At the rate we are using energy, it is inevitable that we will need to source energy from outside of Earth, eg from space. I was wondering how one would transfer this energy from that energy collector (e.g. a solar array) to Earth to be used by us?
Various aspects of space-based solar power systems are described on this wikipedia page To summarise briefly, the power is beamed down as electromagnetic radiation of some frequency to which the atmosphere is reasonably transparent. This is most likely to be optical or near IR or microwave. Microwave power can be converted efficiently at the Earth end, but the antennae needed are much bigger. Optical or IR solutions involve more loss, but can be done with smaller ground stations.