It's the holy grail of renewable-energy research: a liquid fuel that can be harvested sustainably, burned cleanly, and doesn't come from an unstable part of the world.
And maybe, just maybe, it will be manufactured at a plant near you.
The fuel in question is ethanol. Specifically, cellulosic ethanol. Ethanol is an alcohol made from fermenting sugar that can be burned as a fuel in internal combustion engines.
To make traditional ethanol, from corn, requires a lot of fossil fuel. Enough that the energy output from the resulting ethanol isn't a lot more than the energy needed to make it. According to some scientists, traditional ethanol may actually produce less energy than it takes to make it.
Cellulosic ethanol is different. Instead of using the sugars that naturally occur in corn, makers of cellulosic ethanol create those sugars. They do that by using enzymes to convert cellulose --- tough fibers that make up a large portion of organic matter --- into the sugars.
Once it's broken down, the sugar made from cellulose can be fermented in much the same way corn starch is. This means that cellulosic ethanol is actually a bit more complicated to make than traditional ethanol. But that's offset by the fact that cellulose is much more widely available than corn starch. Just about any plant is made of the stuff. Corn has to be planted, cultivated, fertilized, and harvested. It takes up a lot of land, causes erosion, and requires plenty of fossil energy to be burned as fuel or used as fertilizer at each step.
On the other hand, switchgrass, for example, only has to be harvested. Wood chips, a byproduct of the forest industry, might be even easier to come by, depending on where you're located.
In December, in one of his last acts as governor, George Pataki announced state funding for an ethanol demonstration plant to be built in Greece. New YorkState is kicking in $14.8 million for the plant, which will produce half a million gallons of cellulosic ethanol a year. The partners involved in the plant are matching that money. Mascoma, the lead company, is contributing most of it. Other partners include Genencor, a biotech company with a presence in Rochester; CornellUniversity; ClarksonUniversity, and Khosla Ventures, a venture-capital company founded by Sun Microsystems co-founder Vinod Khosla (an ardent proponent of ethanol and frequent backer of ethanol-related companies).
"What we hope the demonstration leads to is a commercial facility, says Larry Bouchie, a spokesperson for Mascoma. While this pilot plant might produce up to 500,000 gallons a year, the goal is a plant that produces millions. This plant is simply a halfway point between the lab and that goal.
"Mascoma is trying to move very quickly from an R and D company" to a production company, Bouchie says. "We're trying to fast-track this out of academia."
Right now, Mascoma is working on turning its research into processes that can reproduce what happens in a lab on an industrial scale. If that can't be done efficiently, the technology won't be worth much in the long run. One of the ways of accomplishing that is by streamlining things.
"We're trying to reduce the number of steps involved," says Bouchie. "We're hoping to use one or two enzymes to keep it at one or two steps." Whittling down the number of enzymes needed to complete the ethanol-making process will ultimately (if it succeeds) make it cheap and efficient enough to commercialize.
David Wu believes a one or two-enzyme "cocktail" to process ethanol is possible. Wu, a professor of biochemical engineering at the University of Rochester, has no connection with any of the players in the proposed Greece plant, but he's devoted his career to researching the same technology.
When the name Mascoma comes up, he beams in recognition. He's aware of their research, as they surely are of his. It's because of research like his that the Greece plant is a possibility. Wu, among others, helped map the genome of a bacteria species called Clostridium thermocellum. It's an anaerobic bacterium you might find growing in a compost pile. Its function in nature is decomposing organic matter --- exactly what ethanol makers need to do. And it's from this species that many of the most promising enzymes for cellulosic ethanol come.
Now Wu is working to pair different enzymes with the genes that trigger their production in the first place. If all goes according to plan, researchers should be able to genetically engineer a microorganism perfectly suited to the twin tasks of breaking down cellulose, then fermenting the resulting starches and sugars. Multiple microorganisms, actually.
Isolating the genes "would allow us to custom design a particular microorganism for a particular substrate," says Wu. (By substrate he means the substance being converted to ethanol.) In other words, you could engineer one strain of bacteria for switchgrass, another for wood chips, and still another for municipal waste. But that's easier said than done. Wu estimates that in nature, one dead tree could be decomposed by tens of thousands of different enzymes. Even in a controlled lab, and focusing only on his one species of Clostridium, at least a hundred different genes and about as many enzymes are related to the process of breaking down cellulose.
He and other researchers are closing in on the right enzyme cocktails or "super enzymes," but "there's room for improvement," he says. "In the next three to five years, people are going to see better enzymes."
Wu's interest in the field that would eventually become his life's work began in the 1970's, during the first energy crisis. But by the time he was finishing up his PhD at MIT in the mid 80's, oil prices had plummeted. The issue was off the public's radar and no longer in the forefront of the minds of many who funded research grants. Still, ever since the early 90's, Wu's Rochester lab has had a steady stream of funding from places like the Department of Energy, the US Department of Agriculture, and the National Renewable Energy Laboratory.
Now, it seems to him the situation has reached something of a full circle. "We're facing a similar problem to what we faced in the 70's," he says, in terms of ever-growing demands on the world's energy supply.
There are some differences this time around, though. There's more competition, he points out, especially from China's booming economy. And there's also a different ecological climate --- literally.
"In the 70's, we were not so aware of the greenhouse effect," he says. "Now we're going through it, in my opinion."
But according to Wu, not all the change since the first energy crisis has been bad.
"We now have the recombinant DNA technology we didn't have in the 70's," he says. Without that technology, his work isolating the genes that produce the best enzymes wouldn't have been possible.
"So the problems have become more severe, but our capability to tackle them has expanded," he says. "There's both challenge and promise."
Wu is clearly enthusiastic about the possibility of ethanol, particularly cellulosic ethanol, to play a key role in the energy supply of the future. In addition to his research, he's on the editorial board of Industrial Biology, for example, a journal that has put glowing stories about the fuel on several of its recent covers.
But not everyone is as bullish about the alcohol's potential.
Robert Bryce is the managing editor of Energy Tribune, an industry newsletter. He criticized a Pataki subsidy for a traditional ethanol plant in a City Newspaper article last spring, and his views aren't much different about the cellulosic variety.
"My opinion on cellulosic ethanol's pretty simple: Where's the beef?" he writes in an e-mail. "Everybody talks about cellulosic ethanol and how it will be wonderful, but the energy input numbers just don't work. They're talking about turning what is essentially hay into motor fuel. Sure. I'll believe it when I see it." And by "see it," Bryce clarifies in a subsequent conversation, he means on a commercial scale, and without government subsidies.
"No matter how much ethanol we produce," he says, "we're still going to be part of the global oil market. We cannot divorce ourselves from it."
Cornell Professor David Pimentel drew national attention in 2005 when he and a colleague published a study claiming that ethanol took more energy to produce than it contained. He shares Bryce's skepticism, if not his blunt approach.
"I must admit that I wish that it were true," says Pimentel, referring to the promises of ethanol's potential. "I still support all the research going on."
And while he seems to be interested in the kind of research Wu is doing, Pimentel is skeptical of ethanol, no matter how it's produced, as a way out of our energy crunch.
"I'm for the use of biomass in a reasonable way," he says. But then, to put that in perspective, he adds: "We already get 3 percent of energy from woody biomass." That's in the form of woodstoves, boilers that burn wood, and even a wood-fired electricity plant. At 3 percent, he says, woody biomass is already contributing the same percentage of energy as hydro power. The problem, then, isn't one of supply, but of demand run amok. Even if this nation made a seismic shift toward using biomass, like ethanol, as a primary energy source, that wouldn't slake our thirst for energy.
"We are burning twice as much fossil energy as all the plants in the US collect," he says. "We should be focusing on conservation."