Hydrogen economy by liwenting

VIEWS: 19 PAGES: 8

									Hydrogen Economy: Feasibility, Technology, and Infrastructure


                      A group report by:

                      Maikel Fernandez
                      Fred Nguyenloc
                        Brian Toole
                        Chip Young


                          EML3002


                       Dr. Chiang Shih


               Due: Monday, December 05, 2005
Introduction

        As has been the theme in past decades, we as Americans are constantly discussing
what the future will hold and what we must do in order to protect future generations.
From wars to protect and ensure world democracy, the constant fight against poverty and
starvation, to environmental concerns, the general public and media recognizes that
changes and sacrifices must be made as new information comes about. The facts that our
vehicles operate off of a finite source of fuel which will some day run out, combined with
the immense amounts of pollution as a byproduct of burning this fuel, and the low rate of
mechanical efficiency should have been enough of a persuasion in the right direction to
cease this behavior. Unfortunately, very little has been done at this point, in the grand
scheme of things, to help protect our planet from further pollution and its destruction in
our search and battles for fossil fuel sources. The purpose of this paper is to offer you,
the reader, some insight as to the capabilities, disadvantages and advantages, and
production methods of hydrogen as a fuel through the following three categories:
feasibility, which is basically whether it would be politically and economically worth the
hassle to switch from petroleum over to hydrogen as a source of fuel; technology, that is
what is available as the different types of platforms to power future hydrogen fueled cars;
and lastly, the infrastructure necessary to sustain a country operating off of hydrogen as
the primary source of fuel for its transportation, supply side as well as material delivery.

Feasibility

        Relying on other countries for a limited source that emits harmful pollutants and
greenhouse gases! This sounds outrageous doesn’t it? Well, that’s what we as a country
have been doing for over a century now. As of May, President George Bush has taken a
step towards the future by announcing Project “Freedom C.A.R. (Cooperative
Automotive Research)”. The Department of Energy, along with auto makers General
Motors, Ford, and Chrysler, will join in a public-private partnership to promote the
development of hydrogen as a primary source of fuel for cars and trucks as stated by
energy secretary Spencer Abraham in the Detroit auto show in the article “Freedom Car:
goodbye Gasoline,...”. In this partnership, the government and these private companies
will fund research into advanced efficient fuel cell technology, which uses hydrogen to
fuel this new breed of cars, the Hydrogen Fueled Car. But is it truly possible for hydrogen
to compete with oil in a global market? Yes, it can.
        Hydrogen is the world’s lightest, safest, most abundant, and most politically and
economically feasible source of fuel. Hydrogen can be produced form water, sewage,
garbage, landfills, agricultural biomass, and paper product waste, and it is extracted in
many different ways as stated in the article “DOE Researches Demonstrate Feasibility of
Hydrogen Production…”
        In the next paragraphs I will point out the different methods of producing
hydrogen as stated by Yuda Yurum in “Hydrogen Energy System. Production and
Utilization of Hydrogen and Future Aspects”. The most common and least expensive
way of producing hydrogen is by a method called Steam Methane Reforming (SMR).
Almost 48% of the world’s hydrogen is produced this way. SMR can be applied to
hydrocarbons, such as ethane and naphtha, but heavier feedstocks cannot be used because
they may contain impurities, and the feed to the reformer must be a vapor. Prices from
this process range from $5-$8/Gigajoule (GJ). The higher hydrocarbons, such as diesel
fuel and residual oil, are broken down by another process named Noncatalytic Partial
Oxidation Hydrocarbons (POX). The overall efficiency of this process is about 65-75%
of that of SMR, in addition the process requires pure oxygen.
         Coal Gasification is where hydrogen is extracted from coal. This method is a
well-established commercial technology but it is only competitive with SMR in places
where natural gas and oil are extremely expensive; this process also has an environmental
impact on the future due to the fact that the coal must be mined. In Biomass Gasification,
as with Coal Gasification, hydrogen may be obtained by both direct and indirect
gasification. Indirect gasification requires a medium such as sand to transfer heat. In
direct gasification, heat is supplied to the gasification vessel by the combustion of a
portion of the feed biomass. Both of these processes can be costly, with the feedstock
making up 40% of the cost of producing hydrogen. The complete combustion of the
feedstock is known as Biomass Pyrolysis. In this process biomass is thermally
decomposed at a high temperature (450-550 °C) in an inert atmosphere to form a bio-oil
composed of 85% oxygenated organics and 15% water, it is then steam-reformed using
conventional technology to produce hydrogen.
        For users needing small amounts of pure hydrogen, Electrolysis may be their way
to go. The main downfall of this process is massive consumption of electricity, thereby
drastically increasing the production cost. This process makes up about 80% of the
selling price of hydrogen, making the cost of hydrogen to range from $11-$25/GJ. The
Photochemical process consists of two types, were semiconductor surfaces are used as
catalysts to capture solar energy and trigger chemical reactions that produce hydrogen
from water molecules. In the first, the surface absorbs the solar energy and acts as an
electrode for water splitting. This technology is still at a very early stage but shows great
potential. The second type of photochemical system is the use of soluble metal complexes
as photochemical catalysts. When the dissolved metal complex absorbs energy, it creates
an electric charge separation that drives the water splitting reaction. Hydrogen can also be
produced by some biological systems, as seen in certain algae that generate hydrogen
under specific conditions, the pigment in the algae absorb solar energy and enzymes in
the cell act as a catalyst to split water. This is known as the Photobiological process.

Techonology

        The primary use of hydrogen in terms of technology is using it as a power source.
The way that engineers harness this power is by creating fuel cells that use hydrogen as a
fuel. In the future, utilizing hydrogen as a fuel will bring about devices and engines
which will function off of hydrogen.
        In recent developments, transportation has been the main focus on the use of
hydrogen. All car companies are investing their money on hydrogen-powered vehicles
for research and development. For example, Ford Motor has introduced their Model U
Concept which is powered by an Internal Combustion Engine (ICE) that runs on
hydrogen, rather than gasoline. The engine is supercharged and intercooled for
maximum efficiency; it is also based off a Ford 2.3-liter, I-4 engine that has been
optimized to burn hydrogen through the use of high-compression pistons, fuel injectors
designed only for hydrogen gas, a coil-on-plug ignition system, an electronic throttle, and
new engine management software. It has been shown by Ford researchers that by
supercharging the induction system, the hydrogen ICE can deliver the same power as a
gasoline car and still provide a near to zero emissions performance and high fuel
economy (Hydrogen Combustion Engine).
        Hydrogen has different properties that need to be examined before the mass
production of a hydrogen ICE can begin. Hydrogen is extremely flammable compared to
other fuels. Considering this fact, hydrogen has the ability to combust in an engine over a
wide range of fuel-air mixtures. This enables an engine to run on hydrogen more easily
because hydrogen can run on a leaner fuel mixture (less fuel than theoretical amount).
Because hydrogen has very low ignition energy, it requires less energy to ignite hydrogen
enabling hydrogen engines to ignite lean mixtures and ensures prompt ignition. A major
concern with low ignition energy is that hot spots on the cylinder can serve as a source of
ignition and create a problem of pre-ignition. Since hydrogen has a very high diffusivity,
this ensures uniform mixtures of fuel and air. In the case that a hydrogen leak develops,
hydrogen will disperse rapidly. These are a few of the properties that are examined in the
process of designing a hydrogen ICE(Module 3).
        Another way that hydrogen can be used to fuel a car, involves hydrogen and
compressed air flowing to the fuel cell module, which contains a fuel cell stack. A fuel
cell stack is made up of individual Proton Exchange Membrane (PEM) fuel cells. The
number of cells depends on how much power output is needed. Each single PEM fuel
cell is made of two flow field plates, two electrodes, and two thin layers of platinum
based catalysts separated by a plastic membrane. When fed hydrogen fuel, it reacts
electrochemically to create electricity. Hydrogen from the storage tank and oxygen from
the air are fed through the channels and into the plates with; hydrogen from one side of
the membrane, and oxygen from the other. The catalyst splits the hydrogen molecule into
protons and electrons, and as protons pass through the membrane, electrons travel
through an external circuit creating additional useful electricity. The unused hydrogen-
air mixture exits through the exhaust system as water vapor. The electricity created
powers the drive system of the vehicle and produces a functional vehicle (How Fuel Cells
Work). Using hydrogen as a fuel for vehicles is an idea that comes to life, with
advancements in hydrogen technology.
        N.A.S.A has powered their space shuttles and rockets with liquid hydrogen since
the 1970's. In recent developments of fuel cells, plans are in development to integrate
hydrogen fuel cells to power the space shuttles and provide the astronaut crew with an
energy source, drinking water, and a heat source (Chapter 20).
        Hydrogen technology has been applied to various naval applications as a source
of power. In the last two years, Germany has launched their first integrated hydrogen
powered submarines, the U212 and U214. The first to be launched was the U-212, and it
was a major advancement because it combined a diesel engine with an air-independent
propulsion (AIP) system to power the submarine. The AIP is powered by nine polymer
electrolyte membrane fuel cells, providing between 30-50 kW each. The fuel cells enable
the submarine to cruise underwater for weeks without having to resurface. A year later,
Germany launched their U-214, an enhancement of the U-212. The submarine was
equipped with an AIP system, operating off of an increased power due to two Siemens
fuel cells that provide around 120 kW per module, enabling the submarines to stay
submersed underwater for two weeks (U212/U214 Attack Submarines).
         Hydrogen can also be used to keep track of time. The U.S. Navy time clock,
U.S.N.O. Master Clock, uses a dozen cesium atomic clocks and a dozen hydrogen maser
clocks. The hydrogen maser clock uses desired hydrogen atoms that will oscillate (US
Navy Time Clock). In essence, a precise “collective” time clock has been created by
combining the timing of both the hydrogen maser clocks and the cesium clocks.
         Branching hydrogen technology into the aircraft and space fields has not
progressed too quickly. Several airplane companies have invested into the research of
hydrogen used as a source of fuel, but that is about as far as technology has progressed.
A prototype aircraft recently had its first flight test using liquid hydrogen as a fuel source.
The aircraft had a wingspan of 50 feet and flew for an hour (AeroVironment). Liquid
hydrogen has also been researched and implemented in the field of spacecrafts, but very
little progress has been made in this field, as well.
         The main concept of hydrogen technology is using hydrogen to produce power in
fuel cells. After this technology has been achieved, different devices and engines can be
powered by these fuel cells. Making hydrogen into a power source will provide many
devices a better source of power.

Infrastructure

         Hydrogen is the most abundant element in the universe, but it is mostly found as
water. Pure hydrogen is most readily produced using a process named “Electrolysis”,
which involves extracting the hydrogen from water. The simple version of this process
occurs when electrodes are placed into purified water and, through the use of a large
electric potential (voltage) involving direct, alkaline current (DC), the hydrogen
molecules separate from the oxygen molecules; the separated hydrogen is then stored.
The alkaline-hydrogen extraction process is approximately sixty-seven percent efficient.
One of the problems with using electrolysis to produce the hydrogen fuel from the water
is the fact of electrical input versus physical output. It would take four hundred, 1000
mega watt power plants, running twenty-four hours a day to produce the needed
electricity to extract hydrogen using electrolysis. Judging by the current national demand,
the amount of power being consumed by this operation would be approximately twice the
current demand. The amount of energy needed for electrolysis has caused problems for
researchers, who realize that in order to use hydrogen as a fuel source; they will have to
develop a reasonable way to produce hydrogen.
         Water is the obvious source for attaining hydrogen as a fuel because it is so
abundant on our planet. The question is this: how will we get the electricity needed to
produce the hydrogen? An idea that has been suggested is to use wind-powered turbine
generators to generate the electricity required in the electrolysis process. A proposed test
site is an island chain in Alaska named the Aleutian Islands. The Aleutian Islands are the
windiest place on earth and would be a great place to put the turbine generators needed
for the production of the hydrogen. Using sea water as the hydrogen source, the turbine
generators would generate the electricity necessary for the electrolysis extraction process.
The hydrogen by-product would be transferred through pipelines to customers thousands
of miles away after production (Secondary Fuel Source 4).
         Another debate about production is whether hydrogen should be produced by a
retail fueling station, or if it should be produced at a centralized location. The problem
with producing hydrogen fuel at a retail fueling station is the fact that, at the present time,
it would cost 450,000 dollars to buy the equipment necessary to produce sixty kilograms
of hydrogen. Sixty kilograms of hydrogen would only be enough to power twelve cars
(Hydrogen as a Fuel 5). The practical solution to this problem is to have a centralized
production plant similar to the production plants used to refine gasoline today.
         There are many devices used to produce hydrogen. Examples of some of these
devices are catalysts, electrolyzers, hydrogen generators, membrane reactors, and
purifiers. Researchers are involved in current, ongoing investigations to decide which one
of these hydrogen extraction materials and methods would be the most efficient method
for producing hydrogen on a large scale. Most believe that electrolysis is the answer.
         After the hydrogen is produced, the materials needed to store the hydrogen are
required to meet several specifications. Since hydrogen is extremely flammable and it
must necessarily be kept at temperatures of around -253 degrees Celsius at a liquid state,
special containers must be designed and fabricated to contain the hydrogen. One type of
storage container consists of a metal hydride compound as the medium for storage. This
material is useful because, when heated, the hydrides release the hydrogen and fuel
becomes available. Fuel cells will use this released hydrogen to produce electricity after
the hydrogen has mixed with oxygen (United States 2). The metal hydride containers, and
other possibilities, are continually being researched because the goal is to create a
portable tank which can be used safely in an automotive fuel cell system application.
                 The main consideration concerning the supply side of the infrastructure
has now become transportation to satellite locations. These satellite locations are simply
the equivalent of modern day gas stations. Since the supply stations (manufacturing
facilities) are typically on the outskirts of large cities or in remote locations, this quickly
becomes very inconvenient for consumers as they must burn up more of their fuel load in
traveling to and from the refueling site. As the market of hydrogen powered vehicles
expands and when production begins, the need for easily accessible refueling will help to
spawn these satellite locations. A few small companies, such as Stuart Energy,
PowerTech, and others, have begun business ventures to bring the fuel closer to the
consumer.
         Involving the oil industry in the hydrogen supply has been an overwhelming
challenge. For years, the oil industry and automotive manufacturers have not put forth a
true effort to follow government initiatives and heed the warnings of environmentalists.
The struggle between the automotive manufacturers and big oil companies to provide a
solution to the consumers has been ongoing. Despite this set back, these companies are
now beginning to team up in an effort to produce a solution, and perhaps corner the
market. GM and Shell have put forth the joint effort to demonstrate to the politicians in
our nation’s capital that the hydrogen fuel conversion can be accomplished. On
November 11, 2004, in an industrial section of Washington, D.C., a Shell Oil gas station
opened a single hydrogen pump at a service station four miles east of the Capitol (Gas
Station First in U.S. to Pump Hydrogen). This pump will only supply enough hydrogen
for approximately eight minivans, and possibly more consumers in the future in an
attempt at good publicity and positive exposure to the public to help encourage the
hydrogen changeover.
        Overseas, the BMW Group teamed with the German Transport Energy Strategy
(TES) to begin opening numerous hydrogen fueling stations to encourage the expansion
of the use of hydrogen powered automobiles. Building on the growing popularity in
Germany, other hydrogen fueling stations have opened up in Britain and France, and
other countries are sure to follow. BMW has been a longtime supporter of incorporating
hydrogen-gasoline hybrid technology. In 2001, a special hybrid edition of the 7-Series
sported a 6.0L, V-12 engine; their first production hydrogen-gasoline hybrid was in 1979
(The BMW Group’s Energy Strategy). The advantage of the hybrid 7-Series is that
BMW has produced them with the ability to run solely on one source of fuel, or as a
hybrid. So as an advantage to the operator, if he or she has traveled into an area where
hydrogen fuel is not available, they have the ability to run entirely on petrol until they are
again able to access a hydrogen fueling station.
        Another issue that is of worthy evaluation is that of public safety. Due the fact
that the general public has not been made properly aware of the safety benefits of
hydrogen storage, many misconceptions still exist. When a hydrogen tank ruptures or
leaks (vents) its contents, the gasses escape in an upward manner; if these gasses were to
ignite, the flames would go directly upward, rather than outward. However, when a
gasoline tank in a car ruptures, an outward explosion typically results, and the gasoline
which is sprayed about onto surrounding areas and surfaces, coats and ignites whatever it
lands upon.
        Possibly one of the greatest advantages to hydrogen fuels is the storage itself.
The supply stations could utilize underground storage as to lessen the chance of an
explosion, which the ground would also somewhat contain an explosion if one were to
occur. By converting from petroleum to a hydrogen fuel source, areas with high aquifers
will benefit. Aquifers are underground water-filled caverns or waterways that can be
tapped as a source of water. Many residences in suburban outskirts and rural areas
operate off of wells for drinking water, such as northern and central Florida, and are
prone to aquifer contamination where leaking gasoline tanks are a constant problem.
Much of the aquifer pollution occurs due to ground-surface petroleum spills and leaking
subterranean tanks and is consistently of environmental concern across the country, as
well as the world. When hydrogen tanks leak, again, they typically vent upward;
however, under the ground leaks would be “contained” and far less likely to ignite and
cause an explosion.

Conclusion

        When taking into consideration the effects that the petroleum-powered age has
had on this planet, the outcome of such an evaluation does not inspire much admiration of
the industrialized nations. Air pollution, soil pollution, global warming, acid rain,
contamination of the drinking water derived from aquifers, every time the waters of an
ocean and the effected shores were coated with oil slick, the widening hole in the ozone
layer over the South Pole and the thinning of the entire ozone layer, can all be traced back
to the burning of fossil fuels as being somewhat responsible for their occurrence. The
warmer global climate which is being blamed for spawning the most active, and certainly
the most destructive, hurricane season in recorded history along the Gulf Coast, and there
is too much scientific data pointing towards the relation to fossil fuels to ignore the
correlation. The obvious issue at hand is that something must be done in order to protect
the future generations of this planet, as well as the planet itself, from ending up in worse
shape than it currently is.
        As previously discussed, the technology exists and is readily available to begin a
new era in the history of the world, a much cleaner era, one powered by hydrogen. It is
well known that hydrogen fuel technology has been in development for decades, though
through lackluster attempts by the automotive manufacturers and big oil companies, the
market has never necessarily taken off. No single company should be expected or
allowed to take on the enormous task of producing both the hydrogen fueled vehicles and
the hydrogen itself. Because of joint efforts, such as the GM-Shell Oil and BMW-TES
alliances, steps in the right direction have been taken in the technology and infrastructure
sectors; additionally, through these advancements, feasibility has become a topic of
discussion. This current phase can still be considered the developmental, introductory
phase of hydrogen fuel technology, so the limitations already discussed are to be
expected at this point, and will most likely soon be overcome. Through further research,
integration, and production of hydrogen powered vehicles, the costs will drop
dramatically for consumers and manufacturers, alike.

								
To top