[Gatac]

Power Storage: Yeah, big-ass water reservoirs are the best we can do now. In the future, you'd probably do well to use it to split water into hydrogen and oxygen, though, especially if we go for hydrogen-powered vehicles.

Power Transfer: Few power networks today are truly independant, and technically speaking, stuff like the European power system is as close to a single linked entity as feasible today, but it's still massively inefficient, and depends on a few high capacity links between countries rather than having a "mesh" over Europe. Of course, that'd be totally impractical, too.

For really long range, I read a long time ago that a focussed microwave beam would be your best bet to transfer energy long-range through an atmosphere, but that's basically require taking a deathbeam and bouncing it off a geostationary satellite to be really long range. (Or use a massive solar satellite and beam down the power from there...)

Solar Power: For a typical household, solar power is not nearly efficient enough, but there are people who do live "off the grid", literally - several custom-made mobile homes can be run almost entirely from solar for their electrical power, and there's also a large share of biodiesel enthusiasts in that crowd.

On the other end of the scale, there are plans to build massive solar towers - basically, very big vertical turbines surrounded by a couple square miles of sealed solar panels. The power would come from both the photovoltaic panels and the wind generated by the heated air under the panels travelling towards the tower in the center and streaming upwards through the turbine. Cost estimates place that at about 250 million dollars initial investment, but the big draw is that would be easy and cheap to maintain.

Gatac