been tested...

Answer 3

It's called radio waves.

The energy is pcked up by the radio antenna and amplified.

The problem with sending energy wirelessly is that unless you use a waveguide of some type, the energy radiates in all directions, so the energy reaching any given point varies inversely with the square of the distance from the source.
i.e. it's inefficient.

Note: When you microwave a buritto, you are transfering energy wirelessly, using radiowaves, to the buritto.

Answer 4

Well, that data transfer IS energy, it's just not very efficient to send enough power to your laptop wirelessly.

Answer 5

Other than lightning or static discharge, electricity can't wirelessly be transferred.
Heat and light energy are wirelessly tranferred though

Answer 6

Well, light is a form of energy, eh? On the config of photo-electric eyes that open doors--light from it's source transmits a continuous
light beam (energy) to a receptor until it's broken, and opens the door.
Maybe someone more learned then I can tell you better. Perhaps I'm wrong about light being energy. shrugs.

Answer 7

yes, just very inefficient.

RFID (radio frequency idenification) tags use wireless power. They use the wireless communication signal (which has a DC offset) to power there circuits. One note its about 1 millionth of a percent effcient, but since the tags only need about a 100 picowatts (10^-10 watts) to run it's circuits it works.

Your comment about wireless data transfer...If no energy is transmitted can you actuall detect the signal? No. Wireless data transfer is actuall wireless energy transfer.

Answer 8

The sun transfers energy from it to earth by means elctromagnetic waves (like heat enery by the infra red radiation) and I don't see a wire running from the earth to the sun (don't take it as an offence).This is being done from the beginnig of time

Answer 9

Try to google on "laser propel spacecraft" and you find lots of links to description of projects of propelling spacecrafts by shooting at them with lasers. This is a pretty cool idea. The power source is on the ground so the spacecraft can be much lighter. Only works if the spacecraft is not too far away. But for sending a satelite into orbit, it could work.

Answer 10

you could not do it with electricity, but say if you could run a comp off of ultraviolet rays, you could convert electricity into ultraviolet rays and send them towards the laptop and when it hits the laptop it could then be caught by solar panels and turned back into electricity to run the comp. this wont yet get you nearly enough electricity but that would be the only possible way.