The Role of Charcoal · Web viewPresently in a dry mill process, the entire kernel of corn is processed with corn oil ending up in distillers’ dried grains. The development of a

3 BiomassThe Role of Charcoal

Biomass is organic matter primarily in the form of wood, crop residues, and animal waste in that order of importance. Biomass as wood is readily available in temperate and tropical regions or collected with ultimately debilitating consequences in semi-arid areas. The great advantage of biomass is that it is free, and in temperate and tropical regions, freely available. Generally speaking, since biomass is “free,” it is inefficiently utilized as a residential or commercial fuel. For instance, about two-thirds of the energy content of wood is lost when transformed into charcoal in developing nations, about double that for producing charcoal in the developed world. Charcoal is made from wood through a process called pyrolysis where wood is heated in the absence of sufficient oxygen to support combustion. Organic gases and water are evaporated leaving a residue of nearly pure carbon. Released gases provide fuel for pyrolysis and for drying fresh wood before being transformed to charcoal. Any backyard barbecue hamburger-flipping aficionado can recite the virtues of charcoal over wood: higher heat content, cleaner burning, and conveniently transportable.

Modern research is underway to transform something as old and mundane as charcoal to a new product. The method of making biochar, a substance with a long history dating back to the aboriginal Indians in the Amazon basin, was lost when their civilization collapsed. Biochar, made from the residue of incomplete organic pyrolysis, was a key component in terra preta soils found in the Amazon. Terra preta soil was highly productive allowing large numbers of Indians to live in well-organized permanent communities where today few can survive on natural red clay soil depleted of nutrients by tropical rains. Terra preta improved soil texture for plant growth by retaining and slowly releasing water, natural fertilizers, and nutrients. It greatly reduced the risk of water table contamination compared to modern practices of spreading animal manure and commercial fertilizers. Biochar promoted plant growth on marginal land increasing agricultural output, which, through photosynthesis, sequestered carbon. Research is underway to try to replicate something the Indians were doing centuries ago.1 One company has developed a fuel efficient process to convert municipal solid waste, sewage sludge, PVC, plastics, rubber tires, wood, food, animal, and agricultural waste to synthetic biofuels via depolymerization employing microwaves with biochar as the residual product.2

Biomass in Home Heating

©Routledge/Taylor & Francis 2016

Biomass is burned for heating homes in New England and other parts of North America and northern Europe. Biomass can be firewood split from logs or bark and edgings residue from a lumber mill. Fireplaces burning split logs provide an attractive background setting in living rooms of millions of homes. Unfortunately conventional fireplaces allow most of the heat to escape up the chimney. Some fireplaces may actually increase heating needs by acting as a heat pump transferring warm indoor air to the outside environment. When firewood is burned in homes in North America and Europe specifically for heating purposes, combustion takes place in specially designed space heaters where relatively little heat escapes along with the products of combustion to the outside. The reason for this is clear: firewood is not free. For those who gather their own firewood, the desire not to dedicate too much time wielding an ax or chain saw when a paying job or some other preferred activity is at stake provides the incentive to have a fuel efficient wood burner. Most wood burners in theUS are located in rural areas of New England and New York not served by natural gas pipelines.3 The Northeastern US is not alone in consuming biomass for heating. Biomass supplies as much as 25 percent of heating requirements in Estonia, Latvia, Finland, and Sweden.4

Wood Pellets

Wood and wood pellets have displaced an estimated 5 billion gallons per year of heating oil and propane in the US. Wood pellets are gaining popularity as a home fuel at the expense of split wood and wood residues. Raw material for making wood pellets can be sawdust, wood chips, lumber mill scrap, and entire trees unsuitable for lumber, either green (freshly cut) or partially dry. To ensure proper operation of wood pellet stoves made by different manufacturers, the varied raw materials must be transformed to a standard product with consistent moisture and ash content, heat value, and burn characteristics. The first step to produce wood pellets is hammer mills reducing raw material to sawdust, then dried to a specific moisture content. Fuel for drying can be either sawdust as a biofuel or propane or natural gas as petrofuel (choice of fuel is critical in determining the impact of wood pellets on carbon emissions). Sawdust is heated by pressurization to release natural lignins and then passed through a high pressure extrusion die to manufacture pellets of correct diameter, length, and density with lignin acting as “glue” to ensure their integrity and durability.5 While pellets have energy content near that of coal, energy consumed in producing pallets is higher than mining and shipping coal to a customer when all factors are taken into consideration including energy consumed in collecting wood waste. Nevertheless carbon emissions of wood pellets should be less than coal net of replacement plant growth.

Wood pellets are sold in 40 pound bags, 50 bags to a skid, delivered to homeowners. When needed, a bag must be carried and emptied into an automatic feeding furnace controlled by a thermostat. Despite this added effort, more than 800,000 homes in the US have switched to wood pellets for space heating. Some consume two tons of pellets a year in more moderate climates or where pellet stoves are


supplementary to the primary means of heating. Other homes more dependent on pellets for heat and located in colder regions consume four tons of pellets (four delivered skids).

An alternative to a wood pellet stove is an anthracite coal stove. Anthracite coal has the highest energy content and lowest sulfur and nitrous oxides and particulate emissions of all coal types. Coal is delivered in bulk by the ton and normally stored in a sheltered space near the coal stove, which is replenished by a coal bucket. Coal stoves do not have an automatic feed feature of wood pellet stoves and require more attention. Wood pellet and anthracite coal stoves are space heaters that may supplement a heating oil furnace. However if properly placed on a lower floor location with inside doors and inter-floor vents open, it may be possible that the furnace never turns on throughout the winter.6 About 100,000 homes a year without access to lower cost natural gas are abandoning heating oil and propane for pellet and, to a lesser degree, anthracite stoves. Anthracite stoves compete with wood pellet stoves and buyers must decide which type stove to purchase based on economic and operational considerations and fuel availability.7

Growth in wood pellet consumption is rapidly accelerating. US capacity to produce pellets tripled between 2008 and 2011 reaching an estimated 9.4 million tons annually in 2012 and is expected to be 15.6 million tons by 2016. While domestic consumption is increasing, real growth is booming exports from southeastern US, up to 2 million tons in 2012 from virtually nothing just a few years earlier. The market is utilities in the UK, the Netherlands, and Belgium burning wood pellets to meet renewable energy standards. Europe’s domestic market for pallets is 13 million tons in 2012, which includes both home and utility consumption. It is slated to continue to grow to 25–30 million tons to allow the European Union to achieve its goal of 20 percent renewables by 2020.8 At that time, 68 percent of renewables in the EU will be biomass segmented with 52 percent for heating purposes, 11 percent biofuels, and 5 percent electricity demand, which is hearty growth!9 In response for this new demand for biomass, bioenergy forest plantations to produce up to 25 million tons of woody biomass are being proposed in the US Southeast. Choice of biomass includes pine, eucalyptus, sweetgum, hybrid poplar, and cottonwood, and other fast growing plant species. Annual forest plantation yields are expected to be 8–15 green tons per acre with harvesting occurring every 5–12 years providing a renewable and sustainable biomass resource for a number of bioenergy applications.10

Utilities in Korea are planning to import 5 million tons of wood pellets by 2020 from Australia, Vietnam, Indonesia, and North America to meet their renewable energy quotas.11 A growing Asian market for wood pellets is spawning projects in northwest Canada to develop biomass farms for wood pellet manufacture. Carbon emission reduction not only has to cover fossil fuels consumed in harvesting and manufacturing wood pellets, but ship’s fuel consumed in moving pellets thousands of miles across the Atlantic or Pacific Oceans. Another area of biomass growth for heating is pellets made from switchgrass,


which will be sold to greenhouses facing high fuel oil bills during the winter months. Monetary savings in switching to biomass can be significant.12

It goes without saying that pellet exports should be conducted on a sustainable basis that does not result in deforestation. Sustainability can be assured if sufficient land for tree farms is set aside whereby biomass converted to pellets is less than replacement growth. Biomass farms may be initially sustainable, but can become nonsustainable if depletion of soil nutrients is left unattended as trees are continually removed. Fertilizers applied to sustain tree growth that are made from fossil fuels would detract from biomass fuel’s capacity to reduce greenhouse gas emissions.

Two Processes for Making Ethanol

Two chief processes for making ethanol from corn have to do with the nature of the products: wet mill and dry mill. The wet mill process produces ethanol plus a variety of food products such as corn sweeteners, corn syrup, corn oil, and gluten feed. The dry mill process produces ethanol and a high-protein animal feed called wet or dried distillers’ grain. Dry mill plants have lower capital and operating costs, make up over 80 percent of ethanol plants, and are attractive investments for farmer cooperatives, entrepreneurs, and private investors. Wet mill plants produce higher-valued coproducts that justify their higher capital and operating costs and are owned by large food corporations who have access to supermarket shelf space.

Ethanol production is presented here in some detail to gain an appreciation that little in energy is done in a simple straightforward fashion. The process begins with truckload deliveries of corn kernels to an ethanol plant with a storage capacity of 7–10 days of production. They are screened to remove debris such as bits of corn stalks and then ground into coarse flour. Milled corn grain is mixed with water to a desired pH factor and cooked as hot slurry. An alpha-amylase enzyme is added and the slurry is heated to 180–190°F for 30–45 minutes to reduce its viscosity. Next is primary liquefaction where the slurry is pumped through a pressurized jet cooker at 221°F, held for five minutes, and then cooled by an atmospheric or vacuum-flash condenser. Then secondary liquefaction holds the mixture for 1–2 hours at 180°F–190°F to allow alpha-amylase enzyme to break down starch into short chain dextrins. After adjusting for pH and temperature, a second enzyme, glucoamylase, is added as the mixture is pumped into fermentation tanks. Now known as mash, the glucoamylase enzyme breaks down the dextrins into simple sugars.


Once starch is converted to sugar, the process is the same as making ethanol from juice extracted from sugarcane. Yeast is added to convert sugar to ethanol and carbon dioxide. Fermentation takes 50–60 hours ending up with a mash of 15 percent ethanol, grain solids, and yeast. Carbon dioxide is captured at some ethanol plants and sold to companies as dry ice for flash freezing and as condensed, pressured gas for carbonating soft drinks. Carbon dioxide may one day be pipelined to played-out oil reservoirs as a tertiary means of enhancing recovery, or to greenhouses to enhance plant growth, or to algal farms to produce more biofuels.

Fermented mash is pumped and heated in a multicolumn distillation system. The columns take advantage of differences in boiling points of ethanol and water to separate hydrous ethanol (95 percent ethanol, 5 percent water) equivalent to 190-proof alcohol. Hydrous ethanol can be consumed directly in pure ethanol burning automobiles. To produce anhydrous ethanol required for gasohol, hydrous ethanol passes through a molecular sieve that separates water and ethanol molecules yielding 200-proof anhydrous or waterless ethanol. Then a denaturant such as gasoline or other petroleum liquid is added to make ethanol unfit for human consumption before entering storage normally sized to hold 7–10 days’ production.

The difference between using corn and sugar as feedstocks once the corn is reduced to a sugar is in the residues. In Brazil, waste of distillation of sugar is vinasse that is applied to sugarcane fields as a form of fertilizer-recycling. In the US, stillage in the bottom of distillation tanks contains solids and yeast as well as water added during the distillation process. It is passed through centrifuges to separate thin stillage, a liquid with 5–10 percent solids and wet distillers’ grain. Some of the thin stillage, referred to as sweetwater, is routed back to the slurry tanks as makeup water, reducing the amount of fresh water required to support ethanol-making. The rest is sent through a multiple evaporation system to concentrate stillage into syrup with 25–50 percent solids. The syrup, high in protein and fat content, is mixed with wet distillers’ grain from centrifuges. With the syrup, wet distillers’ grain contains most of the nutritional value of the original corn or other grain feedstock plus waste residual yeast from fermentation.

Wet distillers’ grain has a limited shelf life, varying between four days to two weeks, and is expensive to transport with its high water content. Wet distillers’ grain, which is 33 percent solid, is sent to dairy farms or cattle feedlots located within 100 miles of the ethanol plant. Dairy cows can be fed rations of up to 43 percent wet distillers’ grain and beef cattle up to 37 percent. Alternatively wet distillers’ grain can be dried into dry distillers’ grain, but the drying process increases energy consumption for older, less efficient plants by as much as 50 percent. Dry distillers’ grain has a shelf life of several months, is less costly to transport, and is commonly used as a high-protein additive in cattle, swine, poultry, and fish feed. Evaporated thin stillage sold as condensed syrup, or thick stillage, can be blended or sprayed over distillers dried grains to produce distillers dried grains with solubles. Ruminant feed (dairy cows and


cattle) can be up to 40 percent dry distillers’ grain and up to 10 percent for nonruminant feed (poultry and swine).

In 2014, US distillers grains were 60 percent dried, 27 percent wet, and 13 percent modified wet. Of total distillers grains, beef cattle consumed 43 percent, dairy cattle 30 percent, swine 16 percent, poultry 10 percent, and other 1 percent. Ethanol plants produced 36 million metric tons of distillers grains plus 2 million tons of corn gluten feed and 1 million tons of corn gluten meal. Distillers grain exports of almost one third of production totaled 11.4 million tons of which China received 43 percent and Mexico 13 percent. Nations receiving 3–6 percent of exports in order of importance were Vietnam, S. Korea, Japan, Turkey, Thailand, Indonesia, and Canada.13

In the wet mill process, grain is first soaked or “steeped” in water and diluted sulfurous acid for 24–48 hours to separate components within the grain. After steeping, corn slurry passes through a series of grinders to separate corn germ from which corn oil is then extracted. Hydroclonic, centrifugal, and screen separators segregate fiber, gluten, and starch components. Steeping liquor is concentrated to heavy steep water in an evaporator, then co-dried with the fiber component and sold as corn gluten feed of 21 percent protein to the livestock industry. A portion of the gluten component is further processed for sale as corn gluten meal to poultry breeders with 60 percent protein content and no fiber. Gluten can find its way into the human food chain, which some find objectionable. Starch can be fermented into ethanol, or dried and sold as cornstarch, or processed into corn syrup.

A typical dry mill will produce 2.8 gallons of ethanol, 17.5 pounds of distillers’ dried grains, and 17 pounds of carbon dioxide in addition to thin stillage from a bushel of corn. Emerging technologies may increase marketable co-products in the form of germ separation prior to final grinding of the corn kernels and other fermentable products such as lactic acid, acetic acid, glycerol, and others. Progress is constantly being made to improve efficiency and productivity of ethanol production. Between the early 1980s and early 2000s, there has been a 50 percent decline in energy required to produce ethanol, an increase in production yield of 23 percent from 2.2 gallons per bushel of corn to 2.7 gallons per bushel and a cut in capital costs of building ethanol plant by 25–30 percent. Earlier plants used azeotropic distillation systems to dehydrate (removal of the last vestiges of water) which proved to be expensive, costly to operate, energy intensive, and hazardous. Today molecular sieves or molsieves are the most popular means to dehydrate ethanol. Molsieves, a bed of ceramic beads, absorb water molecules in vaporized ethanol. Molsieves are lower cost, easier to operate, less energy demanding, and more environmentally friendly compared to azeotropic distillation. Another improvement is energy recycling–thermal capture of waste energy via heat exchangers for heating purposes. Technology improvements for making enzymes, required for hydrolyzing starches to fermentable sugars, have increased yield fivefold. The practice of discarding spent yeast and replacing with a new batch, called “pitching,” has given way to ethanol plants propagating their own yeast. Ethanol plants that once purchased truckloads


of yeast per month now need only a few pounds to start the propagation process. While plant automation has reduced the number of employees required to run an ethanol plant, the remaining workers must have a higher skill set. Automation has improved the efficiency and uniformity of the product, enhancing its quality. Since 1995, natural gas consumption to produce a gallon of ethanol is down 36 percent, electricity use down 38 percent, water consumption down 53 percent, ethanol yield (2.82 gallons of ethanol per bushel of corn) is up 12 percent. Moreover the yield for corn on a trend line basis has increased from 95 bushels per acre in 1980/1981 to 160 bushels per acre in 2012/2013. 2014/2015 was an exceptional good year for corn and estimated yield is 171 bushels per acre. Part of this is improved varieties of corn that require less fertilizer than in the past resulting in a downward trend in the size of the Gulf of Mexico hypoxic zone (waters with insufficient oxygen to sustain marine life from algae blooms fed by fertilizers and other forms of pollution run-off entering the Mississippi River). Moreover, the ethanol yield per bushel has grown from 2.51 gallons in 1995 to 2.82 gallons in 2012 with every expectation for further growth. The aggregate impact of these improvements has been to cut the cost of producing ethanol by nearly half exclusive of buying raw materials and shipping ethanol to market.

Efforts are underway to further lower production costs such as high-gravity fermentation. Currently water is added to reduce the solid content to ferment “beer” mash. High-gravity fermentation will allow fermentation to occur at considerably higher levels of solids, thus reducing the amount of water required, which, in turn, reduces the cost of handling and treating water later in the process. A higher concentration of solids results in higher beer yields in a shorter time. Development of yeast that can withstand higher temperatures will increase the alcohol content of beer and reduce energy costs. Presently in a dry mill process, the entire kernel of corn is processed with corn oil ending up in distillers’ dried grains. The development of a quick steeping process will allow dry millers to separate corn oil prior to processing for sale as a separate and higher valued product. New strains of corn that can raise the starch content from 33 pounds per bushel to 37 pounds will result in lower unit processing costs.

Even with these improvements, ethanol plants are still large consumers of energy requiring a combination of electricity and natural gas to run motors and pumps and generate steam for plant operation. Consumption of electricity and natural gas to power an ethanol plant is a major reason why ethanol from corn is not as effective in replacing fossil fuels as sugar that obtains its power needs from burning bagasse, a biofuel. To counteract this large demand for fossil fuels, a few ethanol plants are planning on using energy supplied by biomass gasification of cattle manure, corn stalks (stover), grasses, and wood chips; fluidized bed reactors to convert biomass into steam; and wind turbines. These projects are under close scrutiny by industry leaders and government program managers to see if they are feasible. If so, they can be a means for improving the energy output–input relationship to enhance ethanol’s capacity to reduce carbon emissions.


Another example of improving the process is a corn-oil extraction technology to make biodiesel. Stillage flow in the evaporation stage of the drying stage is removed when its consistency is that of concentrated syrup and is then heated and sent through an advanced centrifuge to separate the crude corn oil, which is converted to biodiesel. Defatted concentrated stillage residue is dried and sold as defatted dried distillers’ grain. This process increases revenues through the manufacture of biodiesel, reduces operating costs and emissions, and recovers up to 75 percent of the corn oil in dried distillers’ grain. A traditional ethanol processing plant converts a bushel of corn, weighing about 54 pounds, into about 18 pounds of ethanol, 18 pounds of carbon dioxide, and 18 pounds of dried distillers’ grain, which contains about 2 pounds of fat. This corresponds to a corn-to-clean fuel conversion efficiency of about 33 percent, or about 2.8 gallons of clean fuel per bushel of corn. A proposed corn-oil extraction and biodiesel-processing technology converts fat in dried distillers’ grain into a high-grade corn oil that can then be converted into biodiesel on close to a 1:1 volumetric basis. This increases the corn-to-clean fuel conversion efficiency from 33 percent to 36 percent or about 3 gallons of clean fuel per bushel of corn. Another proposal is to incorporate a bioreactor to take advantage of one-third of corn converted to carbon dioxide. The bioreactor will house algae to consume carbon dioxide emissions and give off oxygen and water vapor. If properly cultivated, the algae can double in mass in less than 24 hours and be harvested for conversion into clean fuels. Heating algal biomass with little oxygen (biomass gasification) produces a syngas of carbon monoxide and hydrogen, which can be converted into various petroleum products through a catalytic chemical (Fischer-Tropsch) reaction. This process can also convert defatted dried distillers’ grain into liquid fuels to further enhance corn-to-clean fuel conversion ratios.14

Proposed Solutions

At that time there were five commercial courses of action to react to this imbroglio.

(1) buy RINs to cover shortfalls at any price,

(2) export gasoline,

(3) export ethanol,

(4) cutback on ethanol imports, and

(5) hasten development of biobutanol.

Buying RINs at any price was not a solution as it would affect the price of gasoline for consumers, which would be unequally shared by blenders and refiners depending on their circumstances. Consumers would not pay extra charges that a particular oil company had to pay for RINs, but would simply shift to


lower priced brands; in which case, an oil company would have to absorb losses that their competitors had avoided.

Exported gasoline is ethanol-free and outside the purview of RFS-2. But exporting gasoline to avoid the blend wall affects domestic gasoline availability, and hence its price. Excessive exports could conceivably cause gasoline shortages. Exporting ethanol would relieve the RIN congestion problem. Interestingly ethanol exports peaked in 2011, declined in 2012 and declined further, surprisingly, in 2013.15 Brazil is a net importer of US ethanol because at times it is more profitable for Brazilian sugar growers to sell sugar in the international market than convert sugar to ethanol, creating a market for imported ethanol to satisfy the Brazilian mandate on the percentage of ethanol in gasoline.16 Reducing ethanol imports is another viable option in order for the domestic market to absorb larger quantities of US ethanol. The problem here is that imported ethanol made from sugar (not corn) counts as fulfilling the advanced biofuels requirement. The low cost alternative for fulfilling the advanced biofuels requirement is to import sugar ethanol, the largest supplier being Brazil. Thus, Brazil is a major importer and exporter of ethanol moving in and out of the US more in response to government regulations than market reality. In the collision between Brazilian ethanol imports into the US and domestic production, Brazilian exporters appeared to be the losers as imports were down considerably in the first quarter of 2013 compared to the latter half of 2012.17

Alternatives 3 and 4, increasing US ethanol exports and reducing Brazilian ethanol imports, are in conflict with one another. In the quest to secure an export deal other than with the US, Brazil has an inherent advantage of being the lowest cost ethanol producer. Brazil can do deals that are economically prohibitive to US ethanol exporters. Moreover Brazilian exports to other South American nations may be viewed as a closed market to US ethanol exporters. Hence as Brazil’s imports into the US are cut, US ethanol exporters see a more competitive international market with less opportunity for sales. Curiously, even though Brazil exports to the US are down, so are its exports to the rest of the world. The real reason for the decline in US and Brazilian ethanol exports may have nothing to do with economics. Europe, once thought of as a major potential ethanol importing region, has growing popular opposition to biofuels made from food.

One possible solution is to hasten the development of biobutanol made from ethanol, which is easily absorbed in the gasoline stream and bypasses the blend wall. One process has been fully developed (Butamax) and others appear to be at the doorstep of being fully developed. At this point, it is not clear whether biobutanol can be price competitive with gasoline without some form of government assistance. But once a biobutanol technology proves to be commercially feasible (subsidized or not), it is felt that at least 50 percent of ethanol plants would be converted to biobutanol in short order, thus leveling the blend wall.18


Of course a change in EPA regulations would make the blend wall disappear, but changes to laws and regulations are always problematic. EPA, in common with other regulating bodies, is slow and deliberate in issuing regulations and is equally slow in responding to a rapidly changing commercial environment. Regulators apparently feel that a rapid bureaucratic response to a shifting economic situation somehow reflects poorly on the permanence of their regulations. They agonize over the fact that their regulations have failed to deal with every nuance of the complexities of the commercial world. Their deliberations take a long time as they are subject to a variety of internal checks and balances to ensure inerrancy. Furthermore bureaucrats have no sense of urgency because they have no stake in the game; that is, they have nothing to gain or lose if and when and how they decide to act or not to act. For instance, the Act established the obligation for minimum amounts of cellulosic ethanol to be added to the gasoline stream. Although there were no operating plants, and hence no supply, this did not stop the bureaucrats from imposing fines against blenders and refiners for not complying with the rules. EPA eventually stopped these fines, but it demonstrated the intransience of bureaucrats in dealing with commercial reality.

In October 2013, EPA publicly acknowledged that something should be done about the blend wall. This, at least, was a first step in the right direction compared to one obtuse solution proposed at that time of taking advantage of differentials in RIN prices associated with ethanol, biodiesel, cellulosic ethanol, and advanced biofuel to import biodiesel as a means to counter ethanol hitting the blend wall.19 But one month later in November 2013, much to everyone’s surprise, EPA did the unthinkable of rethinking its position. Despite the criticism of bureaucratic dalliance, EPA demonstrated fluidity in its approach to biofuels as seen in the 2007 revision of renewable fuels mandates as originally proposed in 2005. The proposal would reduce the renewable fuel 2014 statutory role from 18.15 billion gallons (BG) to 15.21 BG in order for the volumetric requirement to better match the 10 percent commercially acceptable limit of ethanol in gasoline. This would obviate problems that were beginning to appear where high RIN prices and heightened exports of gasoline were beginning to be felt at the gas pump. Of this 3 BG requirements reduction, about half will be corn ethanol and advanced biofuels (mainly Brazilian sugar ethanol imports) and a reduction in cellulosic ethanol to better reflect its state of development. The long term role of cellulosic ethanol, however, was slashed to better match a government mandate with technological progress in developing a commercially acceptable way to make cellulosic ethanol. The biodiesel mandate would be increased from 1 BG to 1.28 BG. Support for this change came from Department of Energy spokespeople and energy companies that would benefit from the proposal. Opposition was from a bevy of renewable energy spokespeople.20 The reappraisal of the EPA’s role of bioethanol reopened the door to growing Congressional sentiment that the best way to protect consumers would be a drastic overhaul of the outdated and unworkable renewable fuels program. Thus lines were being drawn in the sand as to the ultimate role of biofuels.


Traditional Means of Making Cellulosic Ethanol

Three traditional means to make ethanol from cellulose are acid hydrolysis, enzymatic hydrolysis, and thermochemical. Acid hydrolysis is a dilute acid process, which under high temperature, can yield over 50 percent of the contained sugars that can produce 50 gallons of ethanol from one ton of dry wood. The problem with this method is that there are two simultaneous reactions–the first converts cellulose to sugar and the second converts sugar to undesired organic compounds. Because these reactions are simultaneous, the yield of ethanol is not only low, but also contaminated with undesired compounds difficult to separate, which makes this process expensive.

Enzymes are naturally occurring proteins that cause certain chemical reactions to occur more quickly. Desired enzymes are those that can penetrate lignin without harming cellulose and hemicellulose and then converting these to sugar (glucose) and then to ethanol. Enzymes found in the digestion system of termites would be highly effective in transforming wood to glucose, but no such man-made enzymes currently exist. Another type of termite has amoeba living within its digestive tract that convert cellulose to sugar in a symbiotic relationship with the host. This opens up the possibility of separating amoeba from the termite and maintaining them in an artificial termite-like stomach environment to convert cellulose to glucose, but no such process currently exists. Research is being conducted on special enzymes in pandas that convert bamboo shoots to sugars. Enzymes in sea life that eats away at marine piers and wooden decks of sunken vessels are also candidates. Cellulosic ethanol could become commercially viable if any of these could be replicated with man-made enzymes–a challenge for scientific genius and entrepreneurial activism.

Hydrolysis process starts with physical and chemical pretreatments to break through the crystalline exterior structure of a cell (lignin) to expose the cellulose and hemicellulose molecules to the enzymes. These are costly because of time, measured in days, for hydrolysis to break through the lignin and time for the enzymes to act on the cellulose and hemi-cellulose to create ethanol. The slow process time requires huge reactor vessels to produce commercial volumes of ethanol. The investment in large capacity reactor vessels utilizing expensive enzymes results in high priced ethanol. Thermochemical ethanol production process used in Germany during the Second World War was gasification of biomass with the resulting syngas passing through a reactor with various catalysts for conversion to gasoline (Fischer-Tropsch process). Like other aforementioned processes, it is not cost effective.21

Modern means of making ethanol from cellulosic biomass starts with agricultural residues going through a grinding process and wood through a chipping process to achieve a uniform size for easier handling and more efficient processing. Biomass is then steeped in hot sulfuric acid which pushes lignin out of the way to free hemicellulose, which decomposes into four


sugars: xylose, mannose, arabinose and galactose, and also free cellulose. The next step is cellulose hydrolysis is to wash off the acid and expose the mixture in tanks where enzymes called cellulases turn cellulose into glucose. The result is a soup of sugars consisting of glucose and hemicellulose’ four sugars. These are placed in tanks for fermentation using different enzymes and microbes depending on the nature of the biomass and its sugars. After fermentation is completed, stillage at the tank bottom is removed for processing and reuse and what’s left is alcohol, which is then purified for use as a fuel.22

Intense research is being dedicated to finding the right combination of thermal and chemical processes plus the right type of enzymes that can efficiently and economically break down cellulose, hemicellulose, and possibly lignin into simple sugars. Research is also being conducted to convert lignin into biofuels, biolubricants, and animal feed and not be “wasted” for biopower. However a cellulosic ethanol plant requires power and if that can be more economically satisfied by burning lignin rather than purchasing natural gas or electricity, then it should be burned. Whether one burns or converts lignin to higher value products requires an analysis of fuel savings of burning lignin compared to converting lignin to higher valued products net of capital and operating processing costs and fuel for running the plant.

The abundance of cellulosic material and its low cost of acquisition have fostered a great deal of entrepreneurial and industrial activity to find a cost-effective process to make cellulosic ethanol. These efforts are paying off in lowering the price of conventionally made cellulosic ethanol. An industry survey conducted by Bloomberg New Energy Finance on production costs of eleven leading cellulosic ethanol producing companies concludes that cost competitiveness with corn ethanol can be achieved by 2016. In 2012, the cost of producing cellulosic ethanol ($3.55 per gallon) was about 40 percent higher than corn ethanol ($2.54 per gallon). The reasons for the anticipated narrowing in costs are further declines in capital requirements and enzyme costs, higher ethanol yields, plus savings from optimizing operations and logistics for large-scale production.23

Another way to lower cellulosic ethanol is to develop new technologies to convert cellulose to ethanol. A great deal of research, development, and entrepreneurial activity is taking place in nonconventional chemical-catalytic processes to dramatically reduce the cost of producing cellulosic ethanol primarily by eliminating the need for fermentation. Current research is focusing on processes that can be carried out at moderate temperatures utilizing chemical catalysts to convert biomass into “platform molecules.” Platform molecules include levulinic acid molecules and their derivatives capable of producing a range of renewable fuels, plastics, and value-added pharmaceutical and agrochemical products. With regard to cellulosic fuels, there is thought that the technology of biomass valorization may reach a point of commercialization in coming years where biomass-derived levulinic acid is transformed into hydrocarbons in relatively simple and efficient steps. Hydrocarbons can then be converted into branched alkanes, the main constituent of gasoline, or straight-chain alkanes, for diesel and jet fuel. The end result of straight substitutes for petrofuels (gasoline, jet fuel and diesel) avoids the necessity of


resorting to costly and time consuming fermentation to produce ethanol that then has to be converted to biobutanol to be a gasoline substitute.24

Success in lowering the cost of producing motor vehicle fuels from cellulose would be a boon for growing nonagricultural crops on marginal lands not suited for agriculture. Switchgrass is a favored high-yielding perennial grass that grows well over most of central and eastern US. Fast-growing trees, normally harvested between 6 and 10 years and replanted for repetitive harvests, include poplar and willow in cooler and sycamore and sweetgum in warmer climates and eucalyptus trees, now grown in tree farms in Brazil for paper pulp and charcoal. While cellulosic biofuel producing facilities, whether as ethanol or substitute petrofuels, are expensive to build, this is compensated by the low feedstock cost (collecting agricultural waste or growing and harvesting grasses and trees). Most importantly the cost of biomass feedstock is fixed depending only on the cost of planting, harvesting, and transportation. This is quite unlike corn and sugar whose price as a food commodity fluctuates markedly, strongly affecting the economics of making biofuels. It is possible that the cost of a feedstock for cellulosic biofuel production, either as ethanol or possibly substitute petrofuel, can be negative; that is, the plant would receive money for consuming a feedstock such as disposing of municipal solid waste. Municipalities would be willing to pay a cellulosic biofuel plant processor to get rid of waste rather than spending more money to treat waste for environmentally safe disposal. Regardless of feedstock, the impact of cellulosic biofuel on agricultural crop output would be marginal or none at all.

The most likely initial candidate for cellulosic biofuel is corn stover, plentiful in corn growing areas. Harvesting stover will require overcoming several challenges. For one thing, corn stover on the ground is contaminated with dirt and rocks. Weather and soil conditions may not allow enough time for field drying, which would be necessary for safe storage. Harvesting corn stover would have to compete with other more valuable crop-harvesting operations. Stover would probably be in bales for storage and transport to ethanol plants similar to bales of forage for farm animals, or conceivably it could be chopped and stored in silos. If converting corn stover to biofuel becomes commercially feasible, then equipment will be developed that both harvests corn kernels and bales or chops stover in a single operation. Not all the corn stover can be removed from a field because stover residue controls erosion, retains moisture, provides winter forage for animals, and adds nutritional value to the soil. It is felt that only about half of the stover should be removed for biofuel production.

A few private companies are building or operating cellulosic ethanol plants. Iogen has a test plant in operation since 2004 handling up to 20–30 tons per day of a variety of plant residues producing approximately 5,000–6,000 liters (1,300–1,600 gallons) of cellulosic ethanol per day. Its entire output is sold through a single gas station. The company has a longstanding reputation in making cellulosic ethanol on a demonstration scale, but has placed greater effort in developing enzymes than building


commercial plants. The following summarizes some of the initiatives in bringing cellulosic ethanol to market:25

Beta Renewables has a commercial cellulosic ethanol plant in operation since 2013 near Turin, Italy with a capacity of 75 million liter (nearly 20 million gallons) per year fed by a variety of harvesting waste from near-by farms augmented by Arundo donax, a tall, perennial reed that grows in soil dampened by either fresh or moderately saline waters. Other ethanol plants are planned or under construction in Italy, the US, Brazil, China, and Slovak Republic. Profitability depends on very low cost feedstocks.26

KiOR operated a cellulosic plant in Mississippi that produced not ethanol, but gasoline and diesel and jet fuel. It began operations in 2013 with a capacity of 13 million gallons per year using pine tree chips and other woody mass as feedstock. Any form of biomass could be used, which is first fed into a fluid catalytic cracking unit similarly used in oil refineries. There it was mixed with a proprietary catalyst that converted biomass into a light crude oil. A separator then removed the catalyst for rejuvenation and recycling. Light gases were burned as fuel to operate the plant with crude sent to a hydrotreater for conversion to “drop in” gasoline, diesel and jet fuel. “Drop-in” means that these products were virtually indistinguishable on the molecular level with petroleum products.27 Demonstrating the inherent risks in breaking new ground, the company filed for bankruptcy protection in 2014 as a result of its production cost being far in excess of market values. While the plant is inoperative, research is continuing to reduce cost and improve quality of drop-in petroleum products.28

Abengoa Bioenergy completed a 25 million gallon per year cellulosic ethanol plant in Kansas in 2014, which consumes 350,000 tons per year of biomass (agricultural waste, nonfeed energy crops, and wood waste). The plant will also generate 21 MW of electricity by burning biomass to be energy self-sufficient.

DuPont is building a 30 million gallon per year cellulosic ethanol plant in Iowa that is nearing completion. The plant will be supplied by corn stover baled in the field and shipped to the plant by truck. Each acre provides 2 tons of baled stover, which is sufficient to yield an ethanol output by 150 gallons. Adding this to the 300 gallons obtained from corn kernels means a 50 percent increase in yield.29

POET-DSM Advanced Biofuels, a joint venture between Royal DSM of The Netherlands and POET, LLC, is the first commercial cellulosic ethanol plant in the US. The plant produces 20 million gallons per year of cellulosic ethanol from corn stover and cobs plus shares facilities with an adjacent 50 million gallon per year conventional ethanol plant.

Fulcrum Bioenergy expects to start construction on a biofuels plant that runs on municipal sewage waste (MSW) in 2015 in Nevada with a slated output of 10 million gallons of


renewable fuel per year consuming 200,000 tons of MSW. The plant, if successful, will serve as a prototype for building much larger plants throughout the US.30

BlueFire Renewables has a demonstration plant in Japan that converts wood and MSW to ethanol and plans to build a biorefinery in Mississippi that converts green wood and wood wastes into 19 million gallons of cellulosic ethanol per year. If successful, plans are to build five larger plants in the US.31

GranBio Investimentos in Brazil started production in 2014 of a biofuel refinery to produce 22 million gallons of cellulosic ethanol annually and 150 mW of electricity. The plant consumes straw and bagasse as fuel and utilizes a newly developed Proesa technology. The plant was built by Areva, the nuclear power plant manufacturer, which has built 95 biomass plants worldwide. GranBio intends to build more such plants if production cost of cellulosic ethanol can match sugar ethanol.32

Cellulosic ethanol plants, more or less sized like those in the US, are being planned or built in Denmark, Italy, Norway, Russia, Spain, and Sweden using adaptations of existing technology or pursuing new ways of extracting ethanol from cellulose.

Although 30 million gallons per year of cellulosic ethanol sounds impressive, this is 82,200 gallons per day or 1,960 bpd at 42 gallons in a barrel. To make this energy-equivalent to gasoline, this has to be multiplied by 0.7 or 1,370 barrels per day of gasoline-equivalent output. Over 80 of these cellulosic ethanol plants would be necessary to substitute for the output of 112,500 bpd gasoline from a single standard-sized 250,000 bpd oil refinery operating at 90 percent capacity with 50 percent gasoline yield. An enormous land area is required to substitute cellulosic ethanol for a single oil refinery. US cellulosic plants are participants in a US Department of Energy program to underwrite the development of biorefineries that produce cellulosic ethanol along with a variety of other bio-based industrial chemicals and products, some of which are in the pilot stage.33


1 International Biochar Initiative Web site www.biochar-international.org.2 Made in America Fuel Web site www.madeinamericafuel.com.3 One of my brothers-in-law connected to natural gas drastically reduced his natural gas bill by having a split wood space heater in his basement with vents open to the single story living space above. Going from natural gas to split wood is not without its costs. Every year the inventory of split wood from trees on his property must be replenished and he must tend to the space heater daily when in service. He’s awarded for his effort with a small heating bill. On several occasions, the public utility visited his home to see if he was somehow bypassing the natural gas meter because his consumption was so low!4 David Appleyard, “Biomass Outlook 2014: Is Biomass About to Go Bang?,” Renewable Energy World (February 10, 2014), Web site www.renewableenergyworld.com/rea/news/print/article/2014/02.5 WoodPellets.com Web site www.woodpellets.com.6 As a young boy, I remember my father daily tending to the coal furnace—once in the morning to ensure that the furnace had enough coal to operate during the day when he was at work and then again at night to stoke the furnace. On weekends, he would remove and spread the ash on a backyard vegetable garden. Now, three-quarters of a century later, my son facing high heating oil costs, and not having the option to switch to less costly natural gas, installed an anthracite stove. Like my father, my son spreads ashes on his backyard garden.7 The extra effort of wood and coal stoves was eliminated when people switched to heating oil, propane, and natural gas. I remember my mother, when we moved to a farm in upstate New York, staring in dismay at a combination wood and coal burning stove. I can’t tell you how quickly that stove was consigned to the dust bin of history and replaced by a spanking new propane stove. What we are witnessing is history of energy in reverse!8 B. Mendell and A. Lang, Wood for Bioenergy (Durham, NC: Forest History Society, 2012) and “The Fuel of the Future,” The Economist (April 6, 2013).9 “Biomass News,” European Biomass Association (AEBIOM), No 15 (April 2009).10 Dr. Jeff Wright of ArborGen, “Bio-energy Forest Plantations for the Southeastern US,” Renewable Energy World (December 30, 2013), Web site www.renewableenergyworld.com/rea/news/article/2013/12/bio-energy-forest-plantations-for-the-southeastern-united-states?cmpid=WNL-Wednesday-January1-2014.11 Renewable Energy World Web site www.renewableenergyworld.com provides news clips on recent goings-on for all renewable energy sources including bioenergy, solar, wind, hydro, geothermal, wave and tidal energy. I highly recommend this Web site if you wish to keep up to date with what’s going on in renewables. Many of these news clips are incorporated in this book.12 Ann Perry, “Measuring the Potential of Switchgrass Pellets,” USDA Agricultural Research Service (April 1, 2013), Web site www.ars.usda.gov/is/AR/archive/mar13/switchgrass0313.htm.13 “Going Global: 2015 Ethanol Industry Outlook,” Renewable Fuels Association (RFA), Web site http://ethanolrfa.3cdn.net/c5088b8e8e6b427bb3_cwm626ws2.pdf.14 Green Shift Web site www.gs-cleantech.com/whatwedo.php?mode=2.15 EIA Web site www.eia.gov/dnav/pet/PET_MOVE_EXPC_A_EPOOXE_EEX_MBBL_M.htm.16 US Department of Agriculture Web site http://gain.fas.usda.gov/Recent%20GAIN%20Publications/Biofuels%20Annual_Sao%20Paulo%20ATO_Brazil_7-27-2011.pdf. Frankly, different reputable sources provide contradictory information over the state of Brazilian ethanol imports and exports.17 University of Illinois Urbana-Champaign Web site http://farmdocdaily.illinois.edu/2013/05/brazilian-ethanol-implications.html.18 Jim Lane, “Can the US Still Meet Its 2022 Biofuels Targets?” Biofuels Digest (February 28, 2013), Web site www.biofuelsdigest.com/bdigest/2013/02/27/can-thEus-still-meet-its-2022-biofuels-targets.19 Clayton McMartin and Graham Noyes, “White Paper America Advances to Performance Based Biofuels,” RinStar and Stoehl Rives (February 26, 2010).See also Ben Montalbano, “Comments on Blend Wall/Duel Compatibility Issues,” Energy Policy Research Foundation (EPRINC) (April 5, 2013).20 Jim Lane, “Obama Messes with the US Renewable Fuel Standard,” Biofuels Digest (November 19, 2013).See also “Nightmare Scenario: Renewable Fuels’ Defenders Pull out the Stops to Persuade EPA to Continue the War on Imported Oil,” Biofuels Digest, Web site www.biofuelsdigest.com/bdigest/2013/12/04/stand-by-me-renewable-fuels-defenders-pull-out-the-stops-to-persuade-epa-to-continue-the-war-on-imported-oil.21 P. C. Badger, “Ethanol from Cellulose: A General Review,” ASHS Press (2002), Web site http://large.stanford.edu/publications/coal/references/docs/badger.pdf is a good description of obtaining ethanol from cellulose.22 Information on cellulosic ethanol drawn from the DOE Biomass Program, Web site http://science.howstuffworks.com/environmental/green-tech/energy-production/cellulosic-ethanol2.htm.23 Erin Voegele, “Survey: Cellulosic Ethanol to be Cost Competitive by 2016,” Ethanol Producer, Web site http://ethanolproducer.com/articles/9658/survey-cellulosic-ethanol-will-be-cost-competitive-by-2016.

24 Mark Mascal, Saikat Dutta, and Inaki Gandarias, "Hydrodeoxygenation of the Angelica Lactone Dimer, a Cellulose-Based Feedstock: Simple, High-Yield Synthesis of Branched C7–C10 Gasoline-like Hydrocarbons," Angewandte Chemie International Edition 2014, volume 53, (2014).See also D. J. Hayes, J. Ross, M. H. B. Hayes, S. Fitzpatrick, “The Biofine Process—Production of Levulinic Acid, Furfural, and Formic Acid from Lignocellulosic Feedstocks,” Web site http://onlinelibrary.wiley.com/doi/10.1002/9783527619849.ch7/summary# DOI: 10.1002/9783527619849.ch7 (January 30, 2008).25 European Biofuels Technology Platform Web site http://biofuelstp.eu/cellulosic-ethanol.html#crescentino.26 Beta Renewables Web site www.betarenewables.com.27 Kior Web site www.kior.com/content/?s=11&t=Technology.28 Dawn McCarty and Justin Doom, “Kior, Inc., Biofuel Company, Files Bankruptcy, Plans Sale,” Bloomburg (November 10, 2014), Web site www.bloomberg.com/news/articles/2014-11-10/kior-inc-biofuel-company-files-bankruptcy-plans-sale.29 Dupont Nevada (Iowa) Site Cellulosic Ethanol Facility Web site http://biofuels.dupont.com/cellulosic-ethanol/nevada-site-ce-facility.30 Fulcrum BioEnergy Web site http://fulcrum-bioenergy.com/facilities.31 Blue Fire Renewables Web site http://bfreinc.com.32 Vanessa Dezem and Gerson Freitas Jr., “GranBio Planning Second Brazil Site for Cellulosic Ethanol,” Bloomberg (October 14, 2014), Web site www.bloomberg.com/news/2014-10-14/granbio-planing-second-brazil-site-for-cellulosic-ethanol.html. Proesa technology described in Web site www.betarenewables.com/proesa/what-is.See also GranBio Web site www.granbio.com.br, which can be translated to English.See also Areva Web site www.areva.com/EN/operations-3924/areva-bioenergy-projects.html.33 Bioenergy Technologies Office Web site www.energy.gov/sites/prod/files/2015/04/f22/mypp_beto_march2015.pdf contains a list of biorefinery projects.See also “Bioenergy Technologies Office 2015 Multi-Year Program Plan,” Web site www1.eere.energy.gov/bioenergy/integrated_biorefineries.html.

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