Like other web giants, Google constantly experiments with new technologies to hedge its chances of stumbling across the next big thing. But one ambitious pet project has apparently turned into something much more, attracting the attention of the U.S. Department of Energy’s DARPA-inspired internal research arm.

That’s the highlight of the latest of the search giant’s alternative energy patent applications to have reached its disclosure date, which has been earmarked with funds from ARPA-E. The contribution gives the government certain rights to the invention, a tethered kite with onboard turbine generators based on technology that Google gained through its acquisition of a startup called Makani two years ago.

The core concept hasn’t changed much since the buyout, with the kite – which is in reality a drone save for the aerodynamics – hovering in a circular pattern that emulates the motion of the blades on a regular stationary turbine. But the focus of the patent filing is the base station, or perch as Google refers to it, which has received a much-needed revamp.

The company came up with an alternative to the basic peg-like structure used to anchor the kite in the early prototypes shown to the public so far that features multiple curved racks set up in a way that makes it possible to smoothly reel the kite into its perch. The landing gear of a wing then simply slides into place using the momentum from the landing.

Every such practical improvement, of which there are no doubt many more waiting in the U.S. Patent and Trademark Office’s long backlog, brings airborne wind turbines closer to reality. That’s encouraging not only for the project but also the renewable energy movement as a whole, which has found an unlikely yet invaluable backer in Google.