From Space.com is an interesting article about an alternative energy source of which you may not be aware:

Scientists Look to Moonbeams for Earth Energy

In one way-out scenario, microwave energy plants are outfitted on the lunar surface collecting the unobstructed microwave particles and then they are redirected to earth. All this talk of moon resources could be due to the recent worldwide discussions about returning to the moon.

Another article from Space.com, The World Needs Energy from Space, describes in more detail how space solar power (SSP) is "the key to an inexhaustible, non-polluting energy supply".