Will green gas fuel the future?

Testing lab
Pilot refineries, each the size of a couple of refrigerators, fill this research facility in Madison, Wisc. They produce biogas from various forms of cane sugar at Virent Energy Systems.
Photo courtesy of Virent

Today, the alternative fuel of choice in the U.S. is ethanol. It's made by fermenting sugars to create alcohol.

"One of the beauties of (our gas, is) it goes right in your tank. We know if we can make it at volume we can sell it right in the current infrastructure."

The problem is that only simple sugar, like that found in kernels of corn, can be fermented. The more complex sugars, like those in corn stalks or switch grass, isn't easily fermented.

It's a challenge that has delayed development of cellulosic ethanol derived from corn stalks or switch grass.

But what if you could take corn stalks or sugar, and create high-octane gasoline for $2.00 a gallon?

"Right now we're making about a half gallon a day of gasoline from sugar," said Virent Energy Systems co-founder Randy Cortright. "We're working on design of a plant (where) we can do 25 gallons a day."

Cortright stands next to what looks like a high- tech still that's about the size of two refrigerators. It's one of 20 small biorefineries in this large, spare room.

Randy Cortright
Virent founder Randy Cortright says biogas contains more energy-per-gallon than the corn-based alternative ethanol. The new green gas also takes less energy to make than ethanol.
Photo courtesy of Virent

The technology is a spin-off from research done at the University of Wisconsin - Madison.

The small biorefinery is a complex piece of machinery, but essentially it works this way; sugar water goes in one end and gasoline comes out the other. The secret is a patented inorganic catalyst material that triggers a chemical reaction.

Consider how the oil pumped from underground was created. Plants were buried under dirt and then over millions of years, the sugars in those plants changed. The oxygen was forced out of its molecular structure, leaving behind hydrocarbons, or crude oil.

Green gas is created with a similar chemical process, but much faster.

"We take these sugars; we make a sugar-water solution," said Cortright. "We run it over a catalytic reactor, reacting out the oxygen as either carbon dioxide or water. What we end up having are molecules that are made up of carbon and hydrogen and that's what your standard gasoline has in it. What took millions of years by nature, we're doing in a matter of minutes."

This technology isn't new. For 50 years catalysts have been used to change crude oil into gasoline, other fuels and chemicals. But using a catalyst is a new approach to creating fuel from biomass.

Virent uses a catalyst process to change sugar from plants into gasoline.
Courtesy Virent

Virent perfected the process over the past three years. The company began by using catalyst technology to make hydrogen from biomass. They quickly discovered the process could be adjusted to make gasoline, diesel fuel, jet fuel or a variety of chemicals.

The challenge now is making it work on a large scale. A biorefinery will need lots of cheap, easily available biomass and building the first large scale biogasoline refinery will pose some engineering challenges.

Virent intends to build the first commercial scale plant within five years.

Green gas is the next generation of biomass fuels, according to John Regalbuto, head of the Catalysis and Bio-Catalysis Program at the National Science Foundation.

He says green gasoline represents a significant advance over ethanol. It can be produced from cellulose, like corn stalks or switch grass, and it's a familiar fuel.

"It's gasoline instead of ethanol. It's a drop-in replacement," said Regalbuto. "It fits into the existing infrastructure so there will be no need for engine modifications, no need for ethanol pipelines which are very expensive. Perhaps it's too rosy a picture, but I see cellulosic gasoline as being the real success."

Regalbuto says green gasoline is gaining support among government agencies and private industry.

Pilot refinery
Virent uses technology similar to that found in a petroleum refinery to change sugar derived from plants into a high-octane gasoline.
Photo courtesy of Virent

Wisconsin-based Virent recently signed partnership agreements with Royal Dutch Shell, Cargill and Honda.

Company President and CEO Eric Apfelbach, says the company will qualify for tax credits of $1.00 a gallon for making biofuel. But he says the company is not counting on that subsidy and he argues, green gasoline will replace ethanol as a primary alternative fuel

"You can't really protect an old technology with policy and laws and mandates," said Apfelbach. "Fuels are a global business. So if the U.S. wants to protect corn ethanol from now to forever, our process will get expanded in other countries."

Apfelbach says Virent will likely build its first plant in Brazil or the Caribbean where sugar cane is cheap and plentiful.

He says biogasoline can be made from a variety of sources. He predicts plants that will use wood waste, switch grass or crops grown specifically for biofuel.

For example, researchers are using genetic manipulation to double the sugar content of sugar beets. But Apfelbach believes alternative fuels should not be made from food crops like corn.

Eric Apfelbach
Eric Apfelbach says having Shell, Honda and Cargill as partners gives his company an edge in the race to bring a new alternative fuel to the market.
Photo courtesy of Virent

Green gas still faces the challenge of moving from a laboratory setting to production of millions of gallons a year. Experts say the technology is proven, the fledgling industry now needs to prove the economics of large scale production.

Virent CEO Eric Apfelbach says the pace of change is rapidly accelerating as companies race to bring the next green fuel to market.

"Like every other technology development, there's going to be dead bodies along the side of the road that don't work," said Apfelbach. "It's just the way it works. We're trying to be one of the survivors and not one of the dead bodies."

Apfelbach says regardless of which companies and technologies survive, one thing is clear. The alternative fuels landscape will change dramatically over the next five years.