University of Wisconsin-Madison

Finally, the capital cost of the SPS concept is compared to selected candidates likely to produce large scale electricity in the same time frame (coal, fission, terrestrial photovoltaics) below. While the optimistic projections of the SPS system overlap the higher cost estimates of the more conventional power sources, the pessimistic estimates are so high as to essentially preclude its commercial use. The key factor is the cost to launch to LEO which must be less than 75 $/kg in 1995 dollars.