Build it on the Moon! The He3 is abundant there! Make it work and then beam the energy to Earth. Gene Cernan is one of the Apollo astronauts who has favored this approach!
"Beaming" energy back to Earth strikes me as remarkably dangerous. One smart terrorist infiltrates the wrong computer system and a city is incinerated. I don't like this.
OTOH, setting up a permanent base to mine the Moon sounds great.