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Disclaimer—This paper partially fulfills a writing requirement for first year (freshman) engineering students at the University
of Pittsburgh Swanson School of Engineering. This paper is a student, not a professional, paper. This paper is based on publicly
available information and may not provide complete analyses of all relevant data. If this paper is used for any purpose other
than these authors’ partial fulfillment of a writing requirement for first year (freshman) engineering students at the University
of Pittsburgh Swanson School of Engineering, the user does so at his or her own risk.
HYDROGEN FUEL CELLS: THE FUTURE OF TRANSPORTATION
Nicholas Sanzo ([email protected])
THE NEED FOR RENEWABLE ENERGY
Over President Obama’s two terms in office, he has
made clear his concerns for our country going forward.
One issue that he has stressed over and over is the
importance of developing technologies in renewable
energy. In an address to Congress, he said, “To truly
transform our economy, protect our security, and save
our planet from the ravages of climate change, we need
to ultimately make clean, renewable energy the profitable
kind of energy” [1]. The ultimate outcome that he is
referring to is the use of energy sources other than fossil
fuels. Today, the most common forms of renewable
energy are solar, wind, and geothermal.
Transportation is the Key
One of the biggest industries that renewable energies
can have an impact on is the auto industry. According to
Environmental Protection Agency, 26 percent of all
greenhouse gas emissions produced by the United States
in 2014 came from transportation. If the U.S. is going to
make significant steps to reduce pollution, find
alternative fuel sources instead of burning gasoline to
power motor vehicles is a good place to start [2].
Almost every American uses motor vehicles for
transportation on a daily basis, whether they’re driving
their cars, motorcycles, or riding on a bus. One thing
that almost all of them have in common is that they run
off an internal combustion engine. These produce
mechanical energy by burning fossil fuels, much of
which is imported from the middle east. Because so
much oil is imported, the cost of gasoline is very
expensive. Foreign oil is also subject to the fluctuating
prices of the global market. Since the middle east
supplies oil to the entire world, the price of oil is
influenced by many different factors throughout the
world. This means that there is little stability in prices,
and sometimes the price will skyrocket. Just a few years
ago gasoline cost over four dollars per gallon, and
Americans felt in in their pockets whenever they went
to a gas station [3].
By developing an energy source to the point that we
no longer need to import fossil fuels would make us
University of Pittsburgh, Swanson School of Engineering 1
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what politicians refer to as “energy independent”. This
would have numerous economic benefits for the U.S.,
including stabilizing domestic gasoline prices and
growing the energy industry in the U.S [3].
THE SOLUTION: HYDROGEN FUEL CELLS
Many people believe that the solution to these
problems is cars powered by electric batteries, but they
have many flaws. While electric cars eliminate
emissions from burning gasoline, they still result in a lot
of pollution. The power that charges the batteries in
electric cars comes from power plants, where power is
produced by burning coal. This process doesn’t produce
as much pollution as burning gasoline, but it is still very
bad for the environment.
How It Works
Figure 1 [4]
Diagram of a Hydrogen Fuel Cell
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of such large vehicles. To make a battery that has enough
energy to power such a vehicle for long distance, it would
be enormous and extremely heavy. To increase the
energy capacity of a hydrogen fuel cell, all that is needed
is bigger hydrogen tanks. Since most of the volume in the
tanks is taken up by hydrogen gas, which is almost
massless, the tanks have a very low mass. As shown in
the graph below, fuel cells have a much higher
volumetric energy density than any battery does.
Volumetric energy refers to the amount of energy stored
per liter of space occupied. For anything that has high
energy demands, whether long range travel or powering
heavy vehicles, hydrogen power cells can provide
enough power while taking up much less space and
weighing much less [9].
A much better solution to powering transportation
is through the use of hydrogen fuel cells. A hydrogen fuel
cell, as depicted above, uses hydrogen gas from a tank
and oxygen, from the environment, as fuel. Hydrogen
gas is pumped into one side of the fuel cell. It then passes
through a membrane that separates electrons travel
through a wire, producing an electric current. This wire
is then used to power the motor. In the diagram, the
electricity is used to power a light, but it can be used to
power any electrical device. In the case of transportation,
it is used to power a motor. The hydrogen molecules
without any electrons travel to the other side of the fuel
cell where there is a flow of air from the outside
environment. The wire with the flowing electrons ends
here, and the electrons, hydrogen, and oxygen from the
air react to produce water vapor, which exits the fuel cell
and goes out of the exhaust pipe.
THE CAR OF THE FUTURE
One such car is the Honda Clarity Fuel Cell. It is
still under development, but it will be available for sale
in 2017. Although this is the first hydrogen powered car
Honda has put out, it is very capable of being an everyday
utility car. With the built in hydrogen tanks, the Clarity
Fuel Cell has a range of 366 miles [5]. For comparison,
the current Tesla Model S, the industry leader in electric
cars, has a range of 270 miles [6]. This makes the
Hydrogen fuel cell a much more reliable fuel source,
since it can go nearly 100 miles farther without refilling
than the tesla can without recharging. 366 miles is a very
long way. To put it into perspective, consider that the
distance between Philadelphia and Pittsburgh is only 304
miles [7].
Figure 2 [9]
Volumetric Energy Density of Batteries vs Fuel
Cells
Hydrogen fuel cells are also much better for the
environment than the alternatives. When gasoline is
burned it produces carbon dioxide, a greenhouse gas that
is harmful to the ozone layer, making it major contributor
to global warming.
At first glance, electric cars appear to be much
better for the environment, but in reality, they are not.
Most of the time, the energy used to charge electric cars
comes from power plants where coal is burned to produce
energy. Burning coal is a more efficient process than
burning gasoline, making it better for the environment,
but it still produces many pollutants such as carbon
dioxide. In 2014, the only sector that produced more
greenhouse gas emissions than transportation was
producing electricity, accounting for 30 percent [2].
Hydrogen fuel cells, however, results in almost no
pollutants. The reaction happening in the fuel cell in the
Honda Clarity Fuel Cell only produces water vapor as a
byproduct, so that is all that exits through the exhaust
pipe. Some electricity is required to run a process known
as electrolysis. This is the process that produces
hydrogen gas from water. An electrical current is run
through water, causing the water molecules to separate
Fuel Cells vs. Battery Power
Hydrogen fuel cells also allow for the opportunity
to refill the hydrogen tanks along a trip. In California
there are currently a handful of hydrogen refueling
stations. There, drivers can refill their car’s hydrogen
tanks in less than five minutes. Electric cars, on the other
hand, take hours to charge, so there is no possibility of
making a quick stop in the middle of a trip to recharge.
As hydrogen powered cars become more prevalent
throughout the country, an increasing number of gas
stations will have hydrogen pumps, even further
increasing the practicality of the Honda Clarity Fuel Cell
[8].
Hydrogen fuel cells are also superior over
batteries when it comes to powering larger vehicles such
as busses and 18-wheeler semi-trailer trucks. These
larger vehicles require much more power since they are
very heavy. Running these vehicles with battery power is
very impractical because of the high energy requirements
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into hydrogen gas and oxygen. This requires only a small
amount of energy, and it would be much easier solar
power to fuel this process than it would be to run electric
cars off of it [4].
And it is not only President Obama and his fellow
Democrats who are preaching the great advantages of
alternative energy sources. Every politician believes it
would be in America’s best interest to better our nation.
Whether it be for the reduction of pollution, the economic
benefits, or the fact that it is another big step towards
energy independence, all politicians believe that
hydrogen fuel cells can make a big impact on the country.
Representative J. D. Hayworth, a Republican from
Arizona, had many positive things to say about fuel cells.
“Producing fuel cells and solar panels requires high tech
facilities and produces high paying jobs. The industry is
booming in Arizona. The state already has about 100
firms in the solar industry and has grown 20% since
2003” [10].
It is not often that you see a Democrat and a
Republican agree on something. On those few occasions
that they do agree, it is about something that will clearly
benefit our nation. The Honda Clarity Fuel Cell is a
practical solution to all of the problems that internal
combustion engines and electric cars cause, and it is soon
going to dominate the auto industry.
[7]
Google
Maps.
Accessed
10.30.2016.
https://www.bing.com/search?q=distance+from+philade
lphia+to+
pittsburgh&form=EDGNTC&qs=AS&cvid=c6ca4d467
3294d4bb5f7d5e5a2bcd674&pq=distance+from+philad
elphia+to+pittsburgh&PC=DCTS
[8] “Pump It Up: We Refuel a Hydrogen Fuel Cell
Vehicle.” Car And Driver. 11.2008. Accessed
10.29.2016.
http://www.caranddriver.com/features/pump-it-up-werefuel-a-hydrogen-fuel-cell-vehicle
[9] “Hydrogen versus Battery Power.” REB Research
Blog.
03.25.2013.
Accessed
10.29.2016.
http://www.rebresearch.com/blog/hydrogen-versusbattery-power/
[10] Hayworth. J.D.. “Fuel Cell Quotes.” Brainy Quote.
Accessed 10.30.2016. http://www.brainyquote.com
/quotes/quotes/j/jdhaywor374054.html?src=t_fuel_cells
ACKNOWLEDGEMENTS
I would like to thanks Abbas Ahmed for
giving me moral support while I wrote this paper
and Tysen Singletary for telling me where to find
the grading rubric.
SOURCES
[1] Obama. Barrack. “Address to Joint Session of
Congress, Feb. 24, 2009.” Notable Quotes. Accessed
10.29.2016.
http://www.notablequotes.com/a/alternative_energy_quotes.html
[2] “Sources of Greenhouse Gas Emissions.”
Environmental
Protection
Agency.
10.16.2016.
Accessed
10.29.2016.
https://www.epa.gov/ghgemissions/sources-greenhousegas-emissions
[3] “6 Reasons Why U.S. Energy Independence Is So
Important.” Propell Technologies Group. 07.16.2014.
Accessed 10.28.16. http://blog.propell.com/6-reasonswhy-us-energy-independence-is-so-important/
[4] “Hydrogen Fuel Cells” Texas Hydrogen 101. 2011.
Accessed
10.30.2016.
http://hydrogen.harc.edu/Hydrogen101Curriculum/H10
1FuelCells/tabid/516/Default.aspx
[5] “2017 Honda Clarity Fuel Cell rated at 366 miles of
range by EPA.” Green Car Reports. 10.24.2016.
Accessed
10.30.2016.http://www.greencarreports.com/news/1106
845_2017-honda-clarity-fuel-cell-rated-at-366-miles-ofrange-by-epa
[6] “Official EPA Figures Reveal Tesla Model S 85D Is
New Range King.” Inside EVs. 2014. Accessed
10.30.2016.
http://insideevs.com/official-epa-figuresreveal-tesla-model-s-85d-new-range-king/
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