Iowa State U. researchers find ways to turn grass into hydrogen fuel

by Wendy Johnson, U-wire

(U-WIRE) AMES, Iowa – Researchers at Iowa State University aretrying to find a way to turn prairie grass into hydrogen gas thatcan be used in new fuel-cell automobiles.

Robert Brown, professor of mechanical engineering, said the goalof the research is to find renewable sources for hydrogen todevelop these vehicles, which will reduce air pollution.

“If you use a renewable source of hydrogen, it doesn’t releasepollutants like fossil fuels do,” Brown said.

The researchers begin with switchgrass — a native prairie grassin Iowa.

The grass is referred to as a biomass, which is any organicmaterial of recent biological origin. Using biomass as a source ofenergy is important because it produces a chemical rather thanelectrical reaction.

“There are no natural sources of hydrogen,” said Brown, “so weare really focusing on the production of hydrogen.”

The process of converting grass to fuel is an elaborate one.

First, the biomass is harvested and chopped up. Then it is putinto a reactor and heated, which causes it to release gases such ashydrogen, carbon monoxide and methane. The hydrogen gas is thentargeted for use as a transportation fuel, Brown said.

There are three types of uses for hydrogen, said Steve Martin,professor of materials science and engineering. It can be used withtransportation as a fuel, but it can also be used as a stationaryunit for heating homes or powering electricity in buildings, hesaid.

Hydrogen is typically used in large fuel cells, such as thosefor cars, but there are also micro-fuel cells hydrogen can be usedfor. These are used in cell phones, laptop computers and otherportable electronics, Martin said.

A fuel cell is a battery with one fuel tank connected to it. Thehydrogen fuel cell only needs one tank because the other componentis oxygen, and there will always be air where a person drives,Martin said.

“The fuel cell allows hydrogen to react within it and makeselectricity rather than heat,” he said. “This is known as athermochemical reaction.”

Both researchers’ work is funded by the U.S. Department ofEnergy through the hydrogen program. This program has recentlybecome important because of the United States’ interest in reducingthe amount of pollutants released into the air by vehicles.

By the third year of working on the research separately, the ISUresearchers were finally able to work together on production andusage of hydrogen, Martin said.

Hydrogen gas is a good fuel because it can go through a fuelcell without combustion, said Shihwu Sung, associate professor ofcivil, construction and environmental engineering. In combustion,the reaction loses a lot of energy.

“The use of hydrogen gas is more efficient,” Sung said.

Hydrogen is a clean fuel because it produces water as abyproduct of the reaction. Petroleum and other fossil fuels,however, release carbon monoxide and other pollutants directly intothe air, Sung said.

“Nature has determined that switchgrass is the most suitableplant to grow in this part of the country,” Brown said. “But, untilnow, there hasn’t been a market for it.”