Black Gold and Green Highways:



Yellow Gold and Green Highways:

Recycled Oil as a Solution to the Nation’s Fuel Crisis

Karen L. Johansen

Pace University School of Law

White Plains, NY 10603

LAW 802: Dr. David Rahni

Spring 2004

Abstract

Both gasoline and diesel fuel pose serious risks to the environment and human health, are becoming increasingly more expensive, and promote reliance on foreign oil-producing nations. In addition, the limited supply of crude oil is projected to run out before the twenty-first century is halfway through. Producing fuel from vegetable oil is environmentally sustainable, far less polluting, more economical, and much healthier for humans. The most polluting activity the average person engages in is driving a personal vehicle. Because diesel fuel is chemically similar to vegetable oil, diesel engines can be successfully run on a vegetable oil fuel known as “biodiesel” in its pure form or mixed with diesel fuel, and they can also be run on straight vegetable oil. With little to no vehicle modification, drivers of diesel vehicles can drastically reduce their contribution to air pollution while protecting their health, the environment, and their wallets.

Introduction

Oil has long been referred to as ‘black gold’ because of its source of wealth and seemingly limitless applications. After some thought, it seems that every facet of the life to which we have grown accustomed is cripplingly dependent on some form of oil. Think of all the things that operate because of methane, butane, propane, gasoline, kerosene, diesel fuel, home heating oil, motor oil, grease, asphalt, tar and wax. All these products originate in crude oil. Many cannot imagine a world without even one of these products. However, if the current consumption rate of 24,000,000,000 barrels per year remains constant, the oil supply would run out around 2040. Consumption rarely remains constant; in fact, it increases about two percent per year, and that rate is also increasing. With that in mind, it has been estimated that between 2010 and 2025, all fossil oil products will be too expensive for the average Western consumer (1).

Blind ignorance will not help, although it seems to be that path that most people have chosen. Not only have people not embraced the notion of conservation, but also many are going in the opposite direction, which is evident on every outing. The number of trucks, minivans and SUVs has increased over the years, both in popularity and in sheer size. Oil and gas is big business; there has certainly been no major push from the automobile industry to encourage smaller, more fuel-efficient vehicles. There has been limited introduction of hybrid and alternative fuel vehicles, but nothing of any real significance when balanced with the number of Chevrolet Suburbans and the new GMC XUVs leaving the dealerships.

Everyone agrees that something must be done; but what, and by whom? Everyone agrees that change is necessary, but few are willing to step up and give up some of the comforts of modern life. However, unless we want the next generation to tell their grandchildren how they walked to school, uphill both ways, in all types of weather, and had no lights and no heat when they arrived, a concerted effort to manage our limited resources and develop sustainable technologies must be a priority of utmost importance.

Although government can be woefully slow at effecting significant, meaningful change, individual consumers have the ability, and some would say, the duty, to take actions at the personal level. One such way is to limit usage of petroleum products.

Theoretical Analysis

Hydrocarbons and Fractional Distillation

Crude oil, or petroleum, is the unprocessed oil that comes out of the ground. It is a fossil fuel, made from naturally decaying plants and animals over millions of years. Crude oil contains hydrocarbons, which are molecules made up of hydrogen and carbon in varying shapes and sizes. These molecules can form in chains, branches and rings, in many combinations. Hydrocarbons contain a lot of energy and can take on many different forms. For these two reasons, hydrocarbons have become an essential part of our society. To make the hydrogen carbons useful, however, the crude oil must be processed in a way that separates and sorts the hydrocarbons into similar groups (2).

The process by which hydrocarbons are sorted is called fractional distillation (see Figure 1). The theory behind this process is that longer hydrocarbon chains have progressively higher boiling points as their length increases. In a distillation column, crude oil is heated and different chain lengths are separated by their vaporization temperatures. The more carbons a chain possesses, the higher that chain’s boiling point. For example, petroleum gas, such as methane (CH4), propane (C3H8) and butane (C4H10), have one to four carbon atoms per molecule and a boiling point of less than 40 degrees Celsius. Gasoline, used for fuel, has between five and twelve carbon atoms, is normally in a liquid state at room temperature, and has a boiling range of 40 to 205 degrees Celsius. Diesel fuel, also normally a liquid at room temperature, contains between twelve and twenty-two carbon atoms, and has a boiling range of 250 to 350 degrees Celsius. The longest chains are found in the residuals, such as coke, asphalt, tar, and waxes. These complex molecules contain more than seventy carbon atoms and boil at 600 degrees Celsius and higher. The molecules with more carbon atoms generally contain more potential energy than smaller molecules. For example, diesel fuel, with twelve to twenty-two carbons, generally contains more energy than gasoline fuel with five to twelve carbons (3).

Figure 1: Fractional Distillation (3)

[pic]

Fractional distillation involves several steps. First, the crude oil is heated, frequently with high-pressure steam at temperatures near 600 degrees Celsius (3). The oil boils, forming a vapor. The vapor then enters the bottom of a tall column filled with trays. Each tray contains many holes to allow vapor to pass through. The column is hottest at the bottom and coolest at the top. When the vapor rises through the column, it cools. As the vapor reaches a point in the column where the column’s temperature equals the vapor’s boiling point, it condenses into liquid form. The liquid is collected on the trays, at which point the fractions are passed to condensers and then to storage tanks, or are sent for further processing (4). The whole process resembles a vertical labyrinth.

Often, there is an overabundance of fractions that boil at higher temperatures, and not enough gasoline to meet the demand. The larger molecules can be broken down into smaller molecules, including gasoline, through a process called cracking. This happens when the larger molecules are heated in the absence of air (2). In Figure 1, a cracking unit has been installed to break down molecules with sixteen to thirty-six carbon atoms into molecules with eight carbon atoms. These smaller molecules are then used in the production of gasoline.

Figure 2: Energy increases with molecule size (5)

|Formula |Energy |Structure | |Formula |Energy |Structure |

| |(kJ/mol) | | | |(kJ/mol) | |

|CH4 |0.00 |[pic] | |C6H14 |14.53 |[pic] |

|Methane | | | |Hexane | | |

|C2H6 |3.41 |[pic] | |C7H16 |17.24 |[pic] |

|Ethane | | | |Heptane | | |

|C3H8 |6.27 |[pic] | |C8H18 |19.96 |[pic] |

|Propane | | | |Octane | | |

|C4H10 |9.09 |[pic] | |C9H20 |22.68 |[pic] |

|Butane | | | |Nonane | | |

|C5H12 |11.81 |[pic] | |C10H22 |25.39 |[pic] |

|Pentane | | | |Decane | | |

Diesel fuel is heavier than gasoline because it contains more carbon atoms in longer chains. Diesel fuel takes less refining, which is why it is usually cheaper than gasoline. Diesel fuel also has a higher energy density. Generally, larger molecules contain more energy than smaller molecules (see Figure 2). One gallon of diesel fuel contains 147,000 BTU, while one gallon of gasoline contains only 125,000 BTU (6). BTU stands for British Thermal Units. One BTU is “the amount of energy required to increase the temperature of 1 pound of water by 1 degree Fahrenheit, at normal atmospheric pressure. Energy consumption is expressed in Btu to allow for consumption comparisons among fuels that are measured in different units.” For example, one kilowatt hour, or kWh, is the energy needed to use a 100-watt light bulb for ten hours) is a unit of energy (7). One kWh of electricity is equivalent to 3,412 BTU (8).

Gasoline and Diesel Engines

Although the inner workings of vehicle engines are becoming more and more complex, the basics behind gasoline and diesel engines are relatively simple. Gasoline engines are internal combustion engines. They take a small amount of high-energy fuel and ignite it, releasing energy in the form of expanding gas. This energy is used to propel a vehicle. Most cars use a four-stroke combustion cycle (See Figure 3). During the intake stroke, the intake valve opens, and the piston moves down to allow in a cylinder of air and gasoline. In the compression stroke, the piston moves back up to compress the fuel and air. When the compression is complete, the spark plug ignites the gasoline, which explodes, and forces the piston back down. This is the combustion stroke. Finally, the exhaust valve opens and the exhaust leaves the cylinder and goes out the tailpipe. This is the exhaust stroke. This cycle repeats over and over to continue to propel the vehicle. When a driver quickly accelerates, this process speeds up (9).

Figure 3: Internal Combustion (Gasoline) Engine (9)

[pic]

In a perfect system, internal combustion engines would produce only pure carbon dioxide and water. However, this is not a reality for several reasons. Carbon monoxide is formed when combustion is incomplete. Not enough oxygen is available fast enough to react completely with all of the carbon. Nitrogen is the most prevalent gas in the earth’s atmosphere, comprising approximately 78 percent by volume. Oxygen comprises nearly 21 percent by volume. Thus, there is nearly four times as much nitrogen as oxygen by volume (10). Because of this fact, and the high temperature and pressure in the cylinder, nitrogen and oxygen combine, resulting in nitrogen oxides. Impurities in the gasoline, such as sulfur, can result in the release of sulfur oxides. Additionally, unburned hydrocarbons are released as a result of incomplete combustion (11).

Diesel engines, created in 1895 by Rudolf Diesel of Germany, work differently from internal combustion engines. Diesel engines also use four steps (See Figure 4). First, air enters the chamber. A piston compresses the air to increase its temperature and pressure. Fuel is then injected into the chamber. The heat of the compressed air ignites the fuel, releasing the energy that propels the vehicle. Finally, the exhaust leaves the chamber and the vehicle and the process repeats (6).

Figure 4: Diesel Engine (12)

[pic]

Diesel engines produce pollutants similarly to gasoline engines. Because diesel fuel has traditionally been less refined, it is a “dirtier” fuel and releases much more soot than gasoline engines. This is not an inherent characteristic of diesel engines; rather, it is the manufacturing of the engines and the fuel itself (13).

There are several main differences between gasoline and diesel engines. Gasoline engines intake a mixture of air and gasoline, compress it, and ignite it with a spark plug. Diesel engines take in just air, and then inject the fuel into the compressed air. Diesel engines have a higher compression ratio than gasoline engines, potentially leading to better efficiency. Gasoline engines use either a carburetor, through which air and fuel mixes before entering the cylinder, or fuel injection, through which fuel is injected just before the intake stroke. Diesel engines use direct injection, whereby the fuel is injected directly into the cylinder (6). Because there is a smaller risk of pre-ignition in diesel engines than gasoline engines, diesels have the potential to run on a wide variety of fuels.

The combustion phase in an internal combustion engine is possible because of the relatively low flash point of gasoline fuel compared to its autoignition point. Flash point is the temperature at which a fuel and air mixture becomes ignitable (14). The higher a fuel’s flash point, the safer it is to store and handle (15). Autoignition point is the temperature at which a substance self-ignites, or spontaneously combusts. Gasoline has a low flash point, below 45 degrees Celsius, so that it will ignite from the spark generated by the sparkplug, but a high autoignition point, 246 degrees Celsius, so that it does not ignite too soon on its own in the engine. Diesel engines are high-combustion engines; air is compressed until its temperature exceeds diesel fuel’s autoignition point, then the fuel is injected, where it self-ignites. Because there is no ignition source in diesel engines, diesel fuel must have a high flash point, over 45 degrees Celsius, and a low autoignition temperature, 210 degrees Celsius (14). Were someone to put diesel fuel in an internal combustion engine, the spark from the spark plug would not raise the fuel above its flash point, and it would not combust. Therefore, diesel fuel is not suitable for a gasoline engine. Conversely, were someone to put gasoline in a diesel engine, the gasoline would not self-ignite, and without a spark, would not combust. For the opposite reason, gasoline is not suitable for a diesel engine.

Gasoline and diesel fuel are mainly comprised of hydrocarbons, but commercial formulas also contain additives such as benzene, toluene, ethylbenzene, and xylene, known as BTEX, and ethanol, methanol, methyl tert-butyl ether, or MTBE. These chemicals are added to improve engine and fuel efficiency (16). However, they have been found to cause cancer and neurological impairment, and have often caused environmental pollution that outweighs its intended benefits (17). A full discussion of these fuel additives is beyond the scope of this paper.

Vegetable Oil as an Alternative Fuel

With a basic understanding of gasoline and diesel engines, it is now appropriate to examine the methods by which a growing number of people are utilizing a more sustainable and cost effective fuel source in their diesel vehicles – vegetable oil.[1] There are three ways to use vegetable oil in a diesel engine; biodiesel, vegetable oil/kerosene mixture, and straight vegetable oil. Each will be discussed in turn.

Biodiesel is a bit of a misnomer, since it contains no petroleum products. Rather, it is a fuel made from 80-90 percent vegetable oil, 10-20 percent alcohol, and less than two percent catalyst. Biodiesel can be used in all diesel engines on its own or mixed with diesel fuel. Using biodiesel requires no vehicle modifications. Pure biodiesel is known as B100. A common mixture is 20 percent biodiesel and 80 percent diesel, known as B20. Both B100 and B20 are commercially manufactured, albeit on a limited scale. Biodiesel can also be made at home, with proper precautions (18). This will be discussed below, after a brief introduction of the basic chemistry involved.

As discussed above, hydrocarbons contain hydrogen and carbon atoms. Alkanes are one type of hydrocarbon. They can be represented by the general formula CnH2n+2. All of the molecules in Figure 2 are alkanes. Note that all of the names end with –ane. All alkanes have certain chemical properties in common. They are less dense than water; when combined, alkanes float at the surface. Alkanes are non-polar molecules. This means that they do not have separate centers of positive and negative charge (as does a magnet) (2). Alkanes dissolve low-polarity molecules, such as fats, oils and waxes. One of the most important properties of alkanes is their ability to burn and produce a great quantity of heat. For this reason, they are excellent fuels. Both gasoline and diesel fuel contain light liquid alkanes (2).

When one hydrogen atom is removed from an alkane, the molecule becomes an alkyl. Functional groups, or groups of atoms that have characteristic chemical and physical properties, attach to alkyl groups. The alkyl then takes on the characteristics of the functional group. The simplest example is methane. (See Figure 5). The formula for methane is CH4. This follows the alkane formula; n=1, 2n+2=4. There is one carbon atom and four hydrogen atoms. Methane, minus one hydrogen atom, becomes methyl. Methyl is an alkyl. Methyl combined with an alcohol group, OH (oxygen-hydrogen), becomes methanol, an alcohol. Methanol is also known as wood alcohol.

Figure 5: Methane, Methyl, and Methanol (19)

[pic] [pic][pic]

Esters are compounds made from a carboxylic acid and an alcohol. The general formula for esters is alkyl+COO+alkyl. Carboxylic acids are a functional group, like alcohols. The general formula for carboxylic acids is alkyl+COOH. Vegetable oils are esters of glycerin and carboxylic acids (2).

Biodiesel is made through a process called transesterification. This literally means changing an ester into a different ester. Through transesterification, vegetable oil is turned into vegetable methyl ester by removing the glycerin molecule from the chain of esters. Glycerin, an alcohol, is what makes vegetable oil thick and sticky. By removing the glycerin, the oil becomes less viscous. To pull out the glycerin, a catalyst, or a substance that starts a reaction, is needed (18).

To make biodiesel, methanol, an alcohol, is mixed with sodium hydroxide (NaOH) or potassium hydroxide (KOH), the catalyst, to create sodium methoxide or potassium methoxide. This is then mixed with the vegetable oil. (See Figure 6). The mixture must then be set aside for eight hours while the glycerin separates. After eight hours, the glycerin can be drained and used as soap if NaOH was used, or as fertilizer if KOH was used. What remains is biodiesel, which can be used in a diesel engine (18).

Figure 6: The Transesterification Reaction (18)

O

II

R – C – O – CH2 OH – CH2

II II

O II O II

II II II II

R – C – O – CH + 3CH3OH ( 3alkyl – C – O – CH3 + OH – CH

II NaOH II

O II or II

II II KOH II

R – C – O – CH2 OH – CH2

=

Vegetable Oil + Methanol (Catalyst) Biodiesel + Glycerin

The second type of vegetable fuel is the vegetable oil/kerosene mixture. At this point, this fuel is considered experimental, requires precise measuring, produces unreliable results, and is not approved or endorsed by any government agency. In addition, it is unstable, hazardous to store, and can damage engines. For these reasons, this type of fuel is not considered a viable alternative to gasoline or diesel at this time, and will not be discussed further (18).

The third type of vegetable fuel is straight vegetable oil (SVO), often called waste vegetable oil (WVO) when recycled from restaurants. This draws on the original spirit of Rudolf Diesel’s invention, with some modifications to accommodate modern diesel engines (18). When Diesel invented his engine, he intended to run it on a variety of fuels, including vegetable oil. In 1900, Diesel showed his engine at the World Exhibition in Paris using peanut oil. The early diesel engines were designed to run on heavy fuels, including straight vegetable oil. Some were so sturdy and strong that they still work. Modern diesel engines have been manufactured to run on the cheapest fuel available: petroleum. As a result, the engines were modified to run on less viscous fuels (18). Viscosity is a property of liquids that resists flow, measured in centipoise. For example, the expression “blood is thicker than water” can be used to understand viscosity. Figurative meaning aside, water flows more easily than blood; water is less viscous. At room temperature, water has a viscosity of 1 to 5 centipoise, while blood has a viscosity of 10 centipoise. Corn oil has a viscosity of 50 to 100 centipoise. Molasses has a viscosity of 5,000 to 10,000 centipoise, and peanut butter has a viscosity of 150,000 to 250,000 centipoise (20).

Below 70 degrees Celsius, the viscosity of SVO and WVO is above 20 centipoise. Most diesel engines require fuel viscosity to be no more than ten or fifteen centipoise. When SVO is heated to 80 degrees Celsius, its viscosity drops below ten centipoise. At that point, it will run in diesel engines as well as diesel fuel (18). (See Figure 7).

Figure 7: Viscosity and Temperature (21)

[pic]

RME = Rapeseed Methyl Ester (Biodiesel)

Because of the inherently different properties of diesel/biodiesel and SVO, the vehicle must be initially started on either diesel or biodiesel. When the temperature of the SVO has reached 80 degrees Celsius, a toggle switch installed on the dash allows the driver to switch from the diesel or biodiesel tank to the custom-installed SVO tank. The vehicle must be switched back to diesel or biodiesel for several minutes before shutting off the car to clear the SVO out of the engine and fuel lines (18).

To run a vehicle on SVO, some modifications must be made to the vehicle. This entails modifying the engine’s heater hoses and installing a second fuel tank for the SVO, usually in the trunk. Many people with only a limited knowledge of automobile mechanics have successfully completed the necessary modifications (18). Several kits are available which contain all the necessary parts to complete a conversion. (See Figure 8).

Although the conversion does take a minimal amount of mechanical knowledge and experience, the basics can be explained very simply. (See Figure 10). To begin, a second fuel tank containing a heating element must be installed. This can be placed in the spare tire compartment, anywhere in the trunk, or within the passenger area. The diesel fuel hoses must then be rerouted so that the fuel supply line is cut to install a solenoid valve between the fuel tank and the injection pump. A solenoid valve is an electromagnet that is used to open or close a valve, or allow or prevent a fluid to run through a pipe or hose. The diesel fuel return line must be rerouted so that it loops back into the supply line, rather than into the diesel fuel tank. The fuel line from the SVO tank must first pass through the newly-installed filter, then into the solenoid valve. From the solenoid valve, one fuel supply line enters the injection pump. On the dashboard near the driver, a toggle switch connected to the solenoid valve must be installed. Before using SVO, it must be filtered to at least 40 microns. (See Figure 9). This can also be done at home with even the most basic equipment, such as a filter and several plastic containers. If a commercial filter is unavailable, even a nylon stocking will suffice. This prevents small food particles and other debris from entering the fuel lines and clogging the engine (18).

Once the conversion is complete and the oil is filtered, the vehicle can be run on SVO. As mentioned above, the viscosity of vegetable oil requires that the vehicle be started and stopped on diesel or biodiesel. After the car has been running for several minutes, the driver can flip the toggle switch on the dashboard to cut off the supply of diesel fuel and start the supply of SVO. Several minutes before shutting off the car, the switch must be flipped back to clear the lines of SVO so that it does not clog the hoses and engine when it cools (18).

Figure 8: SVO Conversion Kits Left: (22); Right: (23)

[pic] [pic]

Figure 9: Filtering Waste Vegetable Oil (22)

[pic] [pic]

Figure 10: Straight Vegetable Oil Simplified Conversion Diagram (22)

[pic]

Discussion

The average price for a gallon of gasoline in the United States on April 12, 2004 was $1.786, up six tenths of a cent from the previous week, and up 19.1 cents from April 12, 2003. The average price for a gallon of diesel fuel in the United States was $1.679 per gallon, up 3.1 cents from the previous week, and up 14.0 cents from last year (24).

According to the United States Department of Transportation Bureau of Transportation Statistics, in 1998, the United States produced 8,140,000 barrels of oil, petroleum and natural gas per day. The United States exported 950,000 barrels per day and imported 10,710,000 barrels per day, for a net of 9,760,000 barrels per day imported into the United States (See Figure 11).

Figure 11: United States Oil Imports and Exports (25)

Transportation accounted for 27.8% of the nation’s entire energy consumption. Passenger cars, motorcycles, and other two-axle, four-tire vehicles (vans, minivans, light pickup trucks, and sport utility vehicles) consumed 122,993,000,000 gallons of gasoline, diesel, and other fuels (26).

Together, these vehicles traveled 2,415,937,000,000 miles. On average, passenger cars got 21.4 miles per gallon of fuel. Mileage per gallon has improved steadily since 1970, with only minor setbacks along the way. Vans, trucks, and SUVs got an average of 17.1 miles per gallon of fuel, a steady decrease since 1993. Before 1993, mileage per gallon had been improving since 1970. With the increasing popularity of larger, less efficient vehicles, these numbers are no surprise (26).

On-road vehicles accounted for 50,390,000 short tons of carbon monoxide emissions, 7,770,000 short tons of nitrogen oxides emissions, 5,330,000 short tons of volatile organic compounds (VOC) emissions, 260,000 short tons of particulate matter (PM-10 – particulate matter less than 10 microns in size) emissions, 200,000 short tons of particulate matter (PM-2.5 – particulate matter less than 2.5 microns in size) emissions, 330,000 short tons of sulfur dioxide emissions, and 20,000 short tons of lead emissions.

That same year, 885,303 gallons of petroleum oil spilled into or impacted United States navigable waterways. Also in 1998, 371,387 gallons of petroleum oil was released from leaking underground storage tanks (26).

The role of air pollution in chronic and acute health conditions is still under investigation, but researchers have determined that exposure to pollutants can exacerbate existing conditions, and can possibly cause the onset of illness. The following is a list of conditions suspected to be caused or worsened by exposure to air pollution: minor lung illnesses, such as sore throat, stuffy and runny nose, coughing, and eye irritation; lung infections, including croup, bronchitis, and pneumonia; asthma, which has been shown to be triggered by sensitivity to non-allergic types of pollutants present in the air; chronic obstructive pulmonary disease, which is comprised of emphysema and chronic bronchitis; lung cancer; coronary artery disease, which is the narrowing or blockage of arteries or blood vessels, which can restrict or stop blood flow; heart failure; and heart-rhythm problems (27).

The advantages of biodiesel are numerous. First, it has a favorable energy balance ratio. This ratio compares the energy stored in a fuel to the energy required to produce and distribute the fuel. According to one study, the energy balance of biodiesel is at least 2.5:1 (18). Biodiesel is both biodegradable and non-toxic. B100 is as biodegradable as sugar and less toxic than table salt. It degrades up to four times faster than petroleum fuels, with ninety-eight percent biodegration within twenty-one days. Transportation and storage of biodiesel is much safer than petroleum fuels because it will not normally spontaneously explode or ignite (18). Biodiesel is also more lubricating than gasoline or diesel fuel, which can help prolong engine life. Biodiesel has been used in jet fuels and fleet vehicles. In 1998, the Department of Energy designated B100 as an alternative fuel, and developed a credit system for its use (28). Most importantly, however, biodiesel significantly reduces the vehicle’s emissions. This will be discussed in detail below.

Biodiesel also has some drawbacks. Currently, it is hard to find. The National Biodiesel Board lists on its website locations across the country where biodiesel can be purchased, and the list is constantly growing (29). It is available in all fifty states, but it is nowhere near as available as gasoline or diesel fuel. However, biodiesel can be made at home with even a basic understanding of chemistry, although some of the ingredients are hard to obtain, or hazardous to use. In some parts of the country, biodiesel cooperatives have made the fuel easier to obtain by purchasing in bulk. The properties of biodiesel can cause the breakdown of rubber components such as fuel lines. This, however, simply means a little extra monitoring and maintenance when necessary. Some users of biodiesel have replaced the rubber engine components with other materials less affected by the fuel. In some cases, biodiesel can clog the fuel filter during the initial switch from diesel fuel. Again, this is not a major problem; it simply requires monitoring and maintenance. Biodiesel as B100 can gel in cold temperatures, reaching a consistency anywhere from pudding to Vaseline. In areas where this poses a potential problem, such as winters in the northeastern United States, using B20 effectively prevents the fuel from gelling.

Biodiesel is slightly less efficient than gasoline and diesel fuel. It contains twelve percent less energy than diesel fuel, approximately 121,000 BTU per gallon (30). However, this is offset by the fact that biodiesel has a combustion efficiency seven percent greater than diesel fuel. This results in a net of a five percent decrease in torque, power, and fuel efficiency. This decrease is barely noticeable, and negligible when compared to the environmental and economic benefits of using biodiesel.

In addition, biodiesel may seem to be more expensive at first glance. However, the increased price per gallon is balanced by an equal decrease in consumption. The following example using a Volkswagen Jetta gasoline and diesel cars illustrates this point. (See Figure 12).

As these figures demonstrate, biodiesel is less expensive per mile than gasoline. As gasoline prices continue to climb and biodiesel becomes more widely available and less expensive, this difference in price will become even more dramatic (31).

Figure 12: Cost Per Mile – Gasoline, Diesel and Biodiesel (31)

|Fuel type |Miles/gallon |Gallons/100miles |Gallons/mile |Price/gallon |Cents/mile |

|Gasoline |30 |3.3 |0.033 |$1.79 |5.91 |

|Diesel |50 |2.0 |0.020 |$1.68 |3.36 |

|Biodiesel |50 |2.0 |0.020 |$2.79 |5.58 |

|SVO |~50 |~2.0 |~0.20 |FREE |FREE |

The advantages of running a vehicle on SVO are impressive. SVO use results in a tremendous reduction in emissions. In addition, after the initial conversion cost, fuel is nearly, or actually, free. Each year, restaurants produce over three billion gallons of used cooking oil. Many have to pay to have their waste oil removed, where it is mixed into consumer products such as pet food and makeup, or it is dumped into sewers and landfills. The latter causes tremendous environmental damage and costs the public millions of dollars in cleanups (18). Many restaurant managers are happy to give away their waste oil for free. Although the waste oil must be filtered to remove tiny food particles, this scheme provides a constant and costless source of fuel. Thought of an additional fuel tank raises some concerns, though they are unfounded. The tank is filled with vegetable oil, which will not spontaneously ignite or combust like gasoline and diesel fuel (18).

Using SVO has some drawbacks. Preparing the vehicle and the oil is time consuming, and requires some skill, although minimal. Maintaining a vehicle running on SVO requires more careful attention than what is required for a gasoline or diesel fueled vehicle. However, as with biodiesel, the small sacrifices and minor inconveniences are worth the reduction in exhaust emissions, health effects, and environmental impact.

The environmental benefits to using B100, B20 or SVO with diesel or biodiesel are astonishing. An EPA study found that even B20, with only twenty percent biodiesel, reduced hydrocarbon emissions up to thirty percent, carbon monoxide up to twenty percent, and total particulate matter up to fifteen percent. Emissions of nitrogen oxides are either slightly reduced or increased depending on vehicle efficiency and testing method (32). A study by the Department of Energy found that B20 produces 78.5 percent less carbon dioxide emissions. B100 fares even better. The EPA determined that it reduced hydrocarbon emissions sixty-seven percent, carbon monoxide emissions forty-eight percent, and total particulate matter twelve percent. As with B20, nitrogen oxides were either slightly increased or decreased. B100 contains no sulfur, thus reducing sulfur oxide emissions to nearly zero. It is not reduced completely, as there is a small amount of sulfur naturally occurring in the air.

In addition to biodiesel and SVO reducing vehicle emissions, their production is ecologically sustainable and has a favorable energy balance. Soybean oil is the most commonly used in restaurants. Soybeans produce 375 kilograms of oil per hectare (equal to 10,000 square meters), and renews within a few months (18). The United States has great but unutilized potential for oil production. In the US, more than 24 million hectares of farmland are not planted. In fact, to maintain prices, many farmers are paid to not grow crops. If that land were used for rapeseed production, which yields 1,000 kilograms of oil per hectare, the US could grow six billion gallons of vegetable oil per year, equal to ten percent of the diesel fuel consumed. The three billion gallons of waste oil constitutes another five percent of diesel consumption. Thus, without displacing any food production, the US could replace fifteen percent of its current diesel usage. Utilizing locally or regionally grown soybean or rapeseed oil reduces production costs, emissions, and environmental damage. Even more energy efficient than soybeans and rapeseed is algae (1). At the National Renewable Energy Laboratory, algae grown in 1000 square meter ponds yielded 9,125 kilograms of oil. These ponds are one tenth of a hectare; algae yields over ninety times more oil than rapeseed and 243 times more oil than soybeans. Algae can be grown anywhere from the desert to wastewater treatment plants (18).

Health benefits are significant as well. Biodiesel and SVO do not contain benzene, a carcinogen in gasoline. Polycyclic aromatic hydrocarbons (PAH’s) and nitrated PAH’s, potential carcinogens, are drastically reduced compared to diesel fuel. Using B100 reduces PAH’s by eighty percent and nitrated PAH’s by ninety percent. B20 reduces PAH’s by thirteen percent and nitrated PAH’s by fifty percent (32, 33).

Few studies have been done to accurately compare biodiesel with SVO. However, from the information currently available, both appear to be viable fuel alternatives to diesel and gasoline.

Legislation and Policy

Few laws and regulations exist regarding biodiesel, and at this time, no laws exist pertaining to SVO. Federal law recognizes biodiesel as an alternative fuel, and as such, Congress has authorized the Secretary of Agriculture to provide competitive grants to entities to educate governmental and private groups that operate fleet vehicles about the benefits of biodiesel fuel use (34). In addition, Congress has authorized the Secretary of Energy to establish a credit system for fleets using biodiesel fuel, as long as the biodiesel is at least B20 (35). Both Secretaries have met this mandate; the USDA promulgated regulations establishing the Biodiesel Fuel Education Program in 2003, USDA Biodiesel Fuel Education Program (36), and the Department of Energy promulgated regulations establishing the Biodiesel Fuel Use Credit in 2001 (37).

Conclusions and Summary

Microeconomics, the national balance of trade and economic security, environmental concerns, and adverse health effects will soon demand an alternative to petroleum fuels. The broad range of concerns regarding the use of gasoline and diesel fuel has pushed many people, including the federal government, to explore alternative fuel sources. One such source is vegetable oil. Perhaps with time, diesel engines will be manufactured more like their predecessors, and can run on SVO without diesel or biodiesel startup. It is feasible to believe gasoline and diesel fuel will go the way of leaded gasoline, with pumps spouting B100 and even SVO for a fraction of their current cost. Like the victory gardens of World War II, the future may find an algae pond in every backyard. This may not be in our lifetime. What is more probable is that society will continue to ignore the fact that the fossil oil supply is being depleted, until it reaches a critical point. Then, oil wars will be fought, probably without the guise of threats to democracy or human rights. The gas crisis of the 1970s will seem like nothing compared to what will happen when the world’s supply dwindles. It may take such a dire situation to compel significant change.

However, an ever-growing number of people are looking for alternatives now – and taking action. The drastic reduction in emissions, minimal environmental impact, sustainability, cost, and reduction in health risks make vegetable oil fuels an easy sell.

Both gasoline and diesel fueled vehicles are highly polluting. Society has come to depend on personal vehicles for work, leisure and social activities. Those needs are not likely to change; however, the fuel used to get there can. Biodiesel, a blend of vegetable oil, alcohol, and a catalyst, reduces vehicle emissions even at such low concentrations as twenty percent mixed with regular diesel fuel. Pure biodiesel fuel reduces emissions even more drastically. One of the drawbacks to biodiesel is that it is currently difficult to obtain, and often impractical or unsafe to produce at home. Until a reliable source becomes widely available, biodiesel will remain a fuel for only the large fleets of vehicles, fuel cooperatives, and a handful of conscientious individuals.

Straight Vegetable Oil reduces emissions, provides a use for waste cooking oil, can be produced without impacting the nation’s food supply, and is sustainable and renewable. Running a vehicle on SVO requires some modification to the fuel system. Until diesel engines become as forgiving as they once were, vehicles using SVO must be started with diesel or biodiesel until the SVO reaches an appropriate temperature. This becomes more of a concern in colder climates.

Although both biodiesel and SVO have some shortcomings in comparison to diesel or gasoline, their benefits are numerous. As the use of biodiesel and SVO becomes more prevalent, many of the drawbacks to these fuels can be lessened or eliminated. This will translate to less air pollution, less environmental degradation, less reliance on foreign politics, and more personal freedom.

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[1] Diesel engines can also run on animal fats. However, because of the environmental and social costs of farming animals from whom the fats are obtained, the author does not support the proposition that it is a practical or sustainable fuel source.

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