The unit was turned into an independent business last year to see if it could fly on its own. "Creating an entirely new kind of wind energy technology means facing business challenges as well as engineering challenges," Makani chief executive Fort Felker said in a post at Medium.

"Despite strong technical progress, the road to commercialization is longer and riskier than hoped, so from today Makani's time at Alphabet is coming to an end." After becoming an independent business, Makani collaborated with gas giant Shell Oil to demonstrate successful flights of energy-generating kites tethered to a floating platform off the coast of Norway, Felker said.

Copyright Agence France-Presse, 2020