The South Koreans are nothing if not ambitious.
There is the little problem of transmitting the power collected in space and getting it to the ground. A tight microwave beam, perhaps? Or the longest transmission wire ever built, stretching from the surface of the earth out to geosynchronous orbit? What about earth shadow, or a total eclipse by the moon of the array?
Reliance on thorium molten-salt reactors seems to be a better all-around answer, but perhaps there is a lot of money in South Korea for these kinds of research grants.
The advantage, according to the article, is that it’s cheap. 30.03/kilowatt. Another advantage, if it works as theorized, is that cloudy days won’t inhibit the productin of power because microwaves will beam through clouds just find, even if there is a bit of loss from rain absorbing the microwaves.
I’m sure they would keep back-up options in the event of a strike by NK or eclipses and what not. A combination of everything is probably what will work.