The physics already works
Radio waves and microwaves carry energy. A transmitting antenna can direct that energy toward a receiving rectenna that converts it back into electricity. The core principle has been demonstrated repeatedly.
The space-solar milestone
Caltech’s Space Solar Power Demonstrator tested components in orbit and demonstrated wireless power transfer in space, with detectable power beamed toward Earth. That is a meaningful proof of concept, not a commercial power station.
Where losses enter
Electricity must be converted to radio-frequency power, transmitted, captured and converted again. Beam spreading, atmospheric effects, misalignment and receiver size reduce end-to-end efficiency, especially over long distances.
Where it may make sense
Power beaming could be useful where wires are expensive or impossible: satellites, remote sensors, high-altitude platforms, disaster zones or specialised space systems. Grid-scale use needs a compelling advantage over ordinary transmission.
Research record
Caltech — Space Solar Power Demonstrator wirelessly transmits power in spaceInstitutional · open sourceCaltechAUTHORS — space solar power demonstrator recordInstitutional · open sourceCaltech Space Solar Power ProjectProject source · open sourceCan We Really Beam Useful Power Through the Air?
Direct answer: Yes, useful power can be transmitted wirelessly. The unresolved question is where it can beat cables, batteries or local generation on efficiency, cost and safety.
Technically demonstrated; commercially selective. Wireless power is real engineering, but the phrase should not be confused with unlimited, lossless or free energy.