Final Report on the Role of Hydrogen Fuel Cells on the Future of the Transportation Industry

Final Report on the Role of Hydrogen Fuel Cells on the Future of the Transportation Industry

Date: 4/19/2013

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Abstract

This report is outlines the hydrogen fuel cell’s place in the future of the transportation industry by analyzing the history of the fuel cell and noting the current technical obstacles and solutions to commercial success. While theoretical hydrogen transportation system presents many structural advantages, many technical and infrastructural challenges persist. After development in the 19th century, NASA utilized hydrogen fuel cells in space travel, significantly impacting the development of the technology. Three major technical issues exist today: gathering hydrogen, storing/transporting hydrogen, and creating a scalable hydrogen infrastructure. Engineers have demonstrated gathering hydrogen through both hydrocarbons and electrolysis, which remains necessary because pure hydrogen does not exist in nature. In terms of storage and transportation, the low volumetric energy density presents issues in terms of moving hydrogen efficiently for refueling and preventing safety concerns associated with leakage of hydrogen gas. With global economic conditions necessitating a change in energy systems, however, hydrogen presents structural advantages superior to electric vehicles that indicate that hydrogen will hold a place in the future of the transportation industry.

Final Report on the Role of Hydrogen Fuel Cells on the Future of the Transportation Industry

Table of Contents

• Executive SummaryPage 3-4
• IntroductionPage 5
• Purpose
• Justification for the Topic
• Basic Information
• History of Hydrogen Fuel Cell DevelopmentPage 6-7
• Initial Development
• Role of General Electric
• Role of NASA
• Resurgence of Interest
• Current State of Hydrogen Fuel Cell Technology
• Harvesting HydrogenPage 8-11
• Hydrogen TransportationPage 11-12
• Hydrogen InfrastructurePage 13-15
• Obstacles to Commercial Success
• Gathering HydrogenPage 15-16
• Hydrogen InfrastructurePage 16
• Fuel CellsPage 16-17
• Discussion of the Future of the Transportation IndustryPage 17-21
• AppendixPage 22-26

Executive Summary

Purpose

This report highlights the significant future of the hydrogen fuel cell in the future transportation industry of developed nations.

Background

First developed in the early 19th century, hydrogen fuel cells and a hydrogen transportation economy remain the holy grail of energy research. Research efforts of the nuclear energy program and NASA put hydrogen technology on the forefront in the mid 20th century, but much of the interest cooled due to high costs and technical issues. Interest in hydrogen fuel cells and transportation has increased due to rising cost of crude oil and the desire to stem global anthropogenic (caused by humans) climate change.

Current State of Hydrogen Transportation

Hydrogen fuel cells work through an electrochemical process that creates electricity—with pure hydrogen and oxygen as inputs and water as the output. Despite the structural advantages of a theoretical zero-carbon situation, significant obstacles remain in the path of the commercial success of a fully functional hydrogen transportation system.

Obstacles to Commercial Success

For hydrogen to become a primary transportation fuel three challenges must be resolved:

• Harvesting Hydrogen—Pure hydrogen does not exist in nature, meaning that it requires harvesting. Notably, researchers have shown the ability to harvest hydrogen through hydrocarbons and electrolysis from water.

• Hydrogen Storage and Transportation—These issues stem almost entirely from the low volumetric energy density of hydrogen, which forces significant compression for gas storage. Gas storage creates significant safety concerns. Other storage systems exist, but these remain even more costly than gas storage. While technically feasible, the development of efficient hydrogen transportation systems represents a high initial cost of investment that could be solved using much of the existing work on natural gas transportation.

• Hydrogen Infrastructure—Fueled by the first two issues, the establishment of an efficient, well-functioning fuel infrastructure cannot develop overnight, making commercial success difficult. This positive feedback loop poses a challenge represented by a scalability problem (how to have a system that is at the same time efficient and grows with the market).

Future of the Transportation Industry

These issues each present unique technical challenges that, for the most part, engineers have solved from a technical standpoint due in large part to research in natural gas infrastructure. These solutions and remaining obstacles focus primarily on cost structures and scale problems, whose solutions could be found through scalable systems that develop with the hydrogen economy. With the cost of gasoline likely to continue to rise due to increased global demand, a clean alternative to gasoline will likely prove necessary and increasingly economically viable. In response, hydrogen represents a more realistic solution than electric vehicles because hydrogen research has developed technical feasibility, unlike electric vehicles. To this end, I argue that hydrogen fuel cells represent the most likely future of the transportation industry available today.

Final Report on the Role of Hydrogen Fuel Cells on the Future of the Transportation Industry

Introduction

Hydrogen fuel cells utilize pure hydrogen and oxygen to create energy through an electrochemical process[1]. Polymer Electrolyte Membrane (PEM) fuel cells remain the primary focus of much of this work, while other fuel cells will be introduced and discussed to some degree. In addition to the PEM cell, many other fuel cell systems involving hydrogen fuel have stimulated research. Hydrogen fuel cells have the potential to replace traditional hydrocarbon-based transportation, although significant obstacles to commercial success exist.

After development of the hydrogen fuel cell in 1939[2], much of the interest cooled, as low-cost gasoline made combustion engines the primary focus of the transportation industry. As gas prices continue to rise, however, hydrogen fuel cells have become more feasible and will likely continue to do so. Following sections will develop more fully the history of the hydrogen fuel cell and the state of current technology.

Significant hurdles still exist, however, for hydrogen fuel to dominate the transportation industry. Some of the most significant issues facing hydrogen researchers include the harvesting, transportation and storage of hydrogen, the development of a hydrogen infrastructure, and the high cost of hydrogen vehicles relative to their gas-powered counterparts.

This report will first outline the history of the hydrogen fuel cell and track its development, from key players such as NASA. A thorough understanding of current hydrogen technology also remains essential, and this will look at gathering hydrogen, transporting hydrogen, and creating a viable infrastructure for hydrogen fuel cells. Following a look at some of the most difficult obstacles remaining to the hydrogen industry, I will argue that hydrogen, despite some of its technological and structural issues, has the potential to significantly alter the transportation industry in developed nations.

History of the Hydrogen Fuel Cell

Initial Development and Basic Information

Christian Friedrich Schonbein developed the first theoretical model of the hydrogen fuel cell, but his colleague Sir William Robert Groves turned Schonbein’s theoretical model into what he called a “gas voltaic battery”3. The basic principles of the fuel cell have changed very little since initial development. Essentially, the fuel cell supports a controlled electrochemical reaction that develops electricity and water through the input of hydrogen and oxygen. The figure below shows Schonbein’s first theoretical drawings of how a hydrogen fuel cell might work.

Figure One: Schonbein’s drawing for the theoretical development of a hydrogen fuel cell, published in Philosophical Magazine

Much of the interest in the fuel cell died down following its initial development and this did not significantly change until Francis Bacon began research again in 19323. General Electric demonstrated the first PEM fuel cell in 1950[3], which stands as the starting point for much of hydrogen fuel cells’ role in NASA’s space travel program. NASA’s need for on-board power without combustion naturally led to fuel cells. PEM fuel cells work with pure hydrogen as a fuel source and operate at much lower temperatures than combustion engines, reducing maintenance costs and wasted frictional heat4. The major appeal of hydrogen fuel cells remains that fuel cells produce only water as a byproduct[4].

Figure 2 and 3: Visual Representations of the PEM and Alkaline Fuel Cell, respectively. Source: U.S. Department of Energy

NASA’s Gemini Space Program in the 1950’s utilized fuel cell technology developed by General Electric.Research into improving hydrogen fuel cells through NASA’s Glenn Institute continues today. The Glenn Institute developed another type of fuel cell, the Alkaline Fuel Cell, which primarily serves space shuttles[5]. Alkaline Fuel Cells will not serve as a primary focus on this work, as they function far better in sealed environments where air and water cannot penetrate, such as in space. Alkaline Fuel Cells have significant maintenance issues, such as problems when contacted by carbon dioxide, that makes these cells currently unsuitable for personal vehicle transportation5.

Research into hydrogen fuel cells continued into the late 20th century, leading to developments by Ballard Power Systems. Ballard developed systems that improved PEM fuel cell components and applications, leading to Dr. David P. Wilkinson holding over 70 hydrogen-related patents from his work with Ballard4. Roger Billings developed the first hydrogen fuel cell vehicle in the early 1990s[6].

Current State of Hydrogen Fuel Cell Technology

Gathering Hydrogen

Gathering Hydrogen—Basic Information

The first major challenge for hydrogen fuel cells remains economically gathering pure hydrogen. H2 does not exist in nature, as its chemical properties dictate that it always present chemically bonded to other materials[7]. For instance, hydrogen can be found as water (H2O) or as a hydrocarbon (CH4 in the case of methane). Water and hydrocarbons serve as a major focus of research into hydrogen gathering. Some of these processes include steam reformation, coal gasification plants, and electrolysis.

Gathering Hydrogen—Natural Gasand Steam Reforming

As Bent Sorensen puts it, “current industrial production of hydrogen starts from methane, CH4, which is the main constituent of natural gas.”[8]Steam reformation represents a realistic option for gathering hydrogen. By mixing natural gas with water vapor at high temperatures, researchers can harvest pure hydrogen through an endothermic reaction8. This type of reaction most lends itself to large-scale industrial applications. This reaction does not, however, remove all pollution from the system. Carbon monoxide remains a byproduct of the reaction that generates hydrogen from natural gas.

The process of using water vapor in steam reforming is contrasted with dry reforming, where pure oxygen replaces water vapor. Dry reforming, considered a more rapid function than traditional steam reforming, has the benefit of being easily stopped and started. The high level of control over the reaction, along with the use of air instead of water vapor, makes dry reforming viable for automotive transportation and other small-scale applications.

Gathering Hydrogen—Coal and Syngas

Coal can also serve as a medium for gathering hydrogen through two major processes: Syngas Chemical Looping (SCL) and Coal Direct Chemical Looping (CDCL)[9]. Both of these coal-based processes gather hydrogen through gasification of coal, which essentially frees up the hydrogen and allows industry experts to reduce carbon emissions. The following figure demonstrates a typical syngas system, with coal as a fuel source. Syngas Chemical Looping produces pure hydrogen through the inputs coal, water and oxygen. Along with pure hydrogen, carbon dioxide remains a byproduct, making this type of system an ideal candidate for Carbon Capture and Sequestration (CCS). With CCS, carbon dioxide from industrial power systems is injected into existing geological formations, typically exhausted coalmines or oil shafts[10]. This type of syngas system has the potential to become carbon neutral though CCS, if the carbon is sequestered properly and sustainably.

Figure 4: Model of Syngas System[11]

The system described above has some major benefits. First, it utilizes a fuel source the remains extremely abundant. The United States currently controls approximately 28% of the world’s proven retrievable coal reserves, the largest share in the world[12]. In comparison, the US controls only 4% of the world’s proven retrievable natural gas reserves12. So while the aforementioned systems involving methane have some advantages, their long-term sustainability remains in question when compared to coal-based systems.

Coal Direct Chemical Looping, while very similar to Syngas Chemical Looping, attempts to reduce the inputs of water and oxygen while improving the H2/CO2 ratio. In doing so, CDCL systems could lower input costs while limiting the amount of carbon requiring sequestration. CDCL systems remain far less developed than syngas systems, but research into Coal Direct Chemical looping remains ongoing.

Gathering Hydrogen—Electrolysis and Fossil Fuels

Gathering hydrogen from electrolysis essentially works as a reverse hydrogen fuel cell. Instead of producing electricity and water from a hydrogen fuel cell, electrolysis gathers pure hydrogen from water through the input of electricity8. When the electricity to generate hydrogen comes from natural gas, this process proves less efficient that simply gathering hydrogen directly from natural gas through steam reforming8. Harvesting hydrogen from a syngas plant, as depicted in figure four, could prove efficient for industrial production if a market for pure hydrogen existed. Generally speaking, however, producing pure hydrogen from electrolysis with electricity generated from fossil fuels creates an unnecessary technical step in the process if energy storage presents no issue.

Gathering Hydrogen—Electrolysis and Renewable Energy

An alternative system includes generating hydrogen from excess supplies of renewable resources in certain circumstances. This type of process has numerable benefits, including cheap electricity and energy storage8. In the case of wind energy, for example, hydrogen can act as energy storage during times of surplus supply, typically during the middle of the night[13]. Wind tends to blow much more during late evening hours, where as energy demand remains extremely low during this time. The gap between supply of electricity and demand for electricity described above creates a place for hydrogen to enter the picture.

Figure 5: Wind to Hydrogen Energy Storage1

In terms of creating an integrated system with other energy generation methods, hydrogen has two structural advantages. First, hydrogen can store energy, which remains a widely accepted technical concern with wind energy. Second, producing pure hydrogen during times of non-peak energy demand lowers the cost of production. Large-scale production of hydrogen near large wind turbine farms, then, could serve as a serious option for hydrogen generation. In this type of system, however, the price of hydrogen is linked directly to the price of electricity, which could make prices highly volatile13.

In terms of small-scale production of hydrogen, excess renewable energy generation serves the same general purpose. When homeowners purchase wind-turbines or solar panels, they often sell excess electricity back to the utility company. With hydrogen generated from electrolysis, homeowners could establish a system whereby hydrogen for their vehicles could be generated from excess electricity on site. This presents an alternative to the large-scale example discussed above, but in both cases the primary focus remains the generation of hydrogen from a surplus of electricity from renewable forms.

Hydrogen Vehicles and Transportation

Hydrogen Vehicles—Cars

Hydrogen vehicles utilize the combination of hydrogen fuel and oxygen to generate electricity, which powers an electric motor. Generally speaking, electric motors achieve higher efficiency than conventional combustion motors, making this design highly attractive. The reasons for this are two fold: first, hydrogen fuel cells operate at much lower temperatures which eliminates energy lost to heat and second, electric motors function at significantly higher levels of efficiency[14]. Honda’s tests indicate a tank-to-wheel efficiency of up to 60% compared to a tank-to-wheel efficiency of roughly 20% for internal combustion engines. Tank to wheel efficiency refers to the efficiency of the system all the way from a tank of gas (or its energy equivalent) to the movement it generates.

The figure below (Figure 6) diagrams the basics of a hydrogen fuel cell vehicle. In this design, a hydrogen fuel tank stores pure hydrogen at the rear of the vehicle. After releasing the hydrogen fuel into the fuel cell, the cell generates electricity, which is then stored in a battery for use in an electric motor. Again, this combines the efficiency of an electric vehicle with the energy storage capacity of hydrogen.

Figure 6: Basic diagram of hydrogen fuel cell vehicle4

Hydrogen in Other Transportation Fields

Infrastructure challenges remain some of the most significant technical and policy issues plaguing the adoption of a hydrogen transportation system, many of which can be alleviated when hydrogen plays a role in non-traditional transportation methods. Buses, for example require less refueling and, more importantly, refuel at a central location. The central refueling aspect of public transport programs might not eliminate, but significantly alleviates infrastructure challenges associated with transporting hydrogen to multiple locations.