BIOMETHANE: AN ECONOMICAL AND SUSTAINABLE ALTERNATIVE VEHICLE FUEL SOURCE

Transcription

1 Session A5 Paper #4040 BIOMETHANE: AN ECONOMICAL AND SUSTAINABLE ALTERNATIVE VEHICLE FUEL SOURCE Justin Traino Bursic 2:00), Bursic 2:00) Abstract Biomethane is a biofuel made from organic waste. Controlled anaerobic digestion of organic matter will generate the methane needed to create vehicle fuel [1]. Biomethane is an economical and sustainable alternative for vehicle fuel with a negative carbon footprint. This type of fuel has two major benefits: it is a renewable fuel with low fossil carbon emissions; and it removes a source of methane that would otherwise be released into the atmosphere if the organic matter decomposed naturally [2]. When these two effects are combined, carbon dioxide equivalent emissions in the atmosphere could actually be reduced, producing a negative carbon footprint. This paper discusses why biomethane is a better fuel source because its resources are renewable and it lessens potential emissions from naturally occurring waste [2]. Cars fueled by biomethane have the lowest carbon dioxide equivalent emissions and have the highest energy yield. This paper will: highlight the use of biomethane as a vehicle fuel source; demonstrate how it positively impacts the environment, and explain why this is an economical and sustainable energy solution. the environment and have a sustainable fuel source for generations to come if there is a shift from gasoline to biomethane powered vehicles. TECHNOLOGY AND PRODUCTION OF BIOMETHANE Biomethane is produced through a process called anaerobic digestion. The three main steps in anaerobic digestion are hydrolysis, acidogenesis, and methanogenesis which are shown in Figure 1 [3]. The Process of Anaerobic Digestion Key Words- Alternative fuel source, Anaerobic Digestion, Biomethane, Environmental Impacts, Sustainability. BIOMETHANE: AN ALTERNATE TRANSPORTATION FUEL SOURCE Today our society relies on gasoline as the primary fuel source for the automotive industry. Carbon dioxide emissions, produced in combustion, are believed to have damaging effects on the environment. Climate change may persist and available resources may run out if no actions are taken to decrease the use of fossil fuels. Gasoline prices are at record highs and will continue to rise as the demand for fuel and energy increases. Many experts believe that the solution to our problems is the renewable alternative energy source, biomethane [2]. Biomethane is a biofuel made from organic waste, created through anaerobic digestion. Using biomethane as a fuel source produces only water vapor and small amounts of carbon dioxide as products. This small amount of carbon dioxide will greatly decrease our current transportation pollution by reducing emissions. Several cars on the road today that use biomethane as fuel, show promise that these vehicles can be integrated into today s society. Using gasoline depletes finite resources, so a renewable fuel is needed to sustain growth [2]. Using organic waste as a new fuel source would also reduce emissions from the decomposition of organic material [2]. Society can improve Figure 1 [3]: This diagram shows the process of anaerobic digestion to produce biomethane. The input materials are organic waste and the products are methane, to be used as fuel, water, and small amounts of carbon dioxide. Hydrolysis: The first step, hydrolysis, takes input materials, which are renewable and come from organic waste, and breaks down insoluble organic polymers within the material [3]. These organic polymers are then converted into soluble molecules, which are made available for other bacteria as shown in Figure 1. Some examples of hydrolysis include lipids to fatty acids, protein to amino acids, and nucleic acids to purines or pyrimidines. The hydrolysis process is of great importance because it determines the amount of methane being produced, University of Pittsburgh Swanson School of Engineering 2014/03/06 1

2 also known as the limiting reactant. The way most companies achieve higher production is to add other chemicals to enhance the process and produce more methane. Acidogenesis: In acidogenesis, the second stage displayed in Figure 1, acetogenic bacteria convert the products of the first phase into simple organic acids, carbon dioxide and hydrogen [3]. Some examples of acids produced are acetic acid, propionic acid, and ethanol [3]. Methanogenesis: Finally, in the third stage, bacteria called methanogens produce the methane that will be used as fuel in two ways. Primarily, methanogens split acetic acid into carbon dioxide and methane as shown in the first equation [3]. The carbon dioxide is then used to react with ethanol to create more methane and acetic as presented in the second equation. The second way methane is produced is by reacting carbon dioxide with hydrogen molecules to create methane and water as displayed in equation three. composite cylinders that have a fiberglass shell and foam that absorbs impact in the event of a vehicle crash. The composite cylinders, also known as pressure cells, are connected to an integrated gas control system. The cylinders are small enough that they can be put together in a threecylinder shape, which is similar to what a typical vehicle s tank looks like [4]. The pressure cells are then connected to vehicles using attachment straps. This enables vehicles fueled by biomethane to be approximately the same size as a typical combustion engine vehicle. Biomethane Engine CH! COOH CH! + CO! 2C! H! OH + CO! CH! + 2CH! COOH CO! + 4H! CH! + 2H! O Purifying The Methane After the process of anaerobic digestion is complete, the next step is to extract the methane from the carbon dioxide, water vapor and other impurities to create the biogas. This process uses a two-membrane module system that will split each solution into two streams [3]. In the first membrane the module splits the gas into methane and the other impurities. The second module is able to extract any additional product from the impurities and then separate the methane and impurities from each other. The purpose of the second module is to obtain the most amount of product and to allow the methane to be as pure as possible [3]. In conclusion, the process of anaerobic digestion creates methane and a few other byproducts that are then separated through a two-step procedure to create the final product of biomethane, which will be used as fuel source for vehicles. Converting Biomethane to Vehicle Fuel The final step is the actual conversion of biomethane into a usable fuel for vehicles. The process in which biomethane is placed into vehicles is identical to that of vehicles which use compressed natural gas. At each fueling station the biogas is compressed to around 3300 psi, which allows it to be pumped into vehicles as a liquid [4]. Figure 2 demonstrates what an engine that uses biomethane as fuel would look like. In the vehicles the biomethane is stored in Figure 2 [4]: This is an engine of a vehicle powered by biomethane. The fuel is stored in composite cylinders, called pressure cells, that have a fiberglass shell and foam that absorbs impact in case of a vehicle crash. Biomethane is a feasible option as a transportation fuel source, and is not difficult to produce using anaerobic digestion. There are an abundance of resources to produce biomethane, such as animal feces, food waste and sewage sludge that will never deplete. These resources are also easily accessible allowing biomethane to be produced anywhere in the world. Most importantly, biomethane is chemically identical to natural gas, allowing for the implementation of biomethane into the grid and vehicles, a viable option in the near future. THE APPLICATIONS OF BIOMETHANE Biomethane is a renewable alternative energy source that can be used in a variety of ways but most importantly for vehicle fuel. Biomethane is chemically identical to natural gas but has a few key process differences. Biomethane is defined as a green source of energy whereas natural gas is a fossil fuel [5]. Another major difference is that natural gas is extracted by drilling into the earth, whereas biomethane can 2

3 be produced through processes described earlier using organic matter. This enables the input materials to produce biomethane to be readily available, but at the same time being sustainable and beneficial to the environment. The State of Biomethane Production Globally There are several examples across the world where biomethane plants are functioning on a large scale, and providing energy for its country. For example, the United Kingdom has three biomethane grid plants. Each plant works in a different sector of organic waste including 108 nonwater industry anaerobic plants, and 146 plants that are in the water industry [6]. There are even plants in the United States. In Junction City, Oregon there is an anaerobic plant that has the capacity of 25,000 tons per year of organic material to produce into biomethane [7]. The organics include material from the Portland metro area, grass straw, and food and beverage industry residues. The plant produces 12,250 MW hours of electricity annually [7]. Even though biomethane is being used for electricity generation in this specific case, it is as easy to use the biomethane produced as a fuel source, if the government offers incentives for producers to create these plants. At this stage in the research, many people question if these biomethane plants would actually work, but there is already successful production and distribution, as stated above, that would disprove these critics. How Biomethane Can Be Used The most notable application of biomethane was a group of Volkswagen engineers who created a car powered by this fuel source in 2004 [8]. This vehicle was a huge breakthrough because there was no loss of boot space. No loss of boot space is a term that means the car s trunk is the same size as a normal combustion engine vehicle. The vehicle has a combination of twin superchargers and a turbocharger allowing the vehicle to go from 0 to 60 mph in 9.7 seconds [8]. With one tank of fuel, a vehicle powered by biomethane has a range of 420 km, which tops gasoline s range of 400 km. The biomethane-fueled car also had a record low of 129-g/km release of carbon dioxide in 2004 [8]. After this vehicle was produced other companies, such as Mercedes-Benz, began to manufacture vehicles that were similar. There was an estimated 70,000 biomethane-fueled vehicles around the world in [9]. Presently, Sweden has the most vehicles that are compatible with biomethane, approximately 15,000 [9]. Since the first biomethane car created in 2004, many scientists have improved the quality of biomethane-powered cars and even reduced the amount of carbon dioxide released. The United States is pursuing research in light-duty vehicles, transit buses, and even solid waste trucks. If research and investment continues more vehicles can be produced in the United States that are compatible with biomethane. Many vehicles today only use gasoline, but there are some vehicles that are designed to use compressed natural gas. Since biomethane and natural gas have the same chemical makeup, these compressed natural gas (CNG) vehicles would also be able to be fueled by biomethane which can be used with biomethane. People believe that they will have to buy a new car to switch to biomethane and are concerned about the initial investment. In reality, there are ways to convert a standard combustion engine vehicle into a biomethane fuelled-vehicle. The first step to convert a car is to install storage cylinders with stainless steel fuel lines, which allow biomethane storage in the vehicle [10]. Drivers will need a regulator to reduce the pressure and a special fuel-air mixer [10]. An example of a converted car would be a Mazda Demio. The Mazda Demio is a vehicle compatible with natural gas and gasoline. This car is a prime example on how car companies can convert cars to be compatible with biomethane, but still be able to use gasoline while the biomethane infrastructure is being developed. These conversions allow for a smooth transition process from gasoline to biomethane. For potential buyers looking to purchase a new vehicle, a car that already has the appropriate type of engine to be compatible with biomethane is readily available. Although these vehicles are slightly more expensive, as the market develops, they will become comparable in price to gasoline-powered cars. People may question why they should take these actions if they cause a greater expense; however, people could actually save money when they purchase the biomethane fuel for their vehicle. Purchasing biomethane fuel would be a sustainable and economical choice given that it benefits the environment. It is also less expensive due to the fact that one is able to drive a further distance on biomethane compared to the distance one could go on the same amount of gasoline. The success of biomethane as a transport fuel in Europe means it has potential for U.S. markets. Specifically, in Germany there are over 900 fueling stations for natural gas that then can be converted into biomethane stations [11]. The natural gas filling stations are connected to the national gas grid, which shows that biomethane can be the dominant fuel source. In each fueling station there are air cooled compressors and storage tanks installed in concrete buildings that have an abundance of safety precautions [11]. These safety precautions allow for no leakage of carbon dioxide into the air and makes sure the fuel is at the appropriate temperature. These fueling stations are implemented in Europe and can be used as biomethane fuel stations as well. Compressed natural gas vehicles have been in use for decades. As of now the compression stations are expensive to build and operate, so there is no chain of stations such as what exists for gasoline. If there are no places to fill up a compressed natural gas vehicle, then people will not purchase this type of car. It is important for the United States government to enable funding for these fueling stations so people are not limited when purchasing a vehicle fueled by biomethane. 3

4 Overall, biomethane has been used, and should continue to be used, as a vehicle fuel throughout the world. There are plants in the United States that produce biomethane through anaerobic digestion. The biomethane created in these plants could then be converted into vehicle fuel. There are vehicles that already use biomethane as vehicle fuel, but existing cars can be easily converted to use both types of fuel. These converters can ease the transition from gasoline to biomethane, while fueling stations are being built. Fueling stations are already present throughout Europe and it is feasible to implement these fueling stations throughout the United States, as well. As seen throughout these applications of biomethane, it is possible to make biomethane the new fuel source because it has already been achieved on a smaller scale. CHALLENGES AND ETHICAL ISSUES With any new technology there are always challenges and ethical issues that arise. Investment risk is the first major challenge. While the production of biomethane will need capital investment, the distribution of it will not because it can easily be transported through existing infrastructure, such as the natural gas grid. In addition, the government often provides subsidies for renewable energy sources to offset the initial financial costs of the new processes [6]. Since biomethane and natural gas are chemically identical, biomethane can be injected into a gas grid as long as it is cleaned of impurities. Although initial costs for plants and machinery do exist, they will fall as the market develops and biomethane has low operating costs because the input materials are inexpensive. One ethical issue with biomethane is where the resources to produce the fuel would come from. Some people believe that there may be a lack of access to organic waste or that the production of biomethane could degrade food security [6]. Biomethane can be produced using crops as input material, but this would not be as sustainable as using organic waste. There are several other options where this organic matter can be obtained such as landfills, waste water treatment plants, or animal manure. Even though replacing gasoline and diesel with biomethane offers some of the greatest carbon saving possible, biomethane producers have no incentive to upgrade biogas for vehicle fuel, which would require additional and more expensive processes [6]. If this new technology is implemented on a large scale it can be comparable in price to the energy sources commonly used today [6]. Although there is an initial economic burden, the production of biomethane as a vehicle fuel needs to be seen from an environmental and sustainable perspective as well. While there may be several challenges these are not hard to overcome if proper planning and investment occurs. Risks If Biomethane Is Not Used As the world s use of fossil fuels increases, potentially contributing to the effects of climate change, many people argue that it would be unethical to ignore our existing situation. Since climate change is a threat to the entire world and future generations, it is society s responsibility to find solutions to the current energy crisis. According to the energy committee of the Royal Academy of Sciences, fossil fuels are a finite resource that will eventually run out or become too expensive to even use [12]. The dependency on oil is dangerous because as supplies become scarce, the price of oil could skyrocket, causing an economic recession [12]. It is essential to lessen the reliance on oil by switching to energy sources that will never run out, so the world will not be in panic when fossil fuels become scarce. As the supply of fossil fuels becomes inadequate, biomethane is a better alternative because it is clean and renewable. Fossil fuels are a harmful energy source because they have long term damaging effects on the environment. The use of biomethane is an action that needs to be taken to slow down the destructive effects energy consumption is causing to the earth and reduce the dependence on foreign oil. Arguments Against Using Biomethane as a Vehicle Fuel The main ethical issue with using biomethane as a vehicle fuel is that methane is a times more potent greenhouse gas than carbon dioxide [13]. Eventual leaks, which could occur during transportation of the fuel or in the production process, would negate the climate change benefits of using biomethane as transportation fuel. A study conducted by scientists at Stanford University, the Massachusetts Institute of Technology and the Department of Energy s National Renewable Energy Laboratory, published in the journal Science indicates that there is already 50% more methane in the atmosphere than previously estimated by the Environmental Protection Agency [13]. This is a signal that more methane is escaping into the atmosphere than previously believed. The study concluded that despite these negative consequences, replacing a coal-fired power plant with biomethane would still lower greenhouse gas emissions overall [13]. Although this is a hurdle in the move forward to make biomethane a commonly used vehicle fuel, this is a serious risk that all chemical plants take. Most chemicals produced in large scale are extremely harmful and have the potential of being leaked into the atmosphere. This should not be an obstacle in making biomethane a widely used vehicle fuel because this is already a current industry issues. Although actions should be taken to prevent leaks in the process, the overall planetwarming emissions are reduced significantly. Over time the technology and storage facilities that produce and keep biomethane will advance, limiting the leaks of methane into the atmosphere, soil, and water. As of now, there are no federal regulations on the release of methane emissions, 4

5 contributing to the problem of methane leaks [13]. With more government control and investment in technology that could capture the leaks, the methane escaping into the environment could be significantly reduced. Long-Term Benefits over Initial Investment Costs Implementing change is never easy. There are always challenges and ethical issues that arise in the process. Switching the commonly used fuel source from gasoline to biomethane has initial investment costs, but long-term benefits. Capital investment is needed to build the plants and machinery used in anaerobic digestion, but the long-term benefits include a reduction in methane emissions and alternative energy source with endless resources. The primary concern in producing biomethane is that methane is far more potent than carbon dioxide. Even though this is already a concern in the chemical industry, once regulations are put into place regarding the release of methane emissions, leaks will be controlled. Biomethane is a sustainable source of vehicle fuel for the future; therefore, the proper investment and planning are necessary to implement this change. ENVIRONMENTAL BENEFITS AND SUSTAINABILTY As energy demands increase and as more greenhouse gases are released into the environment, biomethane is a sustainable solution as a source of vehicle fuel. Biomethane is an alternative energy that is not only renewable, but also has several positive impacts on the environment. Unlike most fuel sources biomethane does not contribute to climate change, it actually helps fight it. Displayed in Figure 3, gasoline, the most commonly used vehicle fuel, produces 164g of carbon dioxide equivalent emissions are released per kilometer. Biomethane, on the other hand, releases only 5g CO 2 eq./km [14]. Environmentally, biomethane is a far superior fuel source to gasoline. Carbon Dioxide Equivalent Emissions Per Kilometer Figure 3 [14]: This graph shows greenhouse gas emission in grams of carbon dioxide equivalents for several types of fuel sources per kilometer. The most notable comparison is the difference between gasoline (petrol) and biomethane. How Biomethane Fights Climate Change Biomethane has the potential to completely substitute natural gas because these two energy sources are chemically identical. Biomethane can also replace oil and coal to a large extent because it is a renewable source of energy. The resources to produce biomethane will never deplete because it is produced from organic wastes, which could come from landfills or wastewater treatment plants. Biomethane is said to be carbon neutral and sometimes even carbon negative because of its use of organic matter as input materials that would have decomposed naturally [2]. Burning biomethane may release some carbon dioxide into the atmosphere, but it does not increase levels of greenhouse gases [5]. The 5

6 pollutants are equivalent to what would have been released if the organic matter from which biomethane is produced was not used. Municipal solid waste-landfills account for over one-quarter of the total methane emissions in the U.S. [15]. The process of anaerobic digestion removes a potential source of carbon dioxide equivalent emissions that would have been released into the environment if the waste were left to decompose on its own. When an activity removes more carbon dioxide from the atmosphere than it is responsible for creating, it is said to have a negative carbon footprint [2]. Methane is a times more potent greenhouse gas than carbon dioxide, so preventing it from escaping into the atmosphere has a more drastic effect than if biomethane only reduced carbon dioxide emissions [13]. Biomethane is a sustainable vehicle fuel because it improves sanitary conditions by processing animal and human waste [16]. This waste would otherwise end up sealed in the ground or burned in an incinerator. Air, water, and soil quality are greatly improved because the burning of trash leads to smog and acid rain [16]. Although most of these sustainable arguments are environmental, they directly correlate to the well being of individuals. The use of biomethane reduces water and soil pollution because it removes waste from the environment and also eliminates fossil fuel contaminants and potential risks such as gasoline leaks or spills [16]. Besides the 2.5 million tons of greenhouse gases, reported by the Department of Energy s Renewable Energy Lab, the United States produces burning fossil fuels each year, there is a significant amount of pollution to the land, water, and air [17]. Burning coal for energy produces air pollutants that make their way into the water cycle causing acid rain. In addition to this, the land around coal mines remain desolate due to the solid wastes and infertile soil [17]. The use of biomethane as a vehicle fuel would cause minimal intervention into nature. The production machinery and storage facilities may have unappealing aesthetic impacts on the landscape, but the production of biomethane does not have harmful effects on nature such as coal mining or oil and natural gas extraction. Why Biomethane Is a Sustainable Fuel As a vehicle fuel, it is shown that biomethane generates the greatest amount of energy for a given amount of feedstock. This makes it more efficient than diesel or gasoline because it has a higher energy yield [18]. Energy yield is the ratio of the energy output to the energy input for growing and producing a fuel. A higher ratio indicates a higher energy yield per unit of energy input [18]. The approximate energy yield for biomethane is 9:1, whereas it is only 1:1 for gasoline [18]. This means that a car fueled by biomethane would be able to drive a further distance given the same amount of input materials. In the long run, this would cause biomethane to be a less expensive fuel source than gasoline or diesel. In 2013 the Developer s Guide to Biomethane as a Vehicle Fuel, reported gasoline prices as $1.20/liter and biomethane as only $1.00/liter [19]. It also has the highest versatility of and most available input materials, which make it possible for this fuel source to be produced anywhere in the world. These input materials also come at a very low cost, which make it an attractive option [19]. The efficient and economic outcome makes biomethane a sustainable fuel source in the transportation industry. Biomethane is a sustainable fuel source for environmental, social, and economical reasons. It has the potential to satisfy the increased need for energy and does not increase the concentration of greenhouse gases in the atmosphere. Biomethane has the lowest carbon-intensity of any transport fuel and has the highest energy yields per area. The production of biomethane has the opposite effect of most energy sources because it eliminates the release of a great deal of methane and other harmful gases into the environment by preventing the exposure of decomposing organic waste to the atmosphere [2]. Biomethane is a sustainable source of fuel in the transportation sector because it is clean, efficient, and available. BIOMETHANE: THE SUSTAINABLE AND ECONOMICAL ENERGY SOURCE OF THE FUTURE Biomethane has the potential to be a major component in the future of transportation primarily for its sustainable attributes. The process of producing biomethane eliminates methane from the atmosphere, reduces waste in landfills, and improves soil, water, and air quality. Anaerobic digestion can be used, not only in the transportation industry, but also for heating and electricity in homes and businesses. By developing the necessary infrastructure for this new technology, it is possible to greatly reduce gasoline from everyday life, for a cleaner environment. Many will argue that this is a huge financial investment for a plan that may not work, but the production of biomethane has been implemented and successful in several countries. With the right government implementation, low cost factories can be created to produce biomethane and pay for the initial costs of switching to this fuel source. In the long run, biomethane could potentially be a cheaper fuel source because its input materials are inexpensive and it generates more energy for a given amount of feedstock compared to other fuels. A plan is needed in the United States to limit the amount of methane released in the atmosphere during production, while ensuring the proper equipment is used so there are no leaks. Once we overcome these few problems biomethane can lessen the depletion of our current fuel resources, and produce a negative carbon footprint. Actions should be taken to continue to invest and improve biomethane as our fuel source to have a cleaner, economical and a sustainable energy solution for the future. 6

7 REFERENCES [1] Tamar Energy (2013). What is Anaerobic Digestion?. Tamar Energy. [2] M. Ahman. (2010). Biomethane In The Transport Sector An Appraisal Of The Forgotten Option. Elsevier pp [3] A. Molino. (2013). Biomethane Production By Anaerobic Digestion Of Organic Waste. Elsevier X pp [4] W. Harris. (2005). How Natural Gas Vehicles Work. HowStuffWorks. pp. 1-6 [5] Biomethane.uk (2012). Biomethane. Biomethane.uk. [6] M. Kindle. (2013). Anaerobic Digestion In The United Kingdom. BioCycle. 4f45-e6aa-4ca9-adee- 28a8988bdebe%40sessionmgr112&vid=4&hid=117 pp [7] JC-Biomethane LLC. (2013). Commercial Organics Digester On Line. BioCycle. 4f45-e6aa-4ca9-adee- 28a8988bdebe%40sessionmgr112&vid=4&hid=117 p. 1. [8] J. Baldwin. (2009). Biomethane Fuelled Vehicles - The Carbon Neutral Option. Waste Management World. world.com/articles/print/volume-10/issue- 1/features/biomethane-fuelled-vehicles-the-carbon-neutraloption.html [9] Clean Energy. (2013). Biomethane. Clean Energy Fuels. [10] S. Clarke. (2012). Vehicle Conversion to Natural Gas or Biogas. Ontario Ministry of Agriculture and Food. [11] J. Selke. (2011). National Report on State of CNG/Biomethane Filling Station - Germany. GERBIO ;1197&params=open;gallery. [12] W. Oliveira, A. Fernandes. (2011). Economic Feasibility Applied to Wind Energy. International Journal of Emerging Sciences. %7CA &v=2.1&u=upitt_main&it=r&p=AONE& sw=w&authcount=1. pp [13] C. Davenport. (2014). Study Finds Methane Leaks Degate Benefits of Natural Gas as a Fuel for Vehicles. The New York Times. [14] Deutsche Energie. (2010). The Role Of Natural Gas And Biomethane. Dena. and-biomethane-in-the-fuel-mix-of-the-future-in- Germany.pdf [15] Westport Power Inc. (2014). Renewable Natural Gas (Biomethane). Westport. [16] B-Sustain. (2013). Environmental and Social Benefits of Biogas Technology. B-Sustain. fits%20of%20b-sustain%20biogas%20technology.pdf [17] R. Siegel. (2012). Wind Power: Pros and Cons. TriplePundit. [18] Sustainable Conservation Company. (2013). Comparing Renewable Fuels. Sustainable Conservation. [19] Viking Strategies. (2013). Developers Guide to Biomethane as a Vehicle Fuel. Biogas Association. s/membersonly/developerguide- BiomethaneVehicleFuel.pdf ACKNOWLEDGEMENTS We would like to thank our co-chair Matt Urich for revising and critiquing our work. We would also like to thank Summer s parents, Collette and Roland Ericsson, for helping us find scholarly sources pertaining to our topic and reviewing our paper. Lastly, we would like to thank Justin s mom, Jackie Traino, for helping us revise sentence structure throughout our paper. 7