Even if we covered the Earth’s surface in turbines, we’d still miss out on the abundance of wind coursing high above our heads. In 2006, a start-up called Makani set out to channel the strong and steady currents at higher altitudes by developing a kite—which looks more like a propeller drone than what you’d fly at a Sunday picnic—that could generate cleaner and more reliable power. Fast-forward to 2013, when the California-based company was acquired by Google—which could give Makani the financial and institutional boost it needs to make a pie-in-the-sky dream a viable green-energy alternative. google.com.

Charles Williams