Depends on many factors. Solar would be useful if the area had extensive terrain that could serve the city, however, in northern latitudes winter would be challenging with short days and low angle sunlight. If the situation allows, wind power could be useful, when the wind is blowing. The fantastic thing about these units is that they’ll crank out the KW day, night, no matter the season or location. They are not restricted to large generator farms with the scale of upkeep and maintenance they require. A city could be isolated in challenging remote areas and be self sustaining for their energy needs. These aren’t meant to be a “fix-all” solution for every situation, but they make tremendous sense in many applications where current methods are not ideal.
Except long distance power transmission losses are not minimal. Depending on many factors, losses can easily be in the 5% - 10% range. With the amount of energy going through those wires, that’s HUGE. The additional complexity and inefficienies of relay stations, all add up. Having worked in the power sector for nearly a decade, I knew engineers who were celebrated in being able to squeeze an improvement of tiny fractions of % efficiency, as that resulted in millions of dollars saved throughout the year.