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August 10, 2009

Green Gasoline

Carbon neutral gasoline ... from plants!

Like everyone else, George Huber knows money doesn't grow on trees. But, ask him where gasoline comes from and he won't just tell you, he'll show you.

To fully understand, Science Nation recently went with Huber to a local lumber yard in Amherst, Mass. A lumber yard is the perfect place to find cellulose, the key building block in plant cells and the organic material that gives plants their structure. So what does cellulose have to do with gasoline? A lot!

"Nature has made this material to be very strong. That's why we can build houses from materials that are made of cellulose," says Huber.

Huber finds all the cellulose he needs in a pile of discarded wood chips near the back of the lumber yard. He collects a few handfuls in a plastic bag.

Where one might just see a tall pile of wood chips, Huber sees something else--stored energy, and plenty of it. "Cellulose is basically stored solar energy that's found in all plant material," he tells us.

Cheap and abundant

With the help of the National Science Foundation (NSF), Huber has been working to unlock the solar energy that's stored in cellulose. Recently, he received additional NSF funding through the American Recovery and Reinvestment Act (ARRA) of 2009, which he says will allow his team to continue developing new processes that can economically produce renewable gasoline and diesel fuels from domestically produced non-food biomass resources.

"These are the first steps towards ending our nation's dependence on foreign oil and moving towards a sustainable economy," Huber explains. "Cellulose happens to be the most common organic compound on Earth. Look at the abundance of it. Our biomass in the U.S. has the energy content of 60 percent of the petroleum we use in this country, so it's both cheap and abundant."

As petroleum oil becomes less cheap and less abundant, our dependence on it poses a danger, not only to our national security, but to our environmental security as well. Finding an alternative to oil is critical.

And that brings us back to Huber and what he found earlier at the lumber yard--woodchips that are loaded with cellulose and the energy stored in that cellulose. He's taking the woodchips to a lab just a few miles away at the University of Massachusetts in Amherst. That's where Huber, along with a team of dedicated researchers, has figured out how to make gasoline from cellulose.

Huber puts the sawdust he collected at the lumber yard into a hopper. The wood is superheated to a vapor state, and the vapor is then injected into a reactor. Inside the reactor is a catalyst. It's a powder that interacts with the superheated vapor.

"Leaving the reactor is a gaseous stream that contains our green gasoline," he explains. "We use a series of these condensers to collect our product, and if we look in one of our condensers, we'll see our product that we're making."

The liquid then cools and settles into a test tube. Huber removes the test tube and holds it up in front of him and, with a proud grin on his face, he proclaims, "And right here is our product that we're making--the green gasoline."

A zero carbon footprint

Production and use of this 'green gasoline' leaves a zero carbon footprint. The carbon dioxide (CO2) our engines will release from green gasoline comes from the plants used to make the fuel. "The CO2 is recycled to the plant when the plant re-grows. It's all one big lifecycle," says Huber.

"The beauty of green gasoline is you don't need to change the existing infrastructure. We're going to make the same gasoline from biomass that you make from petroleum oil, gasoline, and diesel fuel, home heating oil, jet fuel and chemicals. So anything you can make from crude oil, we believe, in the next 10 to 20 years, you'll be making from biomass."

That can also include the biomass that often ends up in landfills, such as plant stems, bark, waste wood, and even discarded paper. Huber predicts a bright future for making fuels from cellulose when "you're going to see these large switch grass farms or you'll see farms that grow corn, and you convert the corn kernels for food and then the stalks you covert to biofuels."

Beyond lab-scale quantities

So far, Huber has created biofuels in lab-scale quantities. On average, each lab run produces just a few ounces at a time.

He's working on creating biofuels on a much larger scale. His next step is to make a reactor that can produce as much as a few tons a day. And, beyond that, Huber envisions a day when green gas is the norm.

"(People) are going to pull up to the gas station, they're going to put green gas in their car, and they're not even going to know they are putting green gas in their car."

The research in this episode was funded by NSF through the American Recovery and Reinvestment Act of 2009.

Miles O'Brien, Science Nation Correspondent
Jon Baime, Science Nation Producer

Any opinions, findings, conclusions or recommendations presented in this material are only those of the presenter grantee/researcher, author, or agency employee; and do not necessarily reflect the views of the National Science Foundation.