Martyn.McNally.FuelCells


 * Introduction to fuel-cells

__The Underlying Problem__**: Global Warming, the issue that has been perplexing scientists for decades, is in general the underlying problem. Fuel cells are not just another way to “cut back” on CO2 emissions in the world. The previous attempts to level CO2 emissions include improving efficiency of gas guzzling vehicles or even taking CO2 itself, when it is produced, and compacting it enough so it can be thrown into the ocean. Neither of these processes totally eliminates the emission of CO2, but fuel-cells do not use fuel that emits CO2 when used. With the recent energy crisis the issue in today’s society is finding new and more efficient ways to use energy. Some suggested processes involve tedious planning and procedure. This would make them too complicated and/or expensive to use in everyday life. Fortunately fuel-cells use simple processes to extract energy from hydrogen molecules. With the discovery of this method scientists are on their way to making it more efficient energy and cost wise.

An excellent example of how a fuel cell works is taken from a fuel-cell powered vehicle. The fuel-cell works simply by converting H2 molecules into electricity and water. When hydrogen gas pumped from the fuel tanks arrives at the anode, which is made of platinum, the platinum catalyzes a reaction that ionizes the gas. Ionization breaks the hydrogen atom down into its positive ions (hydrogen protons) and negative ions (electrons). Both types of ions are naturally drawn to the cathode situated on the other side of the membrane, but only the protons can pass through the membrane (hence the name "proton-exchange"). The electrons are forced to go around the PEM, and along the way they are shunted through a circuit, generating the electricity that runs the car's systems. Using the two different routes, the hydrogen protons and the electrons quickly reach the cathode. While hydrogen is fed to the anode, oxygen is fed to the cathode, where a catalyst creates oxygen ions. The arriving hydrogen protons and electrons bond with these oxygen ions, creating the two "waste products" of the reaction—water vapor and heat. Some of the water vapor gets recycled for use in humidification, and the rest drips out of the tailpipe as "exhaust." This cycle proceeds continuously as long as the car is powered up and in motion; when it's idling, output from the fuel cell is shut off to conserve fuel, and the ultra capacitor takes over to power air conditioning and other components. A single hydrogen fuel cell delivers a low voltage, so manufacturers "stack" fuel cells together in a series, as in a dry-cell battery; The more layers, the higher the voltage. Electrical current, meanwhile, has to do with surface area. The greater the surface area of the electrodes, the greater the current. One of the great challenges automakers face is how to increase electrical output (voltage times current) to the point where consumers get the power and distance they're accustomed to while also economizing space in the tight confines of an automobile. []
 * __How a Fuel Cell Works:__**



Polymer exchange membrane fuel cell (PEMFC) Polymer exchange membrane fuel cells are the most likely candidate for transportation. The PEMFC has a high power density and a relatively low operating temperature (ranging from 60 to 80 degrees Celsius, or 140 to 176 degrees Fahrenheit). An example would be the explanation above of how a fuel cell works. Anode Reaction H_2=2H^++2e^- Cathode Reaction 1/2 O_2+ 2H^++2e^-= H_2 O Overall Reaction H_2+1/2 O_2=H_2 O
 * __Types of Fuel Cells:__**

These fuel cells are best suited for large-scale stationary power generators that could provide electricity for factories or towns. This type of fuel cell operates at very high temperatures (between 700 and 1,000 degrees Celsius). The SOFC has demonstrated the longest operating life of any fuel cell under certain operating conditions. The high temperature also has an advantage: the steam produced by the fuel cell can be channeled into turbines to generate more electricity. This process is called co-generation of heat and power (CHP) and it improves the overall efficiency of the system. Anode Reaction 2 H2 + 2 O2- = 2 H2O + 4 e- Cathode Reaction O2 + 4 e- = 2 O2- Overall Cell Reaction 2 H2 + O2 = 2 H2O
 * Solid oxide fuel cell (SOFC)**

Like the SOFC, these fuel cells are also best suited for large stationary power generators. They operate at 600 degrees Celsius, so they can generate steam that can be used to generate more power. They have a lower operating temperature than solid oxide fuel cells, which means they don't need such exotic materials. This makes the design a little less expensive.
 * Molten-carbonate fuel cell (MCFC)**

The phosphoric-acid fuel cell has potential for use in small stationary power-generation systems. It operates at a higher temperature than polymer exchange membrane fuel cells, so it has a longer warm-up time. Direct-methanol fuel cell (DMFC) Methanol fuel cells are comparable to a PEMFC in regards to operating temperature, but are not as efficient. Also, the DMFC requires a relatively large amount of platinum to act as a catalyst, which makes these fuel cells expensive.
 * Phosphoric-acid fuel cell (PAFC)**

Even though fossil fuels are consumed in the reaction inside of a fuel cell, fuel cells do not do not produce the same unhealthy air pollution emissions that are generated by burning gasoline in cars or burning coal and other fossil fuels in power plants. With fuel cells, there is no combustion, so fewer gases are released into the environment. Although it seems like today there are no immediate benefits of fuel cells, the benefits will be prominent in the near future if this technology is put into place more methodically throughout the world. For example, since there are less harmful emissions in the air, people who suffer with breathing difficulties will not have to worry about being able to go outside or not because of the air quality. Also, the effects of global warming will be reduced due to fewer pollutants in the air.
 * __Impact on the World:__**

The high electrical efficiency of fuel cells provides much more electricity per unit of carbon released than conventional generators of similar size. In other words, more electricity will be produced at a cheaper price. States and nation will save millions, if not billions, of dollars on electricity. This saved money will be able to be used for other important departments in the area.

The use of fuel cells throughout the world can be seen in many applications. Such applications have noticed a significant increase in output and efficiency. The impact of fuel cells is so great that the president of the U.S. has put more than a billion dollars into research to improve the cost and technology. The president’s main concern is eliminating fuel dependency to end the countries deficit. The scientist’s main concern, however, is solving the pollution problem. Fuel cells, in their most obvious applications, are used in vehicles. Cars and other transportation methods use two thirds of the U.S.’s oil. The fuel cell converts the hydrogen into electrical energy for the battery, which then turns the wheels of the vehicle. Here we can see the skeleton of the vehicle and what fuel cells do differently. There are hydrogen storage tanks in the rear. The hydrogen then flows to the fuel cell stack in the front where it is converted to electricity. The converter converts the electricity to DC and it flows to the battery. The energy from the battery flows to the power distributer, which sends electricity to the needed components. The electric drive motor receives a sufficient amount of energy to drive the vehicle in the desired direction. Another widely used application of fuel cells is in industrial, commercial, and residential buildings. Fuel cells are being used already in buildings to produce electricity. Instead of a gasoline powered electrical generator the fuel cell powers the generator, making it highly efficient, quiet, and clean. The energy produced by the fuel cell can also be used for heating and hot water making. Some sites though the U.S. have already started using fuel cells. The sites vary from power plants to laundry facilities.
 * __The Use of Fuel Cells:__**

Sen. John McCain October 2008 – Second Presidential Debate: “We can move forward, and clean up our climate, and develop green technologies, and alternate --alternative energies for -- for hybrid, for hydrogen, for battery-powered cars, so that we can clean up our environment and at the same time get our economy going by creating millions of jobs.” May 2008 – Remarks at Vestas Training Facility, Portland, OR on Climate Change Policy: We will add to current federal efforts to develop promising technologies, such as plug-ins, hybrids, flexfuel vehicles, and hydrogen-powered cars and trucks. We will also establish clear standards in government-funded research, to make sure that funding is effective and focused on the right goals.
 * __What the People Have to Say:__**

With hope going down the drain and the utter hatred for global warming and fossil fuels, fuel cells are looking more and more positive. The possible, and current, impact of fuel cells gives hope to scientists, engineers, politicians, and the general public. With the increase in technology of fuel cells and the increase in demand of a more efficient and clean delivery of energy, fuel cells are becoming more popular. Coming from just an idea in the late 1800’s to scientific reality today, fuel cells have come a long way.
 * __Conclusion:__**

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 * __Citations:__**