About a decade ago, the clean tech boom went bust. Industry darlings were dropping like flies. Solyndra, most famously, shut down after taking a $500 million loan from the U.S. government. Germany’s Q-Cells went bankrupt, too, and was bought by South Korea’s Hanwha. A123 Systems, a battery maker, was snapped up on the cheap by Wanxiang, a Chinese auto parts company. That’s just a partial list.
There are myriad reasons why so many companies went belly up. Some had the right tech at the wrong time. Many relied on venture capital, which typically seeks returns on a timeline that’s unforgivingly brief for deep tech companies. Others were undercut by foreign competitors. Still others succumbed to general market forces that swept across the world during the Great Recession. Whatever the reason, the collapse spooked venture capitalists, who avoided the sector for years despite the potential for enormous long-term gains.
But in the last several years, venture capital has roared back, investing tens of billions of dollars in companies that hope t …
