Space based solar power makes a resurgence about every 15-20 years.
Basic problems: It is expensive to get to space. You can buy a lot of solar power hardware for the cost to launch even a kilo into LEO.
Conversion efficiency. Make the power in space, and you have to transmit it to the ground. The popular scheme uses microwaves, but, conversion efficiencies on both to and from aren't all that hot. You DO gain by having your panels in the sun almost 24 hrs a day, instead of 8 hrs or so. There are also some significant technical challenges in transmitting gigawatts safely and reliably.
All in all, why not just put solar collectors out in the desert. At 1 kW/square meter (typical solar constant on earth's surface), a 1 GW power plant (typical size for one generating unit, would require about 10 sq km (allowing for the fact that the sun doesn't shine 24 hrs a day (so you have to actually generate 3 GW when the sun shines, and that conversion efficiencies are about 30%).
California currently has about 53 GW of total generating capacity. The entire US has about 800 GW. So, you'd need around 8,000 sq km (more correctly, 800,000 hectares) for the entire US.
For comparison to other "big" projects, this is about 3125 square miles, which is comparable to the amount of land given to the railroads when building the transcontinental railroad in the late 1800's. For that effort, the government issued and guaranteed bonds as well, which were all repaid at a profit (a little known fact is that building the transcontinental RR actually turned a profit for the taxpayer).
A similar effort could make solar power a reality.
Created on Friday, February 09, 2001 12:37 PM EDT by James Lux