Table of ContentsScience Leads the Way
- Policy Reasons for Advanced Biofuels
- Technical ChallengesIf It's Such a Great Idea, Why Hasn't It Been Done Before?
- Generations 1, 2, 3 and 4: Talking about biofuels
- Making Advanced Biofuels: Biomass to Building Blocks; Building Blocks to Biofuels
- Energy Feedstocks.
- Energy Crops
- Waste and Residues
- Woody Biomass
- Sorted Municipal Solid Waste
- Overcoming Biomass Recalcitrance
- Biomass to Building Blocks
- Enzymatic Hydrolysis
- Ammonia Fiber Expansion
- Building Blocks to Biofuels (and other Biochemicals and Products)
- Mixed Alcohol Synthesis
- Packed Bed Catalytic Reactors
- Aqueous Phase Reforming (APR)
- Fulfilling the Promise of Advanced Biofuels: What Will It Take?
- More Technical Challenges
- Unique Financing Challenges (and, Everyone Wants to Be First to Be Second)
- Algae and Other Things That Grow in the Water
- Algae 101
- Bio-JetFuels, Focus of Military and Commerical Interests
- Sustainability Analysis
- Use of Biofuels
- Ethanol and Octane for Beginners (from Minnesota Bio-Fuels Association)
- Biofuels U
Science Leads the Way
Policy Reasons for Advanced BiofuelsDid you know there is a home-grown source of renewable fuel that has reduced our oil imports by 1.6 Million barrels/day? It's the 10% ethanol blend sold at gas stations near you, across the US. In addition, ethanol has reduced carbon dioxide emissions from 3-6% compared to 100% gasoline; and has replaced the cancer-causing additive MTBE (methyl tertiary butyl ether). We can - and must-do even better with advanced biofuels, that is, with liquid transportation fuels derived from low nutrient input/high per acre yield crops; agricultural, forestry, food processing or municipal waste; or other sustainable biomass feedstocks including algae and other aquatic species. Why? Because, according to the US Department of Energy's Energy Information Administration, pure electric vehicles will have miniscule market penetration until long after 2035; meaning that all vehicles in the US will require liquid transportation fuel for a long time into the future. READ MORE In addition, jets and other planes will continue to require liquid fuels. Advanced biofuels can provide a home-grown, low carbon lifecycle emissions sustainably produced fuel substitute for ground transportation and aviation. Key concepts are sustainability and low carbon emissions. The Renewable Fuels Standard of the Energy Independence and Security Act of 2007 definition includes these concepts with advanced biofuels having at least 50 percent less lifecycle greenhouse gas emissions when compared to gasoline produced in 2005.
Technical ChallengesIf it's such a great idea, why hasn't it been done before? There are two great technical challenges. One is biomass recalcitrance (that is, "digesting" or converting cellulosic biomass into sugars that can be converted to fuels). The bacteria in the guts of termites do this every day, much to our consternation. Fortunately for us, they do this slowly. If we want to make biofuels economically, we need to figure out how to speed up that process. Greenwire/New York Times' Paul Voosen wrote an easy-to-follow article on the history of work on biomass recalcitrance. The second challenge is the conundrum of biomass logistics: how can enough biomass be sustainably produced, stored and transported to a biorefinery that can make reasonably priced fuel and assure a fair price to the grower and others in the value chain? One solution looks forward to hundreds of small scale systems here and all over the world so that bulky biomass need not be transported far; and so that agricultural, forestry or food processing waste can be productively processed near where it is produced. Others look for initial processing of crops into intermediaries that can be transported economically as "green crude" to biorefineries or evolved petroleum refineries As Brent Erickson of the Biotechnology Industry Organization (BIO) said, "The key to the future of biofuels is biotechnology." Advanced biofuels, he explained, is at the cutting edge of technology. In the work being done in labs today we'll find the keys to enable us to take the processes of nature and apply them to creating green gasolines out of renewable resources.
Generations 1, 2, 3 and 4: Talking about biofuelsTo help people distinguish various biofuels, they are classified based on the type of feedstocks and technologies used to produce them. First generation biofuels are derived from food crops such as corn and soybeans. The fermentation technologies used to create ethanol are thousands of years old; transesterification processes for biodiesel production are also well established. These provide initial steps in our efforts to achieve energy security and to wean ourselves from fossil fuels. These are the ethanol and biodiesels you purchase or make in your garage or high school classes today. Concerns have been raised about using ethanol and biodiesel in engines that were not designed with their use in mind. With regard to caution that should be used when fueling with biodiesel, see the National Biodiesel Board's Guide to Buying Biodiesel which includes pages that briefly address issues related to possible violation of warranties when using biodiesel. Certainly, owners manuals should be consulted for recommended fuel use for specific vehicles. READ MORE You could say that the practice of using straight vegetable oil (usually used fryer oil) in diesel engines is a zero generation technology, as no technology other than filtering is used to prepare the feedstock for use as a fuel. However, there are many details that must be clearly understood when using straight oil as a fuel. For example, regular diesel must be used to start and stop the engine. For one quick overview of this type of system, click here. The US Environmental Protection Agency has been working with ethanol producers to test the effects of various blends of ethanol on engines designed to be used with gasoline. The great majority of gasoline used in the United States is E10 or 10% ethanol blended with 90% gasoline, as an octane enhancer. Engines in newer cars can use E15 (15% ethanol and 85% gasoline) without problems. Testing continues with regard to cars built before 2001. Testing about health effects also continues. Flex-fuel vehicles have been built to accommodate blends of up to 85% ethanol. Ethanol and cellulosic ethanol are widely used in racing, taking advantage of its enhanced performance characteristics. Use of ethanol blends in marine and small engines has also raised concerns. Advanced biofuels comprise the next three generations of biofuels and encompass diverse feedstocks and innovative technologies. Second generation fuels, commonly referred to as cellulosic fuels, are made from non-food plants, trees or agricultural residues. Cellulosic ethanol is the primary 2nd generation fuel. We could be seeing it in our fuel tanks as soon as 2015. The major advantage of 2nd generation biofuels is that they can be more environmentally friendly and more economically sustainable than food-based biofuels. The primary technical challenge, however, is economically converting the cellulose, hemicelluose, pectin, and lignin contained in plant and tree cell walls into biofuels. Trying to mimic what comes naturally to a bacteria that has evolved over billions of years has been harder than it first appeared. Other advanced fuels such as renewable diesel are also second generation fuels. See "What's the Difference between Biodiesel and Renewable (Green) Diesel" by Jesse Jin Yoon for details. Penn State has also published a very useful discussion on this topic, "What’s So Different about Biodiesel Fuel?" a technical paper written for the general public in as non-technical language as possible. Algae and other aquatic species produce oils for third generation biofuels such as jet fuel and sophisticated biodiesels. These molecules often pack more energy per gallon than first or second generation biofuels. Algae can also produce ethanol and other alcohols for fuel. Biofuels made from other acquatic organisms may be included in this category, as well. Click here for international interactive map of algae research, companies and projects. Fourth generation biofuels, in the earliest stages of conception and development, are created "out of thin air," some called solar liquid fuels. They will not rely on plants, trees or algae produced by photosynthesis. Instead, new chemical pathways will transform CO2 directly into high energy hydrocarbon fuels without creating intermediate sugars or oils. Joule Unlimited is a leader in this sector. As is often repeated at advanced biofuels conferences and by the US Departments of Energy and Agriculture, there is no "silver bullet," no single solution to achieving energy security; instead we must explore myriad "silver shot" opportunities to make home-grown fuels. Jim Lane of Biofuels Digest provides expanded descriptions of the 1,2,3,4 generations, along with lists of companies working in each. His warning: Note: The use of 3G or 4G technology, while advanced, should not imply that it is a superior technology in terms of commercial viabiliuty. Some of the best early-stage candidates for commercial-scale advanced biofuels are, in fact, 2G companies. Feedstock cost, and the capital expense and operating expense of the technology, are major factors in commercial appeal, above and beyond the generation of technology used. In the United States, the Renewable Fuel Standard section of the Energy Independence and Security Act of 2007 (EISA) has a much broader definition of advanced biofuels, essentially excluding ethanol made from corn starch from the definition of advanced biofuels. Other fuels made from biomass (essentially recently living "stuff") that meet specific greenhouse gas emissions criteria may be considered advanced biofuels under RFS2. This may include biodiesel, renewable diesel, biobutanol, etc. More specifically in RFS2, The term `cellulosic biofuel' means renewable fuel derived from any cellulose, hemicellulose, or lignin that is derived from renewable biomass and that has lifecycle greenhouse gas emissions, that are at least 60 percent less than the baseline lifecycle greenhouse gas emissions. And, the term `advanced biofuel' means renewable fuel, other than ethanol derived from corn starch, that has lifecycle greenhouse gas emissions, that are at least 50 percent less than baseline lifecycle greenhouse gas emissions. The types of fuels eligible for consideration as `advanced biofuel' may include any of the following: Ethanol derived from cellulose, hemicellulose, or lignin; Ethanol derived from sugar or starch (other than corn starch); Ethanol derived from waste material, including crop residue, other vegetative waste material, animal waste, and food waste and yard waste; Biomass-based diesel; Biogas (including landfill gas and sewage waste treatment gas) produced through the conversion of organic matter from renewable biomass; Butanol or other alcohols produced through the conversion of organic matter from renewable biomass; and Other fuel derived from cellulosic biomass. The baseline to which lifecycle greenhouse gas emissions are compared is the average lifecycle greenhouse gas emissions for gasoline or diesel (whichever is being replaced by the renewable fuel) sold or distributed as transportation fuel in 2005. Thus, by definition, comparisons are not made under RFS2 to gasoline or diesel made from today's crude oil taken from tar sands, deep water drills, fracking, etc. Click here for the complete EISA as signed by President George W. Bush. See Title II, Subtitle A for the Renewable Fuel Standard. The Environmental Protection Agency administers the RFS2. Click here for current information. Another caveat: although a fuel or fuel additive may be determined to meet the RFS2 criteria for advanced biofuels, this does not mean that it has passed all the EPA tests required for it to be used in the US as a fuel or fuel additive for commercial use. Advanced Biofuels USA hopes to develop more educational papers elucidating that typically complex and time-consuming process.
Making Advanced Biofuels: Biomass to Building Blocks; Building Blocks to BiofuelsProducing advanced biofuels requires two essential things: feedstock and technology. And a third important element: responsible scientific innovation. As Novozymes, a company that makes enzymes for numerous uses around the world, puts it, "Biofuel is an important step on a journey that will take us along a new way of thinking about plants-and about our resources in general." One new way to think about plants and other resources is to appreciate their role in storing the sun's energy in carbon-based molecules. Energy Feedstocks. The natural storage mechanism for the sun's energy is in cell walls of plants and trees. Cell walls are constructed from simple sugars and alcohols that are strung together into complex compounds called cellulose, hemicelluloses, pectin and lignin. Scientists are studying grasses, oil-seed crops, fast-growing trees and other plants for energy use because they have inherent abilities to produce large amounts of biomass in limited space with limited soil disturbance, little or no fertilizer and no irrigation. For example, some crops that can provide the building blocks for transportation fuels are perennial grasses such as switchgrass, miscanthus, energy canes; halophytes such as seashore mallow or spartina that can grow in brackish water; sorghum, jatropha, camelina, poplar, salicornia, and many others. The sustainable advantage of these crops is that they can be grown on marginal lands that are not so good for growing food; take little or no fertilizers and should not require irrigation; and, if perennial, require no carbon-releasing tilling. In addition to crops, advanced biofuels can be made from agriculture or food processing waste and residues such as corn cobs, sugar beet pulp, citrus peels, nut shells, rice hulls, fruit pits, cotton gin trash, meat processing residues, and cheese whey, and restaurant wastes such as used fats, oils and grease, etc. Residues from silviculture (wood harvesting) which might be left in dense forest creating forest fire fuel if not burned in controlled settings can be used as feedstock. These include thinnings, underbrush, limbs and tops, branches and leaves, dead or dying trees. Wood processing waste such as sawdust, bark, chips, sander dust, edgings, slabs and pulp/paper mill residues can also serve as feedstocks for advanced biofuels. Some technologies can even turn sorted municipal solid waste into biofuel, including hard-to-get-rid-of items like vehicle tires, construction waste and otherwise unrecyclable plastics. Overcoming Biomass Recalcitrance. If you've ever watched a tree bend but not break in a wind storm or seen tall grasses spring back up after a hard rain, you know how strong and resilient plant and tree biomass can be. It is even more remarkable when you realize that all plants and trees are constructed from simple sugars and alcohols. The same sugars that can be used to produce biofuels. This strength is produced by first stringing the sugars and alcohols into complex compounds called cellulose, hemicelluloses, pectin. In trees lignin is added. Then, all these compounds are intertwined into a complex matrix. Unfortunately this well structured matrix, "evolutionarily engineered" through millions of years of natural selection, does not easily deconstruct into the biofuel sugar building blocks. Even fungi, bacteria, and viruses have limited success breaking down the matrix. It takes them years to decompose a tree. So, if we want to get to these sugars, one way is to learn the bacteria lifestyle, and let evolution help us find the solution. Technologies in today's labs and pilot and demonstration refineries take a number of different approaches. Generally, they start with a pre-treatment step to loosen the chemical bonds in the matrix and separate out the lignin, if any. As George Huber and Bruce Dale explained in their Scientific American article, "Grassoline at the Pump,"
To be commercially viable, the pretreatments must generate easily fermentable sugars at high yields and concentrations and be implemented with modest capital costs. They should not use toxic materials or require too much energy input.
Biomass to Building BlocksEnzymatic Hydrolysis. Atlantic Biomass Conversions, Inc., in Frederick, MD is trying to "think like bacteria" by directing the evolution of bacteria that know how to break down sugar beet pulp so that the cellulose, hemicelluloses and pectin can be released from the matrix. Their process includes engineered enzymes that can use the heat from the beet sugar refining process to speed up the reaction time. Thus, a mid-west beet sugar plant could not only produce granulated sugar, but the sugars contained in the pulp residue could be fermented into ethanol-or transported to a refinery as "green crude" for bio-plastics, biogasoline, bio jet fuel or other products. Ammonia Fiber Expansion. Michigan State University has taken a different approach to converting the biomass in the matrix into sugars. They have developed the ammonia fiber expansion (AFEX) process which cooks cellulosic biomass at 100 degrees C with concentrated ammonia under pressure. Subsequently, enzymes convert the treated biomass to the building block sugars for biofuel production. Gasification. Deconstruction of the solid biomass into smaller molecules can be accomplished with high temperature and pressure processes originally developed to turn coal and other fossil-based feedstocks into synthesis gas (syngas) in a process called gasification. Feedstocks are heated above 700 degrees Celsius inside a pressurized chamber with limited oxygen, turning them into a gas. Scientists and engineers are working on new applications to handle biomass, sorted municipal solid waste and other renewable or recyclable feedstocks. An added benefit of this process is the co-products that can be used to produce electricity to power the process. In addition, biochar, a beneficial soil supplement can be produced. An animated video of a Plasma2Energy's microwave induced plasma gasification gives an idea of the type of equipment used and the chemical changes that occur in gasification chambers. Pyrolysis. A high temperature/high pressure/no oxygen process is pyrolysis. Here, however, the temperatures are lower than gasification (300-600 degrees C) and the adjustable temperature and reaction rates contribute to product composition. Bio-oil, gas and biochar result. Although bio-oil can be used for heating buildings, water and in industrial processes, its use is limited by low energy content. Scientists are working to find ways to make this bio-oil useful as a transportation fuel. Oil refineries might convert this biocrude into usable fuels building on processes developed to manufacture biodiesel. Conoco-Phillips demonstrated the possibilities in Borger, TX, by creating 12,000 gallons of biodiesel a day from beef fat residues from food processing at a near-by Tysons Food facility. For a summary/overview of conversion technologies, see this paper written by an Advanced Biofuels USA volunteer in Finland, Aino Siirala. PDF
Building Blocks to Biofuels (and other Biochemicals and Products)After the complex biomass cellulosic matrix is deconstructed, the resulting sugars can be fermented or chemically converted to ethanol. They can also become the building blocks for construction of drop-in biofuels or hydrocarbons, sophisticated, high energy biodiesels, bio jet fuels and green gasolines that can use existing infrastructure built for petroleum-based products from pipelines to fuel pumps to gasoline or diesel engines. Ancient technologies to make the power of carbohydrates useful in other forms, such as fermentation, are available for use by anyone. Today's scientists have discovered and patented new ways to convert from sugars to more powerful, versatile hydrocarbons. Fermentation. Sugars and simple starches have been converted by humans into alcohols through fermentation for 8000 years. The first to commercialize this conversion of biomass in the Caucasus Mountains reaped such great rewards that they were buried with fortunes in gold. And the ethanol they made was just used for drinking, not driving. Fermentation of cellulosic biomass happens only after other processes break down the cellulose, hemicelluloses and pectin. Once the sugars are freed from the matrix, they are available to be fermented into ethanol or other alcohols. LanzaTech, INEOS and Coskata will turn syngas into ethanol by fermentation. For a more detailed description of this syngas to fermentation process, see Advanced Biofuels USA's paper, Syngas Fermentation: the Third Pathway for Celulosic Ethanol. Mixed Alcohol Synthesis. Range Fuels' plant in Soperton, GA, planed to convert syngas building blocks to make methanol and ethanol chemically via mixed alcohol synthesis (MAS) The cleaned syngas is passed over a proprietary catalyst and transformed into cellulosic biofuels. These cellulosic biofuels can then be separated and processed to yield a variety of biofuels, such as cellulosic ethanol and methanol. The Range Fuels plant is now owned and operated by Lanza Tech which uses a different syngas fermentation technique. Packed Bed Catalytic Reactors. After acquiring the advanced biofuels building blocks from a gasification with plasma arc process, Fulcrum Energy will use packed bed catalytic reactors, their proprietary alcohol-synthesis process, to make 10 million gallons/year of ethanol from sorted municipal solid waste in its Sierra BioFuels McCarran Nevada plant. Aqueous Phase Reforming (APR) uses catalysts to generate chemical intermediates from a variety of sugars, including complex sugars and mixed sugar streams that cannot be converted in a fermentation process. Scientists at Virent Energy Systems combined APR with additional catalytic technologies to create the BioForming® process which converts conventional and nonfood plant sugars into hydrocarbon molecules like those produced at petroleum refineries. Since early 2006, Virent has used the BioForming® process to generate energy dense hydrocarbon mixtures that can be blended at high percentages to make "green" gasoline, biodiesel and biojet fuels with the same chemical composition and performance as petroleum fuels. Meeting our world's energy needs with transformative home-grown solutions takes inspiration, dedication and innovation. For the good of future generations, we must grasp and build on the opportunities given us today. See also the Advanced Biofuels Association Technology pages.
Fulfilling the Promise of Advanced Biofuels: What Will It Take?More Technical Challenges Scientists and engineers continue to work on transformative scientific discoveries, and on the practical aspects of putting it all together in an industrial/commercial environment to produce sufficient volumes of advanced biofuels most efficiently and sustainably. Some scaling-up challenges stem from innovations not being developed by giant oil companies familiar with manufacturing logistics. Rather, they are often developed in small research labs, universities and colleges. Experienced engineers can help scientists bridge the gap between scientific discovery and product implementation. Yet even the most sophisticated inventors and entrepreneurs must contend with the price of scaling up-in the hundreds of millions of dollars.
Unique Financing Challenges (and, Everyone Wants to Be First to Be Second)Government must carry the day for sustainable energy security as it has for other important public projects like landing on the moon, developing nuclear power, maintaining standing armed forces and a safe, reliable interstate transportation system. Specifically, until oil is again $150/barrel, government support is needed to bridge the gap from small proof-of-concept research to commercialization. With commodities markets affecting prices for both feedstock and end product;
- with plant construction costing hundreds of millions;
- with much of the value (environmental and social benefits) not monetizable;
- with credit generally unavailable; and
- with the oil companies' refineries fully depreciated,
- private investment is waiting for someone else to be first, to learn from the mistakes, to refine the operations and processes.
Algae and Other Things That Grow in the WaterThe promise of algae-to-biofuels is in what these little "green machines" can make. They use sunlight to drive synthetic mechanisms (photosynthesis) to produce the various oils, long carbon chains, carbon-rings, and alcohols that are the building blocks of advanced biofuel versions of gasoline, diesel, and jetfuel. On top of that, algae ponds can be located on land that is not being used for food crops. Potential locations include brownfield sites adjacent to coal-fired power plants. As with many things that have great promise, there are challenges in achieving them. Algae, and their close relatives the cyanobacteria (formally known as blue-green algae), do not easily give up the packets of oil, paraffins, and other compounds they produce. They reserve the energy stored in those packets for when the sun doesn't shine and to reproduce. Through millions of years of natural selection they have evolved complex cell walls that keep this good stuff in and most of the bad stuff out. In addition, though algae blooms are reported certain times of the year in waterways like the Chesapeake Bay, getting a population of algae or cyanobacteria to consistently produce desired products in commercial quantities requires a detailed management system for their micro-ecosystem. Too much decayed matter in the water can restrict sunlight or release chemicals that disturb the algae. Too little nitrogen can restrict growth. In cold water their photosynthesis systems become sluggish. These are the challenges that algae biofuel companies and university researchers are addressing. READ MORE Increasing production and maintaining ecosystems go hand in hand. The recent sequencing of the genomes of several algae species will allow researchers to identify genes responsible for the production of the oils and other hydrocarbons that algae use to store energy. Also, the genetics of how the organisms respond to environmental changes can be better understood. Using this information, not only can the rate of production be enhanced, but the organisms' ability to grow in different conditions, such as with less nitrogen or more salt, can be enhanced as well. Companies including Algenol, Aurora Biofuels, Bioalgene, Solazyme, and Sapphire Energy are currently testing new strains of algae. Besides the organism approach, companies including Solix and PetroAlgae have developed proprietary micro-ecosystems designed to maximize microorganism growth with a minimum of inputs. One of the most intriguing aspects of some of these systems is the idea of using CO2 produced by coal-fired electrical plants to increase algae production. Algenol has recently signed an agreement with Linde Gas to commercialize this approach. Implementing these systems would reduce CO2 greenhouse emissions in two ways. First, the CO2 would be captured and recycled by the microorganisms. Second, the biofuel produced by the algae would replace oil-based fuels that also produce CO2. The downside to this approach is that algae producers could become dependent on releasing new fossil-fuel based carbon from its deep earth storage rather than participating in recycling the carbon already in the air. Getting the oils past the carefully constructed cell wall of the microorganisms is probably even a greater challenge. The simplest way is to harvest the algae, dry it out and collect the oils and other hydrocarbons. The only problem is all the organisms are killed meaning you have to start over. Phycal, a Cleveland, Ohio company, is getting the oil out with a proprietary system based on the electro-shock principle used in microbiology labs. A slight electric shock opens pores in the cell walls long enough for the oil packets to flow out. Solix has recently agreed to test a similar system that was developed at Los Alamos National Laboratory. This is called an ultrasonic wave focusing system. Algenol Biofuels is taking a very different approach. Having discovered that some cyanobacteria are able to not only produce ethanol and butanol alcohols, but are also able to diffuse the alcohols out of the cell walls without any assistance, Algenol is now in the process of using genetically enhanced strains to produce alcohols for use as building blocks or as fuels. Making many different systems work together most efficiently and effectively will take a good deal of smart science and engineering. Efforts lead by General Atomics as part of the Department of Defense Advanced Research Projects Agency (DARPA) bio-jetfuel project will go a long way to making that happen. Algae Industry Magazine has a series called Algae 101 which provides basic information about what algae is and how it can be used. They also have published a 3 minute video of Algae Basics. In 2016, the popular Algae 101 blog graduated to Algae Secrets – Innovations that Lift Society. Algae Secrets celebrates algae breakthroughs that make our world better. Mission of Algae Secrets:
- Inspire young people to green careers that benefit society locally and globally.
- Convey exciting breakthroughs for algae growers, processors, marketers and consumers.
- Cut through hype to examine realistic outcomes and to highlight credible solutions.
- Translate scientific breakthroughs and potentials to a broader audience.
- Examine how transdisciplinary innovations create new opportunities and benefits.
- Educate people globally about the challenges and solutions algae offer society.
- Imagine our future with many valuable sustainable solutions made possible by the tiniest, yet the mightiest plant on our planet.