Researchers at Iowa State are trying to find a way to turn prairie grass into hydrogen gas that can be used in new fuel-cell automobiles.

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

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

The researchers begin with switchgrass — a native prairie grass in Iowa.

The grass is referred to as a biomass, which is any organic material of recent biological origin. Using biomass as a source of energy is important because it produces a chemical rather than electrical reaction.

“There are no natural sources of hydrogen,” said Brown, “so we are 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 put into a reactor and heated, which causes it to release gases such as hydrogen, carbon monoxide and methane. The hydrogen gas is then targeted 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 with transportation as a fuel, but it can also be used as a stationary unit for heating homes or powering electricity in buildings, he said.

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

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

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

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

By the third year of working on the research separately, the ISU researchers were finally able to work together on production and usage of hydrogen, Martin said.

Hydrogen gas is a good fuel because it can go through a fuel cell without combustion, said Shihwu Sung, associate professor of civil, 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 a byproduct of the reaction. Petroleum and other fossil fuels, however, release carbon monoxide and other pollutants directly into the air, Sung said.

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