They could double as fish farms for a relatively small add-on cost. The only exceptions are several days around the seasonal equinoxes, March 21 and September 22, when the satellite will be eclipsed briefly around midnite, for up to an hour and 12 minutes. Thus, the SPS fits into a practical scale-up scenario. It may first be located at the site of major factories. Electric powered orbit transfer vehicles could also use beamed power, replacing a heavy solar cell array with a lightweight rectenna to increase vehicle performance and reduce damages by transporting a solar cell array thru the Van Allen radiation belt.
Earth based consumers have energy demands which vary between day and nite.
Daytime power demand is typically twice nitetime power demand. Alternatively, we could scale the SPS for peak daily demand and at nite beam extra energy to other space based facilities equiped with energy storage devices for their own peak and varying consumption. The drop in power demand at nite could also be accomodated by shifting the consumption load of space based industry, e.g., operating the most energy intensive processes when it is nitetime below, as well as electric interorbital transport services. The key is, of course, in the pricing structure. The industry required in space to produce SPS components is relatively modest.