LANSING - Legislators and scientists searching for fuels other than gasoline have multiple renewable options that could eventually replace gasoline.

The challenge is to integrate these fuels into Michigan's infrastructure so people can easily buy and use them, said Sen. Cameron Brown, R-Fawn River Township.

Brown has introduced a bill to require the Department of Transportation to analyze the feasibility of setting up a "hydrogen highway" in the next few years.

It would be a stretch of roadway with hydrogen fuel stations at least every 20 miles, Brown said.

It would promote hydrogen fuel technology, which in turn would promote the economy and help Michigan reach energy and environmental goals, he said.

Last year, Brown sponsored legislation that established a Renewable Fuels Commission.

"It's just to keep the focus on the need to diversify our fuel," he said. "I want us to start looking down the road."

Three main alternatives have emerged as the leading prospects: ethanol, biodiesel and hydrogen, said Allen O'Shea, chair of the Manistee County Board of Commissioners.

"It's like a mosaic right now," he said.

Ethanol is the most common now, said O'Shea, who runs the Michigan State Energy Fair. But that is likely to change.

Ethanol fuel is the same as the alcohol people consume, he said, and state law already mandates ethanol contain at least 5 percent regular gasoline to keep people from drinking it.

It can be made from several sources, including sesame seed oil and tree bark, O'Shea said. But it is most easily and cheaply made from corn oil, which causes concerns about the impact on food supplies.

Mass-producing ethanol fuel out of corn could potentially take corn away from the food market, but that's not a problem yet, O'Shea said.

Ethanol produces much less pollution than regular gasoline, but it also produces less power, O'Shea said. One of its key advantages is that any car that runs on gasoline can run on a gas-ethanol mix.

Similarly, any diesel engine can run on biodiesel, said Jenna Higgins, the director of communications for the National Biodiesel Board in Jefferson City, Mo.

Biodiesel also produces only half the amount of pollution as gasoline, Higgins said, and it has more power than ethanol.

"It's very comparable to the diesel used in the winter," she said. And there is no discernable difference in performance if up to 20 percent biodiesel is combined with diesel.

Like ethanol, biodiesel can be made from a variety of oil sources, including canola oil, sesame seed, soybeans and even discarded cooking oil from fast food restaurants, O'Shea said.

Biodiesel also has a high energy balance at 3.2 to 1, which means for every unit of energy used to produce the fuel, there will be more than triple the energy output, Higgins said.

O'Shea said, "Biodiesel has a whole lot of immediate potential. It's the simplest, safest and the least controversial."

Traverse City already runs all of its public transportation vehicles on B20, which is 20 percent biodiesel, said Don Scharmen, the director of operations at the Bay Area Transportation Authority.

"We've had no trouble with it at all," he said. The exhaust of buses smells noticeably better.

B20 was more expensive than gasoline when the switch was made a year and a half ago. The price has since come down so it costs about the same as gasoline, Scharmen said.

The third major alternative, hydrogen, is the least common and least understood, O'Shea said.

"Hydrogen is getting far less play in industrial circles, but more in scientific circles," he said.

A hydrogen fuel cell, which works like a battery, theoretically is pollution-free, said Gianfranco DiGiuseppe, assistant professor of mechanical engineering at Kettering University in Flint. The only byproduct is water.

"You could drink it," he said.

But unlike biodiesel and ethanol, hydrogen cannot run in a combustion engine, DiGiuseppe said, so vehicles will need a specially designed fuel cell.

That requirement represents the largest hurdle for hydrogen fuel, he said. "The technology is certainly there, the main drive is to make it cheaper."

Brown said, hydrogen fuel pumps differ completely from gas pumps. That's why a hydrogen highway is needed to provide an incentive for buying cars with hydrogen fuel cells.

Higgins said, even though the three alternatives are vying for attention, there is no real need for them to compete.

"It's going to take all of them working together to really make a difference," she said.