Fuel Cells Paper

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CLASSIFICATIONS OF FUEL CELLS
MSE-5390-SPRING-2015
FUNDAMENTALS OF SUSTAINABLE ENERGY
UNIVERSITY OF TEXAS, ARLINGTON

By
MUSALI, DAKSHINI
KOTA, SHANMUKA PRASAD GUPTA
GROUP # 6

ABSTRACT
Fuel cells generate electricity and heat
during electrochemical reaction which
happens between the oxygen and hydrogen
to form the water. Fuel cell technology is a
promising way to provide energy for rural
areas where there is no access to the public
grid or where there is a huge cost of wiring
and transferring electricity. In addition,
applications with essential secure electrical
energy requirement such as uninterruptable
power supplies (UPS), power generation
stations and distributed systems can employ
fuel cells as their source of energy.
The
current
paper
includes
comparative study of basic design, working
principle, applications, advantages and
disadvantages of various technologies
available for fuel cells. In addition, technoeconomic features of hydrogen fuel cell
vehicle (FCV) and internal combustion
engine vehicles (ICEV) are compared. The
results indicate that fuel cell systems have
simple design, high reliability, noiseless
operation, high efficiency and less
environmentally impact.
INTRODUCTION
Fuel cells are basically open
thermodynamics systems. They operate on
the basis of electrochemical reactions and
consume reactant from an external source.
They are favorable alternatives to
conventional electricity generation methods
for small scale applications. Hydrogen and
hydrocarbon fuels contain significant
chemical energy in comparison with
conventional battery materials; hence they

are now widely developed for numerous
energy applications.
Fuel cell technology is a promising
substitute for fossil fuels to provide energy
for rural areas where there is no access to
the public grid or huge cost of wiring and
transferring electricity is required. In
addition, applications with essential secure
electrical energy requirement such as
uninterruptible power supplies (UPS), power
generation stations and distributed systems
can employ fuel cells as their source of
energy. Fuel cell systems perform with the
highest efficiency compared to conventional
distributed energy systems. They have
simple design and reliable operation as well.
In addition, utilizing hydrogen as the
reactant makes them the most environmentally clean and noiseless energy
systems. Currently, fuel cell systems are
employed widely in small scale as well as
large scale applications such as combined
heat and power (CHP) systems, mobile
power systems, portable computers and
military communication equipment. Despite
all the advantages, there are some
limitations for utilizing fuel cells. For
example, life span of fuel cells shortens by
pulse demands and impurities of gas stream.
Low power density per volume, less
accessibility and less durability are other
challenges for fuel cell technology
development. Though, great break through
is yet to be seen, positive progress is
witnessed throughout the recent years.

HISTORY

the membrane, which served as catalyst for

The first references to hydrogen fuel cells
appeared in 1838. In a letter dated October
1838 but published in the December 1838
edition of The London and Edinburgh
Philosophical Magazine and Journal of
Science,

Welsh

physicist

and

barrister William Grove wrote about the
development of his first crude fuel cells. He
used a combination of sheet iron, copper and
porcelain plates, and a solution of sulphate
of copper and dilute acid. In a letter to the
same publication written in December 1838
but published in June 1839, German
physicist Christian

Friedrich

Schönbein discussed the first crude fuel cell
that he had invented. His letter discussed
current

generated

from

hydrogen

and

oxygen dissolved in water. Grove later
sketched his design, in 1842, in the same
journal. The fuel cell he made used similar
materials to today's phosphoric-acid fuel
cell.

oxygen reduction reactions. This became
known

as

Bacon successfully

developed

a

5 kW

stationary fuel cell. In 1955, W. Thomas
Grubb, a chemist working for the General
Electric Company (GE), further modified
the original fuel cell design by using a
polystyrene

ion-exchange

membrane as the electrolyte. Three years
later another GE chemist, Leonard Niedrach,
devised a way of depositing platinum onto

the

"Grubb-Niedrach

fuel

cell". GE went on to develop this technology
with NASA and McDonnell Aircraft, leading
to its use during Project Gemini. This was
the first commercial use of a fuel cell. In
1959, a team led by Harry Ihrig built a
15 kW fuel cell tractor for Allis-Chalmers,
which was demonstrated across the U.S. at
state fairs. This system used potassium
hydroxide as the electrolyte and compressed
hydrogen and oxygen as the reactants. Later
in

1959,

Bacon

and

his

colleagues

demonstrated a practical five-kilowatt unit
capable of powering a welding machine. In
the 1960s, Pratt and Whitney licensed
Bacon's U.S. patents for use in the U.S.
space program to supply electricity and
drinking water (hydrogen and oxygen being
readily available from the spacecraft tanks).
In 1991, the first hydrogen fuel cell
automobile

In 1939, British engineer Francis Thomas

sulphonated

the necessary hydrogen oxidation and

was

developed

by

Roger

Billings.
UTC Power was the first company to
manufacture and commercialize a large,
stationary fuel cell system for use as a cogeneration power

plant

in

hospitals,

universities and large office buildings.
WORKING PRINCIPLE:

Fuel cells generate electricity and heat via
electro chemical reaction which is actually
the reversed electrolysis reaction. It happens
between the oxygen and hydrogen to form
the water. There are a range of designs
available for fuel cells; however, they all
operate with the same basic principles. The
main difference in various fuel cell designs
is the chemical characteristics of the

Nevertheless, fuel cells of ten produce only

electrolyte. The electrochemical reaction

very small amount of current due to

depicts the operating principle of a fuel cell.

diminutive contact area between electrodes,
electrolyte and the gas. Another problem to

2H2 (g) +O2 (g) → 2H2O + energy

be considered is the distance between

Hydrogen + oxygen → water + (electrical
power + heat)

cathode, electrolyte and the external circuit.
At the anode, hydrogen is oxidized in to
protons and electrons, while at the cathode
oxygen is reduced to oxide species and
reacts to form water. Depending on the
electrolyte, either protons or oxide ions are
electron

through
insulating

an

ion

conductor

electrolyte

while

electrons travel through an external circuit to
deliver electric power.

cells and maximize the contact area, a thin
layer

A fuel cell has four main parts: anode,

transported

electrodes. To improve the efficiency of fuel
of

electrolyte

with

flat

porous

electrodes is considered for electrolyte and
the gas penetration. The reaction between
oxygen and hydrogen to generate electricity
is different for various types of fuel cells. In
an acid electrolyte fuel cell, electrons and
protons (H+) are released from hydrogen
gas ionizing at the anode electrode. The
generated electrons pass though an electrical
circuit and travel to the cathode while
protons are delivered via electrolyte. This
exchange

releases

electrical

energy.

Simultaneously at the cathode side, the
water is forming as a result of the reaction
between electrons

from electrode and

protons from electrolyte. The reactions
happening at the anode and cathode are
Anode: 2H2→4H++4e−

Cathode: O2+4e−+4H+→2H2O

Activation
drop due

Loss,
to

Ohmic

resistance

loss
of

(voltage
the

cell

Acid electrolytes and certain polymers that

components and interconnections), Mass

contain free H+ ions are often called “proton

transport loss (depletion of reactants at

exchange membranes”. They serve more

catalyst sites under high loads, causing rapid

properly

proton

loss of voltage). To deliver the desired

delivering functions since they solely allow

amount of energy, the fuel cells can be

the H+ ions passing through it. The

combined in series to yield higher voltage,

electrical current is lost in the case of

and in parallel to allow a higher current to

delivering electrons through the electrolyte.

be supplied. Such a design is called a fuel

and

effectively

for

cell stack. The cell surface area can also be
increased, to allow higher current from each
cell. Within the stack, reactant gases must be
distributed uniformly over each of the cells
DESIGN FEATURES

to maximize the power output

The most important design features in a fuel

TYPES OF FUEL CELLS

cell are:
Fuel cells are different according to
The electrolyte substance. The electrolyte

their

substance usually defines the type of fuel

applications and costs. They are classified

cell.The fuel that is used. The most common

based on the choice of fuel and electrolyte in

fuel is hydrogen.The anode catalyst breaks

to 6 major groups

down the fuel into electrons and ions. The
anode catalyst is usually made up of very
fine platinum powder.The cathode catalyst
turns the ions into the waste chemicals like
water or carbon dioxide. The cathode

operating

temperature,

efficiency,

 Alkalinefuelcell(AFC)
 Phosphoricacidfuelcell(PAFC)
 Solidoxidefuelcell(SOFC)

catalyst is often made up of nickel but it can
also be a nano material-based catalyst.A
typical fuel cell produces a voltage from 0.6
V to 0.7 V at full rated load.

 Moltencarbonatefuelcell(MCFC)
 Protonexchangemembranefuelcell(PEM
FC)

Voltage decreases as current increases, due
to several factors:

 Direct methanol fuel cell(DMFC)

AFCs generally perform in temperatures
between 60 and 90. However, recent designs
ALKALINE FUEL CELL (AFC)

can operate at low temperatures between 23

The AFC generate electric power by
utilizing

alkaline

electrolyte

potassium

hydroxide (KOH) in water based solution.

and 70. AFCs are classified as low operating
temperature fuel cells with low cost
catalysts. The most common catalyst to
speed up electro chemical reactions in
cathode and anodes in this type of fuel cell
is nickel. Electrical efficiency of AFCs is
about 60% and CHP efficiency is more than
80%. They can generate electricity up to
20k. NASA has first used AFCs to supply
drinking water and electric power to the

The presence of the hydroxyl ions travelling
across the electrolyte allows a circuit to be
made and electrical energy could be
extracted. At anode, 2 hydrogen gas
molecules are combined with 4 hydroxyl
ions with a negative charge to release 4
water molecules and 4 electrons. The redox
reaction taking place is oxidation.

shuttle missions for space applications.
Currently, they are employed in submarines,
boats,

fork

lift

trucks

and

nichetran

sportation applications. AFCs are considered
as the most cost efficient type of fuel cells
since the electrolyte used is a standard
chemical potassium hydroxide (KOH). The
catalyst for the electrodes is nickel which is
not expensive compared with other types of
catalysts. AFCs have simple structures due

Oxidation: 2H2 + 4OH− → 4H2O + 4e−

to eliminating bi polar plates. They consume
Electrons released in this reaction, reach the

hydrogen and pure oxygen to produce

cathode through the external circuit and

portable water, heat and electricity sources.

react with water to generate (OH−) ions.

The by-product water produced by AFC is
the drinking water which is very useful in

At cathode, oxygen molecule and 2 water

space crafts and space shuttle fleets. They

molecules

4

have no green house gas emissions and

electrons to form 4 negatively charged

operate with a high efficiency of about 70%.

hydroxyl ions. The occurring redox reaction

In spite of all the advantages of AFCs, they

is reduction.

are defeated by getting easily poisoned with

combined

and

absorbed

Reduction: O2 + 2H2O + 4e− → 4OH−

carbon dioxide. The water based alkaline

solution (KOH) used in AFCs as electrolyte,

operation and system start up is a concern at

absorbs CO2 through the conversion of KOH

40◦C due to Phosphoric acid fuel cell

to

and

(PAFC). Solidity of phosphoric acid at this

cell.

temperature.

potassium

consequently

carbonate
poisons

(K2CO3)

the

fuel

Therefore, AFCs typically use purified air or
pure oxygen which in turn increases the
operating costs. Hence, one concern is to
find a substitute for KOH.
PHOSPHORIC

ACID

FUEL

CELL

(PAFC)
Phosphoric acid fuel cells (PAFC) use
carbon

paper

electrodes

and

liquid

phosphoric acid (H3PO4) electrolyte.

The hydrogen expelled at the anode splits in
to its 4 protons and 4 electrons. The redox
reaction taking place in anode is oxidation.
While at cathode, the redox reaction is

H3PO4 (3.09%H, 31.6%P, 65.3%O) is a clear

reduction where 4 protons and 4 electrons

colorless

combine with the oxygen to form water.

liquid

detergents,

food

used

in

fertilizers,

flavouring

and

pharmaceuticals. The ionic conductivity of
phosphoric acid is low at low temperatures,

Oxidation: 2H2 → 4H+ + 4e−
Reduction: O2 + 4H+ + 4e− → 2H2O

so PAFC can operate at the range of 150–
220◦C temperature. The charge carrier in

The electrons and protons pass through the

this type of fuel cell is the hydrogen ion (H+

external

circuit

and

the

electrolyte,

respectively. The result is generation of
Or proton). They pass from the anode to the

electrical current and heat. The heat is

cathode through the electrolyte and the

usually exploited for water heating or steam

expelled electrons return to the cathode

generation

at

through the external circuit and generate the

however,

steam

electrical current. At the cathode side, water

produces one carbon monoxide (CO) around

is forming as the result of the reaction

the electrodes which might poison the fuel

between electrons, protons and oxygen with

cell and affect the PAFC performance. The

presence of platinum catalyst to speed up

solution to reduce the CO absorption is to

there actions. Expelled water is usually used

increase the anode temperature tolerance.

in

The higher tolerance for CO means higher

heating

applications.

Continuous

atmospheric

pressure;

reforming

reactions

temperature tolerance at anode. At high

Solid oxide fuel cells (SOFCs) are high

temperatures, the CO is desorbed in reversed

temperature fuel cells with metallic oxide

electro-catalyst reaction at cathode. Contrary

solid ceramic electrolyte. SOFCs generally

to other acid electrolytes that need water for

use a mixture of hydrogen and carbon

conductivity, PAFC concentrated phosphoric

monoxide formed by internally reforming

acid electrolyte is capable of operating in

hydro carbon fuel and air as the oxidant in

temperatures higher than boiling point

the fuel cell. Yttria stabilized zirconia

of water. PAFC does not require pure
oxygen for its operation since CO2 does not

(YSZ)

is

the

most

commonly

used

affect the electrolyte or cell performance.

electrolyte for SOFCs because of its high

They run on air and can be easily operated

chemical and thermal stability and pure

with reformed fossil fuels. Besides, H3PO4

ionic conductivity.

has lower volatility and long term stability.
The initial cost is high since PAFC uses air
with 21% oxygen instead of pure oxygen
resulting in 3 times reduction in the current
density. Therefore, PAFC is designed in
stack bipolar plate to increase electrode area
for more energy production which implies
high

initial

cost

for

this

technology.

Currently, PAFC systems are in commercial
stage with capacity up to 200kW and
systems with higher capacities (11MW) are
already tested. The PAFCs are expensive to
manufacture due to the need for finely
dispersed platinum catalyst coating the
electrodes. Unlike AFCs, hydrogen steam
impurity (CO2) does not affect the PAFCs.

Oxygen is oxidized in reduction reaction at
the cathode (air electrode) at1000◦C, while,
fuel oxidation happens at the anode. The
anode should be porous to conduct fuel and
transport the products of fuel oxidation away
from the electrolyte and fuel electrode
interfaces.
Oxidation: (1/2) O2 (g) + 2e− → O2− (s)

Electrical efficiency of this type of fuel cells

Reduction: O2− (S) + H2 (g) → H2O (g) +

is between 40 and 50% and CHP efficiency

2e−

about 85%. They are typically used for
onsite stationary applications.

SOFCs are well adopted with large scale
distributed power generation systems with

SOLID OXIDE FUEL CELL (SOFC)

capacity of hundreds of MWs.

The byproduct heat is usually used to
generate more electricity by turning gas
turbines and hence increasing the CHP
efficiency between 70 and 80%. SOFC
systems are reliable, modular and fuel
adaptable with low harmful gas (NO x and
SO x) emissions. They can be considered as
local power generation systems for rural

In MCFC, the reaction at the hydrogen

areas with no access to public grids.

electrode occurs between hydrogen fuel and

Furthermore, they have noise free operation

carbonate ion, which react to form carbon

and low maintenance costs. On the other

dioxide, water and electrons. At the anode,

hand, long start-up and cooling-down times

the feed gas usually

as well as various mechanical and chemical
compatibility issues limit the use of SOFCs.

Methane CH4 and water H2O are converted

Possible solutions to reduce the operating

to hydrogen (H2), carbon monoxide (CO)

temperature and claimed if successful and

and carbon dioxide (CO2).

sustainable counter measures are builtup,
SOFC may bring energy production to a

Reform1: CH4 + H2O → CO + 3H2

new generation.

Reform2: CO + H2O → CO2 + H2

MOLTEN CARBONATE FUEL CELL

Simultaneously,

(MCFC)

reactions consume hydrogen and carbon

Molten carbonate fuel cells (MCFCs) are
high temperature fuel cells. They use molten
carbonate

salt

mixture

as

electrolyte

two

electro

chemical

monoxide and generate electrons at anode.
Both reactions use carbonate ions (CO 32−)
available in the electrolyte.

suspended in a porous, chemically inert

Oxidation1: H2 + CO32− → H2O + CO2 +

ceramic matrix of beta alumina solid

2e−

electrolyte (BASE).
Oxidation2: CO + CO32− → 2CO2 + 2e−
The reduction happens at cathode and expels
new carbonate ions from oxygen (O2) and
carbon

dioxide

(CO2).

Here

by, the

carbonate ions produced at cathode are

transferred through the electrolyte to the

Cathode: (1/2) O2 (g) + 2H+ + 2e− → H2O

anode. Electric current and cell voltage can
Over all reaction: H2 (g) + (1/2) O2 (g) →

be collected at electrodes.

H2O
Reduction: (1/2) O2 + CO2 + 2e− → CO32−
Basically the PEMFC is comprised of
MCFCs are currently employed for natural

bipolar plates and membrane electrode

gas and coal based power plants in electrical

assembly (MEA). The MEA is composed of

utility, industrial and military applications.

dispersed catalyst layer, carbon cloth or gas

The

diffusion

advantages

and

disadvantages

of

layer

and

the

membrane.

MCFCs are closely related to its high

Membrane is to transport protons from

operating temperature. MCFC may be

anode to cathode and block the passage of

directly fuelled with hydrogen, carbon

electron and reactants. Gas diffusion layer is

monoxide, natural gas and propane. They do

to access the fuel uniformly. Electrons at

not require noble metal catalysts for electro

anode pass through the external circuit and

chemical oxidation and reduction. They also

generate electricity.

do

not

require

any

infrastructure

development for installation; however, long
time is needed to reach to the operating
temperature and generating power.
PROTON EXCHANGE MEMBRANE
FUEL CELL (PEMFC)
In PEMFCs, the hydrogen is activated by
catalyst to form proton ion and eject electron
at the anode. The proton passes through the
membrane while electrons are forced to flow
to

the

external

circuit

and

generate

electricity. The electron then flows back to
the cathode and interact with oxygen and
proton ion to form water. The chemical
reactions occurring at each electrode
Anode: H2 (g) → 2H+ + 2e−

PEMFCs are low temperature fuel cells with
operating temperature between 60 and
100◦C. They are light weight compact
systems with rapid start-up process. The
sealing of electrodes in PEMFCs is easier
than other types of fuel cells because of
solidity of the electrolyte. In addition, they
have longer life time and cheaper to
manufacture. The total cost of car with the
FEMFC system is 500–600$/kW which is
10 folded compare with cars using Internal
Combustion Engine (IEC). Total cost of the

PEMFCs includes the costs of assembly

DIRECT METHANOL FUEL CELL

process, bipolar plate, platinum electrode,

(DMFC)

membrane and peripherals. From efficiency
point of view, the higher the working

Direct methanol fuel cell (DMFC) is

temperature the higher efficiency can be

promoted type of the PEMFCs. It is a

gained. This is due to the higher reaction

suitable source of power for portable energy

rate. Nevertheless, working temperature

purposes due to low temperature operation,

above 100◦C will vaporize the water causing

long life time and rapid refueling system

dehydration to the membrane which leads to

characteristics. In addition, they do not need

the reduction in the proton conductivity of

to be recharged and are addressed as clean

the membrane. Electrical efficiency of

renewable energy source. Energy source of

PEMFCs is between 40 and 50% and the

the DMFC systems is methanol. At anode,

output power can be as high as 250kW.

methanol is reformed in to carbon dioxide

PEMFC systems are usually used in portable

(CO2) while at cathode steam or water is

and

However,

formed using oxygen available in the air.

PEMFCs,

The reactions are

stationary

among

applications.

applications

of

transportation seems to be the most suitable
since they provide continuous electrical
energy supply at high level of efficiency and

Anode: CH3OH+H2O→CO2+6H++6e−
Cathode: (3/2) O2+6e−+6H+→3H2O

power density. They also require minimum
maintenance because there are no moving

DMFC systems are generally classified in to

parts in the power generating stacks of the

active and passive. Active DMFCs are high

fuel cells. Fuel cell vehicles are the most

efficient and reliable systems consisting

promising application of PEMFC systems.

of methanol feed pump, CO2 separator, fuel

The

of

cell stack, methanol sensor, circulation

technology development by people which

pump, pump drivers and controllers. Using

can significantly improve the acceptability

pump for water circulation can significantly

of such systems among communities. A

increase the efficiency of such systems.

reason

is

the

observability

report from McNicoletal states that a FCV
can

successfully

contend

against

conventional ICE vehicles. However, the
initial cost for FCV is higher than that for
ICE vehicles.

Active DMFCs are usually used in control

In addition, it provides high thermal and

applications for quantities such as flow rate,

chemical stability for proper performing of

concentration

the

DMFC. Flemion from Asahi Chemical and

passive DMFC systems, the methanol

Nafion from Dupont are the most common

pumping devices and external process for

per fluorinated ion-exchange polymers used

blowing air in to the cell are eliminated.

for DMFC. They have both mechanical

Hence, oxygen of ambient air is defused in

strength and high hydro phobicity of the

to the cathode via air breathing feature of the

sulphuric acids which is more prominent due

cell. Similarly, methanol is defused in to the

to the presence of the water. As a

anode from an integrated feed reservoir

consequence, water and methanol travel

driven by a concentration gradient between

across per fluorosulfonic acid membrane

the anode and the reservoir. Passive systems

which is a form of methanol cross over that

are cheap, simple and capable of substantial

has negative impact on its performance. The

reduction in parasitic power loss and system

PEM can be modified to overcome this

volume. Methanol is utilized in DMFCs

problem

inform of vapor or liquid. Vapor feed is

preparing composite membrane by the

preferable to liquid feed in term of cell

incorporation

voltage and power density. Methanol does

materials.

and

temperature.

In

in

2

ways:

sulfonation

of

in

organic

of

different

and

ceramic

not perform perfectly for mass transfer and
requires high localized cooling at anode.

Comparison

Furthermore, the extent of methanol cross

technologies

over from anode to cathode and gas release
at the electro catalyst surface leads to the
lower performance of liquid feed cells. On
the other hand, vapor feed cells have some
draw backs as well, such as dehydrating the
membrane,

less

life

time

and

high

temperature required for fuel vaporization.
Consequently, more complex and costly
reformer is needed. In addition, they are not
suitable for portable applications. Proton
Exchange Membrane (PEM) is considered
as the main part in DMFCs to provide low
penetrability and high proton conductivity.

fuel

cell

Applications of fuel cells depend on the type
of fuel cell to be used. With various types of
fuel cell technologies available, it is
necessary to clarify which technology is best
suited to a specific application. Fuel cells
can produce a wide range of power from 1
to 10 MW; hence they can be employed in
almost any application that needs power.
They can be used in small range power
devices and personal electronic equipment
such as mobile phones and personal
computers (PCs). Medium scale power
applications include fuel cell vehicles,

domestic appliances, military applications
and public transportation. Finally, in the
large range power applications (1–10MW),
Fuel cells are used in distributed power
systems and grid quality AC.

Operational Specifications of fuel cell technologies.

Comparisons of technical characteristics of fuel cell technologies.

APPLICATIONS
Fuel cells can be deployed in any
setting where a reliable source of base load,
on-site power is desired and, ideally, where
by-product heat can be effectively utilized.
They are also well-suited as alternatives to
batteries or diesel generators for strictly
back-up power applications, particularly in
remote areas (such as cellular phone

towers), and at critical facilities in urban

Because fuel cells can operate as a

areas with air quality issues. Current Fuel

continuous, baseload source of power

Cell Market There are currently several

(unlike

hundred large fuel cell installations in the

intermittent), these capital costs can be

United States. In 2010, the U.S. market grew

spread out over far more kilowatt-hours

by more than 50%. Globally, 30 to 50

(kWh)

megawatts (MW) of fuel cell capacity are

byproduct heat is captured and re-used. UTC

being installed annually with a projected 213

Power projects that its PureCell® 400 kW

MW of new installed capacity in 2013.

unit will be able to produce power at

Projects are getting larger, with the average

16¢/kWh (with 50% heat utilization), and at

stationary fuel cell installation growing to

14¢/kWh (with 100% heat utilization),

about 1 MW, up from 250 kW in 2005.

before any federal or state subsidies. The

Costs

cell

capital costs of fuel cells can also be

installations have dropped from about

transferred through third-party ownership, in

$600,000 per kW in the 1970s (when fuel

which

cells were developed for NASA) to about

intermediary owns the system, realizes the

$4,500 per kW today for the most widely

tax benefits and sells energy to the host

deployed technologies. This is higher than

facility under a fixed price contract.

Costs

for

stationary

fuel

solar

or

produced,

a

wind

which

especially when

manufacturer

or

are

the

financial

the capital costs for fossil-fuel based
distributed

generation

such

as

diesel

generators and gas turbines. But it is lower
than the capital costs of other distributed
clean energy technologies such as solar
photovoltaics. The U.S. Department of
Energy’s goal is to reduce this cost to about
$400 per installed kW by 2020 for solid
oxide fuel cell technology. It has formed the
Solid State Energy Conversion Alliance
(SECA), a government-industry partnership

BENEFITS OF FUEL CELLS
Stationary

fuel

cells

have

considerable benefits both to the facility
where they are installed and to the public at
large. These benefits will multiply as the
costs of fuel cells continue to decline
relative to grid power and the number of
installations increases.
USER BENEFITS

to achieve that goal. Like renewable energy
technologies, fuel cells are eligible for the

Reliability

30% federal Investment Tax Credit and for
direct financial subsidies, in some states,

Fuel cells are well suited for primary power

lowering their capital costs considerably.

applications, providing both an extremely

any local concerns over on-site hydrogen
storage.
Remote operation
reliable and

Fuel cells can be operated and

high-quality source of on-site power. This

monitored remotely. This is important for

reliability makes them ideal for public safety

fuel cells installed as backup power in

facilities

such

remote

centers,

police

as
and

emergency
fire

dispatch

stations

and

locations

such

as

telecommunications towers.

hospitals. For private facilities such as
computer server farms, data centers and
laboratories where even momentary losses
of power or voltage changes can disrupt
computers and sensitive equipment, fuel
cells deliver the sustained power quality
needed, with grid power acting as a backup.
Even noncritical facilities such as office
buildings, retail stores and hotels can benefit

Base load Clean Energy
Many businesses and public facilities
are installing solar photo voltaics as a way
of providing on-site clean energy. Fuel cells’
high efficiency and ability to produce
constant

power

makes

them

a

good

complement to solar.

from a grid-independent source of power
that can also displace other fuels for heating,
cooling and refrigeration.

Energy Cost Hedge

Siting

The installation of fuel cells can
While fuel cells have some local

siting challenges, in general they are easy to
site relative to other distributed generation
technologies because they can operate
emission-free, are quiet and compact. In
some states such as California, they are
completely

exempt

from

permitting

insulate businesses from unpredictable and
rising electricity costs. While fuel cells still
require hydrogen or natural gas as an input,
these costs might rise less quickly than
electricity, particularly in the event of state,
regional, or federal carbon legislation.
PUBLIC BENEFITS

requirements. Fuel cell technologies that
directly utilize natural gas (or biogas) avoid

Environmental

Stationary

fuel

cells

result

in

also defer the need to build both additional

dramatically reduced onsite air pollution

generation and distribution system upgrades.

relative to back-up diesel generators. They
can also result in reduced emissions relative

Public Safety and Security

to grid power depending on the source of
generation that is displaced. This is due to
the use of natural gas or biogas as the source
of hydrogen, the high conversion efficiency
of fuel cells, and the absence of particulate
emissions.

Fuel

cells

are

driven

by

electrochemistry, not combustion. As a
result, fuel cells emit only trace amounts of
NOx. Because fuel cells are intolerant of
sulfur,

the

fuels

used

have

to

When power blackouts occur, the
need to maintain critical public facilities and
services ranging from police and fire
dispatch to hospitals to water pumping and
wastewater treatment is essential. Fuel cells
provide a reliable way to ensure that these
facilities stay up and running.
CONCLUSIONS

be

desulfurized, and thus fuel cells emit no

Fuel

cells

are

coming

into

SOx. If the direct fuel input is hydrogen,

widespread commercial use for stationary

then only water vapor is generated in the

applications, and their combination of

exhaust. Because of the high electrical

reliability, efficiency, and low environmental

efficiency of fuel cells, the amount of CO2

impact

emitted per kWh of electricity generated is

distributed generation technology for a

lower than from conventional fossil fuel

range of applications. As the technology

generation. Avoided emissions are further

improves and costs decline, more businesses

increased when the facility is configured to

and public institutions should turn to fuel

utilize the waste heat from the fuel cell.

cells as a source of both primary and backup

make

them

an

outstanding

power. However, as with other clean energy
Avoided Generation and Transmission

technologies, states play an important role in

Costs

accelerating their adoption through both
Like other distributed generation

technologies, fuel cells displace utility
purchases of wholesale electricity on the
margin and during peak demand periods.
The cumulative effect of fuel cells with
other distributed generation resources can

public policy and financial support. Policies
such as including fuel cells as eligible
resources

in

state

renewable

portfolio

standards, encouraging or requiring the use
of fuel cells in critical public facilities, and
adopting uniform siting guidelines are
important steps. In addition, providing

financial incentives through state clean
energy funds can help businesses overcome
the first cost hurdles of installing fuel cells.
These policy recommendations are reviewed
in greater depth in an accompanying briefing
paper, “Advancing Stationary Fuel Cells
through State Policies.”















REFERENCES
Fundamentals of Renewable Energy
Processes, First Edition By Aldo V. da Rosa
Fundamentals of Renewable Energy
Processes, Second Edition By Aldo V. da
Rosa
Fundamentals of Renewable Energy
Processes, Third Edition By Aldo V. da Rosa
http://en.wikipedia.org/wiki/Fuel_cell
http://www.yourarticlelibrary.com/fuel/fuelcell-advantages-and-disadvantage-of-fuelcell/12358/
http://www.fuelcelltoday.com/technologies/s
ofc
https://www.clarkson.edu/highschool/k12/pr
oject/documents/energysystems/LP_3fuelcel
l.pdf
http://www.academia.edu/2169263/Compara
tive_study_of_different_fuel_cell_technolog
ies
http://www.cesa.org/assets/2011Files/Hydrogen-and-Fuel-Cells/CESA-FuelCells-Brifing-Papers-for-StatePolicymakers-Aug2011.pdf





http://en.wikipedia.org/wiki/Fuel_cell
http://www.fuelcelltoday.com/media/163713
8/fc_basics_technology_types.pdf
http://www.rsc.org/chemistryworld/2014/03/
microfluidic-fuel-cells-paper

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