For: [ ] Action [ ] Decision [ X] Information. Subject: Recommendation Report Powering the Electric Car of the Future

Eicholtz Consulting Services Betsy Frick Carbon Motor Company 726 Automotive Dr. Detroit, MI 45312 For: [ ] Action [ ] Decision [ X] Information Subject: Recommendation Report Powering the Electric Car of the Future Dear Betsy Frick: On behalf of Eicholtz Consulting Services, I am pleased to submit our recommendation report, Powering the Electric Car of the Future. We have completed the analyses you requested in February looking for innovative technologies in the automotive industry to grow Carbon Motor Company, increase sustainable practices, and improve consumer satisfaction. Based on a thorough review of the current technologies and future predictions, we recommend that Carbon Motor Company pursue fuel cell electric vehicles (FCEV) for future vehicle production. As the attached report shows, the fuel cell electric vehicle is the top new car technology in regards to the cost, environmental effects, convenience and reliability. While a couple barriers remain concerning the implementation of this technology, the FCEV is the best option for the automotive industry s continued growth and success across the globe. We appreciate the opportunity to work with Carbon Motor Company in finding the next vehicle that will drive the world. Do not hesitate to contact me if you have any questions or clarifications regarding the contents of this report. Sincerely, Daniel Eicholtz Chief Chemical Engineer Eicholtz Consulting Services 7212 Forsyth #2W St. Louis, MO 63105 deicholtz@wustl.edu (813) 404-5759 Enclosure: Powering the Electric Car of the Future

Powering the Electric Car of the Future Recommendation Report Prepared for Carbon Motor Company EICHOLTZ CONSULTING SERVICES Authored by: Daniel Eicholtz Chief Chemical Engineer E-mail: deicholtz@wustl.edu Tel: (813)404-5759 Besty Frick Technical Writing

Table of Contents List of Figures ii Abstract 1 Introduction 1 Motor Technology 2 Internal Combustion Engines 2 Electric Motors 3 Electricity Sources 4 Plug In 4 Fuel Cell 4 Components of the PEMFC 5 Factors for consideration 7 Convenience and Reliability 8 Energy Storage 8 Storage Volume and Weight 9 Summary 9 Environmental Effects 10 Electricity Generation 11 Hydrogen Production 11 Cost 12 Operating Costs 13 Conclusions and Recommendations 14 References 15 D. Eicholtz i

List of Figures Figure 1- Historical Trend of Vehicles and Driven Miles 1983-2001 [1]... 1 Figure 2 - U.S. Gasoline Prices Trend (Adapted from [1])... 2 Figure 3 - Flowchart of Internal Combustion Engine Process... 3 Figure 4 - Flowchart of Electric Motor Process... 4 Figure 5 - BEV Energy Process... 4 Figure 6 - Flowchart of Fuel Cell Process... 5 Figure 7 - Oxidation Reduction Chemical Reactions in PEMFC... 5 Figure 8 - Diagram of a PEMFC Cell [fueleconomy.com]... 6 Figure 9 - Correlation of Vehicle Weight to Range [4]... 8 Figure 10 - Comparison of Specific Energies [4]... 9 Figure 11 - Comparison of Energy Densities [4]... 10 Figure 12 - Projected Greenhouse Gases for Different Vehicles [5]... 10 Figure 13 - Hydrogen Production via Steam Reformation Process [http://wpi.edu]... 11 Figure 14 - Natural Gas Usage Comparisons for FCEV and BEV [6]... 12 Figure 15 - Cost Analysis of FCEV and BEV... 13 Figure 16 - Costs per mile Comparisons (Adapted from [1])... 13 Figure 17 - Final Comparisons of Two Electric Vehicle Technologies... 14 D. Eicholtz ii

Total Miles Driven Billions Powering the Electric Car of the Future Eicholtz Consulting Services Abstract With the current downward economic trends, the automotive industry suffers with lower sales, and consequently, less revenue to use for development and innovation. In addition, scientific evidence shows that humans are causing significant damage to the environment from a major source: car pollution. These two trends with countless others force car manufacturers to take risks and innovate in hopeful markets in order to potentially expand the market base, increase revenue, and mitigate environmental problems with every car produced. The current market is moving towards electric vehicles away from the conventional internal combustion engines. Now, research and development must play a large role in confirming which technology, battery plug-in or fuel cell, will be most successful, effective, and profitable. The three main factors considered are the convenience and reliability, environmental effects, and cost of these technologies. This report studies the feasibility of implementing either of the two methods for mass consumer vehicle production and concludes with a well-developed plan for Carbon Motor Company to pursue. Keywords: Electric vehicles, fuel cell, battery, manufacturing Introduction Americans are driving more. Figure 1 shows that the increase in miles driven per year for all Americans has increased more than the increase in total vehicles on the road. This means cars are lasting longer and people are driving them longer than before. De-urbanization of cities has led to an increase in driving distances. For car manufacturers, this situation leads to greater demands for cars. To meet the needs, the market for automobiles is rapidly evolving. Consumers are more educated and demanding more value for their purchases than ever before. Factors such as the green value of a car are becoming more important, with data supporting the contribution of carbon emissions from cars to climate change. Better fuel mileage demands have increased with the extremely volatile and rising gas prices of this day as shown in Figure 2. A new technology to run the cars of this world has emerged and is gaining acceptance quickly. This technology is the electric motor. Car manufacturers across the globe are developing their own models beginning with hybrids and moving to all-electric cars. Vehicles on Road Millions 250 2,500 200 2,000 150 1,500 100 1,000 50 500 0 0 1983 1985 1988 1991 1994 2001 Vehicles on Road Miles Driven Figure 1- Historical Trend of Vehicles and Driven Miles 1983-2001 [1] D. Eicholtz 1

$/gallon Powering the Electric Car of the Future Eicholtz Consulting Services $4.50 $4.00 $3.50 $3.00 $2.50 $2.00 $1.50 $1.00 $0.50 $0.00 1996 1998 2000 2001 2003 2005 2006 2008 2010 2011 Figure 2 - U.S. Gasoline Prices Trend (Adapted from [1]) Carbon Motor Company continues with its longstanding reputation to produce some of the most innovative new cars to hit the market. These modern times should be no different. It is in your company s best interest to move towards the electric car market. The issue arises: how will you power the electric motors in your vehicles? Eicholtz Consulting Services has extensively researched and compiled the data about two emerging technologies to provide my recommendation for which one you should choose. Ultimately, you want to choose the technology that will be the most successful in the long term, keeping your company competitive, profitable, and innovative. The intention of this report is to give you sufficient information about these newer technologies and thus help you better predict market trends in the future. Motor Technology The underlying method for moving the automobile is the motor. Some mechanism converts into mechanical motion to turn a combination of gears and shafts to move the vehicle via its wheels. This section reviews the two motor types in use today: the internal combustion engine (IC) and the electric motor (EM). By viewing both conventional and innovative models, you will be able to see clearly where the improvements and efficiency upgrades occur with the electric motor. Internal Combustion Engines For several centuries now, internal combustion engine technology continues as the most popular motor choice. It utilizes the familiar concept of combustion to convert stored chemical energy into mechanical energy. Fuel combusts using an ignition source and oxygen, creating a mini explosion in the cylinders of an engine and causing them to move rapidly. Various mechanical parts transfer this D. Eicholtz 2

motion to a geared transmission that in turn spins the wheels to cause forward motion. Each step in this process, as shown in Figure 3, loses energy due to inefficiencies, most notably heat and friction in the initial combustion phase. Typical IC engines have a total efficiency of only 20% [2]. Fuel (gasoline) Energy Energy Energy Oxygen Engine Transmission Wheels Ignition Figure 3 - Flowchart of Internal Combustion Engine Process Internal combustion systems become complex with many mechanical parts, adding more points of potential failure. In addition, carbon dioxide is a natural byproduct of the process; this major greenhouse gas contributes to anthropogenic, or human-caused, climate change. The petroleumbased fuel itself is a limited resource and an expensive commodity that increases in price over time. Because of these problems, researchers continue to look for alternatives to the fuel itself, but it is vital for someone to implement a long term to eliminate emissions and cut costs without removing automobiles from our transportation options. Electric Motors A promising solution to the aforementioned issues of the IC engine is the electric motor. As shown in Figure 4, the complete process reduces the system significantly, eliminating the inefficient chemical reaction and mechanical process from the transmission. The electric motor works by powering a magnet, which in turn spins a shaft inside the motor chamber. A power supply feeds electricity to a magnet with intensity proportional to the speed of the shaft. This process is very efficient because friction is minimal. Small energy losses occur due to heat from conduction. In fact, most electric motors can achieve efficiencies above 75% [3]. D. Eicholtz 3

Energy Energy Electricity Source Motor Wheels Figure 4 - Flowchart of Electric Motor Process Electricity Sources Obviously, the electric motor requires electricity. The two innovative technologies discussed in this report, plug-in and fuel cell EVs, generate and store electricity differently, giving each advantages and disadvantages over the other. Plug In This technology, typically referred to as the battery electric vehicle (BEV), utilizes batteries that store the energy originating from a wall outlet. The energy process of a BEV, as shown in Figure 5, transitions from electricity to chemical energy to mechanical energy. Overall, this process has very little efficiency losses, but it relies heavily upon the battery and the method of electricity generation. Electricity Chemical Energy (battery) Mechanical Energy (motor) Figure 5 - BEV Energy Process The BEV is highly dependent on the battery type for its performance, durability, and distance range. Currently, lithium ion batteries are the most popular in these applications due to their low weight to performance ratio and durability. Fuel Cell In 1838, German scientist Christian Friedrich Schönbein first began using the technology of the fuel cell [6]. Then beginning in the 1960s, NASA started using the hydrogen fuel cell to provide electricity and drinking water for its flights into space, and is still using this technology today[6]. D. Eicholtz 4

Hydrogen Gas Oxygen from the air Catalyst Figure 6 - Flowchart of Fuel Cell Process Fuel Source, Storage Electricity & Water So what is a fuel cell? The fuel cell utilizes the chemical concept of oxidation-reduction reactions. This type of reaction utilizes two or more half reactions where either oxidation or reduction occurs in a compound. In other words, the compound either loses or gains one or multiple electrons. Using either of these two half reactions, it is possible to generate an electron flow. A fuel utilizes one chamber using an oxidation reaction and the other using a reduction reaction, with both chambers connected by a wire. This arrangement allows the complete reaction to occur with the electrons flowing through the wire, creating current and producing usable electricity. The distinction between types of fuel cells begins with the types of materials used, the particular half reactions that occur, and the power generation capacity involved. Each has its own operating conditions such as temperature and current draw. PEM fuel cells operate at 50-120 o C (122-248 o F), the typical temperature under the hood of a car. In addition, the fuel utilized, hydrogen, is ideal for storage and use in a vehicle. These facts and testing support the proton exchange membrane fuel cell, or PEMFC, as the superior option for powering an automobile. The PEMFC s total reaction consists of hydrogen gas and oxygen gas reacting to form water and electricity, as seen in Figure 6. This particular 2 H2 + O2 2 H2O 2 H2 4 e - +4 H + (anode) O2 + 4 H + +4 e - 2 H2O (cathode) Figure 7 - Oxidation Reduction Chemical Reactions in PEMFC fuel cell is ideal due to its lack of pollutants produced. In terms of the half-cells as seen in Figure 7, an oxidation reaction occurs with hydrogen and a reduction reaction occurs with oxygen allowing electrons to flow. The fuel in this reaction is hydrogen, and oxygen is the oxidant. Components of the PEMFC In order to function properly, the fuel cell utilizes many components in addition to the fuel and oxidant. As shown in Figure 8, H + ions (or protons) serve as spectator ions meaning they appear in equal amounts on both the reactant side and product side of the final reaction. The fundamental issue is that for each half reaction, the protons only appear on one side of the D. Eicholtz 5

reaction. Without the unhindered flow of protons between the cells, the reaction does not proceed in the forward direction. Another technological problem is that there needs to be a way to prevent the electrons from flowing in the same path as the protons because electrons would short out the circuit and stop the fuel cell. A polymer electrolyte membrane of the PEMFC provides the barrier needed and solves this problem. A hydrogen fuel cell utilizes a polymer membrane, typically Nafion (produced by DuPont ), between the two cells. Nafion serves as a good proton transporter while remaining a good insulator to electrons. The protons can only pass through the membranes if it remains saturated with water. This is the primary reason for the low operating temperature of the PEMFC at 80 o C in order to prevent increasing the temperature and thus drying out the membrane, which would inhibit proton movement. In conclusion, the Nafion membrane is ideal for a few reasons: Highly chemically resistant A good proton conductor when well hydrated The film itself is very strong yet thin (can be produced down to a thickness of 50 μm) Membrane has very little impedance for the flow of protons and durable enough to prevent breaking and shorting out the circuit Figure 8 - Diagram of a PEMFC Cell [fueleconomy.com] D. Eicholtz 6

Each cell runs at a low voltage of 0.4-0.6V, so the fuel cell must utilize multiple cells linked in series to achieve higher voltages. Bipolar plates accomplish that task. The purpose of the bipolar plate is twofold: Disperse the reactant gas evenly over the electrode Conduct electric current to connect each cell in a circuit One last component of the PEMFC is a gas diffusion layer. The layer, usually made of carbon fabric, protects the fragile electrode, helps to disperse the gas equally across the electrode, and provides an electrical connection with the bipolar plate and electrode. A significantly vital component of the PEMFC is the electrode itself. Fuel cell manufacturers fabricate a Membrane Electrode Assembly (MEA) using the Nafion membrane and a solution of electrode material. An operator typically sprays the material directly onto the Nafion membrane in a rectangular configuration. Two bipolar plates then surround the electrodecovered membrane with carbon cloth. The oxidant and fuel can flow freely over the membrane and generate electricity. The overall reaction converting hydrogen gas and oxygen to water is not ideal under normal conditions because it occurs very slowly. The reaction requires a catalyst to make this process faster and feasible to generate enough power for appropriate uses. Platinum is the most ideal material as a catalyst due to its superb electrochemical properties that provide the rapid reaction required. Factors for consideration As you consider the plug-in option and fuel cell electric vehicle, the ultimate decision of which technology Carbon Motor Company will implement lies with the consumers preferences. After a large survey organized by Eicholtz Consulting Services in various regions of the US during a 3 month period of consumers in the market for a new car, people stated these three factors as the most important when it comes to purchasing a new automobile: Convenience and reliability D. Eicholtz 7

Environmental Effects Cost Convenience and Reliability Drivers around the globe want a vehicle that lasts as long as possible and is reliable for the entirety of its lifetime. Cash-conscious consumers want to avoid extra costs associated with repairs and brand new buys. Energy Storage The two technologies differ greatly on their source of energy storage. One uses batteries and the other uses a fuel-hydrogen-to store its energy. The largest factor in limiting the range of the car in miles is the amount of batteries in the car for a BEV and the amount of hydrogen in the tank for a FCEV. A major limiting aspect is the weight of the vehicle. With each additional battery added to the series, weight becomes a bigger factor. Hydrogen, on the other hand, does not contribute significantly to the vehicle s total weight so the volume of the tank limits the feasible mileage range. Figure 9 shows this correlation of weight to range for various battery types versus the FCEV. A FCEV is significantly more convenient in terms of longer ranges with little weight gain. Figure 9 - Correlation of Vehicle Weight to Range [4] An additional factor separating the two technologies is the time required to fill the energy storage bank to full capacity. In the case of the BEV, this requires charging the battery fully. For a FCEV, hydrogen gas fills the tank. FCEV has an advantage in this case due to the relatively little time required to fill up a tank. Similar to gasoline-powered cars, the driver pumps fuel into the tank at a fuel station in a matter of minutes. On the other hand, with a BEV, charging times range from 30 minutes for a partial (~70%) charge to 2-3 hours for a full charge [4]. Longer wait times before use make driving the BEV more inconvenient if fully discharged, especially on D. Eicholtz 8

long trips. Universities and corporations are doing extensive research in the area of battery technology to help improve these shortcomings. Storage Volume and Weight As discussed previously, a significant consideration in terms of reliability and convenience is the weight and volume of the system. Figure 10 shows the comparison of the specific energy of two different pressures with a FCEV and with batteries (USABC = USA Battery Consortium - established to form goals and standards to be met within established deadlines in order for technology to remain feasible and competitive). The fuel cell has a considerably larger specific energy than any of the battery options, meaning that you can achieve the same power output with a smaller mass. The other convenience consideration is the volume the system takes up in the vehicle. The volume differences between the fuel cell and batteries are considerably smaller than their specific energies, as seen in Figure 11. As noted, increasing hydrogen pressure in a fuel cell system increases the energy density. For this reason, it remains beneficial to use high-pressure hydrogen gas. Manufacturers must find a balance between the operating pressure and the energy required to pressurize the hydrogen at the fueling site and increased safety hazards associated with higher-pressure air tanks. Figure 10 - Comparison of Specific Energies [4] Summary Overall, the FCEV requires less volume and mass than any comparable battery for the same amount of energy output. Pumping hydrogen is a faster process than recharging a battery making it more efficient on long trips over large distances. D. Eicholtz 9

Figure 11 - Comparison of Energy Densities [4] Environmental Effects With increasing regulations due to the growing concern over anthropogenic environmental impacts, the public s desires to go green are stronger than before. This factor is a strong selling point; one that you should consider heavily for the health of our planet. A general indication of environmental cleanliness is the level of carbon emissions. This section examines the carbon impact each technology has on the environment. In Figure 12, the graph predicts greenhouse gas emissions for each vehicle technology over an extended period considering factors such as electricity generation for BEV s and hydrogen generation for FCEV s. Figure 12 - Projected Greenhouse Gases for Different Vehicles [5] BEV=Battery Electric Vehicle D. Eicholtz 10

Electricity Generation The plug-in BEV produces no emissions of any kind from the car itself. Nonetheless, one will find the actual emissions and negative externalities after considering the entire lifecycle. The electricity used to charge the battery in the car comes from various regional-dependent sources. Over half of U.S. electricity production comes from the burning of coal with a large percentage from natural gas [1]. Each of these methods burns a carbonaceous fuel releasing CO 2 into the air from combustion. From the power plant, the electricity travels via power lines to the consumer s house or workplace outlet, charging the battery. The entire electrical grid infrastructure is rather outdated and inefficient. This situation lowers the overall efficiency of the electricity generation process, thereby increasing carbon emissions. Without a major overhaul of the U.S. power industry, the BEV will continue to contribute significantly to carbon emissions (although much less than using IC engines). Hydrogen Production Currently, the typical method for generating hydrogen gas is utilizing the Steam Reformation process. This process uses natural gas and high-temperature steam to generate hydrogen gas and carbon dioxide. The process is relatively simple in terms of implementation and can achieve separation efficiencies close to 75% [7]. The obvious issue with this current process is the presence of carbon emissions. It is worth noting that this is the only form of carbon emissions for the FCEV because the byproduct of the PEM fuel cell reaction is water. Steam reformation process is ideal for hydrogen fuel station production because of the onsite production capability, and it eliminates the need for transportation infrastructure, which we would have to build from scratch Universities, corporations, and government-funded programs are doing extensive research on innovative methods for producing hydrogen to eliminate the carbon emissions such as electrolysis. Electrolysis is the splitting of water into hydrogen and oxygen gas by running an electric current through the water. Although very energy-intensive Figure 13 - Hydrogen Production via Steam Reformation Process [http://wpi.edu] D. Eicholtz 11

on its own, researchers are developing methods to speed up this process and thus make it more efficient. These methods will realistically become feasible in a matter of a few years. After widespread implementation of such clean processes, the FCEV will become a zero-emissions vehicle in its complete life cycle. Figure 14 shows the comparison of natural gas usage with fuel cells using the current steam reformation process versus BEVs with natural gas turbine-generated electricity. The best estimates show that a FCEV uses ~50% less natural gas than a BEV for the same mile range. Figure 14 - Natural Gas Usage Comparisons for FCEV and BEV [6] Cost Cost is definitely a large concern for the public when it comes to purchasing a new vehicle. With the recent economic recession and the general trend toward more conservative spending from the public, all car companies alike have to focus on bringing down the costs of the vehicles they make. Vehicle costs split into two categories: 1. Initial capital costs (car purchase, taxes, vehicle registration, etc.) 2. Maintenance (car repairs) 3. Operating costs (fuel, insurance, wear and tear) Figure 15 shows the various costs for both technologies in each cost category. As you will find, the costs are comparable for both the FCEV and BEV in initial capital costs and maintenance. The consumer would incur a large bill for any sort of replacement of the main component, such as the D. Eicholtz 12

$/mile Powering the Electric Car of the Future Eicholtz Consulting Services battery stack or catalyst (more likely replacing the entire fuel cell stack). Each of these repairs costs upwards of $10,000. As a result, there is a definite need for more research and development of more durable, longer-lasting batteries and catalysts to extend the lifetime of these main components. Figure 15 - Cost Analysis of FCEV and BEV FCEV BEV Initial capital costs Fuel cell stack, hydrogen tank, electric motor Lithium battery stack, electric motor Maintenance Replacement of catalysts, infrequent hydrogen tank Replacement of battery stack, electric motor rebuild conditioning, electric motor rebuild Operating Costs Hydrogen Fuel Electricity Operating Costs When purchasing a vehicle, the consumer looks at more than just the actual fixed cost of a car. With skyrocketing gas prices now, it is important more than ever to reduce the regular operating costs. The biggest source of this cost category is the fuel. Figure 16 shows a comparison of both electric vehicles and a gasoline IC vehicle. It is evident that the BEV seems to be the steadiest price in terms of dollar per mile. This is due in part to the steady costs of electricity production at this moment. $0.18 $0.16 $0.14 $0.12 $0.10 $0.08 $0.06 $0.04 $0.02 $0.00 Jan-93 Oct-95 Jul-98 Apr-01 Jan-04 Oct-06 Jul-09 Apr-12 BEV Hydrogen Fuel Cell Gasoline IC Figure 16 - Costs per mile Comparisons (Adapted from [1]) Hydrogen gas production bases its costs on the price of natural gas, which are volatile. This will change with time when different methods of hydrogen production become available. D. Eicholtz 13

Conclusions and Recommendations After analyzing all the factors for consideration in implementing either of these two technologies, it is apparent that both need plenty of research and development before reaching perfection and eliminating the negative externalities to the environment, such as carbon emissions. Although it seems the United States car manufacturers have decided to focus on BEVs, as an international business, you must consider the entire world especially when it comes to your desire for foreign market support. I urge you to be wary of the temptation in the short-term ease of implementation of BEVs and consider long-term goals and benefits. Figure 17 - Final Comparisons of Two Electric Vehicle Technologies Factor Fuel Cell EV Plug-in EV Power Efficiency Weight Cost (cheapest) Size (smallest) Energy Refill Time (shortest) Carbon Emissions Current Implementation As seen in Figure 17, the fuel cell EV is far superior to the battery EV, having an advantage in all categories with a checkmark except cost and the current implementation in the U.S. The hydrogen infrastructure is also a significant roadblock in mass implementation of the FCEV. Nonetheless, I fully recommend that you devote your full resources to the development of a cost-effective, high-performance FCEV. To overcome the lack of hydrogen fuel stations, lobby congress and persuade industry supporters of this technology to invest in new stations across the country. I believe that once we establish the hydrogen infrastructure, the public will fully support fuel cell vehicles, and FCEV production will become a very successful market due to the similar convenience of an IC car with a portable fuel, cheaper overall costs, and the decreased impact each vehicle will have on the environment with each mile driven. (components) (electricity) (U.S.) Feel free to call my office at any point to discuss this report further so I can assist you in your business plan so you may be successful for the future of Carbon Motor Company. D. Eicholtz 14

References 1. U.S. Energy Information Administration. (May 2008). Residential Transportation Historical Data Tables. <http://www.eia.gov/emeu/rtecs/archive/arch_datatables/rtecshist_datatables.html>. 2. "Improving IC Engine Efficiency." UW Courses Web Server. Web. 21 Apr. 2011. <http://courses.washington.edu/me341/oct22v2.htm>. 3. DEPARTMENT OF ENERGY UNITED STATES OF AMERICA DETERMINING ELECTRIC MOTOR LOAD AND EFFICIENCY." EERE: EERE Server Maintenance. Web. 21 Apr. 2011. <http://www1.eere.energy.gov>. 4. Thapa, Khagendra. Http://www.diodes.com/_files/products_appnote_pdfs/zetex/an40.pdf. Publication no. 4. Zetech Semiconductors. Web. <http://www.diodes.com/_files/products_appnote_pdfs/zetex/an40.pdf>. 5. Grove, William Robert. On Voltaic Series and the Combination of Gases by Platinum. Philosophical Magazine and Journal of Science vol. XIV (1839), pp 127-130. 6. "Apollo Space Program Hydrogen Fuel Cells". Spaceaholic.com. 20 Apr. 2011. <http://www.spaceaholic.com/apollo_artifacts.htm>. 7. U.S. DOE Energy Efficiency and Renewable Energy (EERE) Home Page. Web. 20 Apr. 2011. <http://www.eere.energy.gov/>. 8. C.E. Thomas, Comparison of Transportation Options in a Carbon-Constrained World: Hydrogen, Plug-in Hybrids and Biofuels, The National Hydrogen Association Annual Meeting, Sacramento, California, March 31, 2008. 9. DOE Hydrogen Program Home Page. Web. 21 Apr. 2011. <http://www.hydrogen.energy.gov>. D. Eicholtz 15