Biofuel

By…….

Md. Mesbah Uddin Khulna University Bangladesh

Introduction

Energy availability, supply and use play a central role in the way societies organize themselves, from individual welfare to social and industrial development. By extension, energy accessibility and cost is a determining factor for the economical, political and social interrelations among nations. Considering energy sources, human society has dramatically increased the use of fossil fuels in the past 50 years in a way that the most successful economies are large consumers of oil. However, geopolitical factors related to security of oil supply, high oil prices and serious environmental concerns, prompted by global warming - the use of petrol for transportation accounts for one-third of greenhouse gas emissions (Wyman, 1996) - have led to a push towards decreased consumption. Indeed, the world's strongest economies are deeply committed to the development of technologies aiming at the use of renewable sources of energy. Within this agenda, the substitution of liquid fuel gasoline by renewable ethanol is of foremost importance.

Fossil Fuel & Environment Fossil fuels or mineral fuels are fossil source fuels, that is, hydrocarbons found within the top layer of the Earth’s crust. They range from volatile materials with low carbon:hydrogen ratios like methane, to liquid petroleum to nonvolatile materials composed of almost pure carbon, like anthracite coal. Methane can be found in hydrocarbon fields, alone, associated with oil, or in the form of methane clathrates. It is generally accepted that they formed from the fossilized remains of dead plants and animals by exposure to heat and pressure in the Earth's crust over hundreds of millions of years. This is known as the biogenic theory and was first introduced by Georg Agricola in 1556 and later by Mikhail Lomonosov in 1757. There is an opposing more modern theory that the more volatile hydrocarbons, especially natural gas, are formed by abiogenic processes, that is no living material was involved in their formation. It was estimated by the Energy Information Administration that in 2005, 86% of primary energy production in the world came from burning fossil fuels, with the remaining non-fossil sources being hydroelectric 6.3%, nuclear 6.0%, and other (geothermal, solar, wind, and wood and waste) 0.9 percent. Comparative figures • 1 litre of regular gasoline is the time-rendered result of about 23.5 metric tonnes of ancient phytoplankton material deposited on the ocean floor. • The total fossil fuel used in the year 1997 is the result of 422 years of all plant matter that grew on the entire surface and in all the oceans of the ancient earth.

Consumption rates of oil There are two main ways to measure the oil consumption rates of countries: by population or by gross domestic product (GDP). This metric is important in the global debate over oil consumption/energy consumption/climate change because it takes social and economic considerations into account when scoring countries on their oil consumption/energy consumption/climate change goals. Nations such as China and India with large populations tend to promote the use of population based metrics, while nations with large economies such as the United States would tend to promote the GDP based metric.

Selected Nations

GDP-to-consumption ratio (US$1000/(barrel/year))

Switzerland

3.75

United Kingdom

3.34

Norway

3.31

Austria

2.96

France

2.65

Germany

2.89

Sweden

2.71

Italy

Fig: World energy consumption, 1980-2030. Source: International Energy Outlook 2006

Selected Nations

Per capita energy consumption, oil equivalent (barrel/person/year)

DRC

0.13

Ethiopia

0.37

Bangladesh

0.57

Myanmar

0.73

Pakistan

1.95

Nigeria

2.17

India

2.18

Vietnam

2.70

2.57

Philippines

3.77

European Union

2.52

Indonesia

4.63

DRC

2.4

China

4.96

Japan

2.34

Egypt

7.48

Australia

2.21

Turkey

9.85

Spain

1.96

Brazil

11.67

Bangladesh

1.93

Poland

11.67

Poland

1.87

World

12.55

United States

1.65

Thailand

13.86

Belgium

1.59

Russia

17.66

World

1.47

Mexico

18.07

Turkey

1.39

Iran

21.56

Canada

1.35

European Union

29.70

Mexico

1.07

Ethiopia

1.04

United Kingdom

30.18

South Korea

1.00

Germany

32.31

Philippines

1.00

France

32.43

Brazil

0.99

Italy

32.43

Taiwan

0.98

Austria

34.01

China

0.94

Spain

35.18

Nigeria

0.94

Switzerland

34.64

Pakistan

0.93

Sweden

34.68

Myanmar

0.89

Taiwan

41.68

India

0.86

Japan

42.01

Russia

0.84

Australia

42.22

Indonesia

0.71

South Korea

43.84

Vietnam

0.61

Norway

52.06

Thailand

0.53

Belgium

61.52

Saudi Arabia

0.46

United States

68.81

Egypt

0.41

Canada

69.85

Singapore

0.40

Saudi Arabia

75.08

Iran 0.35 Singapore 178.45 (Note: The figure for Singapore is skewed because of its small population compared with its large oil refining capacity. Most of this oil is sent to other countries.)

Energy Reserve Levels of primary energy sources are the reserves in the ground. Flows are production. The most important part of primary energy sources are the carbon based fossil energy sources. Oil, coal, and gas stood for 79.6% of primary energy production during 2002 (in million tonnes of oil equivalent (mtoe)) (34.9+23.5+21.2). Levels (reserves) (EIA oil, gas, coal estimates, EIA oil, gas estimates) • Oil: 1,050 to 1,277 billion barrels (167 to 203 km³) 2003-2005 • Gas: 6,040 - 6,806 trillion cubic feet (171,000 to 192,700 km³) 6,806*0.182= 1,239 billion barrel oil equivalent (BBOE) 2003-2005 • Coal: 1,081,000 million short tons (1,081,000*0.907186*4.879= 4,786 BBOE) (2004) Flows (daily production) during 2002 (7.9 is a ratio to convert tonnes of oil equivalent to barrels of oil equivalent) • Oil: (10,230*0.349)*7.9/365= 77 million barrels per day • Gas: (10,230*0.212)*7.9/365= 47 million barrels oil equivalent per day {MBOED} • Coal: (10,230*0.235)*7.9/365= 52 MBOED Years of production left in the ground with the most optimistic reserve estimates (Oil & Gas Journal, World Oil) • Oil: 1,277,000 million barrel reserve/77 million barrels used per day/365 days per year= 45 years • Gas: 1,239,000 million barrels equivalent reserve/47 million barrel equivalent used per day/365 days per year= 72 years • Coal: 4,786,000 million barrels equivalent reserve/52 million barrel equivalent used per day/365 days per year= 252 years

This calculation assumes that the product could be produced at a constant level for that number of years and that all of the reserves could be recovered. In reality, consumption of all three resources has been increasing. While this suggests that the resource will be used up more quickly, in reality, the production curve is much more akin to a bell curve. At some point in time, the production of each resource within an area, country, or globally will reach a maximum value, after which, the production will decline until it reaches a point where is no longer economically feasible or physically possible to produce.

Environmental Pollution The burning of fossil fuels produces around 21.3 billion tonnes (= 21.3 gigatons) of carbon dioxide per year, but it is estimated that natural processes can only absorb about half of that amount, so there is a net increase of 10.65 billion tonnes of atmospheric carbon dioxide per year (one tonne of atmospheric carbon is equivalent to 44/12 or 3.7 tonnes of carbon dioxide). Carbon dioxide is one of the greenhouse gases that enhances radiative forcing and contributes to global warming, causing the average surface temperature of the Earth to rise in response, which climate scientists agree will cause major adverse effects, including reduced biodiversity and, over time, cause sea level rise.

Fig: Global fossil carbon emission by fuel type, 1800-2004 AD

In the United States, more than 90% of greenhouse gas emissions come from the combustion of fossil fuels. Combustion of fossil fuels also produces other air pollutants, such as nitrogen oxides, sulfur dioxide, volatile organic compounds and heavy metals. Combustion of fossil fuels generates sulfuric, carbonic, and nitric acids, which fall to Earth as acid rain, impacting both natural areas and the Fig: CO2 emission

built environment. Fossil fuels also contain radioactive materials, mainly uranium and thorium that are released into the atmosphere. In 2000, about 12,000 metric tons of thorium and 5,000 metric tons of uranium were released worldwide from burning coal. It is estimated that during 1982, US coal burning released 155 times as much radioactivity into the atmosphere as the Three Mile Island incident. However, this radioactivity from coal burning is minuscule at each source and has not shown to have any adverse effect on human physiology. Harvesting, processing, and distributing fossil fuels can also create environmental concerns. Coal mining methods, particularly mountaintop removal and strip mining, have negative environmental impacts, and offshore oil drilling poses a hazard to aquatic organisms. Oil refineries also have negative environmental impacts, including air and water pollution. Transportation of coal requires the use of diesel-powered locomotives, while crude oil is typically transported by tanker ships, each of which requires the combustion of additional fossil fuels. Oil spill is another form of pollution. The term often refers to marine oil spills, where oil is released into the ocean or coastal waters. The oil may be a variety of materials, including crude oil, refined petroleum products (such as gasoline or diesel fuel) or byproducts, ships' bunkers, oily refuse or oil mixed in waste. Spills take months or even years to clean up. The oil penetrates and opens up the structure of the plumage of birds, reducing its insulating ability, and so making the birds more vulnerable to temperature fluctuations and much less buoyant in the water. It also impairs birds' flight abilities, making it difficult or impossible to forage and escape from predators. As they attempt to preen, birds typically ingest oil that coats their feathers, causing kidney damage, altered liver function, and digestive tract irritation. This and the limited foraging ability quickly cause dehydration and metabolic imbalances. Most birds affected by an oil spill die unless there is human intervention. Marine mammals exposed to oil spills are affected in similar ways as seabirds. Oil coats the fur of Sea otters and seals, reducing its insulation abilities and leading to body temperature fluctuations and hypothermia. Ingestion of the oil causes dehydration and impaired digestion. Table: Energy Content and CO2 Output of Common Fuels

Fuel Type

Specific Volumetric Energy Density Energy Density (MJ/kg) (MJ/L)

CO2 Gas made from Fuel Used (kg/kg)

Energy per CO2 (MJ/kg)

Liquid Fuels

Pyrolysis oil

17.5

21.35

(Assumption Of Fuel: Carbon Content = 23% w/w) 0.84

20.77

Methanol (CH3OH)

19.9 – 22.7

15.9

1.37

14.49-16.53

Ethanol (CH3-CH2OH)

23.4 – 26.8

18.4 - 21.2

1.91

12.25-14.03

EcaleneTM

28.4

22.7

75%C2H6O+9%C3H8O+7%C4H10O+5%C5H12O+4%Hx 2.03

14.02

Butanol(CH3(CH2)3-OH)

36

29.2

2.37

15.16

Fat

37.656

31.68

Biodiesel

37.8

33.3 – 35.7

~2.85

~13.26

Sunflower oil (C18H32O2)

39.49

33.18

(12%(C16H32O2)+16%(C18H34O2)+71%(LA)+1%(ALA))2.81

14.04

Castor oil (C18H34O3)

39.5

33.21

(1%PA+1%SA+89.5%ROA+3%OA+4.2%LA+0.3%ALA)2.67

14.80

33 - 33.48

(15%(C16H32O2)+75%(C18H34O2)+9%(LA)+1%(ALA))2.80

14.03

Olive oil (C18H34O2) 39.25 - 39.82

Fossil Fuels (comparison)

Coal

29.3 – 33.5

39.85 - 74.43

(Not Counting:CO,NOx,Sulfates & Particulates) ~3.59

~8.16-9.33

Crude Oil

41.868

28 – 31.4

(Not Counting:CO,NOx,Sulfates & Particulates) ~3.4

~12.31

Gasoline

45 – 48.3

32 – 34.8

(Not Counting:CO,NOx,Sulfates & Particulates) ~3.30

~13.64-14.64

Diesel

48.1

40.3

(Not Counting:CO,NOx,Sulfates & Particulates) ~3.4

~14.15

Natural Gas

38 – 50

(Liquified) 25.5 – 28.7

(Ethane,Propane & Butane N/C:CO,NOx & Sulfates) ~3.00

~12.67-16.67

Ethane (CH3-CH3)

51.9

(Liquified) ~24.0

2.93

17.71

Uranium-235 (235U)

77,000,000

[Greater for lower ore conc.(Mining,Refining,Moving)] 0.0

(NETT) >12.67

(Pure)1,470,70

Renewable Source of Energy Fossil fuels are non-renewable resources because they take millions of years to form, and reserves are being depleted much faster than new ones are being formed. Concern about fossil fuel supplies is one of the causes of regional and global conflicts. The production and use of fossil fuels raise environmental concerns. A global movement toward the generation of renewable energy is therefore under way to help meet increased energy needs. Biofuel can be a good choice for that. Biofuel is any fuel that is derived from biomass — recently living organisms or their metabolic byproducts, such as manure from cows. It is a renewable energy source, unlike other natural resources such as petroleum, coal and nuclear fuels. One definition of biofuel is any fuel with an 80% minimum content by volume of materials derived from living organisms harvested within the ten years preceding its manufacture. Like coal and petroleum, biomass is a form of stored solar energy. The energy of the sun is "captured" through the process of photosynthesis in growing plants. One advantage of biofuel in comparison to most other fuel types is it is biodegradable, and thus relatively harmless to the environment if spilled. Agricultural products specifically grown for use as biofuels include corn and soybeans, primarily in the United States; as well as flaxseed and rapeseed, primarily in Europe; sugar cane in Brazil and palm oil in South-East Asia. Biodegradable outputs from industry, agriculture, forestry, and households can also be used to produce bioenergy; examples include straw, timber, manure, rice husks, sewage, biodegradable waste and food leftovers. These feedstocks are converted into biogas through anaerobic digestion. Biomass used as fuel often consists of underutilized types, like chaff and animal waste. Bioenergy covers about 15% of the world's energy consumption. Most bioenergy is consumed in developing countries and is used for direct heating, as opposed to electricity production. However, Sweden and Finland supply 17% and 19% respectively, of their energy needs with bioenergy, quite high for industrialized countries. Biomass can be used both for centralized production of electricity and district heat, and for local heating The production of biofuels to replace oil and natural gas is in active development, focusing on the use of cheap organic matter (usually cellulose, agricultural and sewage waste) in the efficient production of liquid and gas biofuels which yield high net energy gain. The carbon in biofuels was recently extracted from atmospheric carbon dioxide by growing plants, so burning it does not result in a net increase of carbon dioxide in the Earth's atmosphere. As a result, biofuels are seen by many as a way to reduce the amount of carbon dioxide released into the atmosphere by using them to replace non-renewable sources of energy.

History of Biofuel Biofuel was used since the early days of the car industry. Nikolaus August Otto, the German inventor of the combustion engine, conceived his invention to run on ethanol. While Rudolf Diesel, the German inventor of the Diesel engine, conceived it to run on peanut oil. The Ford Model T, a car produced between 1903 and 1926 used ethanol. However, when crude oil began being cheaply extracted from deeper in the soil, cars began using fuels from oil. Nevertheless, before World War II, biofuels were seen as providing an alternative to imported oil in countries such as Germany, which sold a blend of gasoline with alcohol fermented from potatoes under the name Reichskraftsprit. In Britain, grain alcohol was blended with petrol by the Distillers Company Ltd under the name Discol and marketed through Esso's affiliate Cleveland. After the War cheap Middle Eastern Oil lessened interest in biofuels. Then with the oil shocks of 1973 and 1979, there was an increase in interests from governments and academics in biofuels. However, interest decreased with the counter-shock of 1986 that made oil prices cheaper again. But since about 2000 with rising oil prices, concerns over the potential oil peak, greenhouse gas emissions (Global Warming), and instability in the Middle East are pushing renewed interest in biofuels. Government officials have made statements and given aid in favour of biofuels. For example, U.S. president George Bush said in his 2006 State of Union speech, that he wants for the United States, by 2025, to replace 75% of the oil coming from the Middle East. Brazil has been a front-runner in the use of renewable fuels. The substitution of gasoline by ethanol started in 1975, when the Brazilian Government launched the “Proálcool Program" (Programa Nacional do Álcool). At the time of the first oil crisis, in the 1970s, the country imported 85% of its oil needs and the potential for ethanol production from sugarcane as a transportation fuel was in good agreement with the Government policy regarding energy supply independence. The Proálcool Program included incentives for distilleries and automobile companies that made ethanol-only cars. Although in the mid-1970s environmental concern was not a major driving force for substituting the use of gasoline, it is worth pointing out the global environmental benefits that have resulted from this policy since then.

Presently, the ethanol industry in Brazil runs without government incentives and the biofuel is distributed by the Brazilian oil company Petrobras. The Brazilian fleet of 20 million cars (the total vehicle fleet including cars, light commercials, trucks and buses is around 24 million) runs on either a gasoline blend containing 22-24% ethanol or on 100% ethanol. Natural gas has also been marginally used. Ethanol consumption is forecast to increase as the number of “flex-fuel" cars, with engines able to run on both gasoline blend or ethanol, is forecast to increase from the present 4 million to 15 million in 2013.

Brazil has 851 million hectares from which around 5 million are presently used for sugar cane plantations. The State of São Paulo is the biggest sugar cane producer in Brazil with 68% (3.35 million hectares) of the total sugar cane plantations in Brazil. The country has 365 sugar/ethanol producing units from which 240 produce both sugar and ethanol, 109 produce only ethanol and 15 produce only sugar. It is forecast that 41 new distilleries will be built before 2010 (Carvalho, 2006). In the units that can produce both sugar and ethanol, the pressed sugar-cane juice can go either to huge fermentation vats to make alcohol from the sugarcane sucrose or be spun in centrifuges to produce sugar (sucrose) and molasses, depending on which product is priced more favourably on any given day. About 70,000 farmers produced 385 million tons of sugar cane in 2006, and refineries made 4 billion gallons of alcohol fuel; enough to replace 460 million barrels of oil. Brazilian alcohol is the cheapest and more sustainable in the world, with a production cost of U$ 0.16-0.20 / L. In each sugar and/or alcohol mill the crushed stalk of the cane (bagasse) is burned for the production of steam (heat) and for power/electricity generation. However, the majority of the sugar and alcohol production plants have not yet optimized the processes for electricity generation due to the low price of the electricity that is usually sold to neighbouring agro-industries. Seventy five million tonnes of dry bagasse are produced annually by the ethanol and sugar industry.

Comparison of key characteristics between the ethanol industries in the United States and Brazil Characteristic

Feedstock

Total ethanol production (2007) Total arable land Total area used for ethanol crop

Productivity per hectare

Energy balance (input energy productivity)

Brazil

U.S.

Units/comments

Sugar cane

Maize

Main cash crop for ethanol production, the US has less than 2% from other crops.

5,019.2

6,498.6

Million U.S. liquid gallons

355

270(1)

Million hectares.

3.6 (1%)

7,500

8.3 to 10.2 times

Estimated greenhouse gas 86-90%(2) emission reduction

10 (3.7%) Million hectares (% total arable)

4,000

Liters of ethanol per hectare. Brazil is 727 to 870 gal/acre (2006), US is 424 gal/acre (2006)

1.3 to 1.6 Ratio of the energy obtained from ethanol to times the energy expended in its production

10-30%(2)

% GHGs avoided by using ethanol instead of gasoline, using existing crop land.

As % of total fueling gas stations in the 873 (0,5%) country. U.S. has 170,000 (see Inslee, op cit pp. 161)

Ethanol fueling stations in the counrty

33,000 (100%)

Fuel ethanol used by the road transport sector

20%(3)

3.6%

As % of the sector's total on a volumetric basis for 2006.

0.83

1.14

2006/2007 for Brazil (22¢/liter), 2004 for U.S. (35¢/liter)

Cost of production (USD/gallon)

Government subsidy (in USD)

0

0.51/gallon

U.S. as of 2008-04-30. Brazilian ethanol production is no longer subsidized.

Import tariffs (in USD)

0

0.54/gallon

As of April 2008, Brazil does not import ethanol, the U.S. does

Notes: (1) Only contiguous U.S., excludes Alaska. (2) Assuming no land use change. (3) Excluding diesel-powered vehicles, ethanol consumption in the road sector is more than 40%

Classification of Biofuel A. Biologically produced alcohols Biologically produced alcohols, most commonly ethanol and methanol, and less commonly propanol and butanol are produced by the action of microbes and enzymes through fermentation. • Methanol, which is currently produced from natural gas, can also be produced from biomass — although this is not economically viable at present. The methanol economy is an interesting alternative to the hydrogen economy. • Biomass to liquid, synthetic fuels produced from syngas. Syngas in turn, is produced from biomass by gasification. • Ethanol fuel produced from sugar cane is being used as automotive fuel in Brazil. Ethanol produced from corn is being used mostly as a gasoline additive (oxygenator) in the United States, but direct use as fuel is growing. Cellulosic ethanol is being manufactured from straw (an agricultural waste product) by Iogen Corporation of Ontario, Canada; and other companies are attempting to do the same. ETBE containing 47% Ethanol is currently the biggest biofuel contributor in Europe. • Butanol is formed by A.B.E. fermentation (Acetone, Butanol, Ethanol) and experimental modifications of the ABE process show potentially high net energy gains with butanol being the only liquid product. Butanol can be burned "straight" in existing gasoline engines (without modification to the engine or car), produces more energy and is less corrosive and less water soluble than ethanol, and can be distributed via existing infrastructures. • Mixed Alcohols (e.g., mixture of ethanol, propanol, butanol, pentanol, hexanol and heptanol, such as EcaleneTM), obtained either by biomass-to-liquid technology (namely gasification to produce syngas followed by catalytic synthesis) or by bioconversion of biomass to mixed alcohol fuels.

•

GTL or BTL both produce synthetic fuels out of biomass in the so called Fischer Tropsch process. The synthetic biofuel containing oxygen is used as additive in high quality diesel and petrol.

B. Biologically produced gases Biogas is produced by the process of anaerobic digestion of organic material by anaerobes. Biogas can be produced either from biodegradable waste materials or by the use of energy crops fed into anaerobic digesters to supplement gas yields. The solid output, digestate, can also be used as a biofuel. Biogas contains methane and can be recovered in industrial anaerobic digesters and mechanical biological treatment systems. Landfill gas is a less clean form of biogas which is produced in landfills through naturally occurring anaerobic digestion. Paradoxically if this gas is allowed to escape into the atmosphere it is a potent greenhouse gas.

C. Biologically produced gases from wastes Biologically produced oils and gases can be produced from various wastes: • Thermal depolymerization of waste can extract methane and other oils similar to petroleum. • Pyrolysis oil may be produced out of biomass, wood waste etc. using heat only in the flash pyrolysis process. The oil has to be treated before using in conventional fuel systems or internal combustion engines (water + pH). • One company, GreenFuel Technologies Corporation, has developed a patented bioreactor system that utilizes nontoxic photosynthetic algae to take in smokestacks flue gases and produce biofuels such as biodiesel, biogas and a dry fuel comparable to coal.

D. Biologically produced oils Biologically produced oils can be used in diesel engines: • Straight vegetable oil (SVO). • Waste vegetable oil (WVO) - waste cooking oils and greases produced in quantity mostly by commercial kitchens • Biodiesel obtained from transesterification of animal fats and vegetable oil, directly usable in petroleum diesel engines.

E. Direct biofuel Direct biofuels are biofuels that can be used in existing unmodified petroleum engines. Because engine technology changes all the time, exactly what a direct biofuel is can be hard to define; a fuel that works without problem in one unmodified engine may not work in another engine. In general, newer engines are more sensitive to fuel than older engines, but new engines are also likely to be designed with some amount of biofuel in mind. Straight vegetable oil can be used in some (older) diesel engines. Only in the warmest climates can it be used without engine modifications, so it is of limited use in colder climates. Most commonly it is turned into biodiesel. No engine manufacturer explicitly allows any use of vegetable oil in their engines.

Fuel Ethanol Production

Depending on the raw materials and microbes used fermentation process varies in country to country, e.g. USA uses corn while Brazil uses sugarcane as raw material for ethanol production. Other agricultural crop residues such as corn stover, wheat and rice straw, residues generated from citrus processing, coconut biomass, grasses and residues from the pulp and paper industry (paper mill sludge), as well as municipal cellulosic solid wastes, will eventually be also used as raw materials to produce ethanol.

Raw Materials Sugar: The most widely used sugar for ethanol fermentation is blackstrap molasses which contains about 35 – 40 wt% sucrose, 15 – 20 wt% invert sugars such as glucose and fructose, and 28 – 35 wt% of non-sugar solids. Blackstrap (syrup) is collected as a by-product of cane sugar manufacture. The molasses is diluted to a mash containing ca 10 –20 wt% sugar. After the pH of the mash is adjusted to about 4 – 5 with mineral acid, it is inoculated with the yeast, and the fermentation is carried out non-aseptically at 20 – 32°C for about 1 – 3days. The fermented beer, which typically contains ca 6 – 10 wt% ethanol, is then set to the product recovery in purification section of the plant. Starches: All potable alcohol and most fermentation industrial alcohol is currently made principally from grains. Fermentation of starch from grain is somewhat more complex than fermentation of sugars because starch must first be converted to sugar and then to ethanol. Starch is converted enzymatically to glucose either by diastase presents in sprouting grain or by fungal amylase. The resulting dextrose is fermented to ethanol with the aid of yeast producing CO2 as co-product. A second co-product of unfermented starch, fiber, protein and ash known as distillers grain (a high protein cattle feed) is also produced.

Cellulosic Materials: Each step in the process of the conversion of cellulose to ethanol proceeded with 100% yield; almost two-thirds of the mass would disappear during the sequence, most of it as carbon dioxide in the fermentation of glucose to ethanol. This amount of carbon dioxide leads to a disposal problem rather than to a raw material credit. Another problem is that the aqueous acid used to hydrolyze the cellulose in wood to glucose and other simple sugars destroys much of the sugars in the process.

Choice of Suitable Microorganism

Bacteria A great number of bacteria are capable of ethanol formation. Many of these microorganisms, however, generate multiple end products in addition to ethyl alcohol. These include other alcohols (butanol, isopropylalcohol, 2,3-butanediol), organic acid (acetic acid, formic acid, and lactic acids), polyols (arabitol, glycerol and xylitol), ketones (acetone) or various gases (methane, carbon dioxide, hydrogen). Those microbes that are capable of yielding ethanol as the major product (i.e. a minimum of 1 mol ethanol produced per mol of glucose utilized) are shown in table 4: Table 4: Bacterial Species Which Produce Ethanol as the Main Fermentation Product Mesophilic Organisms Clostridium sporogenes Clostridium indolis (pathogenic) Clostridium sphenoides Clostridium sordelli (pathogenic) Zymomonas mobilis (syn. Anaerobica) Zymomonas mobilis Ssp. Pomaceas Spirochaeta aurantia Spirochaeta stenostrepta Spirochaeta litoralis Erwinia amylovora Leuconostoc mesenteroides Streptococcus lactis Sarcina ventriculi (syn. Zymosarcina) a) b)

mmol Ethanol Produced per Mmol Glucose Metabolized up to 4.15 a) 1.96 a) 1.8 a) (1.8) b) 1.7 1.9 (anaerobe) 1.7 1.5 (0.8) 0.84 (1.46) 1.1 (1.4) 1.2 1.1 1.0 1.0

In the presence of high amounts of yeast extract Values in brackets were obtained with resting cells.

Many bacteria (i.e. Enterobacteriaceas, Spirochaeta, Bacteroides, etc.) metabolize glucose by the Embden-Meyerhof pathway. Briefly, this path utilizes 1 mol of glucose to yield 2 mol of pyruvate which are then decarbosylated to acetaldehyde and reduced to ethanol. Beside that the Entner-Doudoroff pathway is an additional means of glucose consumption in many bacteria. As reported by Naim Kosaric et.al. (1983), for Z. mobilis on synthetics media containing either glucose, fructose or sucrose, the specific rates of sugar uptake and ethanol production are at a maximum when utilizing the glucose medium. Table 5: Kinetic Parameters for Growth of Zymomonas mobilis Strain ZM4 in Batch Culture with Different Carbon Substrates (initial concentration 250g/L) Kinetic Parameter Glucose Fructose Specific growth rate, μ (h-1) 0.18 0.10 Specific substrate consumption rate, 11.3 10.4 qs (g/g/hr) Specific ethanol production rate, qp (g/g/hr) Cell yield, Y(g/g) Ethanol yield, Yp/s (g/g) Ethanol yield, (% of theoretical) Maximum ethanol concentration (g/L) Time period of calculation of maximum

Sucrose 0.14 10.0a)

5.4

5.1

4.6

0.015 0.48 117 0 0 – 19

0.009 0.48 94.1 119 0 – 28

0.014 0.46 90.2b) 89 0 – 15

rates (hr) a) Based on changes in total reducing sugar after inversion b) Not corrected for levan formation

The continuous cultivation of Z. mobilis on glucose media has been investigated in 1980, with a glucose feed concentration of 100g/L, stable growth was achieved with ethanol concentrations up to 49 g/L. Complete utilization of this glucose solution was achieved at a dilution rate of 2.0 hr-1 in a Z. mobilis bioreactor employing cell recycle by mean of filtration. Volumetric ethanol productivity was reported to be 120 g/L/h with a steady state ethanol concentration of 48 g/L.

Yeast The organisms of primary interest to industrial operations in fermentation of ethanol include Saccharomyces cerevisiae, S. uvarum, Schizosaccharomyces pombe, and Kluyueromyces sp. Yeast, under anaerobic conditions; metabolize glucose to ethanol primarily by way of the Embden-Meyerhof pathway. The overall net reaction involves the production of 2 moles each of ethanol, but the yield attained in practical fermentations however does not usually exceed 90 – 95% of theorectical. This is partly due to the requirement for some nutrient to be utilized in the synthesis of new biomass and other cell maintenance related reactions.

A small concentration of oxygen must be provided to the fermenting yeast as it is a necessary component in the biosynthesis of polyunsaturated fats and lipids. Typical amounts of O2 maintained in the broth are 0.05 – 0.10 mm Hg oxygen tension. The relative requirements for nutrients not utilized in ethanol synthesis are in proportion to the major components of the yeast cell. These include carbon oxygen, nitrogen and hydrogen. To leaser extent quantities of phosphorus, sulfur, potassium, and magnesium must also be provided for the synthesis of minor components. Minerals (i.e. Mn, Co, Cu, Zn) and organic factors (amino acids, nucleic acids, and vitamins) are required in trace amounts. Yeast is highly susceptible to ethanol inhibition. Concentration of 1-2% (w/v) is sufficient to retard microbial growth and at 10% (w/v) alcohol, the growth rate of the organism is nearly halted.

Bacteria vs. Yeast According to P. Gunasekaran (1999), the yeast Saccharomyces cerevisiae and facultative bacterium Zymomonas mobilis are better candidates for industrial alcohol production. Z. mobilis possesses advantages over S. cerevisiae with respect to ethanol productivity and tolerance. But the bottlenecks in Z. mobilis are: • • •

its inability to convert complex carbohydrate polymers like cellulose, hemicellulose, and starch to ethanol, its resulting in byproducts such as sorbitol, acetoin, glycerol and acetic acid, Formation of extracellular levan polymer.

As reported in batch fermentation, sugar concentrations as high as 223 g/l could be fermented to 105 g/L ethanol in 70 hours. The percentage theoretical yield was 92%. Whereas in a continuous fermentation using mixed cultures of Z. mobilis and S. cerevisiae, production of 54.3 g/L of ethanol was observed within 3 days. A high ethanol productivity of 70.7 g/L/hr was obtained with a final ethanol concentration of 49.5 g/L and yields of 0.5 g/g. this amount to 98% of the theoretical yield and 99% substrate conversion.

Table 6: Kinetic Parameters for Zymomonas mobilis and Saccharomyces uvarum on 250g/L Glucose Media in Non-aerated Batch Culture (30°C, pH 5.0) Kinetic Parameters Z. mobilis

S. uvarum

Specific growth rate, μ (h-1) Specific glucose uptake rate,

0.13 5.5

0.055a) 2.1b)

qs (g/g/hr) Specific ethanol production rate,

2.5

0.87c)

0.019 0.47 92.5 102

0.033 0.44 86 108

qp (g/g/hr) Cell yield, Y(g/g) Ethanol yield, Yp/s (g/g) Ethanol yield, (% of theoretical) Maximum ethanol concentration (g/L)

a) Based on the difference between initial and residual glucose concentrations b) A molar reaction stoichiometry of 1 glucose

2 ethanol + 2CO2 has been assumed for a

theoretical yield c) Kinetic parameters calculated for fermentation run between 16 and 22 hour when the culture was growing fully anaaerobically

Ethanol production from corn

In the United States, ethanol is produced primarily from starch in corn kernels. Most of the 4 billion gallons of ethanol produced in 2005 came from 13% of the U.S. corn crop (1.43 billion bushels of corn grain). When corn is harvested, the kernels make up

about half of the above-ground biomass, and corn stover (e.g., stalks, leaves, cobs, husks) makes up the other half. Ethanol production from corn grain involves one of two different processes: Wet milling or dry milling. In wet milling, the corn is soaked in water or dilute acid to separate the grain into its component parts (e.g., starch, protein, germ, oil, kernel fibers) before converting the starch to sugars that are then fermented to ethanol. In dry milling, the kernels are ground into a fine powder and processed without fractionating the grain into its component parts. Most ethanol comes from dry milling. Key steps in the dry mill ethanol-production process include:

 Milling: Corn kernels are ground into a fine powder called "meal."  Liquefying and Heating the Cornmeal: Liquid is added to the meal to produce a mash, and the temperature is increased to get the starch into a liquid solution and remove bacteria present in the mash.  Enzyme Hydrolysis: Enzymes are added to break down the long carbohydrate chains making up starch into short chains of glucose (a simple 6-carbon sugar) and eventually to individual glucose molecules.

 Yeast Fermentation: The hydrolyzed mash is transferred to a fermentation tank where microbes (yeast) are added to convert glucose to ethanol and carbon dioxide (CO2). Large quantities of CO2 generated during fermentation are collected with a CO2 scrubber, compressed, and marketed to other industries (e.g., carbonating beverages, making dry ice).  Distillation: The broth or "beer" produced in the fermentation step is a dilute (10 to 12%) ethanol solution containing solids from the mash and yeast cells. The beer is pumped through many columns in the distillation chamber to remove ethanol from the solids and water. After distillation, the ethanol is about 96% pure. The solids are pumped out of the bottom of the tank and processed into protein-rich coproducts used in livestock feed.  Dehydration: The small amount of water in the distilled ethanol is removed using molecular sieves. A molecular sieve contains a series of small beads that absorb all remaining water. Ethanol molecules are too large to enter the sieve, so the dehydration step produces pure ethanol (200 proof). Prior to shipping the ethanol to gasoline distribution hubs for blending, a small amount of gasoline (~5%) is added to denature the ethanol making it undrinkable.

Dry grind ethanol production The dry grind process is designed to ferment as much of the corn kernel as possible. There are five basic steps in the conventional dry grind ethanol process: grinding, cooking, liquefaction, saccharification, and fermentation. Little is wasted in the production of this fuel—in addition to ethanol, the manufacturing process also produces distillers grains, a high-quality livestock feed, and carbon dioxide, a food and industrial product. In the dry grind method of ethanol production, nothing is done to preseparate the corn starch from the kernel. The entire corn kernel is ground into coarse flour through a hammer mill, to pass through a 30 mesh screen, then slurried with water to form a “mash”. Each bushel of corn generates ~22 gallons of mash.

Starch conversion Starch exists as insoluble, partially crystalline granules in the endosperm of the corn kernel. Corn starch is made up of individual units of glucose, linked together in chains by alpha 1–4 and occasional alpha 1–6 linkages. The 1–4 linkages produce linear chains that primarily comprise molecules called “amylose”, whereas the alpha 1–6 linkages serve as branching points to produce branchedchain molecules called amylopectin. Normal corn starch contains about 27% amylose, with the remainder being amylopectin. Starch cannot be metabolized directly by yeast, but must first be broken down into simple six carbon sugars prior to fermentation. To accomplish this conversion, the pH of the mash is adjusted to pH 6.0, followed by the addition of alpha-amylase. A thermostable alpha-amylase enzyme is added to begin breaking down the starch polymer to produce soluble dextrins by quickly and randomly hydrolyzing alpha 1–4 bonds. The mash is heated above 100°C using a jet cooker, which provides the high temperature and mechanical shear necessary to cleave and rupture starch molecules, especially those of a high molecular weight. The corn mash is kept at the elevated temperature for several minutes by pumping it through a holding tube equipped with a backpressure valve. The mash flows from the holding tube into a flash tank and the temperature is allowed to fall to 80–90°C. Additional

alpha-amylase is added and the mash is liquefied for at least 30 min. Liquefaction greatly reduces the size of the starch polymer. The dextrinized mash is then cooled, adjusted to pH 4.5, and glucoamylase enzyme is added. Glucoamylase converts liquefied starch into glucose. Enough glucoamylase is added such that the saccharification of the starch to glucose, which occurs continually through the fermentation, does not limit the rate of ethanol production.

Fermentation After cooking, the mash is cooled to 32°C and transferred to fermenters where yeast is added. Often, ammonium sulfate or urea is added as a nitrogen source for the growth of yeast. Recently, the ethanol dry grind mills have also begun to add proteases that break down the corn protein to free amino acids, which serve as an additional source of nitrogen for the yeast. The fermentation requires 48–72 h and has a final ethanol concentration of 10–12%. The pH of the beer declines during the fermentation to below pH 4, because of carbon dioxide formed during the ethanol fermentation. The decrease in pH is important for increasing the activity of glucoamylase and inhibiting the growth of contaminating bacteria. Dry grind plants can reduce the amount of glucoamylase added by saccharifying the liquefied starch at 65°C prior to fermentation. Many plants, however, have gone to simultaneous saccharification and fermentation (SSF) because it lowers the opportunity for microbial contamination, lowers the initial osmotic stress of yeast by avoiding a concentrated glucose solution, and is generally more energy-efficient. In addition, it can provide yields of up to 8% more ethanol per bushel of grain. Upon completion, the beer is distilled through the beer column. Either batch or continuous fermentation systems may be used, although batch processing is more common. Some new fermentation systems are designed to minimize dilution water, which reduces the evaporation requirements and thus the energy required in the feed-processing stages after fermentation.

The carbon dioxide released during fermentation is often captured and sold, especially by larger dry grind facilities. The carbon dioxide is used in carbonating soft drinks and beverages, manufacturing dry ice, and in other industrial processes.

Ethanol production from Cellulose

Conversion of cellulosic biomass to ethanol is less productive and more expensive than the conversion of corn grain to ethanol. Cellulosic biomass, however, is a less expensive and more abundant feedstock than corn grain; more efficient processing is needed to take advantage of this plentiful and renewable resource. The structural complexity of cellulosic biomass is what makes this feedstock such a challenge to break down into simple sugars that can be converted to ethanol. Most plant matter consists of three key polymers: Cellulose (35 to 50%), hemicellulose (20 to 35%), and lignin (10 to 25%). These polymers are assembled into a complex, interconnected matrix within plant cell walls. Cellulose and hemicellulose are carbohydrates that can be broken down into fermentable sugars. The cellulosic and hemicellulosic portions of plant biomass are processed separately because they have different structures and sugar content. Cellulose consists of long chains of glucose molecules (simple 6-carbon sugars) arranged into a solid, threedimensional, crystalline structure. Hemicellulose is a branched polymer composed primarily of xylose molecules (simple 5-carbon sugars) and some other sugars. Lignin, a rigid aromatic polymer, is not a carbohydrate and cannot be converted into ethanol.

Fig: Plant Cell

Fig: Ethanol from Starch

Efficiently separating and breaking down the different polymers in cellulosic biomass is an important challenge that is not an issue for corn ethanol production. One multistep process for converting cellulosic biomass to ethanol is outlined below. Key steps in the conversion process are:  Mechanical Preprocessing: Dirt and debris are removed from incoming biomass (e.g., bales of corn stover, wheat straw, or grasses), which is shred into small particles.  Pretreatment: Heat, pressure, or acid treatments are applied to release cellulose, hemicellulose, and lignin and to make cellulose more accessible to enzymatic breakdown (hydrolysis). Hemicellulose is hydrolyzed into a soluble mix of 5- and 6-carbon sugars. A small portion of cellulose may be converted to glucose. If acid treatments are used, toxic by-products are neutralized by the addition of lime. Since cellulose biomass can come from many different sources (e.g., grasses, wheat straw, corn stover, paper products, hardwood, softwood), a single pretreatment process suitable for all forms of biomass does not exist.  Solid-Liquid Separation: The liquefied syrup of hemicellulose sugars is separated from the solid fibers containing crystalline cellulose and lignin.  Fermentation of Hemicellulosic Sugars: Through a series of biochemical reactions, bacteria convert xylose and other hemicellulose sugars to ethanol.  Enzyme Production: Some of the biomass solids are used to produce cellulase enzymes that break down crystalline cellulose. The enzymes are harvested from cultured microbes. Purchasing enzymes from a commercial supplier would eliminate this step.  Cellulose Hydrolysis: The fiber residues containing cellulose and lignin are transferred to a fermentation tank where cellulase enzymes are applied. A cocktail of different cellulases work together to attack crystalline cellulose, pull cellulose chains away from the crystal, and ultimately break each cellulose chain into individual glucose molecules.  Fermentation of Cellulosic Sugars (Glucose): Yeast or other microorganisms consume glucose and generate ethanol and carbon dioxide as products of the glucose fermentation pathway.  Distillation: Dilute ethanol broth produced during the fermentation of hemicellulosic and cellulosic sugars is distilled to remove water and concentrate the ethanol. Solid residues containing lignin and microbial cells can be burned to produce heat or used to generate electricity consumed by the ethanol-production process. Alternately, the solids could be converted to coproducts (e.g., animal feed, nutrients for crops).  Dehydration: The last remaining water is removed from the distilled ethanol.

Fig: Flow-diagram of Bioethanol production

Distillation and dehydration Distillation is the process of separating the ethanol from the solids and water in the mash. Alcohol vaporizes at 78°C and water at 100°C (at sea level). This difference allows water to be separated from ethanol by heating in a distillation column. Conventional distillation/rectification methods can produce 95% pure (190 proof) ethanol. At this point, the alcohol and water form an azeotrope, which means further separation by heat cannot occur. In order to blend with gasoline, the remaining 5% water must be removed by other methods. Modern dry grind ethanol plants use a molecular sieve system to produce absolute (100%, or 200 proof) ethanol. The anhydrous ethanol is then blended with approximately 5% denaturant (such as gasoline) to render it undrinkable and thus not subject to beverage alcohol tax. It is then ready for shipment to gasoline terminals or retailers.

Stillage processing The solid and liquid fraction remaining after distillation is referred to as “whole stillage”. Whole stillage includes the fiber, oil, and protein components of the grain, as well as the non-fermented starch. This coproduct of ethanol manufacture is a valuable feed ingredient for livestock, poultry, and fish. Although it is possible to feed whole stillage, it is usually processed further before being sold for feed. First, the “thin stillage” is separated from the insoluble solid fraction using centrifuges or presses/extruders. The stillage leaving the beer column is centrifuged with a decanter. Between 15% and 30% of the liquid fraction (thin stillage) is recycled as backset. The remainder is concentrated further by evaporation and mixed with the residual solids from the fermentation. After evaporation, the thick, viscous syrup is mixed back with the solids to create a feed product known as wet distillers’ grains with solubles (WDGS).

Key Biological Barriers to Cellulosic Ethanol Production

Compared to cornstarch ethanol production, several factors make cellulosic ethanol production more costly and less efficient. One important barrier is lower sugar yields due to the heterogeneous and recalcitrant nature of cellulosic biomass. More effort is needed to pretreat and solubilize hemicellulose and cellulose because they are locked into a rigid cell-wall structure with lignin. Harsher thermochemical pretreatments generate chemical by-products that inhibit enzyme hydrolysis and decrease the productivity of fermentative microbes. The crystallinity of cellulose also makes it more difficult for aqueous solutions of enzymes to convert cellulose to glucose. Another barrier is the mix of sugars generated from hemicellulose hydrolysis. Microorganisms that can ferment both 5- and 6-carbon sugars exist, but they have lower production rates and exhibit less tolerance for the end-product ethanol. Broth produced from a mix of 5- and 6-carbon sugars is about 6% ethanol instead of 10 to 14% ethanol produced from cornstarch glucose fermentation. Overcoming these and other barriers will require a more complete understanding of several biological factors that impact the conversion process:  Understanding what aspects of plant cell-wall structure and composition make some plant materials easier to break down than others.  Investigating regulatory mechanisms that control cell-wall synthesis so that new bioenergy crops optimized for efficient biomass breakdown can be developed. For example, minimizing lignin content would improve enzyme access to cellulose during the hydrolysis step, thus increasing sugar yields.  Surveying natural microbial communities to discover and analyze a more diverse range of enzymes that can break down cellulose, hemicellulose, and lignin. Perhaps novel enzymes capable of breaking down lignin and hemicellulose could be used to reduce the severity and improve the effectiveness of pretreatment.  Creating new enzyme mixtures and analyzing their collective activities to determine the best combinations needed for rapid and complete breakdown of different components of biomass.  Identifying the many genes that determine the most-desirable traits for fermentative microbes and understanding how these genes are regulated. Some of these traits include tolerance of higher ethanol concentrations, improved uptake and conversion of all sugars generated from biomass hydrolysis, elimination of unnecessary metabolic pathways, and achieving optimal fermentation productivity at higher temperatures to prevent contamination. Identifying these genes and understanding how they are controlled will be critical to developing the ideal fermentative microbe that possesses all these traits.  Integrating all hydrolysis and fermentation steps into a single microbe or stable mixed culture to streamline the entire process and reduce costs.

Use of Biofuel One widespread use of biofuels is in home cooking and heating. Typical fuels for this are wood, charcoal or dried dung. The biofuel may be burned on an open fireplace or in a special stove. The efficiency of this process may vary widely, from 10% for a well made fire (even less if the fire is not made carefully) up to 40% for a custom designed charcoal stove1. Inefficient use of fuel may be a minor cause of deforestation (though this is negligible compared to deliberate destruction to clear land for agricultural use) but more importantly it means that more work has to be put into gathering fuel, thus the quality of cooking stoves has a direct influence on the viability of biofuels.

Motor Fuel Ethanol is the most common biofuel, and over the years many engines have been designed to run on it. Many of these could not run on regular gasoline. It is open to debate if ethanol is a direct replacement in these engines though - they cannot run on anything else. In the late 1990's engines started appearing that by design can use either fuel. Ethanol is a direct replacement in these engines, but it is debatable if these engines are unmodified, or factory modified for ethanol. Ethanol performs well as a fuel in cars, either in a neat form or in a mixture with gasoline. In addition to ethanol/gasoline blend markets, ethanol has other motor fuel applications including: (1) Use as E85, 85% ethanol and 15% gasoline, (2) Use as E100, 100% ethanol with or without a fuel additive, and (3) Use in oxy-diesel, typically a blend of 80% diesel fuel, 10% ethanol and 10% additives and blending agents.

Direct electricity generation The methane in biogas is often pure enough to pass directly through gas engines to generate green energy. Anaerobic digesters or biogas powerplants convert this renewable energy source into electricity. This can either be used commercially or on a local scale.

Use on farms In Germany small scale use of biofuel is still a domain of agricultural farms. It is an official aim of the German government to use the entire potential of 200,000 farms for the production of biofuel and bioenergy. (Source: VDI-Bericht "Bioenergie Energieträger der Zukunft".

Home use Different combustion-engines are being produced for very low prices lately. They allow the private house-owner to utilize low amounts of "weak" compression of

methane to generate electrical and thermal power (almost) sufficient for a well insulated residential home.

Bioethanol and the environment The concern about the threat of global climate change has during the years increased the search for ways to reduce the build up of greenhouse gases. Carbon dioxide (CO2) is the most prevalent greenhouse gas and therefore CO2 is the major focus of domestic and international strategies. CO2 exists naturally in our atmosphere and is part of the Earth’s natural carbon cycle. Since the beginning of the industrial age, our increased use of fossil fuels for energy has released tremendous quantities of CO2 into the atmosphere, threatening the natural balance of the carbon cycle. CO2 that was stored in “fossils” for millions of years is now being released quickly. Atmospheric CO2 concentrations have increased by 25% since pre-industrial times. More than half of this increased has occurred during the past three decades.

By using bioethanol instead of fossil fuels, the emissions from fossil fuel use are avoided. CO2 reductions occur because the biomasses that serve as raw material for the bioethanol production require CO2 to grow. Thus, much of the CO2 released when biomass is converted into a biofuel and burned in automobile engines is recaptured from the atmosphere when new biomass is grown to produce more biofuels. This is called a closed circle.

Examples of potential CO2 reduction by using bioethanol instead of gasoline (source: Lew Fulton, IEA 2002): • Bioethanol from grain/corn: 20-40% reduction compared to gasoline • Bioethanol from sugar beet: 30-50% reduction compared to gasoline • Bioethanol from sugar cane: 50-90% reduction comapred to gasoline • Bioethanol from lignocellulosic: 75-100% reduction compared to gasoline

Biofuel & the Food Insecurity in Developing Countries

Recent hikes in oil prices have raised serious concerns in lowincome countries, both because of the financial burden of the higher energy import bill and potential constraints on imports of necessities like food and raw materials. Higher oil prices also have sparked energy security concerns worldwide, increasing the demand for biofuel production. The use of feed crops for biofuels, coupled with greater food demand spurred by high income growth in populous countries, such as China and India, has reversed the long-term path of declining price trends for several commodities. Worldwide agricultural commodity price increases were significant during 2004-06: corn prices rose 54 percent; wheat, 34 percent; soybean oil, 71 percent; and sugar, 75 percent. But this trend accelerated in 2007, due to continued demand for biofuels and drought in major producing countries. Wheat prices have risen more than 35 percent since the 2006 harvest, while corn prices have increased nearly 28 percent. The price of soybean oil has been particularly volatile, due to high demand growth in China, the U.S., and the European Union (EU), as well as lower global stocks. The Food and Agriculture Organization of the United Nations (FAO) estimated that the high food prices of 2006 increased the food import bill of developing countries by 10 percent over 2005 levels. For 2007, the food import bill for these countries increased at a much higher rate, an estimated 25 percent.

Fig: A border guard sells rice at a government subsidized outlet at Nawabganj in Dhaka, Bangladesh, Friday, April 11, 2008.

The 2007 controversy: Ethanol diplomacy in the Americas In March 2007, "ethanol diplomacy" was the focus of President George W. Bush's Latin American tour, in which he and Brazil's president, Luiz Inácio Lula da Silva, were seeking to promote the production and use of sugar cane based ethanol throughout Latin America and the Caribbean. The two countries also agreed to share technology and set international standards for biofuels. The Brazilian sugar cane technology transfer will permit various Central American countries, such as Honduras, Nicaragua, Costa Rica and Panama, several Caribbean countries, and various Andean Countries tariff-free trade with the U.S. thanks to existing concessionary trade agreements. Even though the U.S. imposes a USD 0.54 tariff on every gallon of imported ethanol, the Caribbean nations and countries in the Central American Free Trade Agreement are exempt from such duties if they produce ethanol from crops grown in their own countries. The expectation is that using Brazilian technology for refining sugar cane based ethanol, such countries could become exporters to the United States in the short-term. In August 2007, Brazil's President toured Mexico and several countries in Central America and the Caribbean to promote Brazilian ethanol technology. This alliance between the U.S. and Brazil generated some negative reactions. While Bush was in São Paulo as part of the 2007 Latin American tour, Venezuela's President Hugo Chavez, from Buenos Aires, dismissed the ethanol plan as "a crazy thing" and accused the U.S. of trying "to substitute the production of foodstuffs for animals and human beings with the production of foodstuffs for vehicles, to sustain the American way of life." Chavez' complaints were quicky followed by then Cuban President Fidel Castro, who wrote that "you will see how many people among the hungry masses of our planet will no longer consume corn." "Or even worse," he continued, "by offering financing to poor countries to produce ethanol from corn or any other kind of food, no tree will be left to defend humanity from climate change."' Daniel Ortega, Nicaragua's President, and one of the preferencial recipients of Brazil technical aid, said that "we reject the gibberish of those who applaud Bush's totally absurd proposal, which attacks the food security rights of Latin Americans and Africans, who are major corn consumers", however, he voiced support for sugar cane based ethanol during Lula's visit to Nicaragua.

The 2008 controversy: Global food prices As a result of the international community's concerns regarding the steep increase in food prices, on April 14, 2008, Jean Ziegler, the United Nations Special Rapporteur on the Right to Food, at the Thirtieth Regional Conference of the Food and Agriculture Organization (FAO) in Brasília, called biofuels a "crime against humanity", a claim he had previously made in October 2007, when he called for a 5year ban for the conversion of land for the production of biofuels. The previous day, at their Annual IMF and World Bank Group meeting at Washington, D.C., the World Bank's President, Robert Zoellick, stated that "While many worry about filling their gas tanks, many others around the world are struggling to fill their stomachs. And it's getting more and more difficult every day." Luiz Inácio Lula da Silva gave a strong rebuttal, calling both claims "fallacies resulting from commercial interests", and putting the blame instead on U.S. and European agricultural subsidies, and a problem restricted to U.S. ethanol produced

from maize. He also said that "biofuels aren't the villain that threatens food security." In the middle of this new wave of criticism, Hugo Chavez reaffirmed his opposition and said that he is concerned that "so much U.S.-produced corn could be used to make biofuel, instead of feeding the world's poor", calling the U.S initiative to boost ethanol production during a world food crisis a "crime." German Chancellor Angela Merkel said the rise in food prices is due to poor agricultural policies and changing eating habits in developing nations, not biofuels as some critics claim. On the other hand, British Prime Minister Gordon Brown called for international action and said Britain had to be "selective" in supporting biofuels, and depending on the U.K.'s assessment of biofuels' impact on world food prices, "we will also push for change in EU biofuels targets". Stavros Dimas, European Commissioner for the Environment said through a spokewoman that "there is no question for now of suspending the target fixed for biofuels", though he acknowledged that the EU had underestimated problems caused by biofuels. On April 29, 2008, U.S. President George W. Bush declared during a press conference that "85 percent of the world's food prices are caused by weather, increased demand and energy prices", and recognized that "15 percent has been caused by ethanol". He added that "the high price of gasoline is going to spur more investment in ethanol as an alternative to gasoline. And the truth of the matter is it's in our national interests that our farmes grow energy, as opposed to us purchasing energy from parts of the world that are unstable or may not like us." Regarding the effect of agricultural subsidies on rising food prices, Bush said that "Congress is considering a massive, bloated farm bill that would do little to solve the problem. The bill Congress is now considering would fail to eliminate subsidy payments to multimillionaire farmers", he continued, "this is the right time to reform our nation's farm policies by reducing unnecessary subsidies". Just a week before this new wave of international controversy began, U.N. Secretary General Ban Ki-moon had commented that several U.N. agencies were conducting a comprehensive review of the policy on biofuels, as the world food price crisis might trigger global instability. He said "We need to be concerned about the possibility of taking land or replacing arable land because of these biofuels", then he added "While I am very much conscious and aware of these problems, at the same time you need to constantly look at having creative sources of energy, including biofuels. Therefore, at this time, just criticising biofuel may not be a good solution. I would urge we need to address these issues in a comprehensive manner." Regarding Jean Ziegler's proposal for a five-year ban, the U.N. Secretary rejected that proposal. On July 4, a leaked report done by the World Bank said that the use of biofuels have forced global food prices up by 75%. The "month-by-month" five year analysis disputes that increases in global grain consumption and droughts were responsible for price increases, reporting that this had had only a marginal impact and instead argues that the EU and US drive for biofuels has had by far the biggest impact on food supply and prices. Although completed in April, economists believe the report has not been published to avoid embarrassing President George Bush. The study also found that biofuels derived from sugarcane did not have as dramatic an impact as that derived from grains and vegetable oil.

Food vs fuel

One systemic cause for the price rise is held to be the diversion of food crops (maize in particular) for making first-generation biofuels. An estimated 100 million tonnes of grain per year are being redirected from food to fuel. (Total worldwide grain production for 2007 was just over 2000 million tonnes.) As farmers devoted larger parts of their crops to fuel production than in previous years, land and resources available for food production were reduced correspondingly. This has resulted in less food available for human consumption, especially in developing and least developed countries, where a family's daily allowances for food purchases are extremely limited. The crisis can be seen, in a sense, to dichotomize rich and poor nations, since, for example, filling a tank of an average car with biofuel, amounts to as much maize (Africa's principal food staple) as an African person consumes in an entire year. Since late 2007, "Agflation," caused by the increased diversion of maize harvests to biofuels, the tying of maize to rising oil prices by commodity traders, and a resulting price rise, has caused market substitution, with price rises cascading through other commodities: first wheat and soy prices, then later rice, soy oil, and a variety of cooking oils. Brazil, the world's second largest producer of ethanol after the U.S., is considered to have the world's first sustainable biofuel economy and its government claims Brazil's sugar cane based ethanol industry has not contributed to the 2008 food crises. German Chancellor Angela Merkel said the rise in food prices is due to poor agricultural policies and changing eating habits in developing nations, not biofuel as some critics claim. Second- and third-generation biofuel (such as cellulosic ethanol and algae fuel, respectively) may someday ease the competition with food crops, as non food energy crops can grow on marginal lands unsuited for food crops, but these advanced biofuel require further development of farming practices and refining technology; in contrast, ethanol from maize uses mature technology and the maize crop can be shifted between food and fuel use quickly.

Fig: Energy & Food Security, the future of biofuel

Conclusion The socio-economic and political condition throughout the world has been greatly influenced by the petroleum crisis. In this regard, as the world is coming towards an end of its fossil fuel, there is no way elsewhere but invent new replacement of petroleum that can efficiently be seated in position. The advents of biotechnology have shown the way by BIOFUEL. Though the question about food grain usage that is said to arise food crisis can’t be knocked down, but there is no other way out. So, the task is upon us. We have either to invent a renewable source, or develop modified energy crops to make a balance between food & fuel. But seemingly the only path that can lead us to overcome the current power crisis is BIOFUEL and BIOFUEL ONLY.

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