Going Against the Grain: Ethanol from Lignocellulosics

The urgency of the quest to produce fuel from woody and other plant wastes has been heightened by the ‘food versus fuel’ debate. Technologies for processing plant matter into usable fuels are evolving. Pilot labs are racing to perfect chemical techniques and produce the ultimate new, second-generation biofuel. Will it work at large scale? And what will it cost? Jeff Decker reports.

While leaps in ethanol conversion technologies and techniques have attracted serious investment, those wells are now running dry. Funding has followed the ‘food versus fuel’ debate and now favours lignocellulosic feedstocks, which have few other uses. An array of pilot plants steadily perfecting conversion into cellulosic ethanol will soon be joined by the first large-scale commercial facilities.

The impact on fossil fuel dependence and carbon dioxide emissions will potentially be significant. For instance, in the United States, the Department of Energy’s (DOE) Argonne National Laboratory estimates that cellulosic ethanol production consumes as little as 10% of the fossil energy needed to produce conventional gasoline, and has the potential to reduce greenhouse gas emissions by more than 86%.

As attractive as that is, cellulosic ethanol is not right around the corner just yet. For example, Range Fuels is building the largest commercial plant in the USA in Soperton, Georgia, but recently pushed back both the completion date and production targets. The site, already under construction, was to produce 76 million litres per year (Ml/y) by the end of 2009, but now aims for 38 Ml/y by 2010 before ramping up to 378 Ml/y.

Nonetheless, even as other plans are suspended or scaled back, a series of major projects are on track. Range’s rival in size across the globe is the China Resources Alcohol Corporation, which means to generate 1.24 billion litres per year by 2012 from corn stalks and leaves. Bluefire Ethanol Fuels might win the race to be first in the US, if it starts producing 72 Ml/y near Los Angeles before 2010. Meanwhile, Mascoma Corporation intends to produce 151 Ml/y in Michigan by early 2011.

Formerly known as Broin, Poet is also nearing completion of a $4 million pilot-scale cellulosic ethanol facility in Scotland, South Dakota. In Emmetsburg, Iowa, 95 Ml/y of ethanol will be made from corn cobs alongside 378 Ml/y from corn starting in 2011. The Iowa plans were awarded US$80 million from the DOE and $20 million from the state of Iowa.

In addition to its 19 Ml/y target pilot plant in Spain, Abengoa is using a $76 million DOE grant to produce 42 Ml/y in the United States (Hugoton, Kansas), from wheat straw by 2010, that could ramp up to 185 Ml/y. The biomass plant will be situated next to a conventional cereal-to-ethanol facility to share feedstocks. (The edible cuts go into one part and the stalks and leaves go into the other.) The investment of both will exceed $300 million. By 2012 Abengoa plans to invest more than $500 million on research and development into cellulose ethanol production

Technologies and techniques

Second-generation technologies are still new and evolving, and so far there’s no consensus on the best process.

Cellulose and hemicellulose, along with lignin, combine to make lignocellulose, which gives plants their durable structure. Lignin is a complex polymer found in all the cell walls of woody plants. This lignin must be separated – physically or chemically – to open the cellulose to hydrolysis. It’s also the world’s most abundant aromatic, and an extremely durable compound.

Different labs are working on different angles to separate the lignin and then to break the long sugar chains of the cellulose into manageable shorter chains. That process almost always uses biochemical or thermo-chemical processes, or both. The first uses enzymes to break down the matter before fermenting it, while the second uses gasification and carbohydrate-reforming.

While the types of plant wastes that can be used as cellulosic feedstocks are cheaper than their edible predecessors, the 5- and 6-carbon sugars in both cellulose and hemicellulose are tougher and more expensive to break down – a process as much as three times more expensive when capital costs are factored in.

So far, no-one has proven a way to break down those cheaper feedstocks and ferment the cellulose and hemicellulose affordably enough to offset the capital investment.

‘There are a number of ongoing technological advances that are still emerging,’ says Matt Carr, policy director of the Biotechnology Industry Organization in the US. ‘One of the things that’s most challenging about cellulosic ethanol conversion is there are so many steps in the process you need to pre-prep the biomass to make it easier for the enzymes to get at. Then you need the enzymes to break down the material into cellulose and sugars, and you need the microbes to ferment the sugars – and sometimes you need a whole range of microbes because there are different types of sugars.’

One trick being sought is a wonder-microbe that can handle several steps of that process.

‘A microbe that can do it all – take the biomass and start chewing on it and ferment it and create the fuel all in one place,’ explains Carr. Once that’s perfected, he predicts, ‘We’ll see the cost of the biorefineries come down.’

Already these innovations are being applied to other processes that would make fuels chemically identical to petroleum. ‘We already have microbes in nature that make ethanol,’ Carr says, ‘There aren’t so many microbes in nature that make these more sophisticated energy supplies.’

Nonetheless, ethanol will maintain its prominent place for decades if it stays affordable. Co-ordinating research toward that end, New Improvements for Ligno-Cellulosic Ethanol (NILE) is keeping 21 private and public partners around the world on the same page. ‘The next big step will be the demonstration of a cost-effective and sustainable process opening the way to commercialization of second-generation biofuels,’ states NILE project manager Frédéric Monot. ‘There are already private investors in this field, showing they trust in the success of the conversion of ligno-cellulosic biomass’, he says, though he adds that government grants are also essential. NILE is co-funded by the European Commission under the Sixth Framework Programme. ‘There are also incentives and financial supports in the EU for new demonstration plants including thermo-chemical conversion and biorefineries’, though, ‘Regarding ethanol from lignocellulosic biomass, the grants from the US DOE are much larger’, says Monot.

Professor Ed Bayer of the Weizmann Institute for Science, a NILE partner in Israel, cautions: ‘The real question is how much funding reaches (or will reach) the scientists who actually study processes which lead to bioethanol production. This problem is not only confined to Israel.’

In China, for instance, a whopping $5 billion commitment to ethanol is focused on cellulosic feedstocks, with China’s government forbidding new ethanol facilities that would tap the food supply.

In the US, the DOE allocated more than $1 billion toward cellulosic ethanol projects in 2007, hoping to see $5.03 per (US) gallon ($1.33 per litre) by 2012. This year, 2008, the DOE could spend $2 billion. The wide-ranging farm bill passed in June 2008 suggests mandated production of nearly 76 billion litres per year of cellulosic ethanol by 2017. It also allows for loan guarantees of up to $250 million for building commercial-scale biorefineries to produce advanced biofuels. Perhaps the greatest incentive is a tax credit of $3.82 per gallon ($1.01 per litre) that applies only to fuel produced and used in the United States.

Australia is also providing matching grants, ranging from A$1 to A$5 million (US$0.7-$3.5 million), for eligible projects involving the production of second generation biofuels in a sustainable manner. A$15 million (US$10.3 million) will be delivered between 2009 and 2012. The first recipient planning to produce cellulosic ethanol there is Ethtec (Ethanol Technologies Limited), which is building a A$20 million (US$14 million) pilot plant in New South Wales that will use wood residues (including pine), bagasse and other lignocellulosic materials as feedstock.

Meanwhile, the Danish government has given $15 million in grants to support a $62.8 million pilot facility being built in Kalundborg by Dong Energy, Denmark’s largest energy company. Construction began in September (2008) and could be complete by the time of the Climate Change Conference in Copenhagen in November 2009. Waste heat from the neighbouring power plant will help break down the wheat straw source material.

Enzymes and plant species

Dong Energy is looking to a company called Novozymes to supply specialized enzymes to break down wheat straw. Enhancing the traits of the fungus known as Tricoderma reesei, the firm has selected 30 acres (12 ha) in Blair, Nebraska, to produce enzymes for corn-based ethanol conversion and then for cellulosic ethanol production. They’re breaking ground this year and expect to invest up to $100 million by the time operations begin in 2010. And in October this year, Novozymes was awarded a $12.3 million, 2.5 year contract from the US DOE to improve the enzymes necessary to produce cellulosic ethanol. Novozymes’ project DECREASE (Development of a Commercial-Ready Enzyme Application System for Ethanol) aims to improve the performance of Novozymes’ most advanced enzyme system, to further reduce the cost of cellulosic ethanol production.

The DSM Innovation Center and Genencor are among the labs speeding up evolution to secrete the most efficient enzymes they can find. DuPont is in a joint venture with Genencor and the University of Tennessee Research Foundation to build pilot facilities to test enzymes, including one in Vonore, Tennessee. It could produce ethanol in 2009 by converting switchgrass and corn stover with an alkaline pretreatment and enzymes, and then use a proprietary biocatalyst to convert the sugars into ethanol.

Since its launch in August 2007, Butalco GmbH has continued development of its genetically optimized yeast strains to increase yields in ethanol and biobutanol production. The Zug, Switzerland-based company is exploring new partnerships and refining its process with financial help from Volkswind of Germany.

SunEthanol calls its discovery the Q Microbe – and it might pull double duty and save time and money over the traditional two-step conversion process. By August 2008 the microbe had exhibited a 20-fold increase in efficiency since the beginning of the year.

‘The Q Microbe has exhibited great versatility in converting a wide variety of non-food biomass feedstocks to ethanol,’ says Dr Susan Leschine, professor of microbiology at the University of Massachusetts, Amherst, and discoverer of the microbe.

Along with a $750,000 grant to SunEthanol, the DOE funded screening trials of potential energy crops that can be used as feedstocks for cellulosic ethanol production. These trials included 34 species on a wide range of soil types in 31 different sites. The tests pointed to switchgrass as a top priority for further development.

Sorghum, leftovers from agriculture and forest operations, corn stover, hybrid poplar and hybrid willow are all also being used. Even grass clippings and orange peels are in the mix.

Miscanthus is a top pick of Dr El Nassir Bassam, director of the International Research Centre for Renewable Energy (IFEED) in Germany. For now the price of petroleum is too low for markets to favour cellulosic ethanol, states Bassam, but forward-looking politicians could shift the taxes that build an artificial oil price and throw support behind green technology.

Breakthroughs in genetics open doors that were recently closed, Bassam adds. Mark Emalfarb, CEO of Dyadic International, agrees. He sends gratitude to the genome projects that give companies like his detailed problems to solve. ‘In modern biology we upgrade the genes we want and downgrade the genes we don’t want, to isolate the glucose and to allow us to secrete these enzymes.’

His Florida-based company is marketing C1, a micro-organism found on a forest floor in Russia. ‘You can take what nature spent a billion years on and try to make it more efficient and better,’ says Emalfarb. ‘When we found this thing in nature it was making maybe half a gram per year of enzymes. So now we have our C1 that can produce 100 grams per year.’ One big contribution is breaking filamentous material into shorter-chain sugars which improves viscosity.

Worldwide research and production

C1, or the next version of it, will be working in Babilafuente, Spain, at the pilot plant of Abengoa New Technologies. The two companies are in a research and development agreement as Abengoa prepares to produce 19 Ml/y from wheat and barley straw by the end of 2008.

SunOpta Bioprocesses of Brampton, Ontario, provided the pre-treatment process, and also licensed its conversion technology to the China Resources Alcohol Corporation. Their goal is the most ambitious in the world, seeking to generate 1250 Ml3 of cellulosic ethanol by 2012.

Conditions in Brazil still favour sugarcane feedstocks, but within five years the Sugar Cane Technology Centre could develop an efficient process for other parts of the plant left after ethanol and sugar production. The centre is already running a pilot facility and the state-owned energy company Petrobras is supporting it.

The sugar and ethanol co-operative Copersucar is supporting Dedini S/A Indústrias de Base’s pilot plant called the DHR project, for Dedini Rapid Hydrolysis. The plant in Pirassununga, Sao Paulo state, could produce 1.81 million litres. The process separates C5 and C6 sugar molecules from lignin using an acid wash.

In France, the oil and gas heavyweight Total is supporting Futurol, a $104 million, eight-year project that aims to collect the best coming from French research groups, manufacturers and financial institutions.

Royal Dutch Shell is expanding its ethanol research and in July 2008 increased its shareholding in Iogen Energy Corporation to 50%. That commercial deal between Shell and Iogen of Canada led to the September 2008 delivery of the first 100,000 litres of an initial 180,000 litre cellulosic ethanol order from Shell. The ethanol is made from agriculture residues such as cereal straw and corn cobs and stalks. Wheat, oat and barley straw are the raw materials at Iogen’s Saskatchewan pilot plant, and they hope to produce 87 Ml/y north of Saskatoon, Canada, by 2011. However, their plan to build a 68 Ml/y plant in Shelley, Idaho has been suspended, as have the 53 Ml/y ambitions of land management company Alico.

The partnership between Canada’s largest ethanol producer, Greenfield Ethanol, and SunOpta to produce 151 Ml/y by 2008 has long since dissolved, but in summer 2008, Greenfield and Enerkem – a gasification and catalysis technology company – partnered to build an industrial-scale facility converting ethanol from municipal solid waste by the end of 2010. The $70 million plant will be built in Edmonton, Alberta, and produce 34 Ml/y. ‘This is the world’s first agreement signed between a large urban centre and a biofuel producer to turn municipal waste into ethanol’, says Vincent Chornet, president and CEO of Enerkem.

In Burnaby, Canada, Lignol Innovations has found ways to profit from the lignin they separate from wood to make ethanol. The tough lignin ends up in motor fuel and foundry binders, among other products. ‘Our lignin is of such a high quality it’s too valuable to just burn’, explains Paul Hughes, vice president of corporate development. ‘Having less lignin is important in a number of ways. It reduces the overall cost of producing the ethanol, and secondly it reduces the greenhouse gasses and then the offset.’

Colusa Biomass Energy Corporation also markets lignin. The California company will convert 132,000 tonnes of waste rice straw and hulls annually, producing 47 Ml/y of ethanol and ramping up to 76 Ml/y.

The Lignol Innovations pilot plant outside Vancouver will be running this winter with support from the Canadian government. Plus $30 million from the US DOE is helping build an $88 million demonstration plant in Grand Junction, Colorado.

If the price is right

The need for biofuel production to be sustainable is clearer than ever, and the long wait for lignocellulosic ethanol could almost be over – provided the price is right. As Bill Roe, president and CEO of Coskata said of his company’s new demonstration plant: ‘It will be a significant demonstration, before building our first commercial plant, that we can produce ethanol from non-food based sources for less than $1 a gallon,’ (approximately £0.22 per litre).

When that price is reached, commercial production of cellulosic ethanol will be widespread, with the initial risks and challenges a fading memory.

Jeff Decker is a freelance writer from the US, specializing in biofuels, renewable energy and aviation.
e-mail: rew@pennwell.com

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