This might sound like a naive question, but will there ever come a day when electricity can be sent without the use of wires? Is this within the realm of physical possibility according to science as we know it?
We can do it now. Heck, Nikola Tesla did it on a limited scale almost a hundred years ago. The problem is, it’s impractical and/or dangerous. Tesla used a giant, umm, Tesla coil to create an large electric field which could light an electric bulb from quite a distance, but the inverse square law meant that the field intensity would drop of rapidly as the distance from the coil increased. Today, we can send power via microwaves using feedhorns and waveguides to eliminate the inverse square problems, but it’s dangerous, since the intensity needed to transfer large amounts of power would basically cook anything that wandered through the beam. Plus, the equipment is expensive to build, operate and maintain. Kilowatt for kilowatt, wires are still the most practical means of transferring large amounts of power from one place to another.
If by this question you mean large amounts of electric power, the probable answer is is no. However such a thing can’t be ruled out absolutely. As things stand now, power loss in wireless transmission is proportional to the square of the distance (see below about lasers) while the loss over wires is proportional to distance.
Power can also be transmitted by fiber optic cables but so far that is limited to low power for communication. I’m not up on the technology to be able to estimate future developments in sending large amounts of power by this means.
And large amounts of power, at least in pulses, can currently be transmitted by lasers without much loss. It is at least conceivable that a powerful laser could send power to a receiver where it could be converted back to electrical power. However there are serious safety concerns about powerful laser beams slicing around through the air and the practicality of such is scheme is certainly questionable.
I’m talking about wires for computers, stereos, televisions, etc. It’s rather sobering to come to terms with the idea that someday we’ll have super powerful computers and ultra-high tech gizmos that will make our current technology seem laughable… but all the while we’ll still be condemned to live with legions of infernal cables flowing all over the floor and cluttering up our houses… for eternity!
I see a future where each home has it’s own means of power generation. Perhaps something along the lines of Mr. Fusion (as seen in Back to the Future). As frightening as this may seem to us primitives, I recall how many people refused to have their homes retro-fitted for electricity for fear of bringing lightning into their homes.
A handful of coffee grounds and egg shells once a month of so…
Well, I have devices in my home that can fill a room with beamed power. I also have electronic devices (wristwatches and calculators) that can run off this power.
For data transmission, wires will most certainly give way to some form of wireless communication a la Bluetooth. Many now use wireless keyboards, mice and networks and there’s no reason to assume this trend couldn’t continue to monitors, speakers, scanners and other peripheral devices. For televisions, remember that ALL televisions were “wireless” until the advent of cable/satellite broadcasts. Cable was needed for reasons of limited bandwidth in the public airwaves and the ability to charge you for “premium” services. With advances in digital signal processing and encryption those services could become wireless as well.
For power transmission, there’s nothing to suggest that copper wire is going away any time soon. Barring some monumental breakthrough in battery technology or some science fiction-esque advance in technology, you’ll be telling your kids (assuming you have them) not to poke things into wall sockets for the foreseeable future.
Yep, we got them new-fangled ee-lectric light bulbs in the Rhubarb household too!
Yes, but these wireless devices are still considerably more expensive than their wired counterparts, and the option to go wired still exists across the board. There’s no reason to believe that wired peripherals are going away any time soon. Wires, despite being unsightly, are inexpensive, reliable and secure–Bluetooth is none of these things to any great degree, yet.
Thanks for asking the question - I’m currently typing on my trusty iBook that’s free and clear of wires - well, except this pesky one to the power adapter. 
I can imagine wires being reduced in visibility as more things plug right into the wall - e.g. plasma TVs installed on the wall. (You don’t worry about the power cord to your microwave and fridge; they’re tucked neatly away. Hopefully audio/video equipment will head in this direction, in some sense.) Other applications might benefit from a breakthrough in battery technology. But yeah, wall sockets I imagine are here to stay for most of my lifetime. (Of course, ask a guy 30 years ago whether record players are ever going away.)
There are certain experimental computer designs that use light pulses rather than electricity over circuit traces or busses to transmit data signals. Specifically, sending out the clock pulses, which are needed all over the computer to keep everything in sync. These need to go from one place (the clock) to lots of places all over the computer. Transmitted by light, they can take advantage of currently unused space (like up above, off the surface of the motherboard). And they have the advantage of non-nterferance; 2 light waves can cross each other without interfering with either signal.
But such designs are still experimental. They aren’t yet able to compete in cost with the current systems.
Also, for transmission of electrical power, rather than data, metal wires are likely to continue to be used for decades to come. Nothing seems to be able to compete with that economically. Someday, when room temperature superconductors are perfected, we might see copper wires replaced by metal/ceramic superconducting wires. But you’ll still be plugging appliances in to provide them with power.
You might begin to see small current appliances that use onboard solar cells to replace (or recharge) batteries. This is already common in calculators & some writswatches. Probably won’t be long before cell phones, PDA’s, ipods, etc. have onboard solar panels to eliminate the need to recharge them so often.
Not 100% wireless but inductive charging pads look to be the most viable alternative. Inductive charging can work within ranges of about 3 - 5 cm and can be engineered to be fairly safe and reliable. Imagine smart walls lined with inductive circuits. Instead of having to hunt for a power point, you could just slap a patch onto the wall and it would intelligently route all power and data through that patch. Imagine sidewalks embedded with inductive circuits and smart clothing which powers your Personal Area Network through the soles of your shoes.
Broadcast eectricity, like Tesla envisioned, probably wouldn’t be workable – it’s wasteful, you get lots of unwanted side-effects (we’d have to go around getting rid of or fixing a lot of things), and it interferes with radio transmission. Not a good idea.
You can transmit power on narrow beams. They talked about sending power down to earth on microwave systems from orbiting solar collectors. But you wouldn’t use a system like that to send power to homes and businesses everywhere.
Considering that many people are concerned about AC power possibly causing cancers and other illnesses with our existing systems (and , while most of the claims are bunk, I think there’s still a scintiolla of possibility of deleterious effects, who would champion a system like this?
I see the OP’s question as similar to
“Will there ever be a day when we don’t need wheels for transport?”
In similar vein though alternatives to wheels and wires exist, and in some uses may be prefferable, the simplicity and reliability of wheels and wires will mean they always have a significant place in the world.
It doesn’t make any difference how narrow the beam. If it diverges the area of the beam increases as the square of the distance and the power density falls of as that same square. So for a given receiver area the power decreases as the square.
I think the proposal was to use mirrors and reflect down to solar cells, or the futuristic equivalent, sunlight that would ordinarily pass by the earth. However that has the same drawback as high powered laser transmittion of energy. Anything that crosses the beam gets fried.
Also, it’s quite easy to transmit power over very short distances - say, through 1/4 inch of plastic. It’s already used in some products, like electric toothbrushes. There are no electrical contacts on the toothbrush or the charger; you just place the toothbrush on the charger, and power is transmitted through the waterproof plastic housing.
Also induction cooking ranges work the same way. It transmits power through the insulating glass (?) surface and into the pan, where electricity is converted into heat.
I think this can have wider applications. For example, transmitters could be built into office desks and coffee shop tables to power laptops and cell phones.
Well, improvements in battery technology - or portable methanol fuel cells, which have been proposed for cell phones and PDAs - could conceivably replace wires. If very powerful, very small, very cheap batteries became available, we might well start running even household appliances off of them, and only use outside power (or our home’s “fusion buddy”) for the purpose of recharging batteries. While that isn’t likely in the immediate future, it wouldn’t require some “science fiction-esque advance in technology” the way beaming electricity through the air would.
Dave Simmons writes:
The power density will eventually increase as the square of the distance, but that doesn’t mean that every method of beaming down power will be as inefficient as broadcasting in all directions. A narrow beam that broadens as the square of the distance can still be a relatively narrow beam when it hits. Even laser beams, for insdtance, lose intensity as the square of the distance once you get well beyond the Rayleigh Range, yet no one would deny that lasers are still tightly-focused beams with little spread even that far from the source.
The original plan for beaming power down from their orbiting power satellites did indeed envision microwave beaming of the power down to earth.
I hear Tesla could send power over long distances using “scalar energy”.
Anything to do with “scalar weapons”? 
[waits for the 1920s-style death pile-on]