Without running the numbers, my knee jerk reaction is this makes zero sense over generating the power here on earth.

Taking the article at face value, they claim this microwave beam will generate 250W/m^2. The RF collector on the ground would need to span an area of at least 8 million m^2 (~2000 acres) for a capacity of 2GW. The largest solar power plant in the world, Bhadla solar park, spans an area of 14000 acres with similar capacity. I’d guess antennas are much cheaper than photovoltaics too, so to a rough approximation the ground facility would be a lot more efficient than a solar plant.

The question is how much of the efficiency gains will be offset by the launch cost of the satellite. If Musk delivers on his promise of sub-$10M starship launches then space-based solar generation might actually be cost-competitive with terrestrial PV systems.