"wow" weapons aside, what about Global Communications and everything that depends upon it, or GPS...
Travel, Shipping, Rescue, Weather hell the Global economy would falter for an extremely long time and fall hard enough I question if it would be able to get back up without those who hold control of the Sat's did not allow it.
Technological Hostages, a whole freaking planet... ( might seem a bit extreme, but if you really go through the lists, it would be the way to hold the world at a stand still if even for only a short period of time such as a few months up to whenever people could take back control, if they ever could )
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Well if you think about positioning Mirrors, Collectors and Beam Space side which would stay in Sun light 24/7 none stop and Collectors planet side as a first step. Power would be a moot issue once it was achieved, naturally it would evolve and other sources would come about. But that is something that they should be able to do and only funding and time would really be the issue. Of course the Energy Industries would throw a fit and hold it up forever and a day because they would want, no, demand to sap the planet of as much Oil and Coal as they could before their profits from the plants and such were cut off.
but, mmm, yeah it is an interesting and thought provoking subject which spawns many others