Wireless electricity

I ran across an old SciAm article on Nikola Tesla and was surprised to learn that he had experimented with transmitting electricity without wires. Wireless energy transfer sounds great and has in fact already found its way to the market (without my realizing it):

From How Stuff Works:
Nicola Tesla proposed theories of wireless power transmission in the late 1800s and early 1900s. One of his more spectacular displays involved remotely powering lights in the ground at his Colorado Springs experiment station.

Tesla's work was impressive, but it didn't immediately lead to widespread, practical methods for wireless power transmission. Since then, researchers have developed several techniques for moving electricity over long distances without wires. Some exist only as theories or prototypes, but others are already in use. If you have an electric toothbrush, for example, you probably take advantage of one method every day.

A toothbrush's daily exposure to water makes a traditional plug-in charger potentially dangerous. Ordinary electrical connections could also allow water to seep into the toothbrush, damaging its components. Because of this, most toothbrushes recharge through inductive coupling.

But like all dreamers:
'Drilling Up' Into Space for Energy
The Defense Department this October quietly issued a 75-page study conducted for its National Security Space Office concluding that space power -- collection of energy by vast arrays of solar panels aboard mammoth satellites -- offers a potential energy source for global U.S. military operations.

It could be done with today's technology, experts say. But the prohibitive cost of lifting thousands of tons of equipment into space makes it uneconomical.

That's where Palau, a scattering of islands and 20,000 islanders, comes in.

In September, American entrepreneur Kevin Reed proposed at the 58th International Astronautical Congress in Hyderabad, India, that Palau's uninhabited Helen Island would be an ideal spot for a small demonstration project, a 260-foot-diameter "rectifying antenna," or rectenna, to take in 1 megawatt of power transmitted earthward by a satellite orbiting 300 miles above Earth.

That's enough electricity to power 1,000 homes, but on that empty island the project would "be intended to show its safety for everywhere else," Reed said in a telephone interview from California.