Tellingly, the type of companies placing bets on the field has started to expand. The earliest were small start-ups founded by people with more technological vision than business experience. Now some of the giants of global business, including Honeywell, Dupont, General Motors, Shell and BP, are taking stakes in the nascent industry.

The dream of making fuel from plants is almost as old as the internal combustion engine. Henry Ford himself was fascinated by the idea, and it re-emerges in periods of fuel scarcity and high prices. These days, advancing technology has made the notion more plausible.

Virtually any material containing hydrogen, carbon and oxygen could potentially be turned into motor fuel. That includes plastics, construction debris, forest and lawn trimmings, wood chips, wheat straw and many other types of agricultural waste.

The potential fuels include ethanol, which can be blended with gasoline, or other liquids that could displace gasoline or diesel entirely. Government studies suggest the country could potentially replace half its gasoline supply in this way — even more if cars became more efficient.

The government is pushing to get the industry off the ground. Legislation passed last year mandates the use of 36 billion gallons of biofuels a year by 2022, less than half of it from corn ethanol. Almost all the rest is supposed to come from nonfood sources, though the requirement could be waived if the industry faltered.

“One has to say upfront that what Congress has done is remarkable in its bravery,” said David Morris, vice president of the Institute for Local Self Reliance, a group in Minneapolis that advocates biofuels.

Image KL Process Design is using pine waste to make ethanol. The lab manager, Audra Locke, right, with a sample. Credit... Dick Kettlewell for The New York Times

Much of the new money flowing into the field is coming from Silicon Valley, where the venture capitalists who gave the world the Internet revolution see an opportunity to do something similar with the fuel supply.