Traditionally, the firm has split its investments between digital-technology companies and health-related companies. Occasionally there are forays into businesses that fit neither category, however. One of these was Kleiner’s humiliating investment in Segway, the maker of the battery-powered scooter, which, back in 2001, John Doerr predicted would be the fastest company in history to hit $1 billion in sales. Seven years later, Segway is not even close. Nonetheless, Segway yielded a different kind of return. The vehicle’s creator, the inventor Dean Kamen, spent time at Kleiner talking with Doerr and his partners about the challenges in providing a growing and increasingly urban global population with clean water and energy. And, as it happened, around the time of the Segway’s debut, Kleiner received a proposal from a professor at the University of Arizona named K. R. Sridhar, a former NASA scientist, who was working on a solid-oxide fuel cell in his garage in Tucson. Fuel cells are an old technology, dating back more than 150 years; they convert a fuel, like natural gas, into electricity through chemical reaction rather than combustion. Sridhar’s pitch had some novel technological aspects, and his business plan called for making energy generators — essentially, large box-shaped units for a home basement, or an office building — for buyers who either had no access to an electrical grid or wanted to disconnect themselves from one. “You could put natural gas into it and get electricity out,” Aileen Lee, the partner at Kleiner who researched Sridhar’s proposal, told me. “Or it could be fuel-flexible” — meaning the boxes could run on, say, ethanol. At least in theory, the units, which Sridhar called Bloom boxes, would be reliable, quiet and very low in carbon emissions.

I heard a number of explanations about why the firm paused after investing in Bloom Energy in 2002. The consensus seems to be that it took time for the partnership to be persuaded that the economy would move in a greener direction and that green tech would have far larger potential payoffs than, say, the ideas for Web sites that were being financed at the time. Then, in late 2006, at one of Kleiner’s corporate retreats, Bill Joy, a founder of Sun Microsystems and a new partner at the firm, displayed what later became known within Kleiner as “the map of grand challenges.” This was a matrix of colored squares that itemized the firm’s progress in locating potential investments in about 40 different categories: water, transportation, energy efficiency, electricity generation, energy storage and the like. In the blank spots there were lists of “things that ought to be possible,” in Doerr’s words — ideas, in short, that might produce huge changes and, if Kleiner bought a stake, huge profits. Thus the grand map was a rough, imaginary outline of a clean-energy economy that didn’t really exist and perhaps wouldn’t in any meaningful way for decades. But it helped Kleiner understand what to look for. That same year, Kleiner officially informed its investors that it would begin putting $100 million of its newest fund in green technology. Doerr, Joy, Ray Lane and John Denniston all joined the green-tech group.

There was little doubt that partners like Lane and Doerr, who have countless connections within America’s high-tech worlds, would get good green-tech pitches as word got around. In the meantime, Joy and his more technically minded colleagues “went outbound,” in Joy’s words, which meant they started scouring laboratories throughout the United States, as well as academic departments around the world, for energy ideas that could satisfy challenges on the grand map. It has become a kind of received wisdom that American and European laboratories have yet to come up with enough innovations to ease our dependence on fossil fuels, or that effective (and affordable) technological solutions to climate change are still many decades away. In truth, there have been scores of recent scientific developments in wind, solar, biofuels and energy efficiency that have not yet entered the market, in part because the private sector has deemed them risky investments in a world where gas, coal and electricity are cheap. As Andy Karsner, who recently stepped down as the Department of Energy assistant secretary in charge of renewables, told me, “Venture capital’s interest in the sector didn’t arise until price signals and climate change came into play a few years ago.” Before that, he says, green technology “was in a state of suspended animation.” Dan Arvizu, the head of the National Renewable Energy Laboratory in Golden, Colo., echoes this sentiment. Whenever Arvizu testifies in front of Congress on the state of renewables, he told me: “They always ask the same questions — ‘When is this going to be real?’ And I say: ‘It’s real now.’ ”

Kleiner’s partners largely shared this view. “Our overarching thesis,” Bill Joy says, “was that a lot of stuff had already been developed, but there were things that were not yet commercialized because they had been frozen by the low price of oil. The innovation had occurred, but they hadn’t been deployed.” In addition to a number of California ventures, Joy and his colleagues ultimately tracked down worthy ideas in Massachusetts, Florida, Texas, Pennsylvania, New York, New Jersey and Georgia, as well as in Israel, Germany and China. One morning early in the summer, I had breakfast with Joy in Manhattan, and he took a folded sheet of paper from his pocket to show me what remained of the map of grand challenges, under the condition that I would keep confidential the technologies that were not public knowledge. Some slots remained open, but the firm had identified a number of projects that could be deployed quickly as well as longer-term proposals that might be called breakthroughs. Whether any would turn into flourishing companies — let alone another Google — was a far more unpredictable matter. For the time being, at least, Kleiner’s partners had assembled the ideas for what they intuited to be the future. At one point during his globe-trotting pursuits, Joy recalled, John Doerr turned to him and said, “I don’t think anyone has ever really done venture capital this way.”

Image Ausra, a start-up in Palo Alto, Calif., uses mirrors to concentrate solar energy on water pipes to produce steam and, ultimately, electricity. The first installation, in 2011, should power more than 100,000 homes. Credit... Mitch Epstein for The New York Times

From Idea to I.P.O.

If you look over Kleiner’s clean-energy portfolio, it’s apparent that the firm has made a number of large and risky bets. In part this is because of the evolving economics of venture capital: to get the returns its investors have come to expect — the firm says it has returned an average of $1 billion in profits per year to its investors over the past decade — Kleiner has to produce one or two magical success stories every few years. Some of the risk taking, however, is a product of the firm’s culture. Brook Byers, the firm’s longest-serving partner, told me the place depends on a complementary mix of talents. This has been the case since the beginning, in 1972, when Eugene Kleiner, an engineer who had worked at the valley’s earliest semiconductor companies, went into business with Tom Perkins, a former executive at Hewlett-Packard. Kleiner, who died a few years ago, was an Austrian-born intellectual of modest tastes — “a very soft-spoken, very wise, very gentle man,” according to Doerr. Perkins was a brash gambler who would later build one of the world’s most expensive yachts. You could argue that Perkins, now retired, left the larger imprint on the firm. As Doerr told me, “Tom would say, ‘When you have a great opportunity, push all the chips, all the resources that you can, to the center of the table.’ ” Perkins, Doerr added, was more his mentor than Kleiner was.

Bloom Energy is a good example of a venture where the chips are now piled high. Though you wouldn’t know it from appearances. Located in a modest, unmarked one-story building with large plate-glass windows off the highway in Sunnyvale, Calif., Bloom is one of the companies in the Kleiner portfolio closest to unveiling a commercial product. Over the past two and a half years, engineers at the University of Tennessee in Chattanooga have been testing a five-kilowatt Bloom box, which looks like a squat refrigerator and produces about as much electricity as a typical home requires. And at this point there seems little doubt that the idea K. R. Sridhar pitched to Kleiner in 2001 has become a high-functioning machine. “We installed one of his first units here to assess its durability and performance, to see if it matched the claims,” Henry McDonald, a professor at Tennessee who is overseeing the Bloom box, says. McDonald ran the box nonstop on natural gas for 6,000 hours, and its performance beat expectations. In everyday terms, the box was twice as efficient as a boiler burning natural gas, and its carbon emissions were 60 percent lower.