Focus the Sun

At an energy density of 9 megawatts per square meter, a Fresnel lens 2815 meters in diameter orbiting the Sun would act like a lighthouse creating a 56-Terawatt collimated beam of light all the way out to Earth orbit. About 25 percent of that light could be converted into electricity using the Rankine Cycle. That's 14 Terawatts of electricity, equal to the entire world's energy output from all sources.

Materials sufficient to withstand the solar irradiance at the proposed distance:

- quartz (Fresnel lens material)
- quartz fiber optics (cable for truss structures)
- graphite (solar sail panels)

In the absense of conduction and convection, optical quartz can withstand higher temperatures than any other material I can find. Graphite would not melt either, even though it would become much hotter than quartz, but conduction of heat from graphite to quartz would ironically melt the quartz!

Quite a challenge!