Taylor Dinerman in The Space Review:
Solar power from both the Moon and from satellites would provide energy for operations in space and could be beamed down to Earth using either lasers or microwaves. The great advantage of beamed power is that it does not have to be transmitted across the giant transcontinental grids as it done today. Multiple solar power satellites, along with a large set of arrays on the Moon, would be the basis of a system that would be far more robust and reliable than our current one, which suffers from occasional blackouts such as the one suffered along the US East Coast in August 2003, or the terrorist campaign that is being carried out today against the Iraqi electricity grid.
Distributed receiver antennas (rectennas) would receive power directly from space and would be easier to isolate from a large grid than is the case with today’s large power plants. It is also the case that it would be fairly easy to replace one beam with another in case a satellite or lunar array went down.
More here.