 One proposal is to capture the asteroid Apophis into earth orbit and convert it into 150 solar power satellites of 5 GW each or the larger asteroid 1999 AN10 which is 50x the size of Apophis and large enough to build 7,500 5-Gigawatt Solar Power Satellites

The use of microwave transmission of power has been the most controversial issue in considering any SPS design.At the Earth's surface, a suggested microwave beam would have a maximum intensity at its center, of 23 mW/cm2 (less than 1/4 the solar irradiation constant), and an intensity of less than 1 mW/cm2 outside the rectenna fenceline (the receiver's perimeter).These compare with current United States Occupational Safety and Health Act (OSHA) workplace exposure limits for microwaves, which are 10 mW/cm2, - the limit itself being expressed in voluntary terms and ruled unenforceable for Federal OSHA enforcement purposes.