How can solar energy from satellites be transferred to earth?
Hi. By microwave transmission to an antenna on Earth.
Microwaves. A microwave transmitter on the satellite sends a beam to rectifying antenna (called a rectenna) on the surface. This converts the microwave energy to electrical current. This method was first proposed by Peter Glaser in 1973.
The problems are: 1) this method of transferring power has been demonstrated on a small scale here on Earth, no one has ever tried it from orbit, and 2) in order to transmit enough power from space to be usable commercially the rectenna would have to be massive, say 14 square kilometers in size.
Given the cost of that much land, not to mention the cost of launching the materials to build the solar array in orbit, solar power from space simply doesn't make sense economically given the availability of fossil fuels. Maybe when we run out of oil, politicians will give this option more thought.
Not with reasonable efficiency... yet.
Rather expensive. Much cheaper to collect it on earth.