It looks like gasoline, smells like gasoline and runs in regular gasoline engines, but it isn't made from crude oil; it comes from crops.

It's called "biogasoline," and under a partnership announced last week between Royal Dutch Shell and Virent Energy Systems, it could be coming to a filling station near you.

The European oil giant and the Madison, Wis.-based bioscience firm said they are working on a way to convert plant sugars found in nonfood crops such as switchgrass or sugar-cane pulp into a synthetic gasoline that can be substituted for petroleum-based gasoline.

The fuel could be a breakthrough. Unlike ethanol, it can be used in high concentrations in conventional gasoline engines, and it can be stored and transported in the existing oil industry infrastructure -- eliminating the need to build a whole new biofuels distribution system, the companies said.

In addition, they said, biogasoline has a higher energy content and is more fuel- efficient than ethanol, the leading renewable fuel.

"Our products match petroleum gasoline in functionality and performance," said Randy Cortright, Virent's co-founder and executive vice president, in a joint statement by the companies. "Our results to date fully justify accelerating commercialization of this technology."

But the companies were vague on details, declining to disclose the costs of producing the fuel or when it may be available to consumers.

That may be because the challenges of bringing the fuel to market are bigger than the companies suggest, said John Kruse, an agricultural economist and biofuels expert with research firm Global Insight of Waltham, Mass.

"I still wonder if there isn't a cost issue," he said.

Graeme Sweeney, Shell's executive vice president of future fuels and CO2, said of that issue: "We believe this technology has the potential to be cost-competitive. Otherwise we wouldn't be taking this route."

The venture comes as many nations are mandating the use of biofuels to reduce fossil-fuel consumption and curb greenhouse gas emissions.

In December, President Bush signed legislation that calls for a sixfold increase in U.S. ethanol production to 36 billion gallons by 2022.

Critics charge that a huge expansion of corn-based ethanol production in recent years has driven up food prices globally, is damaging the environment and has limited potential to replace fossil fuels -- claims that the ethanol industry rejects. Still, a number of U.S. companies are working to make ethanol from nonfood sources.

But even with nonfood ethanol, there will be costs in equipping the nation's automobiles and fuel distribution infrastructure to handle the highly corrosive fuel. Biogasoline, Shell and Virent said, has the potential to bypass some of those challenges.

"It's one of those exciting technologies that brings an exciting opportunity to bring a fundamental sea change to the biofuels world," said Michael McAdams, executive director of the Advanced Biofuels Coalition, a Washington group that advocates for next-generation renewable fuels.

Surpassing internal goals

To make the fuel, Shell and Virent will use catalysts to convert plant sugars into hydrocarbon molecules like those produced at a petroleum refinery. By contrast, ethanol is made through a fermentation and distillation process that converts starch found in crops such as corn into sugar and then to ethanol.

Shell and Virent said they have collaborated for one year as part of a five-year agreement on the biogasoline research program and have exceeded internal goals for yield, product composition and cost. Future efforts will focus on further improving the technology and scaling it up for larger-volume commercial production.

Because the fuel can be made from many crops, plants can be built all over the world, but the companies did not identify potential locations for fuel-making facilities. Shell and Virent also are testing their belief that biogasoline likely will reduce some smog-forming tailpipe emissions when compared with ethanol and petroleum gasoline.

The U.S. government has tried to clean the air in major cities, including Houston, by requiring gasoline to include 10 percent ethanol, which helps cut emissions. Such a blend can be used in gasoline engines without modifying them. Automakers also sell modified engines that can accommodate a blend of 85 percent ethanol and 15 percent gasoline called E-85.

Shell and Virent suggested such modifications may be unnecessary with biogasoline, saying high blend rates can be used in standard gasoline engines.

Does the ethanol industry view biogasoline as a threat?

No, said Matt Hartwig, spokesman for the Renewable Fuels Association, an ethanol trade group in Washington.

"To address the energy concerns that our nation faces, as well as those around the globe, we are going to need to develop a whole toolbox of solutions," he said.