Zachary Trimmer

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					Zachary Trimmer
EGEE 101H
Semih Eser

                    Hydrogen Production and Future Fuel Possibilities

         You wake up in the morning, turn on the lights, and make yourself a cup of

coffee. The television reports to you the daily news and weather conditions. Your toast

is ready, and you eat it quickly; it is time to go to work. You get in your car and drive,

noticing that your tank is low. However, yours is not the only low tank. The world’s

tank is low, not only on petroleum, but on fossil fuels as a whole. Look back at what you

used this morning: lights, coffee maker, television, toaster, and car. Renewable energies

such as wind power and solar power can help replace the burning of coal and other fossil

fuels for the generation of electricity to power your home appliances. Yet, wind power is

not a mobile source of energy that can refuel your car. Neither is tidal, hydro, nor nuclear

power.

         In an age where transportation is so vital that over 89% of Americans own one or

more cars, a replacement for gasoline is essential (Pendley 4). Biomass fuels could be

used, but how much food can be sacrificed for gas? Batteries could be used, but limited

distance and lengthy recharges hinder their practicality. Another replacement could be

hydrogen. Unfortunately, hydrogen is not the perfect energy source that the public

believes it to be. It actually is not an energy source at all. Hydrogen can not be mined; it

must be produced. It is, however, a great energy carrier. According to Smil, author of

Energy, “Its key advantages are superior energy density (liquid hydrogen contains 120

MJ/kg compared to 44.5 MJ/kg for gasoline), a combustion that yields only water, and

the possibility of using it in fuel cells” (Smil 172). Before discussing the feasibility of
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hydrogen as a fuel for transportation vehicles, it is important to understand the different

methods of hydrogen production being researched today. Since the goal is to replace

fossil fuels, the generation of hydrogen from natural gas and other fossil fuels will be

omitted.

        To begin, hydrogen can be produced from the photolysis of water in membranes

by solar radiation. One of the key benefits of this method is that solar energy is infinite.

However, the yield is very small. Only around .2 - .4 m3 of hydrogen per day can be

generated at one atmospheric pressure per square meter of surface. At a 30% conversion

efficiency of solar energy at all wavelengths, an area of 33,000,000 m2 is required to

produce 7,100,000 m3/day of hydrogen which is the equivalent of a 2000 MW electricity

generating station (Melvin 223-224).

       Next, biophotolysis of water by cyanobacteria and microalgae produces hydrogen.

Cyanobacteria and microalgae are capable of oxygenic photosynthesis as seen in the

reaction CO2 + H2O 6 [CH2O] + O2. According to Kazuhisa Miyamoto, professor at

Osaka University, Japan, “Photosynthesis consists of two processes: light energy

conversion to biochemical energy by a photochemical reaction, and CO2 reduction to

organic compounds” (Miyamoto 2). Instead of decreasing CO2, under certain conditions

cyanobacteria and microalgae consume biochemical energy to generate hydrogen. There

are two enzymes capable of hydrogen production: hydrogenase and nitrogenase.

       Hydrogenase hydrogen production was first discovered in 1942 when scientists

Gaffron and Rubin observed that a green alga created hydrogen under light conditions

after being deprived of light and oxygen. Hydrogenase catalyzes the reaction 2H+ +

2Xreduced  6 H2 + 2Xoxidized (Miyamoto 2-3). Further studies have shown that the
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reducing power of hydrogenase does not have to come from water; it can also be derived

from starch. In 1988, a group of scientists led by Eli Greenbaum, a research scientist at

Oak Ridge National Laboratory, reported 10 to 20% efficiencies of light conversion to

hydrogen. Unfortunately, hydrogenase is very oxygen-labile, so light-dependent

hydrogen production can only be sustained for several tens of minutes because of the

oxygen produced in photosynthesis. In 1986, a light/dark cycle was proposed.

According to Miura and Miyamoto, “CO2 is reduced to starch by photosynthesis in the

daytime (under light conditions) and the starch thus formed, is decomposed to hydrogen

gas and organic acids and/or alcohols under anaerobic conditions during nighttime (under

dark conditions)” (Miyamoto 4). Miyamoto more recently proposed a way to improve

the yield of starch degradation by chemical digestion of algal biomass.

       Nitrogenase-dependent hydrogen production was discovered later than

hydrogenase-dependent in 1974. Miyamoto explains how nitrogenase produces hydrogen

very well:

               Molecular nitrogen is reduced to ammonium with consumption of

               reducing power (e' mediated by ferredoxin) and ATP. The reaction is

               substantially irreversible and produces ammonia:

               N2 + 6H1+ + 6e-  2HN3
               12ATP    12(ADP+Pi)

               However, nitrogenase catalyzes proton reduction in the absence of

               nitrogen gas (i.e. in an argon atmosphere).

               2H+ + 2e-  H2
               4ATP 4(ADP+Pi) (Miyamoto 4-5).
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Unfortunately, the nitrogenase-catalyzed hydrogen production occurs as a side reaction at

a rate of around a fourth of nitrogen-fixation. Nitrogenase is also oxygen-labile, but

cyanobacteria have developed ways of protecting nitrogenase from oxygen by decreasing

power and providing it with ATP. Miami BG-7 is one of the most effective hydrogen-

producing cyanobacteria. One of its strains, Synechococcus, has an estimated conversion

efficiency of 3.5% using an artificial light source (Miyamoto 5).

       Another method of hydrogen production is using photosynthetic bacteria. A

benefit of this method is that light energy is not required making the efficiency of light

energy conversion to hydrogen gas much higher than that from cyanobacteria. Miyamoto

states, “Photosynthetic bacteria undergo anoxygenic photosynthesis with organic

compounds or reduced sulfur compounds as electron donors” (Miyamoto 6). There are

also some non-sulfur photosynthetic bacteria that are powerful hydrogen generators; they

utilize organic acids. The maximum energy conversion efficiency obtained from

photosynthetic bacteria was demonstrated by Miyake and Kawamura at 6 - 8% efficiency

using Rhodobacter.

       Finally, nuclear power can be used to generate hydrogen. Hydrogen can be

produced from nuclear energy by way of electrolysis, high-temperature steam electrolysis

(HTSE), and thermochemical water splitting cycles (TWSC). Current day nuclear

reactors are only capable of producing hydrogen via electrolysis. This approach would

be employed during off-peak hours and utilize existing water electrolysis production

technologies. With the production of Generation IV nuclear reactors, temperatures in the

range of 700-1000ºC would be attainable, making HTSE and TWSC possible (Hydrogen

2). HTSE is more efficient than normal electrolysis because it “uses heat, instead of
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electricity, to provide some of the energy needed to split water” (Hydrogen 1). TWSC

also uses heat; around 1000ºC is used to split water into its component parts. In each

case, the high temperatures come from nuclear waste heat.

        So, is hydrogen the answer to our fuel-related needs? It has the potential to be.

However, not one production method will be omnipotent. Each method should be

employed. Photolysis on a mass production scale is infeasible. Not only will the

facilities be too large, but the vast amount of equipment is very capital intensive (Melvin

224). What about on a smaller scale? Scientists in Melbourne, Australia, have made an

incredible breakthrough. They have developed a solar-powered hydrogen fueling station

that fits in anyone’s garage. Todd Woody interviewed the scientists who said at “the

heart of the fuel station is an electrolyzer – essentially a fuel cell run in reverse” (Datta

1). Photovoltaic solar panels or wind turbines, depending on which suits the owner more,

will send electric currents to separate water into hydrogen and oxygen. The hydrogen is

then compressed and stored in the station (about the size of a file cabinet) ready to be

used in a fuel-cell car. The fueling station is expected to generate enough hydrogen in

one day to power a car around 100 miles (Datta 1). At only $500, it will pay for itself in

less than a year. The station is perfect for public transportation vehicles and people who

do not have a long commute to work. However, what if people need to drive greater

distances?

        In order for hydrogen to dominate the transportation fuel market, people will need

to be able to refuel on the road at stations. One of the main concerns associated with the

switch to hydrogen is the need of an infrastructure. The home fueling station alleviates

much of that problem, but there still will have to be filling stations on major high ways.
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Can enough hydrogen be produced to meet American needs? Currently, photosynthetic,

anaerobic, and bacterial hydrogen productions have low conversion efficiencies alone.

However, you can combine these methods to generate more hydrogen. Miyamoto

explains how the combination of anaerobic and photosynthetic bacteria could increase the

potential of their application in hydrogen production:

               Anaerobic bacteria metabolize sugars to produce hydrogen gas and

               organic acids, but are incapable of further breaking down the organic acids

               formed…theoretically, one mole of glucose can be converted to 12 moles

               of hydrogen through the use of photosynthetic bacteria capable of

               capturing light energy in such a combined system. From a practical point

               of view, organic wastes frequently contain sugar or sugar polymers. It is

               not however easy to obtain organic wastes containing organic acids as the

               main components (Miyamoto 6-7).

Greenbaum, with other Oak Ridge scientists, succeeded in the combination. They

produced 11.6 hydrogen molecules for every glucose molecule used (Producing 3).

Genetic engineering is also trying to increase the amounts of hydrogen achieved by

altering antennae in certain algae. Greenbaum hopes to have “mutant algae that will

produce 10 times more hydrogen if we increase the light intensity 10 times” (Producing

2).

       Still, photobiological hydrogen production will not be the end all method of

production. It will not be able to create enough hydrogen to fit the needs of the American

public who, according to the Energy Information Administration, consume around 103.6

billion gallons of gasoline a year. Therefore, nuclear hydrogen production should be
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incorporated. In order to achieve optimum hydrogen production from nuclear power,

Generation IV plants must be produced. Public opinion needs to grow for nuclear energy

in order for the Generation IV plants to be built. Luckily, the public is beginning to view

nuclear energy in a positive light again in the United States; environmentalists are

beginning to support nuclear energy as seen in the Environmentalists for Nuclear Energy

organization. In 2004, James Lovelock, most known for his concept of Gaia, called for

an increase in nuclear power (Morris 91). Unfortunately, nuclear energy is not viewed

the same way in Europe. Many countries within the European Union are planning to

decommission their sites prematurely. Germany, for instance, plans to shut down its

nuclear power plants only after 32 years rather than the 40 planned years (Morris 77).

       Nuclear energy will work in the U.S., but if Europe maintains its decommission

trend, do they have alternatives for more hydrogen production? Using Germany as an

example again, the answer is yes. The same principle that is applied to modern nuclear

hydrogen production can be used with Germany’s windmills. During off-peak hours, the

windmills can be used to create hydrogen. Other countries that have an abundance of

renewable energies can follow suit. Iceland is planning on using geothermal energy to

produce hydrogen via electrolysis and thermochemical methods (Arnason 3). It is

probable that other nations along the Ring of Fire could utilize Iceland’s geothermal

hydrogen production.

       An additional concern affecting hydrogen’s progress is the public disposition that

hydrogen is dangerous. In many ways, hydrogen is safer than gasoline. Hydrogen spills

won’t pollute the earth like petroleum spills do. But, if the tank does leak, how much

damage would it do if ignited? The College of Engineering at Miami University
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performed tests and concluded that temperatures inside a car that had an ignited hydrogen

leak only rose 1 – 2 degrees centigrade. The outside of the car did not get any hotter than

it would on a sunny day. Lastly, pressurized hydrogen tanks are made to endure

tremendous impacts. Simulated crashes at 55 mph have left the hydrogen tanks intact

while the cars are totaled. BMW has tested its hydrogen-fueled vehicles in accident

simulations that include collision, fire, and tank ruptures. In each case, the hydrogen cars

performed as well as conventional cars (Is 1-2).

       In conclusion, the age of fossil fuels is coming to an end. Preemptive efforts must

be taken to decrease the negative effects of a switch to new energy sources and carriers.

Europe has become the leader in renewable energy advances. The United States has the

potential to become the forefront for hydrogen advancement. The U.S. has 103 light

water nuclear reactors at 64 sites to use for nuclear hydrogen production (Hydrogen 3).

Oak Ridge National Laboratory is making advances in genetic engineering to increase the

potential of photobiological hydrogen production. However, not only do the scientists

need to help, but so do the American people. They must embrace hydrogen and call for

more hydrogen cars and infrastructure. They need to show their commitment by

purchasing the Australian home fueling station. Once the consumer demands hydrogen-

fueled cars, the industry will respond.



                                          Works Cited

Arnason, Bragi, and Thorsteinn I. Sigfusson. "Application of Geothermal Energy to

       Hydrogen Production and Storage." University of Iceland. 25 Mar. 2007

       <http://theochem.org/bragastofa/CD/essen.pdf>
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Datta, Saheli, and Todd Woody. "8 Technologies for a Green Future." CNNMoney. 7

       Mar. 2007. 20 Mar. 2007

       <http://money.cnn.com/magazines/business2/business2_archive/2007/02/01/8398

       988/index.htm>.

"Hydrogen Production - Nuclear." 2007. New York State Energy Research and

       Development Authority. 20 Mar. 2007

       <http://www.getenergysmart.org/Files/HydrogenEducation/7HydrogenProduction

       Nuclear.pdf>.

"Is Hydrogen Dangerous?" Rocky Mountain Institute. 2006. 25 Mar. 2007

       <http://www.rmi.org/sitepages/pid536.php>.

Melvin, A. “The Impracticality of Large-Scale Generation of Hydrogen From Water

       Photolysis By Utilization of Solar Radiation.” Int. J. Hydrogen Energy. Vol. 4.

       Great Britain: Pergamon Press Ltd. 1979. 223-224.

Miyamoto, Kazuhisa, ed. Renewable biological systems for alternative sustainable

       energy production. FAO, 1997.

Morris, Craig. Energy Switch. Canada: New Society Publishers, 2006.

"New Hydrogen-Producing Reaction Could Lead to Micropower Sources." ORNL.Gov.

       2000. U.S. Dept. of Energy. 24 Mar. 2007

       <http://www.ornl.gov/info/ornlreview/v33_2_00/micropower.htm>.

Pendley, Wayne L. "All-Consuming Passion: Waking Up for the American Dream."

       EcoFuture. 17 Jan. 2002. New Road Map Foundation. 24 Mar. 2007

       <http://www.ecofuture.org/pk/pkar9506.html>.
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"Producing and Detecting Hydrogen." ORNL.Gov. 2000. U.S. Dept. of Energy. 20 Mar.

      2007 <http://www.ornl.gov/info/ornlreview/v33_2_00/hydrogen.htm>.

Smil, Vaclav. Energy. Oxford: Oneworld Publications, 2006.

				
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