Biofuels and Biodiesels: Renewable Energy Explained

Biofuels and Biodiesels Renewable Energy Explained

Biofuels and Biodiesels

Radha Agarwal

Biofuels and Biodiesels: Renewable Energy Explained

Radha Agarwal

ISBN - 9789361529689

COPYRIGHT © 2025 by Educohack Press. All rights reserved.

This work is protected by copyright, and all rights are reserved by the Publisher. This includes, but is not limited to, the rights to translate, reprint, reproduce, broadcast, electronically store or retrieve, and adapt the work using any methodology, whether currently known or developed in the future.

The use of general descriptive names, registered names, trademarks, service marks, or similar designations in this publication does not imply that such terms are exempt from applicable protective laws and regulations or that they are available for unrestricted use.

The Publisher, authors, and editors have taken great care to ensure the accuracy and reliability of the information presented in this publication at the time of its release. However, no explicit or implied guarantees are provided regarding the accuracy, completeness, or suitability of the content for any particular purpose.

If you identify any errors or omissions, please notify us promptly at educohackpress@gmail.com & sales@educohackpress.com We deeply value your feedback and will take appropriate corrective actions.

The Publisher remains neutral concerning jurisdictional claims in published maps and institutional affiliations.

Published by Educohack Press, House No. 537, Delhi- 110042, INDIA

Email: educohackpress@gmail.com & sales@educohackpress.com

Cover design by Team EDUCOHACK

Preface

Energy is one of the most valuable resources for humankind and its sustainable development. Today, the energy crisis is becoming one of the global challenges facing us. Fuels are of great significance because they can be burned to generate significant amounts of energy. Many facets of everyday life depend on fuels, in specific the transport of goods and people. With increasing awareness of the depletion of fossil fuel resources and environmental issues, biodiesel has become increasingly attractive in recent years. Rapid depletion in the world’s oil reserves and instability in the supply of oil due to political and economic reasons, as well as a rapid rise in oil prices, have simulated the quest for alternatives to petroleum-based fuels, particularly diesel and gasoline. Moreover, the bulk of petroleum fuels are consumed by agriculture and the transport sector for which diesel engines happen to be used. Biodiesel development is a promising and significant area of research because of the importance it has gained from rising oil prices and its environmental advantages.

Due to scarce conventional petroleum fuel, there is a need to search for alternative renewable fuel that can be adapted for use in place of fossil fuel oil. Even ester-based biodiesel has many limitations, such as low energy content, oxidative stability etc. Renewable hydrocarbon-based diesel obtained by hydroprocessing of vegetable oils/fats (2nd generation biodiesel) is one of the alternatives that is getting attention from both academia and industry. The present book reviews the emerging processes, catalysts and operating conditions for the catalytic conversion of vegetable oils/fats into hydrocarbon-based diesel via hydroprocessing.

This book covers the history and recent developments of biodiesel, including the different types of biodiesel, the characteristics, processing and economics of the Biodiesel industry. The application of biodiesel in the automobile industry, the challenges of biodiesel industry development and the biodiesel policy are discussed as well. The production of biofuels in general and biodiesel, in particular, is gradually becoming a vital issue due to the rarefaction of fossil fuels and the urgent need to decrease the amounts of greenhouse gas emissions. Thus, the energy concerns, the growing environmental awareness and the economic considerations are the major driving forces behind the worldwide direction towards producing biofuel from bioresources. The main objective of this book is to present the latest information and innovations in the scientific and industrial communities on biodiesel production from various bioresources and wastes.

Table of Contents

1 An Introduction to Biofuels 1

1.1 Biofuels 1

1.1.1 Types of Biofuels 2

1.1.2 Economic and Environmental Considerations 4

1.2 Need for Biofuels 6

1.2.1 Biofuels for Energy Security 6

1.2.2 Biofuels for the U.S. Economy 7

1.2.3 Biofuels for the Environment 7

1.2.4 Biofuels and Global Climate Change 8

1.2.5 Biofuels and Air Quality 8

1.2.6 Biofuels and Water Quality 8

1.2.7 Biofuels and Waste Disposal 8

1.2.8 Biofuels In The Market 9

1.3 Feedstock for Biofuels 9

1.3.1 Sugar and Starch Crops 10

1.3.2 Fiber and Grass Cellulosic Crops 11

1.3.3 Crop Residues, Manures, and Organic Wastes 12

1.3.4 Biogas and Anaerobic Digestion 13

1.3.5 Wood Products 13

1.4 Various Advantages and Disadvantages of Biofuels 14

1.4.1 Advantages of Biofuels 14

1.4.2 Disadvantages of Biofuels 17

1.4.3 The Advantages of Biofuels over Fossil Fuels 20

1.4.4 Biofuels vs. Fossil Fuels 22

1.5 Uses of Biofuels in Transport 24

1.5.1 What Are The Economic And Policy Factors

Influencing Biofuel Development? 28

1.5.2 The Raw Material Accounts For The Largest Share

Of Total Biofuel Costs. 29

1.5.3 How Are Biofuel Markets And Production Evolving? 29

1.6 What Are The Environmental Impacts Of Biofuel Production? 30

1.7 How Will Biofuel Production Affect Food Security And Poverty? 31

1.8 How Could Biofuel Policies Be Improved? 32

1.9 Exercise 33

2 Hydrogen - A New Biofuel and its Production 34

2.1 Applications of Hydrogen in different Areas 34

2.1.1 Long Established Uses – Hydrogen As A Feedstock (Material Based Uses) 35

2.1.2 Ammonia - Fertilizers 36

2.1.3 Industrial Fields 36

2.1.4 Fuel Production 37

2.1.5 Commencing Uses - Energy-Based Uses 37

2.2 Hydrogen in Transport 38

2.2.1 Aviation 38

2.2.2 Maritime Applications 39

2.2.3 Trains 39

2.2.4 Material Handling Vehicles 40

2.2.5 Buses 41

2.2.6 Passenger Cars 42

2.2.7 Stationary Energy Applications 43

2.3 Hydrogen Energy 45

2.3.1 What is Hydrogen Energy? 45

2.3.2 Hydrogen Fuel Cells 47

2.4 Hydrogen Fuel Production 48

2.4.1 Thermal Processes 48

2.4.2 Electrolytic Hydrogen Production 57

2.4.3 Solar-Driven Processes 60

2.4.4 Biological Processes 66

2.5 Production of Bio-hydrogen 70

2.5.1 By Photosynthetic Bacteria 70

2.5.2 By Fermentation 71

2.5.3 By Legume Crops 71

2.6 Advantages and Disadvantages of Hydrogen Fuel Cells 71

2.6.1 Advantages of Hydrogen Fuel Cells 72

2.6.2 Disadvantages of Hydrogen Fuel Cells 73

2.6.3 Capabilities of Hydrogen Fuel Cells 74

2.7 Advantages and Disadvantages of Hydrogen Energy 75

2.7.1 Advantages of Hydrogen Energy 75

2.7.2 Disadvantages of Hydrogen Energy 77

2.8 Exercise 79

3 Bioalcohols as Alternative Fuel 80

3.1 Alcohol as a Fuel 80

3.1.1 Why Alcohol Used As An Alternative Fuel 82

3.1.2 Fuel Economy and Octane 83

3.2 Biological Production versus Refining 84

3.2.1 Methanol 84

3.2.2 Ethanol 86

3.2.3 Propanol 89

3.2.4 Butanol 90

3.2.5 Understanding Carbon Dioxide and Carbon Fuels 92

3.2.6 Long Chain Alcohols 94

3.3 Alcoholic Fuels: Economic, Environmental Issues And S

Ustainable Development 94

3.3.1 Economic Aspects 95

3.3.2 Environmental Issues 95

3.3.3 Sustainable Development 96

3.4 Properties of Alcohol Fuels 99

3.5 Feedstock for Alcohol Fuels 101

3.5.1 First Generation: Grain Feedstock 103

3.5.2 Second Generation: Lignocellulosic Biomass 103

3.5.3 Third generation: Algae Species 105

3.5.4 Current Biofuel Yields From Various Biomass 106

3.6 Manufacturing Processes 107

3.6.1 Ethanol Production 108

3.6.2 Pretreatment 109

3.6.3 Saccharification (hydrolysis) 110

3.6.4 Fermentation 111

3.6.5 Comparison Between SSF and SHF Processes 112

3.7 Use of Alcohol Fuels 114

3.7.1 Fuel for Automobiles 115

3.7.2 Fuel Cells 116

3.7.3 Jet Fuel 118

3.7.4 Ways For Wider Utilization 118

3.7.5 Securing Energy Security 119

3.7.6 Distributed Energy Applications 120

3.8 Alcohol As Alternative Fuels In Spark Ignition Engine:

Advantages And Disadvantages 120

3.8.1 Conversion From Diesel To Spark Ignition 122

3.8.2 The Advantages And Disadvantages Of Ethanol Fuel 122

3.9 Alcohol Fuels: Current Trends and Future Prospects 124

3.9.1 Current Trends 126

3.9.2 Future Prospects 128

3.10 Exercise 129

4 Biodiesel Production: Methods and Technologies 130

4.1 Meaning and Definition of Biodiesel 131

4.1.1 Definition 131

4.2 Biodiesel Production from Oils and Fats 132

4.2.1 Production Process 134

4.3 Feedstock for Biodiesel Production 144

4.3.1 Typical Oil Crops Useful for Biodiesel Production 145

4.3.2 Characteristics of Oils and Fats Used in Biodiesel Production 152

4.3.3 Characteristics of Alcohols Used in Biodiesel Production 155

4.3.4 Other Feedstocks 155

4.4 Methods of Oil Extraction 156

4.4.1 Mechanical Extraction Method 156

4.4.2 Chemical (Solvent) Extraction Method 157

4.4.3 Enzymatic Extraction Method 157

4.5 Technologies Used in Biodiesel Production 157

4.5.1 Pyrolysis Or Catalytic Cracking 158

4.5.2 Transesterification (Alcoholysis) 158

4.5.3 Homogeneous Alkali-Catalyzed Transesterification 159

4.5.4 Homogeneous Acid-Catalyzed Transesterification 159

4.5.5 Heterogeneous Acid And Base-Catalyzed Transesterification 159

4.5.6 Enzymatic Transesterification 160

4.5.7 Supercritical Alcohol Transesterification 160

4.6 Current Challenges and Future Prospects 161

4.6.1 Vegetable Oil As A Feedstock For Biodiesel 161

4.6.2 Non-Food Crops 161

4.6.3 Effects Of Moisture And Ffa 162

4.6.4 Pyrolysis 162

4.6.5 Alcohol 162

4.6.6 Supercritical Alcohol Process 163

4.6.7 Biodiesel/Glycerol Separation And Fame Quality 163

4.6.8 Use Of Cosolvents 164

4.6.9 Nox Emissions 164

4.6.10 Economic Analysis 164

4.7 Exercise 166

5 Waste-Derived Fuel: Converting Waste to Energy 167

5.1 Refuse-derived Fuel: Concept and Definition 167

5.1.1 RDF Defined 168

5.1.2 What Types of Materials Are Processed? 168

5.1.3 What Production Steps Are Involved in RDF? 169

5.1.4 Is This A Landfill Alternative? 169

5.2 Production Process of Refuse-derived Fuel 170

5.2.1 The Process Of Converting Waste To Energy 170

5.2.2 What Waste Products Can Be Used? 171

5.2.3 Density of Refuse-derived Fuel 177

5.3 Benefits of Refuse-derived Fuels 177

5.3.1 Energy Efficiency 179

5.3.2 Homogeneity 179

5.3.3 Better Recycling 180

5.3.4 Uniformity 180

5.3.5 Transportation 180

5.3.6 Emissions 181

5.4 Refuse-Derived Fuel (Rdf) Systems 181

5.4.1 Processing Systems 181

5.4.2 Wet RDF Processing 181

5.4.3 Dry Processing Systems 182

5.4.4 Precautions 185

5.5 Utilization of Refuse – Derived Fuel (RDF) As an Alternative

Energy Resource 186

5.6 Refuse-derived Fuel Market Forecast and Trend Analysis 188

5.7 Exercise 191

6 Natural Gas Flaring–Alternative Solutions 192

6.1 Origin of Natural Gas 192

6.1.1 The Biological Stage 193

6.1.2 The Thermal Stage 194

6.2 What is Gas Flaring – Why is it Done & Viable Alternatives? 194

6.2.1 What is Gas Flaring? 196

6.2.2 Why Flare Gas? 196

6.2.3 How Is Gas Flaring Regulated? 197

6.2.4 Flare Gas Power Generation & Other Alternatives 197

6.3 Feedstock for Petrochemical Plants 198

6.3.1 Liquefied Natural Gas 198

6.3.2 Compressed Natural Gas 198

6.3.3 Flare Stack Configuration 201

6.4 Discovery and Early Application of Natural Gas 203

6.4.1 Improvements in Gas Pipelines 203

6.4.2 Natural Gas as a Premium Fuel 204

6.5 Effects of Natural Gas Flaring 204

6.6 Alternative Solutions to Gas Flaring 206

6.6.1 Reinjection for Secondary Oil Recovery 206

6.6.2 Source of Energy and Feedstock for Petrochemical Plants 207

6.6.3 Liquefied Natural Gas (LNG) 208

6.6.4 Compressed Natural Gas (CNG) 208

6.7 Composition and Properties of Natural Gas 210

6.7.1 Hydrocarbon Content 210

6.7.2 Nonhydrocarbon Content 210

6.7.3 Chemical Composition of Natural Gas 211

6.7.4 Typical Combustion Properties Of Natural Gas 212

6.7.5 Characteristics of Natural Gas 213

6.8 Natural Gas Benefits and Considerations 215

6.8.1 Energy Security 215

6.8.2 Vehicle Performance 215

6.8.3 Lower Emissions 216

6.8.4 Infrastructure and Vehicle Availability 216

6.9 Processing and Transport of Natural Gas 217

6.9.1 Measurement Systems 217

6.9.2 Field Processing 218

6.9.3 Dehydration 218

6.9.4 Recovery of Hydrocarbon Liquids 218

6.9.5 Physical and Chemical Properties of Natural Gas 219

6.10 Compressed Natural Gas (CNG) as Alternative Fuel 221

6.10.1 What Is Natural Gas and CNG? 222

6.10.2 Benefits of CNG 223

6.10.3 Drawbacks of CNG 224

6.10.4 Natural Gas in Transportation 224

6.10.5 CNG and LNG as Alternative Transportation Fuels 229

6.11 Exercise 229

7 Vegetable Oil as an Alternative Fuel 231

7.1 Vegetable Oils: An overview 232

7.1.1 Structure of Vegetable Oils 232

7.1.2 Saturated and Unsaturated Fats and Oils 233

7.1.3 Emulsifiers 234

7.1.4 Bromine Water Test 235

7.1.5 Hydrogenation- Higher tier 235

7.2 Vegetable Oil: Nutritional and Industrial Perspective 236

7.2.1 Biosynthesis of Fatty Acids and Triacylglycerols 237

7.2.2 Beneficial Effects of Omega-3 Fatty Acids 240

7.2.3 Fatty Acids of Industrial Importance 241

7.3 Biodiesel: An Alternative Fuel Produced From Vegetable Oils 243

7.4 How to Make Biodiesel From Vegetable Oil 244

7.4.1 Background Of Biodiesel 247

7.4.2 Vegetable Oils As Diesel Fuels 248

7.4.3 Chemical Compositions Of Vegetable Oils 249

7.5 Properties Of Vegetable Oils As Fuel 250

7.5.1 Fuel Properties Of Biodiesel 251

7.6 Process of Biodiesel Production 252

7.6.1 Simple Transesterification Reaction 252

7.6.2 Chemistry Of Transesterification Reaction 252

7.7 Most Important Variables That Influence

The Transesterification Reaction 255

7.7.1 Reaction Temperature 255

7.7.2 Ratio Of Alcohol To Oil 255

7.7.3 Catalysts 255

7.7.4 Mixing Intensity 256

7.7.5 Purity Of Reactants 256

7.8 Environmental Considerations 256

7.9 Economic Feasibility 256

7.10 Biodiesel Production from Waste Cooking Oil and

Process Influencing Parameters 257

7.10.1 Basic Reaction Mechanism Involved in

the Production of Biodiesel 260

7.10.2 Factors Affecting the Production of Biodiesel

from Waste Cooking Oil 263

7.10.3 Process Description 267

7.11 Vegetable Oil as Alternative Fuel for Internal

Combustion Engine 269

7.11.1 Internal Combustion Engine Basics 270

7.11.2 How Does An Internal Combustion Engine Work? 270

7.11.3 Improving Combustion Engines 271

7.11.4 Challenges and Difficulties 273

7.11.5 Technical Difficulties 274

7.11.6 Remedies 275

7.12 Exercise 277

Glossary 278

References 281

Index 288

Chapter 1. An Introduction to Biofuels

Unlike other renewable energy sources, biomass can be converted directly into liquid fuels, called biofuels, to help meet transportation fuel needs. The two most common types of biofuels in use today are ethanol and biodiesel, both of which represent the first generation of biofuel technology. Replacing fossil fuels with biofuels—fuels produced from renewable organic material—has the potential to reduce some undesirable aspects of fossil fuel production and use, including conventional and greenhouse gas (GHG) pollutant emissions, exhaustible resource depletion, and dependence on unstable foreign suppliers. While world oil production is expected to increase 30 percent by 2030, production from unconventional fossil fuels will increase even faster, according to the U.S. Department of Energy. Global biofuel production is projected to more than double. In addition, biofuels act as carbon sinks while they grow -- they capture carbon. Another benefit to biofuels is the reduced danger of an environmental disaster.

1.1 Biofuels

Biofuel is any fuel that is derived from biomass—that is, plant or algae material or animal waste. Since such feedstock material can be replenished readily, biofuel is considered to be a source of renewable energy, unlike fossil fuels such as petroleum, coal, and natural gas. Biofuel is commonly advocated as a cost-effective and environmentally benign alternative to petroleum and other fossil fuels, particularly within the context of rising petroleum prices and increased concern over the contributions made by fossil fuels to global warming. Many critics express concerns about the scope of the expansion of certain biofuels because of the economic and environmental costs associated with the refining process and the potential removal of vast areas of arable land from food production.

Biofuels are transportation fuels such as ethanol and biomass-based diesel fuel that are made from biomass materials. These fuels are usually blended with petroleum fuels (gasoline and distillate/diesel fuel and heating oil), but they can also be used on their own. Using ethanol or biodiesel reduces the consumption of gasoline and diesel fuel made from crude oil, which can reduce the amount of crude oil imported from other countries. Ethanol and biodiesel are also cleaner-burning fuels than pure gasoline and diesel fuel.

What is ethanol?

Ethanol is an alcohol fuel made from the sugars found in grains such as corn, sorghum, and barley.

Other sources of sugars to produce ethanol include

• Sugar cane

• Sugar beets

• Potato skins

• Rice

• Yard clippings

• Tree bark

• Switchgrass

Most of the fuel ethanol used in the United States is distilled from corn. Scientists are working on ways to make ethanol from all parts of plants and trees rather than just grain and are experimenting with fast-growing woody crops such as poplar and willow trees and switchgrass to see if they can be used to produce ethanol.

1.1.1 Types of Biofuels

Some long-exploited biofuels, such as wood, can be used directly as a raw material that is burned to produce heat. The heat, in turn, can be used to run generators in a power plant to produce electricity. A number of existing power facilities burn grass, wood, or other kinds of biomass.

Liquid biofuels are of particular interest because of the vast infrastructure already in place to use them, especially for transportation. The liquid biofuel in greatest production is ethanol (ethyl alcohol), which is made by fermenting starch or sugar. Brazil and the United States are among the leading producers of ethanol. In the United States, ethanol biofuel is made primarily from corn (maize) grain, and it is typically blended with gasoline to produce gasohol, a fuel that is 10 percent ethanol. In Brazil, ethanol biofuel is made primarily from sugarcane, and it is commonly used as a 100-percent-ethanol fuel or in gasoline blends containing 85 percent ethanol. Unlike the first-generation ethanol biofuel produced from food crops, second-generation cellulosic ethanol is derived from low-value biomass that possesses a high cellulose content, including wood chips, crop residues, and municipal waste. Cellulosic ethanol is commonly made from sugarcane bagasse, a waste product from sugar processing, or from various grasses that can be cultivated on low-quality land. Given that the conversion rate is lower than with first-generation biofuels, cellulosic ethanol is dominantly used as a gasoline additive.

An ethanol production plant in South Dakota, U.S.

© Jim Parkin/Shutterstock.com

The second most common liquid biofuel is biodiesel, which is made primarily from oily plants (such as soybean or oil palm) and to a lesser extent from other oily sources (such as waste cooking fat from restaurant deep-frying). Biodiesel, which has found the greatest acceptance in Europe, is used in diesel engines and usually blended with petroleum diesel fuel in various percentages. The use of algae and cyanobacteria as a source of third-generation biodiesel holds promise but has been difficult to develop economically. Some algal species contain up to 40 percent lipids by weight, which can be converted into biodiesel or synthetic petroleum. Some estimates state that algae and cyanobacteria could yield between 10 and 100 times more fuel per unit area than second-generation biofuels.

Research technician, Nick Sweeney, inoculates algae being grown in a tent reactor in the algal lab in the Field Test Laboratory Building (FTLB) at the National Renewable Energy Laboratory in Golden, Colorado.

Other biofuels include methane gas and biogas—which can be derived from the decomposition of biomass in the absence of oxygen—and methanol, butanol, and dimethyl ether—which are in development.

1.1.2 Economic and Environmental Considerations

In evaluating the economic benefits of biofuels, the energy required to produce them has to be taken into account. For example, the process of growing corn to produce ethanol consumes fossil fuels in farming equipment, in fertilizer manufacturing, in corn transportation, and in ethanol distillation. In this respect, ethanol made from corn represents a relatively small energy gain; the energy gain from sugarcane is greater and that from cellulosic ethanol or algae biodiesel could be even greater.

Biofuels also supply environmental benefits but, depending on how they are manufactured, can also have serious environmental drawbacks. As a renewable energy source, plant-based biofuels, in principle, make a little net contribution to global warming and climate change; the carbon dioxide (a major greenhouse gas) that enters the air during combustion will have been removed from the air earlier as growing plants engage in photosynthesis. Such a material is said to be carbon neutral. In practice, however, the industrial production of agricultural biofuels can result in additional emissions of greenhouse gases that may offset the benefits of using a renewable fuel. These emissions include carbon dioxide from the burning of fossil fuels during the production process and nitrous oxide from the soil that has been treated with nitrogen fertilizer. In this regard, cellulosic biomass is considered to be more beneficial.

Land use is also a major factor in evaluating the benefits of biofuels. The use of regular feedstock, such as corn and soybeans, as a primary component of first-generation biofuels, sparked the food versus fuel debate. In diverting arable land and feedstock from the human food chain, biofuel production can affect the economics of food price and availability. In addition, energy crops grown for biofuel can compete for the world’s natural habitats. For example, emphasis on ethanol derived from corn is shifting grasslands and brushlands to corn monocultures, and emphasis on biodiesel is bringing down ancient tropical forests to make way for oil palm plantations. Loss of natural habitat can change hydrology, increase erosion, and generally reduce the biodiversity of wildlife areas. The clearing of land can also result in the sudden release of a large amount of carbon dioxide as the plant matter that it contains is burned or allowed to decay.

Some of the disadvantages of biofuels apply mainly to low-diversity biofuel sources—corn, soybeans, sugarcane, oil palms—which are traditional agricultural crops. One alternative involves the use of highly diverse mixtures of species, with the North American tallgrass prairie as a specific example. Converting degraded agricultural land that is out of production to such high-diversity biofuel sources could increase wildlife area, reduce erosion, cleanse waterborne pollutants, store carbon dioxide from the air as carbon compounds in the soil, and ultimately restore fertility to degraded lands. Such biofuels could be burned directly to generate electricity or converted to liquid fuels as technologies develop.

The proper way to grow biofuels to serve all needs simultaneously will continue to be a matter of much experimentation and debate, but the fast growth in biofuel production will likely continue. In the United States, the Energy Independence and Security Act of 2007 mandated the use of 136 billion liters (36 billion gallons) of biofuels annually by 2022, more than a sixfold increase over 2006 production levels. The legislation also requires, with certain stipulations, that 79 billion liters (21 billion gallons) of the total amount be biofuels other than corn-derived ethanol, and it continued certain government subsidies and tax incentives for biofuel production.

As prices of crude oil are soaring day by day, most people are switching to biofuels to save money and reduce their dependence on oil. Biofuels are produced from wheat, corn, soybeans and sugarcane, which can be produced again and again on demand, so they are sustainable.

Though biofuels have many advantages over their counterparts, there are some other complicating aspects that we need to look at.

1.2 Need for Biofuels

The need for biofuels several compelling issues drive a national effort to develop and improve technology to make biofuels. Our dependence on petroleum for fueling the transportation sector threatens our energy security, affects our environment, and weakens our economy. Developing the technology to produce and use biofuels will create transportation fuel options that can positively impact these issues and establish safe, clean, sustainable alternatives to petroleum.

1.2.1 Biofuels for Energy Security

Perhaps the most important issue surrounding the status of our transportation fuel is that no one knows how long the world’s petroleum resources will last. Adding to our country’s vulnerability, our limited domestic petroleum resources do not meet our energy needs. The Persian Gulf region holds nearly two-thirds of the world’s known oil reserves, and the United States imports more than 53% of its petroleum—much of it from the Persian Gulf. The U.S. Department of Energy estimates that this will increase to 75% by the year 2010. In 1990, Congress voted that a dependence on foreign oil of more than 50% should be considered a perilous point for the United States. Members of Congress recognize that high levels of imported oil leave our country defenseless against sudden severe energy disruptions that could capsize our economy. Producing and using fuels from renewable, domestic biomass resources can help ease our dependence on foreign oil imports and reduce our vulnerability to severe energy disruptions.

1.2.2 Biofuels for the U.S. Economy

Oil imports account for almost half the U.S. trade deficit, which has an enormous impact on our economy and the creation of new jobs. A high trade imbalance from dependence on foreign oil also leaves our economy vulnerable to price hikes from supply disruptions. Developing a stronger market for domestically produced biofuels in the United States will help alleviate the negative implications