Hydrogen Fuel Cells The Fuel Of The Future Environmental Sciences Essay
|✅ Paper Type: Free Essay||✅ Subject: Environmental Sciences|
|✅ Wordcount: 3201 words||✅ Published: 1st Jan 2015|
Ever since the beginning of the human era, there has been an ever growing necessity for energy. Energy is the most basic aspect of human development. From lighting and communication to cooking and transport, quick and easy access to energy makes the modern way of life possible. Currently, planet earth is addicted to inefficient, polluting, and non-renewable sources of energy such as coal and oil. These energy sources allow for the unequal distribution of the benefits of energy. Some communities may receive the wealth and cheap energy that coal and oil bring, while others receive only polluted streams, acid rain, and deadly toxins. Fortunately, there is an answer to this problem: hydrogen fuel cells. Because hydrogen fuel cells are an emission-free fuel source, are more efficient than current fossil fuel sources, and have the possibility to create a diversified energy economy, more investments need to be made in this budding technology.
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Hydrogen is the most abundant element in the universe and has been present since the beginning of time. The earth’s own life-giving star, its sun, is composed almost entirely of this element (Bose and Malbrunot 22). As the smallest element in the universe, hydrogen consists as a diatomic, gaseous molecule with a single proton and a single electron. Hydrogen does not exist in its pure form on the planet, but it is present as a compound in molecules like water, glucose, natural gas, and even oil (Busby). Because it is found in such a variety of sources, hydrogen is the perfect power source for fuel cells.
What exactly are hydrogen fuel cells and why will they be the fuel of the future? Hydrogen fuel cells are a mechanical device that convert the electrochemical energy found in a fuel source, like hydrogen, into electrical energy, with the only byproducts being heat and water (Hoffmann 6). In all fuel cells there are two electrodes, an anode and a cathode, with an electrolyte, a membrane capable of moving ions, in between the two (Sorenson 73). During their operation, hydrogen fuel is injected into the anode side, while oxygen, usually from the air, is pumped to the cathode. The hydrogen molecule disassociates, and the proton passes through the electrolyte to join the oxygen, while the electron from the hydrogen molecule travels in an outside circuit, producing electrical current (Brus and Hotek 22). Because of the fact that fuel cells have no moving parts, they are much more efficient than conventional internal combustion engines, which makes them a great investment for the future of the planet’s energy.
In addition, there are multiple types of fuel cells, each with their own sets of merits and each able to be used a different way in today’s energy economy. Proton exchange membrane fuel cells (PEMFCs) are the most prevalent type of fuel cell today. They deliver a high power density and a low weight to volume ratio (Sorensen 81). Because of this, and their abnormally low operating temperature of 80° Celsius, PEMFCs are ideal for use in cars, buses, and other small scale portable applications. Also, the low operating temperature of PEMFCs allow for less wear and tear on the electrolyte, thereby reducing maintenance costs (Hordeski 145). Although PEMFCs have excellent performance characteristics in vehicles, they do not produce the amount of power necessary for large scale operations, like power plants.
Molten carbonate fuel cells (MCFCs) are the answer to this problem. MCFCs have a higher operating temperature, around 800° Celsius, which allows them to create a much higher amount of energy per unit of fuel. This also makes them difficult to use in portable applications (Kandlikar). In addition, MCFCs can reach efficiencies of up to seventy percent if cogeneration, the capturing of waste heat, is used. This is much higher than the twenty five to thirty five percent efficiencies of coal fired power plants (Brus and Hotek). Because of the large amount of energy produced in MCFCs, their excellent efficiency, and their possible cogeneration applications, they are much better suited for stationary applications, such as power plants, than are fossil fuels.
Currently, the main reasons that hydrogen fuel cells are not in more widespread use is the lack of production, delivery, and storage infrastructure. Almost all of the energy infrastructure in the United States, and indeed the world, is geared toward fossil fuels (Busby). With a forward looking investment, the current fossil fuel infrastructure can easily be converted to hydrogen.
The first step in creating a reliable hydrogen infrastructure is to invest in renewable hydrogen production methods. Renewable production methods include wind, solar, and hydroelectric. All of these methods produce energy, which leads to the eventual electrolyzing or splitting of water to produce both hydrogen, which is used in fuel cells, and oxygen, which can be captured as a useful byproduct (“Hydrogen Energy”). One of the main reasons experts such as Peter Hoffmann argue for a more widespread use of hydrogen fuel cells is because they have the possibility to become a zero emission fuel source. Hoffmann recognizes that a “future hydrogen economy” would consist of hydrogen being produced from “clean, primary sources of energy.” (8-9). Although the conversion of the existing fossil fuel based infrastructure would cost billions of dollars, citizens of the United States must evaluate whether the continued damage to the planet is worth the cost of switching to a renewable hydrogen based infrastructure.
Before switching to a hydrogen based economy, one of the problems that must be solved is hydrogen storage. Hydrogen is an excellent energy storage medium, with energies in the range of 142 MJ kg-1 per unit of mass, but it has a low density (Broom 5). This produces the above mentioned storage problem, because although fossil fuels have a much lower energy content per unit of mass, 47 MJ kg-1, they are a liquid at ambient temperatures, which gives them a much higher density (Farndon). How can the high energy hydrogen be stored in such a way that it gives off the greatest amount of energy per unit of volume, rather than per unit of mass? Multiple options are available, the first of which is storing hydrogen as a compressed gas. Compressing hydrogen results in acceptable pressures, which are around 70 MPa per liter (Broom 5). Compressed hydrogen can also be transferred from dispenser to car in much the same way as gasoline. This makes it both easier and less costly to modify the current gasoline based infrastructure to accommodate hydrogen, although more money is needed to begin to facilitate the transition.
The second option for hydrogen storage in the future would be as a complex solid metal hydride. These metal hydrides are transition metals, chiefly lanthanum, which soak up hydrogen like a sponge and then release it when given small amounts of energy (Sorensen). An advantage of these hydrides is that they can store hydrogen at densities higher than compressed hydrogen and gasoline, therefore providing more energy per unit of volume, which allows for smaller storage tanks on vehicles and other portable applications (Ogden). This allows for smaller cars, cell phones, and even power plants. Although the technology of complex metal hydrides is only just beginning to become available, it has great potential for a future hydrogen storage source and now only needs investments to make it become a reality.
The only remaining infrastructure necessity for a future hydrogen based economy is a hydrogen delivery system that effectively moves hydrogen from its production source to its destination quickly and efficiently. Fortunately, because of the recent natural gas boom in the United States, this problem may have solved itself. Natural gas and hydrogen are similar: both are a gas at room temperature, both have similar densities, and both can be transported in vehicles and pipelines (Backus 6). Because of their similar properties, it is possible to modify the existing natural gas transportation network to transport hydrogen in place of natural gas. This would result in the quick and easy movement of hydrogen from its production source to its final destination, whether it be a fuel pump, a power plant, or even a cell phone charger (Potera). However, additional investments are needed to convert the natural gas network to hydrogen.
One of the most overlooked advantages of a hydrogen based economy are the diverse uses for fuel cells. Commonly thought that their only applications would be in vehicles, fuel cells can actually be used for both small and large scale power generation as well as in vehicles. The most promising frontier is probably large scale power generation. As noted before, fuel cells produce electricity, heat, and water as byproducts (Hoffmann 6). Both forms of energy, the heat and the electricity, can be used to generate power on an industrial scale, making fuel cells far more efficient than fossil fuels (6). Also, hydrogen fuel cells have a possibility fossil fuels never had. They can be used for large scale localized power generation to power homes and neighborhoods. This reduces energy loss that takes place with power plants (153). The size and cogeneration ability of fuel cells makes them a great candidate for the future of the centralized power grid.
Another application for fuel cells is in the portable electronics field. Because they produce direct current, fuel cells can be used to power virtually anything that batteries are able to power (Potera). Currently, some companies, like Jadoo Power, are marketing small scale consumer electronics that are fueled solely by hydrogen fuel cells. The fuel cells in these electronics are not only smaller than most batteries, but they also deliver more power for a longer period of time (Hoffmann 154). Because of their size and longevity, the military is beginning to take notice of the potential applications for fuel cells in the armed forces. “The military is in need of smaller and lighter power sources for portable devices, and Jadoo’s technology ideally suits them,” says Bob Unger, program manager at Kuchera Defense Systems (qtd. in Potera). Although the prospective applications for portable hydrogen fuel cells are only beginning to emerge, the industry is already in need of investments to kick-start the development of hydrogen fuel consumer electronics.
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While both the portable and the stationary applications of hydrogen fuel cells are still emerging markets, the hydrogen fuel cell vehicle is not. Fuel cell vehicles (FCVs) have been under development since the 1970s, with the main goal of making them cost effective. Currently, approximately 10,000 fuel cell vehicles are on the road worldwide, with the eventual goal of increasing that number to around 500,000 by 2025 (“Peter Hoffmann Responds”). Advancements in technologies such as complex metal hydrides have reduced the size, cost, and weight of FCVs. It is estimated that if mass produced, hydrogen fuel cell vehicles would cost between 20,000 and 50,000 dollars, which is comparable with the cost of current vehicles (Ogden). Also, FCVs have driving ranges from 300 to 400 miles and refueling times of five minutes or less, which is also comparable with those of the current gasoline powered cars (Brown). So the question now becomes, why are there not more FCVs on the road right now? The answer to this is the lack of infrastructure, mainly refueling stations. If more investments are made in a hydrogen based economy and its infrastructure, then the possibilities for growth are limitless.
Although there are numerous advantages of a hydrogen economy, it is possibly easier to make an argument against the continued use of a fossil fuel based energy economy. Fossil fuels are a polluting, climate-warming, and non-renewable source of energy (Dawson and Spannagle 17). During their combustion, fossil fuels release greenhouse gasses like carbon dioxide, nitrogen dioxide, and sulphur dioxide. In addition to being extreme irritants for people with breathing difficulties, these compounds also cause the acidification of water, often resulting in acid rain, and the death of many organisms that survive in coral reefs (18). The emission of the above compounds also causes a severe depletion in the ozone layer, the high altitude barrier over the earth that protects its inhabitants from the harmful ultraviolet radiation of the sun (17). Because of the amount of harmful pollutants emitted into the atmosphere by fossil fuels, their use should be discontinued in favor of hydrogen fuel cells.
Although the amount of pollutants that fossil fuels emit is astounding, there are other disadvantages of their use. Climate change, which has only part of the international agenda since the 1970’s, has continued to gain importance, especially in the wake of natural disasters like hurricanes Katrina, Isaac, and most recently, Sandy (Dawson and Spannagle 3). These natural disasters have also drawn attention to some of the effects of climate change, like rising sea levels and changing planetary climate patterns. There is significant evidence that supports the conclusion that humans, through the combustion of fossil fuels, are warming the atmosphere of the earth, roughly 1.4° F so far. Although that number may seem insubstantial, over the next 100 years, the earth’s temperature is expected to rise anywhere from 5° F to 14° F if emissions of carbon dioxide and carbon monoxide continue at their current rates (“Climate Change Basics”). For that reason, investments in renewable resources, such as hydrogen fuel cells, are needed.
The final argument against fossil fuels is their non-renewability. Unlike hydrogen, fossil fuels cannot be replenished, and their reserves are currently being depleted. At present, there are an estimated 1.3 trillion barrels of oil left in the world. This is expected to last for no more than forty years. (Dawson and Spannagle 7). Fossil fuels are merely a short fix to the long term energy problem facing the planet. As John and ÇiÄŸdem Sheffield so eloquently put it, “a coherent energy strategy is required, addressing both energy supply and demand, taking account of the whole energy life cycle” (1). Fossil fuels are not the solution that the planet needs for its energy crisis.
In addition to the numerous disadvantages of fossil fuels, there are many advantages to a completely hydrogen based economy. The first of these is complete energy security and independence. Because hydrogen can be produced from such a wide variety of sources, there is no possibility that one single country, like Saudi Arabia, would control a monopoly on its production (Hoffmann 8). Any country where the sun shines, the wind blows, and there is water can produce enough hydrogen to satisfy its energy needs. If the United States completely switched to a hydrogen fuel based economy, there would be no need to import oil, coal, or natural gas from other countries (Sheffield and Sheffield 7). However, before that transition can come about, more investments are needed in hydrogen fuel cells.
Yet another major advantage of hydrogen fuel cells as a future energy source is the lack of emissions. As mentioned previously, hydrogen fuel cells produce only water as their emissions, which is not a greenhouse gas (“Benefits”). Because of this, water would have no effect on the climate. This is possibly the greatest advantage of hydrogen fuel cells. A fuel cell running on hydrogen emits little to no pollutants over the course of the chemical process (“Benefits”). Based on data gathered by the United States department of energy, a stationary fuel cell power plant emits less than half an ounce of pollution per 1,000 Kw/h of produced electricity, while fossil fuels create around twenty five pounds of greenhouse gasses and pollutants for the equivalent quantity of produced electricity (Sperling and Cameron 27). Emissions of pollutants from fuel cells are so small that some places in the United States have allowed fuel cells to be exempt from air quality controls (“Benefits”). Because of their low emissions, hydrogen fuel cells should be used in place of fossil fuels in a future energy economy.
The final main advantage of hydrogen fuel cells is their excellent efficiency when compared with fossil fuels. Because fuel cells create energy using an electrochemical process and do not combust fuel, they are essentially have greater efficiencies than combustion engines (Brus and Hotek 23). Fuel cell systems today achieve forty to fifty percent fuel to electricity efficiency using only the electricity produced from the electrochemical reaction as power. If cogeneration is used, a fuel cell’s efficiency can be dramatically increased to between eighty five and ninety percent. Cogeneration can even help reduce a building’s heating costs in the winter by around thirty percent (“Benefits”). Even fuel cell vehicles are between two and three times more efficient than regular fossil fuel vehicles (Hoffmann 37). Because of their incredible efficiencies when compared with fossil fuel combustion sources, hydrogen fuel cells deserve the money and subsidies that governments currently give to fossil fuel companies.
Although hydrogen fuel cells have large amounts of advantages, there is one main disadvantage: cost. The current price for 1kg of hydrogen, the energy equivalent of one gallon of gasoline, is around twelve dollars (“Hydrogen Energy”). Most citizens of the United States are used to paying three to four dollars for a gallon of gas, which is much less expensive than hydrogen. However, the price of gas fails to take into account the environmental damage associated with fossil fuels. If factored into the price, one gallon of gasoline costs between ten and eleven dollars (Hoffmann 64). Although the initial price of hydrogen may seem high when compared with gasoline, when the environmental damage is taken into account, hydrogen is actually less expensive than gasoline.
Since hydrogen fuel cells emit no harmful pollutants, have efficiencies greater than current fossil fuel sources, and can create a diversified energy economy, they need more investments. Planet earth is facing an energy crisis. The human race must grow, develop, and move past old and inefficient ways of generating energy and into a future where clean and efficient hydrogen fuel cells generate energy for eons to come. If this transition into a hydrogen economy can be made, then the human race has utilized an energy source that can power the earth for thousands more years. If not, then the human race may face a bleak future without one of the main essentials for human existence: energy.
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