Solar Panels...IN SPACE
I believe this is going to be a major source of energy in the future. If you keep an eye on any scientific news source, you'll see the occasional article on the topic: there are companies in America and Japan with contracts to beam energy down from space already. And if this technology sees some success it could help drive down the costs of space travel, making it an increasingly viable option.
The idea is fairly simple: you rocket some solar panels and a microwave generator into space. You aim the microwave at the Earth (think of like a space-based death ray), but instead of reducing the countryside into irradiated wasteland, you catch the microwaves in a receiver, which converts the energy into electricity. And then you turn on a light, or fill up your electric car or something. Hurrah!
Why is beaming microwaves down from space better then catching light here on Earth? First, we've got night and clouds to contend with. A satellite can spend more time in the sun then any point on Earth. Then there's all that atmosphere hugging our planet. If you didn't know, visible light is just a small part of the electromagnetic spectrum. To one side you've got things like X-Rays, to the other you've got radio waves. Weird as it seems, its all the same stuff, the distance between peaks of the waves just differs. For some reason (magic? science?) depending on these distance between the waves, different molecules will either absorb the light or let them pass. If you've got a red shirt, it's because the molecules in it absorb green and blue, and bounce back red. Glass doesn't really absorb any red, green or blue light waves so you can see through it. The atmosphere absorbs a lot of the energy the sun beams down at us. It doesn't absorb microwaves very well though.
So the short of it is that if you take the energy from the sun and turn it into microwaves, you can shoot it through the atmosphere without losing so much of the energy. Hence space based Solar panels. If you can get the panel up into space without using too much energy, you'll get much better results then if you leave the panels on Earth. If we build factories on the moon, we can get the panels into space for even less.
Anyways, you can expect to start purchasing space electricity from your local electric company (you do live in California, right?) as early as 2016. Look for the percentage of space energy to only increase from there.