When POET planned to build their cellulosic ethanol plant, Project LIBERTY, next to their existing refinery, POET Biorefining – Emmetsburg, they knew it made good economic sense.
The roads and power lines were already in place. POET already had 700 or so farmers delivering their grain to POET Biorefining – Emmetsburg, and those same farmers could come to the same site and bring corn cobs and crop residue from those very same fields.
They knew that the byproduct of the cellulosic ethanol process, lignin, would make an excellent fuel for an alternative energy system. This waste product from the cellulosic ethanol plant, they figured, could be turned into a biogas, mostly methane, which could then be used to power the facility.
“We knew it would be a good fit,” says Jim Sturdevant, Director of Project LIBERTY, the Emmetsburg, Iowa facility that is slated to begin production in 2012 and produce 25 million gallons of cellulosic ethanol per year. “It just seemed like common sense.”
And a recent study has shown that the co-location of the two biorefineries makes outstanding environmental sense as well.
Field to Wheels
The independent study, a life cycle analysis of Project LIBERTY performed by Air Improvement Resource, tracked the carbon emissions associated with creating and burning a gallon of cellulosic ethanol versus creating and burning a gallon of gasoline.
This “field to wheels” analysis determined that Project LIBERTY will reduce carbon emissions by 111 percent over gasoline. That means that Project LIBERTY will actually offset more greenhouse gases than it produces.
“POET has simply done the right things and, because of that, they’ve gotten good results,” says Tom Darlington, President of Air Improvement Resource. “You don’t build the number of plants that they have built and operate and manage them at this cost structure without knowing what you’re doing. They’re obviously a technological leader in this whole area, and it’s paid off on the environmental side as well.”
And while Sturdevant knew that the Project LIBERTY plant would fare well against any fossil fuel facility, the final number surprised even him.
“We suspected that our greenhouse gas emissions would be very good compared to gasoline,” Sturdevant says. “We suspected we’d easily make the 60 percent reduction required by the government. Did we think that it would be a reduction of over 100 percent? Probably not.”
The factors in the Project LIBERTY study included everything associated with the biomass process–harvesting the cobs and crop residue, transporting it, storing it, converting the biomass into ethanol, producing the coproducts (like biogas), and storing and transporting the ethanol.
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In addition to these numbers, the researchers also had to plug in certain values, some of which have been questioned by POET, as determined by the Environmental Protection Agency’s Renewable Fuel Standard (RFS2) (see “Adapting the Standard”, Vital, Summer 2010).
“We’ve met the RFS2 requirements,” Sturdevant says. “In order to achieve the LIBERTY emissions number, we had to plug LIBERTY inputs and some general EPA –provided inputs into the EPA model. We followed their rules and we still came up with a negative emissions number.”
“I’ve never seen a process like this with negative emissions,” says George Wolff, Principal Scientist for Air Improvement Resource. “The key here that makes the emissions negative is that they’re taking a byproduct produced in the process–biogas–and using some of that power to replace the natural gas used in the co-located and corn-based ethanol plant. The way they convert the waste product to a biogas is very smart. It’s an engineering masterpiece.”
Converting the Biogas
While the lignin-to-biogas conversion process is a complicated combination of ideal temperatures, PH balances, and nutrients, it all comes down to “keeping our anaerobes as happy as possible,” says Dr. Jason Bootsma, Senior Development Engineer at POET. “If we give the anaerobes what they want, they give us a burnable biogas and we don’t have to do a lot of extra processing.”
Those anaerobes, micro-organisms that break down biodegradable material and turn it into biogas, will be the key behind eliminating the need for natural gas at Project LIBERTY while significantly reducing the need for the natural gas at the adjacent corn plant as well.
“We’ll simply take the residual from the ethanol process and put it in an anaerobic digester,” Bootsma says. “We’re harnessing a natural process of breaking down sugars and fats and carbohydrates and other materials into biogas. Biogas is primarily methane, 60 to 70 percent methane, which we’ll use to power the facility. The cellulosic plant generates more biogas than it needs to operate, so it will effectively sell some of that biogas to the adjacent grain to ethanol facility, and then the other plant will use less natural gas.”
By the end of the process, virtually all of the biomass brought into Project LIBERTY will be converted into something useful.
“The biogas will power the Project LIBERTY plant and power the adjacent corn-based plant,” says Sturdevant. “From an environmental or life cycle analysis perspective, you can look at the whole complex. Here you have in one site, a 50-million-gallon-per-year corn-based plant sitting right next to a 25-million-gallon-per-year cellulosic plant. And when you look at them collectively as a single biorefinery, because that biogas can be used by both, you are significantly reducing the emissions of both. The entire complex can be viewed as a clean, green biorefinery with extremely low greenhouse gas emissions when compared to gasoline.”
Even the main waste product of the biogas process, a relatively clean water, is recycled in the process. And the other waste product often associated with anaerobic digestion–the smell–will also be refined.
“One of the nice things about the biorefinery is that it’s enclosed–it has to be enclosed to capture the gas, and then you don’t have to worry about odors,” Bootsma says. “When some people think of anaerobic digestion, they think of hog facilities and the smells there. While there is anaerobic digestion going on there, it’s just not controlled. Here we’ll be capturing the gas and controlling it.”
According to Bootsma, the synergy–and simplicity–of co-locating the two plants is one of those technological breakthroughs brought on by sticking to the basics.
“It’s such a natural combination to add an alternative energy process to the cellulosic ethanol process–it’s just one of those simple ideas that turns out to be right for all the right reasons,” he says. “POET is at the cutting edge of this type of synergy, and it’s driven by using common sense.”
New industry
It’s that common sense, from-the-ground-up approach that continues to put POET at the forefront of what is essentially a new industry–the first commercial-scale harvest of corn cobs and crop residue for cellulosic ethanol.
“Feedstock collection represents what is potentially a huge shift in agriculture that we haven’t seen in a long time,” says Chad Schell, Project Officer with the Department of Energy, which has committed $100 million to Project LIBERTY. “Look at the traditional corn ethanol industry and how far it has come since its inception. For example increases in efficiencies that have been made are substantial. We often compare ethanol to the oil industry. The oil industry’s had a 100-year head start, so ethanol’s got a lot of catching up to do in terms of process efficiency, but they’re catching up fast.
Like with any new industry, though, it is those involved at the ground level that, out of economic necessity, move the technology forward.
In recent years, one of the few ways a farmer could make more money, it seemed, was by buying more land,” says Sturdevant. “Now, farmers can make more money without buying more land. They just need to tweak their harvest practices a bit and they can get $45 to $55 per ton for corn crop residue that’s currently going to waste.”
And it’s the farmers who continue to drive the technology forward. More than 85 Emmetsburg area farmers signed on to harvest biomass for Project LIBERTY in the fall of 2010. POET had to turn away many others.
“These 85 farmers are the innovators, the first-movers,” says Sturdevant. “This fall, they are going to harvest 56,000 tons of biomass and bring it to the plant and drop it off just like they will when the plant is up and running in 2012. We’ll learn a lot from this process, and we also know the farmers will teach us a lot about even more efficient ways to collect and transport and store the biomass.”
For Sturdevant, those 85 farmers represent the future of the cellulosic ethanol industry. “The farmers are the ones who understand whether this process will work or not,” he says. “And they’re the ones saying ‘Hey, this is real. This is going to work, so let’s get involved.’ They understand first-hand that it’s a way to make more money, and they know that it’s going to get even better as we move forward.”
Moving forward
“This is an exciting time in cellulosic ethanol,” says the DOE’s Chad Schell. “We’re looking at a potential new industry that could have a great positive economic impact on this country. You look at the job creation and the fact that we won’t be sending money to other countries for fuel. It’s a great thing.”
Schell understands that every step in the process is a step forward for the future of cellulosic ethanol.
“Any time you have a new industry, there are always lots of improvements to be made,” Schell says. “It’s new technology, so there will be some growing pains and some learning that needs to take place to optimize the process and get it running properly. This first plant will probably look a lot different from the second and the third and the fourth. It will take a few iterations to get the best design, but Project LIBERTY has made great progress, and keeps moving forward.”
For POET CEO Jeff Broin, the recent life cycle analysis of Project LIBERTY reinforces the reasons to keep moving forward on all fronts.
“Our process that produces 25 million gallons of clean transportation fuel annually for our nation’s vehicles will be greenhouse gas negative,” Broin told the Fuel Ethanol Workshop in June. “This is an opportunity to create jobs in any state, and clearly the environmental implications are tremendous.”
POET, though, can’t do it alone, Broin stressed.
“If our nation is serious about decreasing our reliance on foreign sources of energy, cleaning up our environment and creating American jobs, strong policies will be needed,” he said. “Department of Energy loan guarantees for the first cellulosic plants, such as Project LIBERTY, are crucial. Under the right political environment, POET and our industry will continue our quest to significantly reduce fossil energy use and make ethanol the competitor that has long been sought for gasoline.”
Proving the Points
POET’s common sense, keep-it-simple approach continues to generate the greatest results. Sure, the scientific studies – with statistics like a “111 percent reduction in greenhouse gases” – prove the points, but it’s that in-the-field experience and attention to detail that drive those original decisions.
“All of the little things we do add up to make everything better,” says Sturdevant. “We’re always looking at every step along the line. We know we will get better at anaerobic digestion and creating more biogas. We know the farmers will get more efficient at harvesting the biomass. We know the equipment manufacturers will keep making even better harvesting equipment. We know we will get more efficient at the transportation and packaging.”
“We work hard to do what we know is right in the first place,” he says. “When the studies show that we’re going in the right direction, it just reinforces the fact that we’ve worked hard to make that process more efficient. We’re doing something that’s never been done before, so we get great input from the farmers and the equipment manufacturers and the scientists. Then we just try to apply common sense on a large scale.”
How does POET make cellulosic ethanol? Visit, projectliberty.com to view POET’s “How to make cellulosic ethanol” video.
YouTube: "How to make cellulosic ethanol"
