The following paper shows a possibility of use of an area of altitude between 17 km and 22 km where the wind speed is very low after a peak at 10-12 km altitude (see the figure 4).
In the abstract:
High altitude platform station HAPS is unmanned airplane provides the wireless communication service to the wider area.
Could some untethered AWES be or feed these HAPS unmanned airplanes, taking advantage of a maximum wind gradient by drawing their energy from the fast jet streams a few kilometers below, without having to land?
Other uses such like feeding stations to launch sattelites?
High-altitude platform station - Wikipedia:
Power
Power is required for continuous operation, limiting endurance by the need for refueling. Persistent solar-powered aircraft need to store daylight energy for the night, in electric batteries,[11] or in fuel cells.[12]
High altitude wind power (HAWP) could possibly be added to solar power. Jet streams can still be fast at an altitude of 15 km, a few kilometers below the station, which is still a little above almost all commercial air travel.