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A fuel cell is an
electrochemical cell An electrochemical cell is a device capable of either generating electrical energy from chemical reactions or using electrical energy to cause chemical reactions. The electrochemical cells which generate an electric current are called voltaic o ...
that converts the
chemical energy Chemical energy is the energy of chemical substances that is released when they undergo a chemical reaction and transform into other substances. Some examples of storage media of chemical energy include batteries, Schmidt-Rohr, K. (2018). "How ...
of a fuel (often
hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-to ...
) and an
oxidizing agent An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or " accepts"/"receives" an electron from a (called the , , or ). In other words, an oxi ...
(often oxygen) into electricity through a pair of
redox Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or ...
reactions. Fuel cells are different from most
batteries Battery most often refers to: * Electric battery, a device that provides electrical power * Battery (crime), a crime involving unlawful physical contact Battery may also refer to: Energy source *Automotive battery, a device to provide power t ...
in requiring a continuous source of fuel and oxygen (usually from air) to sustain the chemical reaction, whereas in a battery the chemical energy usually comes from substances that are already present in the battery. Fuel cells can produce electricity continuously for as long as fuel and oxygen are supplied. The first fuel cells were invented by Sir William Grove in 1838. The first commercial use of fuel cells came more than a century later following the invention of the hydrogen–oxygen fuel cell by
Francis Thomas Bacon Francis Thomas Bacon OBE FREng FRS (21 December 1904 – 24 May 1992) was an English engineer who in 1932 developed the first practical hydrogen–oxygen fuel cell. It is used to generate power for space capsules and satellites. Life and w ...
in 1932. The
alkaline fuel cell The alkaline fuel cell (AFC), also known as the Bacon fuel cell after its British inventor, Francis Thomas Bacon, is one of the most developed fuel cell technologies. Alkaline fuel cells consume hydrogen and pure oxygen, to produce potable wa ...
, also known as the Bacon fuel cell after its inventor, has been used in
NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeedin ...
space programs since the mid-1960s to generate power for
satellites A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotop ...
and
space capsule A space capsule is an often-crewed spacecraft that uses a blunt-body reentry capsule to reenter the Earth's atmosphere without wings. Capsules are distinguished from other satellites primarily by the ability to survive reentry and return a payl ...
s. Since then, fuel cells have been used in many other applications. Fuel cells are used for primary and backup power for commercial, industrial and residential buildings and in remote or inaccessible areas. They are also used to power
fuel cell vehicle A fuel cell vehicle (FCV) or fuel cell electric vehicle (FCEV) is an electric vehicle that uses a fuel cell, sometimes in combination with a small battery or supercapacitor, to power its onboard electric motor. Fuel cells in vehicles generate e ...
s, including forklifts, automobiles, buses, trains, boats, motorcycles and submarines. There are many types of fuel cells, but they all consist of an
anode An anode is an electrode of a polarized electrical device through which conventional current enters the device. This contrasts with a cathode, an electrode of the device through which conventional current leaves the device. A common mnemonic is ...
, a
cathode A cathode is the electrode from which a conventional current leaves a polarized electrical device. This definition can be recalled by using the mnemonic ''CCD'' for ''Cathode Current Departs''. A conventional current describes the direction in whi ...
, and an
electrolyte An electrolyte is a medium containing ions that is electrically conducting through the movement of those ions, but not conducting electrons. This includes most soluble salts, acids, and bases dissolved in a polar solvent, such as water. Upon ...
that allows ions, often positively charged hydrogen ions (protons), to move between the two sides of the fuel cell. At the anode a catalyst causes the fuel to undergo oxidation reactions that generate ions (often positively charged hydrogen ions) and electrons. The ions move from the anode to the cathode through the electrolyte. At the same time, electrons flow from the anode to the cathode through an external circuit, producing
direct current Direct current (DC) is one-directional flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor such as a wire, but can also flow through semiconductors, insulators, or ev ...
electricity. At the cathode, another catalyst causes ions, electrons, and oxygen to react, forming water and possibly other products. Fuel cells are classified by the type of electrolyte they use and by the difference in startup time ranging from 1 second for
proton-exchange membrane fuel cell Proton-exchange membrane fuel cells (PEMFC), also known as polymer electrolyte membrane (PEM) fuel cells, are a type of fuel cell being developed mainly for transport applications, as well as for stationary fuel-cell applications and portable ...
s (PEM fuel cells, or PEMFC) to 10 minutes for
solid oxide fuel cell A solid oxide fuel cell (or SOFC) is an electrochemical conversion device that produces electricity directly from oxidizing a fuel. Fuel cells are characterized by their electrolyte material; the SOFC has a solid oxide or ceramic electrolyte. ...
s (SOFC). A related technology is flow batteries, in which the fuel can be regenerated by recharging. Individual fuel cells produce relatively small electrical potentials, about 0.7 volts, so cells are "stacked", or placed in series, to create sufficient voltage to meet an application's requirements. In addition to electricity, fuel cells produce water vapor, heat and, depending on the fuel source, very small amounts of
nitrogen dioxide Nitrogen dioxide is a chemical compound with the formula . It is one of several nitrogen oxides. is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year for use primarily in the productio ...
and other emissions. The energy efficiency of a fuel cell is generally between 40 and 60%; however, if waste heat is captured in a
cogeneration Cogeneration or combined heat and power (CHP) is the use of a heat engine or power station to generate electricity and useful heat at the same time. Cogeneration is a more efficient use of fuel or heat, because otherwise- wasted heat from elec ...
scheme, efficiencies of up to 85% can be obtained.


History

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 Sir 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 Christian Friedrich Schönbein HFRSE(18 October 1799 – 29 August 1868) was a German-Swiss chemist who is best known for inventing the fuel cell (1838) at the same time as William Robert Grove and his discoveries of guncotton and ozone. Life ...
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 Phosphoric acid fuel cells (PAFC) are a type of fuel cell that uses liquid phosphoric acid as an electrolyte. They were the first fuel cells to be commercialized. Developed in the mid-1960s and field-tested since the 1970s, they have improved sig ...
. In 1932, English engineer
Francis Thomas Bacon Francis Thomas Bacon OBE FREng FRS (21 December 1904 – 24 May 1992) was an English engineer who in 1932 developed the first practical hydrogen–oxygen fuel cell. It is used to generate power for space capsules and satellites. Life and w ...
successfully developed a 5 kW stationary fuel cell. The
alkaline fuel cell The alkaline fuel cell (AFC), also known as the Bacon fuel cell after its British inventor, Francis Thomas Bacon, is one of the most developed fuel cell technologies. Alkaline fuel cells consume hydrogen and pure oxygen, to produce potable wa ...
(AFC), also known as the Bacon fuel cell after its inventor, is one of the most developed fuel cell technologies, which
NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeedin ...
has used since the mid-1960s. In 1955, W. Thomas Grubb, a chemist working for the
General Electric General Electric Company (GE) is an American multinational conglomerate founded in 1892, and incorporated in New York state and headquartered in Boston. The company operated in sectors including healthcare, aviation, power, renewable ene ...
Company (GE), further modified the original fuel cell design by using a sulphonated polystyrene ion-exchange membrane as the electrolyte. Three years later another GE chemist, Leonard Niedrach, devised a way of depositing platinum onto the membrane, which served as catalyst for the necessary hydrogen oxidation and oxygen reduction reactions. This became known as the "Grubb-Niedrach fuel cell". GE went on to develop this technology with NASA and McDonnell Aircraft, leading to its use during
Project Gemini Project Gemini () was NASA's second human spaceflight program. Conducted between projects Mercury and Apollo, Gemini started in 1961 and concluded in 1966. The Gemini spacecraft carried a two-astronaut crew. Ten Gemini crews and 16 individual ...
. 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 Allis-Chalmers was a U.S. manufacturer of machinery for various industries. Its business lines included agricultural equipment, construction equipment, power generation and power transmission equipment, and machinery for use in industrial s ...
, 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 & Whitney Pratt & Whitney is an American aerospace manufacturer with global service operations. It is a subsidiary of Raytheon Technologies. Pratt & Whitney's aircraft engines are widely used in both civil aviation (especially airlines) and military av ...
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 was developed by Roger E. Billings.
UTC Power UTC Power was a fuel cell company based in South Windsor, Connecticut. It was part of United Technologies Corporation; it was purchased by ClearEdge Power in February 2013. The company specialized in fuel cells for buildings, buses and automobi ...
was the first company to manufacture and commercialize a large, stationary fuel cell system for use as a
cogeneration Cogeneration or combined heat and power (CHP) is the use of a heat engine or power station to generate electricity and useful heat at the same time. Cogeneration is a more efficient use of fuel or heat, because otherwise- wasted heat from elec ...
power plant in hospitals, universities and large office buildings. In recognition of the fuel cell industry and America's role in fuel cell development, the United States Senate recognized 8 October 2015 as National Hydrogen and Fuel Cell Day, passing S. RES 217. The date was chosen in recognition of the atomic weight of hydrogen (1.008).


Types of fuel cells; design

Fuel cells come in many varieties; however, they all work in the same general manner. They are made up of three adjacent segments: the
anode An anode is an electrode of a polarized electrical device through which conventional current enters the device. This contrasts with a cathode, an electrode of the device through which conventional current leaves the device. A common mnemonic is ...
, the
electrolyte An electrolyte is a medium containing ions that is electrically conducting through the movement of those ions, but not conducting electrons. This includes most soluble salts, acids, and bases dissolved in a polar solvent, such as water. Upon ...
, and the
cathode A cathode is the electrode from which a conventional current leaves a polarized electrical device. This definition can be recalled by using the mnemonic ''CCD'' for ''Cathode Current Departs''. A conventional current describes the direction in whi ...
. Two chemical reactions occur at the interfaces of the three different segments. The net result of the two reactions is that fuel is consumed, water or carbon dioxide is created, and an electric current is created, which can be used to power electrical devices, normally referred to as the load. At the anode a
catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
oxidizes the fuel, usually hydrogen, turning the fuel into a positively charged ion and a negatively charged electron. The electrolyte is a substance specifically designed so ions can pass through it, but the electrons cannot. The freed electrons travel through a wire creating the electric current. The ions travel through the electrolyte to the cathode. Once reaching the cathode, the ions are reunited with the electrons and the two react with a third chemical, usually oxygen, to create water or carbon dioxide. Design features in a fuel cell include: * The electrolyte substance, which usually defines the ''type'' of fuel cell, and can be made from a number of substances like potassium hydroxide, salt carbonates, and phosphoric acid. * The fuel that is used. The most common fuel is hydrogen. * The anode catalyst, usually fine platinum powder, breaks down the fuel into electrons and ions. * The cathode catalyst, often nickel, converts ions into waste chemicals, with water being the most common type of waste. * Gas diffusion layers that are designed to resist oxidization. A typical fuel cell produces a voltage from 0.6 to 0.7 V at full rated load. Voltage decreases as current increases, due to several factors: * Activation loss * Ohmic loss (
voltage drop Voltage drop is the decrease of electrical potential along the path of a current flowing in an electrical circuit. Voltage drops in the internal resistance of the source, across conductors, across contacts, and across connectors are undesirab ...
due to resistance of the cell components and interconnections) * Mass transport loss (depletion of reactants at catalyst sites under high loads, causing rapid loss of voltage). To deliver the desired amount of energy, the fuel cells can be combined in series to yield higher
voltage Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to ...
, and in parallel to allow a higher
current Currents, Current or The Current may refer to: Science and technology * Current (fluid), the flow of a liquid or a gas ** Air current, a flow of air ** Ocean current, a current in the ocean *** Rip current, a kind of water current ** Current (stre ...
to be supplied. Such a design is called a ''fuel cell stack''. The cell surface area can also be increased, to allow higher current from each cell.


Proton-exchange membrane fuel cells

In the archetypical hydrogen–oxide
proton-exchange membrane fuel cell Proton-exchange membrane fuel cells (PEMFC), also known as polymer electrolyte membrane (PEM) fuel cells, are a type of fuel cell being developed mainly for transport applications, as well as for stationary fuel-cell applications and portable ...
(PEMFC) design, a proton-conducting polymer membrane (typically
nafion Nafion is a brand name for a sulfonated tetrafluoroethylene based fluoropolymer-copolymer discovered in the late 1960s by Dr. Walther Grot of DuPont. Nafion is a brand of the Chemours company. It is the first of a class of synthetic polymers with ...
) contains the
electrolyte An electrolyte is a medium containing ions that is electrically conducting through the movement of those ions, but not conducting electrons. This includes most soluble salts, acids, and bases dissolved in a polar solvent, such as water. Upon ...
solution that separates the
anode An anode is an electrode of a polarized electrical device through which conventional current enters the device. This contrasts with a cathode, an electrode of the device through which conventional current leaves the device. A common mnemonic is ...
and
cathode A cathode is the electrode from which a conventional current leaves a polarized electrical device. This definition can be recalled by using the mnemonic ''CCD'' for ''Cathode Current Departs''. A conventional current describes the direction in whi ...
sides. This was called a ''solid polymer electrolyte fuel cell'' (''SPEFC'') in the early 1970s, before the proton-exchange mechanism was well understood. (Notice that the synonyms ''polymer electrolyte membrane'' and ''proton-exchange mechanism'' result in the same
acronym An acronym is a word or name formed from the initial components of a longer name or phrase. Acronyms are usually formed from the initial letters of words, as in ''NATO'' (''North Atlantic Treaty Organization''), but sometimes use syllables, as ...
.) On the anode side, hydrogen diffuses to the anode catalyst where it later dissociates into protons and electrons. These protons often react with oxidants causing them to become what are commonly referred to as multi-facilitated proton membranes. The protons are conducted through the membrane to the cathode, but the electrons are forced to travel in an external circuit (supplying power) because the membrane is electrically insulating. On the cathode catalyst, oxygen
molecule A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and b ...
s react with the electrons (which have traveled through the external circuit) and protons to form water. In addition to this pure hydrogen type, there are
hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...
fuels for fuel cells, including
diesel Diesel may refer to: * Diesel engine, an internal combustion engine where ignition is caused by compression * Diesel fuel, a liquid fuel used in diesel engines * Diesel locomotive, a railway locomotive in which the prime mover is a diesel engi ...
,
methanol Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical and the simplest aliphatic alcohol, with the formula C H3 O H (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is ...
(''see:'' direct-methanol fuel cells and indirect methanol fuel cells) and chemical hydrides. The waste products with these types of fuel are
carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is t ...
and water. When hydrogen is used, the CO is released when methane from natural gas is combined with steam, in a process called
steam methane reforming Steam reforming or steam methane reforming (SMR) is a method for producing syngas ( hydrogen and carbon monoxide) by reaction of hydrocarbons with water. Commonly natural gas is the feedstock. The main purpose of this technology is hydrogen prod ...
, to produce the hydrogen. This can take place in a different location to the fuel cell, potentially allowing the hydrogen fuel cell to be used indoors—for example, in fork lifts. The different components of a PEMFC are # bipolar plates, #
electrode An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or air). Electrodes are essential parts of batteries that can consist of a variety of materials ...
s, #
catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
, # membrane, and # the necessary hardware such as current collectors and gaskets. The materials used for different parts of the fuel cells differ by type. The bipolar plates may be made of different types of materials, such as, metal, coated metal,
graphite Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on la ...
, flexible graphite, C–C
composite Composite or compositing may refer to: Materials * Composite material, a material that is made from several different substances ** Metal matrix composite, composed of metal and other parts ** Cermet, a composite of ceramic and metallic materials ...
,
carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon ma ...
polymer A polymer (; Greek '' poly-'', "many" + '' -mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic a ...
composites etc. The
membrane electrode assembly A membrane electrode assembly (MEA) is an assembled stack of proton-exchange membranes (PEM) or alkali anion exchange membrane (AAEM), catalyst and flat plate electrode used in fuel cells and electrolyzers. PEM-MEA The PEM is sandwiched between ...
(MEA) is referred to as the heart of the PEMFC and is usually made of a proton-exchange membrane sandwiched between two
catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
-coated
carbon paper Carbon paper (originally carbonic paper) consists of sheets of paper which create one or more copies simultaneously with the creation of an original document when inscribed by a typewriter or ballpoint pen. History In 1801, Pellegrino Turri, ...
s. Platinum and/or similar type of
noble metal A noble metal is ordinarily regarded as a metallic chemical element that is generally resistant to corrosion and is usually found in nature in its raw form. Gold, platinum, and the other platinum group metals ( ruthenium, rhodium, palladium, o ...
s are usually used as the catalyst for PEMFC, and these can be contaminated by
carbon monoxide Carbon monoxide ( chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simpl ...
, necessitating a relatively pure hydrogen fuel.Coletta, Vitor, ''et al.'
"Cu-Modified SrTiO 3 Perovskites Toward Enhanced Water-Gas Shift Catalysis: A Combined Experimental and Computational Study"
''ACS Applied Energy Materials'' (2021), vol. 4, issue 1, pp. 452–461
The electrolyte could be a polymer
membrane A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Membranes can be generally classified into synthetic membranes and biological membranes. ...
.


Proton-exchange membrane fuel cell design issues

; Cost: In 2013, the Department of Energy estimated that 80-kW automotive fuel cell system costs of per kilowatt could be achieved, assuming volume production of 100,000 automotive units per year and per kilowatt could be achieved, assuming volume production of 500,000 units per year. Many companies are working on techniques to reduce cost in a variety of ways including reducing the amount of platinum needed in each individual cell.
Ballard Power Systems Ballard Power Systems Inc. is a developer and manufacturer of proton exchange membrane (PEM) fuel cell products for markets such as heavy-duty motive (consisting of bus and tram applications), portable power, material handling as well as engine ...
has experimented with a catalyst enhanced with carbon silk, which allows a 30% reduction (1.0–0.7 mg/cm2) in platinum usage without reduction in performance.
Monash University Monash University () is a public research university based in Melbourne, Victoria, Australia. Named for prominent World War I general Sir John Monash, it was founded in 1958 and is the second oldest university in the state. The university has ...
,
Melbourne Melbourne ( ; Boonwurrung/ Woiwurrung: ''Narrm'' or ''Naarm'') is the capital and most populous city of the Australian state of Victoria, and the second-most populous city in both Australia and Oceania. Its name generally refers to a metro ...
uses
PEDOT Poly(3,4-ethylenedioxythiophene) (PEDOT or PEDT; ''IUPAC'' name poly(2,3-dihydrothieno ,4-''b''1,4]dioxane-5,7-diyl)) is a conducting polymer based on 3,4-ethylenedioxythiophene or EDOT. It was first reported by Bayer AG in 1989. Polymer PEDOT p ...
as a
cathode A cathode is the electrode from which a conventional current leaves a polarized electrical device. This definition can be recalled by using the mnemonic ''CCD'' for ''Cathode Current Departs''. A conventional current describes the direction in whi ...
. A 2011-published study documented the first metal-free electrocatalyst using relatively inexpensive doped
carbon nanotube A scanning tunneling microscopy image of a single-walled carbon nanotube Rotating single-walled zigzag carbon nanotube A carbon nanotube (CNT) is a tube made of carbon with diameters typically measured in nanometers. ''Single-wall carbon na ...
s, which are less than 1% the cost of platinum and are of equal or superior performance. A recently published article demonstrated how the environmental burdens change when using carbon nanotubes as carbon substrate for platinum. ; Water and air management (in PEMFCs): In this type of fuel cell, the membrane must be hydrated, requiring water to be evaporated at precisely the same rate that it is produced. If water is evaporated too quickly, the membrane dries, resistance across it increases, and eventually it will crack, creating a gas "short circuit" where hydrogen and oxygen combine directly, generating heat that will damage the fuel cell. If the water is evaporated too slowly, the electrodes will flood, preventing the reactants from reaching the catalyst and stopping the reaction. Methods to manage water in cells are being developed like electroosmotic pumps focusing on flow control. Just as in a combustion engine, a steady ratio between the reactant and oxygen is necessary to keep the fuel cell operating efficiently. ; Temperature management: The same temperature must be maintained throughout the cell in order to prevent destruction of the cell through thermal loading. This is particularly challenging as the 2H2 + O2 → 2H2O reaction is highly exothermic, so a large quantity of heat is generated within the fuel cell. ; Durability,
service life A product's service life is its period of use in service. Several related terms describe more precisely a product's life, from the point of manufacture, storage, and distribution, and eventual use. Service life has been defined as "a product's ...
, and special requirements for some type of cells:
Stationary fuel cell applications Stationary fuel-cell applications (or stationary fuel-cell power systems) are applications for fuel cells that are either connected to the electric grid (distributed generation) to provide supplemental power and as emergency power system for critic ...
typically require more than 40,000 hours of reliable operation at a temperature of −35 °C to 40 °C (−31 °F to 104 °F), while automotive fuel cells require a 5,000-hour lifespan (the equivalent of ) under extreme temperatures. Current
service life A product's service life is its period of use in service. Several related terms describe more precisely a product's life, from the point of manufacture, storage, and distribution, and eventual use. Service life has been defined as "a product's ...
is 2,500 hours (about ). Automotive engines must also be able to start reliably at −30 °C (−22 °F) and have a high power-to-volume ratio (typically 2.5 kW/L). ; Limited
carbon monoxide Carbon monoxide ( chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simpl ...
tolerance of some (non-PEDOT) cathodes.


Phosphoric acid fuel cell

Phosphoric acid fuel cells (PAFCs) were first designed and introduced in 1961 by G. V. Elmore and H. A. Tanner. In these cells, phosphoric acid is used as a non-conductive electrolyte to pass protons from the anode to the cathode and to force electrons to travel from anode to cathode through an external electrical circuit. These cells commonly work in temperatures of 150 to 200°C. This high temperature will cause heat and energy loss if the heat is not removed and used properly. This heat can be used to produce steam for air conditioning systems or any other thermal energy consuming system. Using this heat in
cogeneration Cogeneration or combined heat and power (CHP) is the use of a heat engine or power station to generate electricity and useful heat at the same time. Cogeneration is a more efficient use of fuel or heat, because otherwise- wasted heat from elec ...
can enhance the efficiency of phosphoric acid fuel cells from 40 to 50% to about 80%. Since the proton production rate on the anode is small, platinum is used as catalyst to increase this ionization rate. A key disadvantage of these cells is the use of an acidic electrolyte. This increases the corrosion or oxidation of components exposed to phosphoric acid.


Solid acid fuel cell

Solid acid fuel cells (SAFCs) are characterized by the use of a solid acid material as the electrolyte. At low temperatures,
solid acid Solid is one of the four fundamental states of matter (the others being liquid, gas, and plasma). The molecules in a solid are closely packed together and contain the least amount of kinetic energy. A solid is characterized by structural ...
s have an ordered molecular structure like most salts. At warmer temperatures (between 140 and 150°C for CsHSO4), some solid acids undergo a phase transition to become highly disordered "superprotonic" structures, which increases conductivity by several orders of magnitude. The first proof-of-concept SAFCs were developed in 2000 using cesium hydrogen sulfate (CsHSO4). Current SAFC systems use cesium dihydrogen phosphate (CsH2PO4) and have demonstrated lifetimes in the thousands of hours.


Alkaline fuel cell

The alkaline fuel cell (AFC) or hydrogen-oxygen fuel cell was designed and first demonstrated publicly by Francis Thomas Bacon in 1959. It was used as a primary source of electrical energy in the Apollo space program. The cell consists of two porous carbon electrodes impregnated with a suitable catalyst such as Pt, Ag, CoO, etc. The space between the two electrodes is filled with a concentrated solution of KOH or
NaOH Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly caustic base and alkali ...
which serves as an electrolyte. H2 gas and O2 gas are bubbled into the electrolyte through the porous carbon electrodes. Thus the overall reaction involves the combination of hydrogen gas and oxygen gas to form water. The cell runs continuously until the reactant's supply is exhausted. This type of cell operates efficiently in the temperature range 343–413K and provides a potential of about 0.9V.
Alkaline anion exchange membrane fuel cell An alkaline anion exchange membrane fuel cell (AAEMFC), also known as anion-exchange membrane fuel cells (AEMFCs), alkaline membrane fuel cells (AMFCs), hydroxide exchange membrane fuel cells (HEMFCs), or solid alkaline fuel cells (SAFCs) is a type ...
(AAEMFC) is a type of AFC which employs a solid polymer electrolyte instead of aqueous potassium hydroxide (KOH) and it is superior to aqueous AFC.


High-temperature fuel cells


Solid oxide fuel cell

Solid oxide fuel cell A solid oxide fuel cell (or SOFC) is an electrochemical conversion device that produces electricity directly from oxidizing a fuel. Fuel cells are characterized by their electrolyte material; the SOFC has a solid oxide or ceramic electrolyte. ...
s (SOFCs) use a solid material, most commonly a ceramic material called yttria-stabilized zirconia (YSZ), as the
electrolyte An electrolyte is a medium containing ions that is electrically conducting through the movement of those ions, but not conducting electrons. This includes most soluble salts, acids, and bases dissolved in a polar solvent, such as water. Upon ...
. Because SOFCs are made entirely of solid materials, they are not limited to the flat plane configuration of other types of fuel cells and are often designed as rolled tubes. They require high
operating temperature An operating temperature is the allowable temperature range of the local ambient environment at which an electrical or mechanical device operates. The device will operate effectively within a specified temperature range which varies based on the de ...
s (800–1000 °C) and can be run on a variety of fuels including natural gas."Types of Fuel Cells"
. Department of Energy EERE website, accessed 4 August 2011
SOFCs are unique because negatively charged oxygen ions travel from the
cathode A cathode is the electrode from which a conventional current leaves a polarized electrical device. This definition can be recalled by using the mnemonic ''CCD'' for ''Cathode Current Departs''. A conventional current describes the direction in whi ...
(positive side of the fuel cell) to the
anode An anode is an electrode of a polarized electrical device through which conventional current enters the device. This contrasts with a cathode, an electrode of the device through which conventional current leaves the device. A common mnemonic is ...
(negative side of the fuel cell) instead of
proton A proton is a stable subatomic particle, symbol , H+, or 1H+ with a positive electric charge of +1 ''e'' elementary charge. Its mass is slightly less than that of a neutron and 1,836 times the mass of an electron (the proton–electron mass ...
s travelling vice versa (i.e., from the anode to the cathode), as is the case in all other types of fuel cells. Oxygen gas is fed through the cathode, where it absorbs electrons to create oxygen ions. The oxygen ions then travel through the electrolyte to react with hydrogen gas at the anode. The reaction at the anode produces electricity and water as by-products. Carbon dioxide may also be a by-product depending on the fuel, but the carbon emissions from an SOFC system are less than those from a fossil fuel combustion plant. The chemical reactions for the SOFC system can be expressed as follows: :''Anode reaction'': 2H2 + 2O2− → 2H2O + 4e :''Cathode reaction'': O2 + 4e → 2O2− :''Overall cell reaction'': 2H2 + O2 → 2H2O SOFC systems can run on fuels other than pure hydrogen gas. However, since hydrogen is necessary for the reactions listed above, the fuel selected must contain hydrogen atoms. For the fuel cell to operate, the fuel must be converted into pure hydrogen gas. SOFCs are capable of internally reforming light hydrocarbons such as
methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane ...
(natural gas), propane and butane. These fuel cells are at an early stage of development. Challenges exist in SOFC systems due to their high operating temperatures. One such challenge is the potential for carbon dust to build up on the anode, which slows down the internal reforming process. Research to address this "carbon coking" issue at the University of Pennsylvania has shown that the use of copper-based cermet (heat-resistant materials made of ceramic and metal) can reduce coking and the loss of performance. Another disadvantage of SOFC systems is the long start-up, making SOFCs less useful for mobile applications. Despite these disadvantages, a high operating temperature provides an advantage by removing the need for a precious metal catalyst like platinum, thereby reducing cost. Additionally, waste heat from SOFC systems may be captured and reused, increasing the theoretical overall efficiency to as high as 80–85%. The high operating temperature is largely due to the physical properties of the YSZ electrolyte. As temperature decreases, so does the ionic conductivity of YSZ. Therefore, to obtain optimum performance of the fuel cell, a high operating temperature is required. According to their website,
Ceres Power Ceres most commonly refers to: * Ceres (dwarf planet), the largest asteroid * Ceres (mythology), the Roman goddess of agriculture Ceres may also refer to: Places Brazil * Ceres, Goiás, Brazil * Ceres Microregion, in north-central Goiás ...
, a UK SOFC fuel cell manufacturer, has developed a method of reducing the operating temperature of their SOFC system to 500–600 degrees Celsius. They replaced the commonly used YSZ electrolyte with a CGO (cerium gadolinium oxide) electrolyte. The lower operating temperature allows them to use stainless steel instead of ceramic as the cell substrate, which reduces cost and start-up time of the system.


Molten-carbonate fuel cell

Molten carbonate fuel cells (MCFCs) require a high operating temperature, , similar to SOFCs. MCFCs use lithium potassium carbonate salt as an electrolyte, and this salt liquefies at high temperatures, allowing for the movement of charge within the cell – in this case, negative carbonate ions."Molten Carbonate Fuel Cell Technology"
U.S. Department of Energy, accessed 9 August 2011
Like SOFCs, MCFCs are capable of converting fossil fuel to a hydrogen-rich gas in the anode, eliminating the need to produce hydrogen externally. The reforming process creates emissions. MCFC-compatible fuels include natural gas, biogas and gas produced from coal. The hydrogen in the gas reacts with carbonate ions from the electrolyte to produce water, carbon dioxide, electrons and small amounts of other chemicals. The electrons travel through an external circuit creating electricity and return to the cathode. There, oxygen from the air and carbon dioxide recycled from the anode react with the electrons to form carbonate ions that replenish the electrolyte, completing the circuit. The chemical reactions for an MCFC system can be expressed as follows: :''Anode reaction'': CO32− + H2 → H2O + CO2 + 2e :''Cathode reaction'': CO2 + ½O2 + 2e → CO32− :''Overall cell reaction'': H2 + ½O2 → H2O As with SOFCs, MCFC disadvantages include slow start-up times because of their high operating temperature. This makes MCFC systems not suitable for mobile applications, and this technology will most likely be used for stationary fuel cell purposes. The main challenge of MCFC technology is the cells' short life span. The high-temperature and carbonate electrolyte lead to corrosion of the anode and cathode. These factors accelerate the degradation of MCFC components, decreasing the durability and cell life. Researchers are addressing this problem by exploring corrosion-resistant materials for components as well as fuel cell designs that may increase cell life without decreasing performance. MCFCs hold several advantages over other fuel cell technologies, including their resistance to impurities. They are not prone to "carbon coking", which refers to carbon build-up on the anode that results in reduced performance by slowing down the internal fuel reforming process. Therefore, carbon-rich fuels like gases made from coal are compatible with the system. The United States Department of Energy claims that coal, itself, might even be a fuel option in the future, assuming the system can be made resistant to impurities such as sulfur and particulates that result from converting coal into hydrogen. MCFCs also have relatively high efficiencies. They can reach a fuel-to-electricity efficiency of 50%, considerably higher than the 37–42% efficiency of a phosphoric acid fuel cell plant. Efficiencies can be as high as 65% when the fuel cell is paired with a turbine, and 85% if heat is captured and used in a
combined heat and power Cogeneration or combined heat and power (CHP) is the use of a heat engine or power station to generate electricity and useful heat at the same time. Cogeneration is a more efficient use of fuel or heat, because otherwise- wasted heat from elect ...
(CHP) system. FuelCell Energy, a Connecticut-based fuel cell manufacturer, develops and sells MCFC fuel cells. The company says that their MCFC products range from 300 kW to 2.8 MW systems that achieve 47% electrical efficiency and can utilize CHP technology to obtain higher overall efficiencies. One product, the DFC-ERG, is combined with a gas turbine and, according to the company, it achieves an electrical efficiency of 65%.


Electric storage fuel cell

The electric storage fuel cell is a conventional battery chargeable by electric power input, using the conventional electro-chemical effect. However, the battery further includes hydrogen (and oxygen) inputs for alternatively charging the battery chemically.


Comparison of fuel cell types

Glossary of terms in table: ;
Anode An anode is an electrode of a polarized electrical device through which conventional current enters the device. This contrasts with a cathode, an electrode of the device through which conventional current leaves the device. A common mnemonic is ...
: The electrode at which oxidation (a loss of electrons) takes place. For fuel cells and other galvanic cells, the anode is the negative terminal; for electrolytic cells (where electrolysis occurs), the anode is the positive terminal. ;
Aqueous solution An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, or sodium chloride (NaCl), in water would be r ...
;
Catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
: A chemical substance that increases the rate of a reaction without being consumed; after the reaction, it can potentially be recovered from the reaction mixture and is chemically unchanged. The catalyst lowers the activation energy required, allowing the reaction to proceed more quickly or at a lower temperature. In a fuel cell, the catalyst facilitates the reaction of oxygen and hydrogen. It is usually made of platinum powder very thinly coated onto carbon paper or cloth. The catalyst is rough and porous so the maximum surface area of the platinum can be exposed to the hydrogen or oxygen. The platinum-coated side of the catalyst faces the membrane in the fuel cell. ;
Cathode A cathode is the electrode from which a conventional current leaves a polarized electrical device. This definition can be recalled by using the mnemonic ''CCD'' for ''Cathode Current Departs''. A conventional current describes the direction in whi ...
: The electrode at which reduction (a gain of electrons) occurs. For fuel cells and other galvanic cells, the cathode is the positive terminal; for electrolytic cells (where electrolysis occurs), the cathode is the negative terminal. ;
Electrolyte An electrolyte is a medium containing ions that is electrically conducting through the movement of those ions, but not conducting electrons. This includes most soluble salts, acids, and bases dissolved in a polar solvent, such as water. Upon ...
: A substance that conducts charged ions from one electrode to the other in a fuel cell, battery, or electrolyzer."Fuel Cell Technologies Program: Glossary"
. Department of Energy Energy Efficiency and Renewable Energy Fuel Cell Technologies Program. 7 July 2011. Accessed 3 August 2011.
; Fuel cell stack: Individual fuel cells connected in a series. Fuel cells are stacked to increase voltage. ; Matrix: something within or from which something else originates, develops, or takes form. ;
Membrane A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Membranes can be generally classified into synthetic membranes and biological membranes. ...
: The separating layer in a fuel cell that acts as electrolyte (an ion-exchanger) as well as a barrier film separating the gases in the anode and cathode compartments of the fuel cell. ; Molten carbonate fuel cell (MCFC): A type of fuel cell that contains a molten carbonate electrolyte. Carbonate ions (CO32−) are transported from the cathode to the anode. Operating temperatures are typically near 650 °C. ;
Phosphoric acid fuel cell Phosphoric acid fuel cells (PAFC) are a type of fuel cell that uses liquid phosphoric acid as an electrolyte. They were the first fuel cells to be commercialized. Developed in the mid-1960s and field-tested since the 1970s, they have improved sig ...
(PAFC): A type of fuel cell in which the electrolyte consists of concentrated phosphoric acid (H3PO4). Protons (H+) are transported from the anode to the cathode. The operating temperature range is generally 160–220 °C. ;
Proton-exchange membrane fuel cell Proton-exchange membrane fuel cells (PEMFC), also known as polymer electrolyte membrane (PEM) fuel cells, are a type of fuel cell being developed mainly for transport applications, as well as for stationary fuel-cell applications and portable ...
(PEM): A fuel cell incorporating a solid polymer membrane used as its electrolyte. Protons (H+) are transported from the anode to the cathode. The operating temperature range is generally 60–100 °C for Low Temperature Proton-exchange membrane fuel cell (LT-PEMFC). PEM fuel cell with operating temperature of 120-200 °C is called High Temperature Proton-exchange membrane fuel cell (HT-PEMFC). ;
Solid oxide fuel cell A solid oxide fuel cell (or SOFC) is an electrochemical conversion device that produces electricity directly from oxidizing a fuel. Fuel cells are characterized by their electrolyte material; the SOFC has a solid oxide or ceramic electrolyte. ...
(SOFC): A type of fuel cell in which the electrolyte is a solid, nonporous metal oxide, typically zirconium oxide (ZrO2) treated with Y2O3, and O2− is transported from the cathode to the anode. Any CO in the reformate gas is oxidized to CO2 at the anode. Temperatures of operation are typically 800–1,000 °C. ;
Solution Solution may refer to: * Solution (chemistry), a mixture where one substance is dissolved in another * Solution (equation), in mathematics ** Numerical solution, in numerical analysis, approximate solutions within specified error bounds * Solutio ...


Efficiency of leading fuel cell types


Theoretical maximum efficiency

The energy efficiency of a system or device that converts energy is measured by the ratio of the amount of useful energy put out by the system ("output energy") to the total amount of energy that is put in ("input energy") or by useful output energy as a percentage of the total input energy. In the case of fuel cells, useful output energy is measured in
electrical energy Electrical energy is energy related to forces on electrically charged particles and the movement of electrically charged particles (often electrons in wires, but not always). This energy is supplied by the combination of electric current and elect ...
produced by the system. Input energy is the energy stored in the fuel. According to the U.S. Department of Energy, fuel cells are generally between 40 and 60% energy efficient. This is higher than some other systems for energy generation. For example, the typical internal combustion engine of a car is about 25% energy efficient. Steam power plants usually achieve efficiencies of 30-40% while
combined cycle A combined cycle power plant is an assembly of heat engines that work in tandem from the same source of heat, converting it into mechanical energy. On land, when used to make electricity the most common type is called a combined cycle gas tur ...
gas turbine and steam plants can achieve efficiencies as high as 60%. In
combined heat and power Cogeneration or combined heat and power (CHP) is the use of a heat engine or power station to generate electricity and useful heat at the same time. Cogeneration is a more efficient use of fuel or heat, because otherwise- wasted heat from elect ...
(CHP) systems, the
waste heat Waste heat is heat that is produced by a machine, or other process that uses energy, as a byproduct of doing work. All such processes give off some waste heat as a fundamental result of the laws of thermodynamics. Waste heat has lower utilit ...
produced by the primary power cycle - whether fuel cell, nuclear fission or combustion - is captured and put to use, increasing the efficiency of the system to up to 85–90%. The theoretical maximum efficiency of any type of power generation system is never reached in practice, and it does not consider other steps in power generation, such as production, transportation and storage of fuel and conversion of the electricity into mechanical power. However, this calculation allows the comparison of different types of power generation. The theoretical maximum efficiency of a fuel cell approaches 100%, while the theoretical maximum efficiency of internal combustion engines is approximately 58%.


In practice

In a
fuel cell vehicle A fuel cell vehicle (FCV) or fuel cell electric vehicle (FCEV) is an electric vehicle that uses a fuel cell, sometimes in combination with a small battery or supercapacitor, to power its onboard electric motor. Fuel cells in vehicles generate e ...
the tank-to-wheel efficiency is greater than 45% at low loadsEberle, Ulrich and Rittmar von Helmolt
"Sustainable transportation based on electric vehicle concepts: a brief overview"
Energy & Environmental Science,
Royal Society of Chemistry The Royal Society of Chemistry (RSC) is a learned society (professional association) in the United Kingdom with the goal of "advancing the chemical sciences". It was formed in 1980 from the amalgamation of the Chemical Society, the Royal Inst ...
, 14 May 2010, accessed 2 August 2011
and shows average values of about 36% when a driving cycle like the NEDC (
New European Driving Cycle The New European Driving Cycle (NEDC) was a driving cycle, last updated in 1997, designed to assess the emission levels of car engines and fuel economy in passenger cars (which excludes light trucks and commercial vehicles). It is also refer ...
) is used as test procedure. The comparable NEDC value for a Diesel vehicle is 22%. In 2008 Honda released a demonstration fuel cell electric vehicle (the
Honda FCX Clarity The Honda Clarity is a nameplate used by Honda on alternative fuel vehicles. It was initially used only on hydrogen fuel-cell electric vehicles such as the 2008 Honda FCX Clarity, but in 2017 the nameplate was expanded to include the battery-elec ...
) with fuel stack claiming a 60% tank-to-wheel efficiency. It is also important to take losses due to fuel production, transportation, and storage into account. Fuel cell vehicles running on compressed hydrogen may have a power-plant-to-wheel efficiency of 22% if the hydrogen is stored as high-pressure gas, and 17% if it is stored as
liquid hydrogen Liquid hydrogen (LH2 or LH2) is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form. To exist as a liquid, H2 must be cooled below its critical point of 33  K. However, for it to be in a fully l ...
. Fuel cells cannot store energy like a battery, except as hydrogen, but in some applications, such as stand-alone power plants based on discontinuous sources such as solar or
wind power Wind power or wind energy is mostly the use of wind turbines to generate electricity. Wind power is a popular, sustainable, renewable energy source that has a much smaller impact on the environment than burning fossil fuels. Historically ...
, they are combined with electrolyzers and storage systems to form an energy storage system. As of 2019, 90% of hydrogen was used for oil refining, chemicals and fertilizer production (where hydrogen is required for the Haber–Bosch process), and 98% of hydrogen is produced by
steam methane reforming Steam reforming or steam methane reforming (SMR) is a method for producing syngas ( hydrogen and carbon monoxide) by reaction of hydrocarbons with water. Commonly natural gas is the feedstock. The main purpose of this technology is hydrogen prod ...
, which emits carbon dioxide. The overall efficiency (electricity to hydrogen and back to electricity) of such plants (known as ''round-trip efficiency''), using pure hydrogen and pure oxygen can be "from 35 up to 50 percent", depending on gas density and other conditions. The electrolyzer/fuel cell system can store indefinite quantities of hydrogen, and is therefore suited for long-term storage. Solid-oxide fuel cells produce heat from the recombination of the oxygen and hydrogen. The ceramic can run as hot as 800 degrees Celsius. This heat can be captured and used to heat water in a micro combined heat and power (m-CHP) application. When the heat is captured, total efficiency can reach 80–90% at the unit, but does not consider production and distribution losses. CHP units are being developed today for the European home market. Professor Jeremy P. Meyers, in the
Electrochemical Society The Electrochemical Society is a learned society (professional association) based in the United States that supports scientific inquiry in the field of electrochemistry and Solid State Science, solid-state science and related technology. The Socie ...
journal ''Interface'' in 2008, wrote, "While fuel cells are efficient relative to combustion engines, they are not as efficient as batteries, primarily due to the inefficiency of the oxygen reduction reaction (and ... the oxygen evolution reaction, should the hydrogen be formed by electrolysis of water).... ey make the most sense for operation disconnected from the grid, or when fuel can be provided continuously. For applications that require frequent and relatively rapid start-ups ... where zero emissions are a requirement, as in enclosed spaces such as warehouses, and where hydrogen is considered an acceptable reactant, a EM fuel cellis becoming an increasingly attractive choice f exchanging batteries is inconvenient.Meyers, Jeremy P
"Getting Back Into Gear: Fuel Cell Development After the Hype"
The Electrochemical Society ''Interface'', Winter 2008, pp. 36–39, accessed 7 August 2011
In 2013 military organizations were evaluating fuel cells to determine if they could significantly reduce the battery weight carried by soldiers.


Applications


Power

Stationary fuel cells are used for commercial, industrial and residential primary and backup power generation. Fuel cells are very useful as power sources in remote locations, such as spacecraft, remote weather stations, large parks, communications centers, rural locations including research stations, and in certain military applications. A fuel cell system running on hydrogen can be compact and lightweight, and have no major moving parts. Because fuel cells have no moving parts and do not involve combustion, in ideal conditions they can achieve up to 99.9999% reliability. This equates to less than one minute of downtime in a six-year period. Since fuel cell electrolyzer systems do not store fuel in themselves, but rather rely on external storage units, they can be successfully applied in large-scale energy storage, rural areas being one example.
. Fuel Cells 2000. Accessed 2 August 2011.
There are many different types of stationary fuel cells so efficiencies vary, but most are between 40% and 60% energy efficient. However, when the fuel cell's waste heat is used to heat a building in a cogeneration system this efficiency can increase to 85%. This is significantly more efficient than traditional coal power plants, which are only about one third energy efficient. Assuming production at scale, fuel cells could save 20–40% on energy costs when used in cogeneration systems. Fuel cells are also much cleaner than traditional power generation; a fuel cell power plant using natural gas as a hydrogen source would create less than one ounce of pollution (other than ) for every 1,000 kW·h produced, compared to 25 pounds of pollutants generated by conventional combustion systems. Fuel Cells also produce 97% less nitrogen oxide emissions than conventional coal-fired power plants. One such pilot program is operating on Stuart Island in Washington State. There the Stuart Island Energy Initiative has built a complete, closed-loop system: Solar panels power an electrolyzer, which makes hydrogen. The hydrogen is stored in a tank at , and runs a ReliOn fuel cell to provide full electric back-up to the off-the-grid residence. Another closed system loop was unveiled in late 2011 in Hempstead, NY. Fuel cells can be used with low-quality gas from landfills or waste-water treatment plants to generate power and lower
methane emissions Increasing methane emissions are a major contributor to the rising concentration of greenhouse gases in Earth's atmosphere, and are responsible for up to one-third of near-term global heating. During 2019, about 60% (360 million tons) of methane r ...
. A 2.8 MW fuel cell plant in California is said to be the largest of the type. Small-scale (sub-5kWhr) fuel cells are being developed for use in residential off-grid deployment.


Cogeneration

Combined heat and power (CHP) fuel cell systems, including micro combined heat and power (MicroCHP) systems are used to generate both electricity and heat for homes (see home fuel cell), office building and factories. The system generates constant electric power (selling excess power back to the grid when it is not consumed), and at the same time produces hot air and water from the
waste heat Waste heat is heat that is produced by a machine, or other process that uses energy, as a byproduct of doing work. All such processes give off some waste heat as a fundamental result of the laws of thermodynamics. Waste heat has lower utilit ...
. As the result CHP systems have the potential to save primary energy as they can make use of waste heat which is generally rejected by thermal energy conversion systems. A typical capacity range of home fuel cell is 1–3 kWel, 4–8 kWth. CHP systems linked to absorption chillers use their waste heat for
refrigeration The term refrigeration refers to the process of removing heat from an enclosed space or substance for the purpose of lowering the temperature.International Dictionary of Refrigeration, http://dictionary.iifiir.org/search.phpASHRAE Terminology, ht ...
. The waste heat from fuel cells can be diverted during the summer directly into the ground providing further cooling while the waste heat during winter can be pumped directly into the building. The University of Minnesota owns the patent rights to this type of system. Co-generation systems can reach 85% efficiency (40–60% electric and the remainder as thermal). Phosphoric-acid fuel cells (PAFC) comprise the largest segment of existing CHP products worldwide and can provide combined efficiencies close to 90%. Molten carbonate (MCFC) and solid-oxide fuel cells (SOFC) are also used for combined heat and power generation and have electrical energy efficiencies around 60%. Disadvantages of co-generation systems include slow ramping up and down rates, high cost and short lifetime. Also their need to have a hot water storage tank to smooth out the thermal heat production was a serious disadvantage in the domestic market place where space in domestic properties is at a great premium. Delta-ee consultants stated in 2013 that with 64% of global sales the fuel cell micro-combined heat and power passed the conventional systems in sales in 2012. The Japanese ENE FARM project stated that 34.213 PEMFC and 2.224 SOFC were installed in the period 2012–2014, 30,000 units on LNG and 6,000 on LPG.


Fuel cell electric vehicles (FCEVs)


Automobiles

By year-end 2019, about 18,000 FCEVs had been leased or sold worldwide. Three fuel cell electric vehicles have been introduced for commercial lease and sale: the
Honda Clarity The Honda Clarity is a nameplate used by Honda on alternative fuel vehicles. It was initially used only on hydrogen fuel-cell electric vehicles such as the 2008 Honda FCX Clarity, but in 2017 the nameplate was expanded to include the battery-el ...
,
Toyota Mirai The (from , Japanese for 'future') is a mid-size hydrogen fuel cell vehicle (FCV) manufactured by Toyota, and is one of the first FCV automobiles to be mass-produced and sold commercially. The Mirai was unveiled at the November 2014 Los Ang ...
and the
Hyundai ix35 FCEV The Hyundai ix35 FCEV or Tucson FCEV is a hydrogen fuel cell electric vehicle developed by Hyundai. The model is a left-hand drive only conversion to the SUV platform it is based on and was the first of its type to be mass-produced and sold comme ...
. Additional demonstration models include the
Honda FCX Clarity The Honda Clarity is a nameplate used by Honda on alternative fuel vehicles. It was initially used only on hydrogen fuel-cell electric vehicles such as the 2008 Honda FCX Clarity, but in 2017 the nameplate was expanded to include the battery-elec ...
, and
Mercedes-Benz F-Cell The F-Cell is a hydrogen fuel cell electric vehicle developed by Daimler AG. Two different versions are known - the previous version was based on the Mercedes-Benz A-Class, and the new model is based on the Mercedes-Benz B-Class. The first genera ...
. As of June 2011 demonstration FCEVs had driven more than , with more than 27,000 refuelings. Fuel cell electric vehicles feature an average range of between refuelings. They can be refueled in less than 5 minutes. The U.S. Department of Energy's Fuel Cell Technology Program states that, as of 2011, fuel cells achieved 53–59% efficiency at one-quarter power and 42–53% vehicle efficiency at full power,Garbak, John
"VIII.0 Technology Validation Sub-Program Overview"
DOE Fuel Cell Technologies Program, FY 2010 Annual Progress Report, accessed 2 August 2011
and a durability of over with less than 10% degradation.
. Fuel Cell Technology Program, U.S. Dept. of Energy, 24 June 2011
In a 2017 Well-to-Wheels simulation analysis that "did not address the economics and market constraints", General Motors and its partners estimated that, for an equivalent journey, a fuel cell electric vehicle running on compressed gaseous hydrogen produced from natural gas could use about 40% less energy and emit 45% less greenhouse gasses than an internal combustion vehicle. In 2015, Toyota introduced its first fuel cell vehicle, the Mirai, at a price of $57,000. Hyundai introduced the limited production
Hyundai ix35 FCEV The Hyundai ix35 FCEV or Tucson FCEV is a hydrogen fuel cell electric vehicle developed by Hyundai. The model is a left-hand drive only conversion to the SUV platform it is based on and was the first of its type to be mass-produced and sold comme ...
under a lease agreement. In 2016, Honda started leasing the Honda Clarity Fuel Cell. In 2020, Toyota introduced the second generation of its Mirai brand, improving fuel efficiency and expanding range compared to the original Sedan 2014 model.


=Criticism

= Some commentators believe that hydrogen fuel cell cars will never become economically competitive with other technologies or that it will take decades for them to become profitable. Elon Musk, CEO of battery-electric vehicle maker Tesla Motors, stated in 2015 that fuel cells for use in cars will never be commercially viable because of the inefficiency of producing, transporting and storing hydrogen and the flammability of the gas, among other reasons."Elon Musk on why Hydrogen fuel cell is dumb (2015)"
YouTube, 14 January 2015, at 10:20 of the clip
In 2012, Lux Research, Inc. issued a report that stated: "The dream of a hydrogen economy ... is no nearer". It concluded that "Capital cost ... will limit adoption to a mere 5.9 GW" by 2030, providing "a nearly insurmountable barrier to adoption, except in niche applications". The analysis concluded that, by 2030, PEM stationary market will reach $1 billion, while the vehicle market, including forklifts, will reach a total of $2 billion.Brian Warshay, Brian

, Lux Research, Inc. January 2013
Other analyses cite the lack of an extensive
hydrogen infrastructure A hydrogen infrastructure is the infrastructure of hydrogen pipeline transport, points of hydrogen production and hydrogen stations (sometimes clustered as a hydrogen highway) for distribution as well as the sale of hydrogen fuel, and thus a cruci ...
in the U.S. as an ongoing challenge to Fuel Cell Electric Vehicle commercialization. In 2014,
Joseph Romm Joseph J. Romm (born June 27, 1960) is an American author, editor, physicist and climate expert, who advocates reducing greenhouse gas emissions to limit global warming and increasing energy security through energy efficiency, green energy techno ...
, the author of ''
The Hype About Hydrogen ''The Hype About Hydrogen: Fact and Fiction in the Race to Save the Climate'' is a book by Joseph J. Romm, published in 2004 by Island Press and updated in 2005. The book has been translated into German as ''Der Wasserstoff-Boom''. Romm is an ex ...
'' (2005), said that FCVs still had not overcome the high fueling cost, lack of fuel-delivery infrastructure, and pollution caused by producing hydrogen. "It would take several miracles to overcome all of those problems simultaneously in the coming decades." He concluded that renewable energy cannot economically be used to make hydrogen for an FCV fleet "either now or in the future."Romm, Joseph
"Tesla Trumps Toyota: Why Hydrogen Cars Can’t Compete With Pure Electric Cars"
CleanProgress.com, 5 August 2014
Greentech Media's analyst reached similar conclusions in 2014. In 2015, ''
CleanTechnica ''CleanTechnica'' is a US-based website dedicated to aggregating news in clean technology, sustainable energy, and electric vehicles, with a focus on Tesla. Content CleanTechnica publishes stories on a wide range of topics that are cited by m ...
'' listed some of the disadvantages of hydrogen fuel cell vehicles. So did ''Car Throttle''. A 2019 video by ''Real Engineering'' noted that, notwithstanding the introduction of vehicles that run on hydrogen, using hydrogen as a fuel for cars does not help to reduce carbon emissions from transportation. The 95% of hydrogen still produced from fossil fuels releases carbon dioxide, and producing hydrogen from water is an energy-consuming process. Storing hydrogen requires more energy either to cool it down to the liquid state or to put it into tanks under high pressure, and delivering the hydrogen to fueling stations requires more energy and may release more carbon. The hydrogen needed to move a FCV a kilometer costs approximately 8 times as much as the electricity needed to move a BEV the same distance. A 2020 assessment concluded that hydrogen vehicles are still only 38% efficient, while battery EVs are 80% efficient. In 2021 ''
CleanTechnica ''CleanTechnica'' is a US-based website dedicated to aggregating news in clean technology, sustainable energy, and electric vehicles, with a focus on Tesla. Content CleanTechnica publishes stories on a wide range of topics that are cited by m ...
'' concluded that while hydrogen cars are far less efficient than electric cars, the vast majority of hydrogen being produced is polluting grey hydrogen, and delivering hydrogen would require building a vast and expensive new infrastructure, the remaining two "advantages of fuel cell vehicles – longer range and fast fueling times – are rapidly being eroded by improving battery and charging technology." A 2022 study in '' Nature Electronics'' agreed.


Buses

, there were about 100
fuel cell bus A fuel cell bus is a bus that uses a hydrogen fuel cell as its power source for electrically driven wheels, sometimes augmented in a hybrid fashion with batteries or a supercapacitor. The only emission from the bus is water. Several cities aro ...
es in service around the world."National Fuel Cell Bus Program Awards"
Calstart. Accessed 12 August 2011
Most of these were manufactured by
UTC Power UTC Power was a fuel cell company based in South Windsor, Connecticut. It was part of United Technologies Corporation; it was purchased by ClearEdge Power in February 2013. The company specialized in fuel cells for buildings, buses and automobi ...
, Toyota, Ballard,
Hydrogenics Hydrogenics is a developer and manufacturer of hydrogen generation and fuel cell products based on water electrolysis and proton exchange membrane (PEM) technology. Hydrogenics is divided into two business units: OnSite Generation and Power Syst ...
, and Proton Motor. UTC buses had driven more than by 2011. Fuel cell buses have from 39% to 141% higher fuel economy than diesel buses and natural gas buses. , the NREL was evaluating several current and planned fuel cell bus projects in the U.S.


Trains

In 2018, the first fuel cell-powered trains, the Alstom Coradia iLint multiple units, began running on the Buxtehude–Bremervörde–Bremerhaven–Cuxhaven line in Germany. These trains offer the advantages of electric trains over
Diesel locomotives A diesel locomotive is a type of railway locomotive in which the prime mover is a diesel engine. Several types of diesel locomotives have been developed, differing mainly in the means by which mechanical power is conveyed to the driving wheels ...
and DMU’s in eliminating smokestack emissions from the trains themselves without the use of
electrification Electrification is the process of powering by electricity and, in many contexts, the introduction of such power by changing over from an earlier power source. The broad meaning of the term, such as in the history of technology, economic histo ...
by overhead catenerary infrastructure. Such trains have been ordered or are being tested in Sweden and the UK.


Trucks

In December 2020,
Toyota is a Japanese multinational automotive manufacturer headquartered in Toyota City, Aichi, Japan. It was founded by Kiichiro Toyoda and incorporated on . Toyota is one of the largest automobile manufacturers in the world, producing about 10 ...
and
Hino Motors Hino Motors, Ltd., commonly known as Hino, is a Japanese manufacturer of commercial vehicles and diesel engines (including those for trucks, buses and other vehicles) headquartered in Hino, Tokyo. The company was established in 1942 as a corpo ...
, together with Seven-Eleven (Japan),
FamilyMart is a Japanese convenience store franchise chain. It is Japan's second largest convenience store chain, behind 7-Eleven. There are now 24,574 stores worldwide in Japan, Taiwan, China, Philippines, Thailand, Vietnam, Indonesia, and Malaysia. Its ...
and
Lawson Lawson may refer to: Places Australia * Lawson, Australian Capital Territory, a suburb of Canberra * Lawson, New South Wales, a town in the Blue Mountains Canada * Lawson, Saskatchewan * Lawson Island, Nunavut United States * Lawson, Arkansas * ...
announced that they have agreed to jointly consider introducing light-duty fuel cell electric trucks (light-duty FCETs). Lawson started testing for low temperature delivery at the end of July 2021 in Tokyo, using a Hino Dutro in which the
Toyota Mirai The (from , Japanese for 'future') is a mid-size hydrogen fuel cell vehicle (FCV) manufactured by Toyota, and is one of the first FCV automobiles to be mass-produced and sold commercially. The Mirai was unveiled at the November 2014 Los Ang ...
fuel cell is implemented. FamilyMart started testing in Okazaki city. In August 2021, Toyota announced their plan to make fuel cell modules at its Kentucky auto-assembly plant for use in zero-emission big rigs and heavy-duty commercial vehicles. They plan to begin assembling the electrochemical devices in 2023. In October 2021, Daimler Truck's fuel cell based truck received approval from German authorities for use on public roads.


Forklifts

A
fuel cell forklift A fuel cell forklift (also called a fuel cell lift truck) is a fuel cell powered industrial forklift used to lift and transport materials. History * 1960Allis-Chalmers builds the first fuel cell forklift. Market In 2013 there were over 4,000 fue ...
(also called a fuel cell lift truck) is a fuel cell-powered industrial
forklift truck A forklift (also called lift truck, jitney, hi-lo, fork truck, fork hoist, and forklift truck) is a powered industrial truck used to lift and move materials over short distances. The forklift was developed in the early 20th century by various ...
used to lift and transport materials. In 2013 there were over 4,000 fuel cell forklifts used in
material handling Material handling involves short-distance movement within the confines of a building or between a building and a transportation vehicle. It uses a wide range of manual, semi-automated, and automated equipment and includes consideration of the pro ...
in the US, of which 500 received funding from DOE (2012). Fuel cell fleets are operated by various companies, including Sysco Foods, FedEx Freight, GENCO (at Wegmans, Coca-Cola, Kimberly Clark, and Whole Foods), and H-E-B Grocers. Europe demonstrated 30 fuel cell forklifts with Hylift and extended it with HyLIFT-EUROPE to 200 units, with other projects in France and
Austria Austria, , bar, Östareich officially the Republic of Austria, is a country in the southern part of Central Europe, lying in the Eastern Alps. It is a federation of nine states, one of which is the capital, Vienna, the most populous ...
. Pike Research projected in 2011 that fuel cell-powered forklifts would be the largest driver of hydrogen fuel demand by 2020. Most companies in Europe and the US do not use petroleum-powered forklifts, as these vehicles work indoors where emissions must be controlled and instead use electric forklifts."Global and Chinese Forklift Industry Report, 2014-2016"
Research and Markets, 6 November 2014
Fuel cell-powered forklifts can provide benefits over battery-powered forklifts as they can be refueled in 3 minutes and they can be used in refrigerated warehouses, where their performance is not degraded by lower temperatures. The FC units are often designed as drop-in replacements.


Motorcycles and bicycles

In 2005, a British manufacturer of hydrogen-powered fuel cells, Intelligent Energy (IE), produced the first working hydrogen-run motorcycle called the
ENV env is a shell command for Unix and Unix-like operating systems. It is used to either print a list of environment variables or run another utility in an altered environment without having to modify the currently existing environment. Using env, ...
(Emission Neutral Vehicle). The motorcycle holds enough fuel to run for four hours, and to travel in an urban area, at a top speed of . In 2004
Honda is a Japanese public multinational conglomerate manufacturer of automobiles, motorcycles, and power equipment, headquartered in Minato, Tokyo, Japan. Honda has been the world's largest motorcycle manufacturer since 1959, reaching a producti ...
developed a fuel cell motorcycle that utilized the Honda FC Stack. Other examples of motorbikes and bicycles that use hydrogen fuel cells include the Taiwanese company APFCT's scooter using the fueling system from Italy's Acta SpA and the
Suzuki is a Japanese multinational corporation headquartered in Minami-ku, Hamamatsu, Japan. Suzuki manufactures automobiles, motorcycles, all-terrain vehicles (ATVs), outboard marine engines, wheelchairs and a variety of other small internal co ...
Burgman scooter with an IE fuel cell that received EU Whole Vehicle Type Approval in 2011. Suzuki Motor Corp. and IE have announced a joint venture to accelerate the commercialization of zero-emission vehicles.


Airplanes

In 2003, the world's first propeller-driven airplane to be powered entirely by a fuel cell was flown. The fuel cell was a stack design that allowed the fuel cell to be integrated with the plane's aerodynamic surfaces. Fuel cell-powered unmanned aerial vehicles (UAV) include a
Horizon The horizon is the apparent line that separates the surface of a celestial body from its sky when viewed from the perspective of an observer on or near the surface of the relevant body. This line divides all viewing directions based on whether i ...
fuel cell UAV that set the record distance flown for a small UAV in 2007.
Boeing The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and ...
researchers and industry partners throughout Europe conducted experimental flight tests in February 2008 of a manned airplane powered only by a fuel cell and lightweight batteries. The fuel cell demonstrator airplane, as it was called, used a proton-exchange membrane (PEM) fuel cell/
lithium-ion battery A lithium-ion or Li-ion battery is a type of rechargeable battery which uses the reversible reduction of lithium ions to store energy. It is the predominant battery type used in portable consumer electronics and electric vehicles. It also s ...
hybrid system to power an electric motor, which was coupled to a conventional propeller. In 2009, the Naval Research Laboratory's (NRL's) Ion Tiger utilized a hydrogen-powered fuel cell and flew for 23 hours and 17 minutes. Fuel cells are also being tested and considered to provide auxiliary power in aircraft, replacing fossil fuel generators that were previously used to start the engines and power on board electrical needs, while reducing carbon emissions."Hydrogen-powered unmanned aircraft completes set of tests"
.www.theengineer.co.uk. 20 June 2011. Accessed 2 August 2011.
In 2016 a Raptor E1 drone made a successful test flight using a fuel cell that was lighter than the
lithium-ion battery A lithium-ion or Li-ion battery is a type of rechargeable battery which uses the reversible reduction of lithium ions to store energy. It is the predominant battery type used in portable consumer electronics and electric vehicles. It also s ...
it replaced. The flight lasted 10 minutes at an altitude of , although the fuel cell reportedly had enough fuel to fly for two hours. The fuel was contained in approximately 100 solid pellets composed of a proprietary chemical within an unpressurized cartridge. The pellets are physically robust and operate at temperatures as warm as . The cell was from Arcola Energy. Lockheed Martin Skunk Works Stalker is an electric UAV powered by solid oxide fuel cell.


Boats

In Norway, the first ferry powered by fuel cells running on liquid origin is scheduled for its first test drives in December 2022.


Submarines

The Type 212 submarines of the German and Italian navies use fuel cells to remain submerged for weeks without the need to surface. The U212A is a non-nuclear submarine developed by German naval shipyard Howaldtswerke Deutsche Werft. The system consists of nine PEM fuel cells, providing between 30 kW and 50 kW each. The ship is silent, giving it an advantage in the detection of other submarines. A naval paper has theorized about the possibility of a nuclear-fuel cell hybrid whereby the fuel cell is used when silent operations are required and then replenished from the Nuclear reactor (and water).


Portable power systems

Portable fuel cell systems are generally classified as weighing under 10 kg and providing power of less than 5 kW. The potential market size for smaller fuel cells is quite large with an up to 40% per annum potential growth rate and a market size of around $10 billion, leading a great deal of research to be devoted to the development of portable power cells. Within this market two groups have been identified. The first is the microfuel cell market, in the 1-50 W range for power smaller electronic devices. The second is the 1-5 kW range of generators for larger scale power generation (e.g. military outposts, remote oil fields). Microfuel cells are primarily aimed at penetrating the market for phones and laptops. This can be primarily attributed to the advantageous
energy density In physics, energy density is the amount of energy stored in a given system or region of space per unit volume. It is sometimes confused with energy per unit mass which is properly called specific energy or . Often only the ''useful'' or extrac ...
provided by fuel cells over a lithium-ion battery, for the entire system. For a battery, this system includes the charger as well as the battery itself. For the fuel cell this system would include the cell, the necessary fuel and peripheral attachments. Taking the full system into consideration, fuel cells have been shown to provide 530Wh/kg compared to 44 Wh/kg for lithium ion batteries. However, while the weight of fuel cell systems offer a distinct advantage the current costs are not in their favor. while a battery system will generally cost around $1.20 per Wh, fuel cell systems cost around $5 per Wh, putting them at a significant disadvantage. As power demands for cell phones increase, fuel cells could become much more attractive options for larger power generation. The demand for longer on time on phones and computers is something often demanded by consumers so fuel cells could start to make strides into laptop and cell phone markets. The price will continue to go down as developments in fuel cells continues to accelerate. Current strategies for improving micro fuel cells is through the use of
carbon nanotube A scanning tunneling microscopy image of a single-walled carbon nanotube Rotating single-walled zigzag carbon nanotube A carbon nanotube (CNT) is a tube made of carbon with diameters typically measured in nanometers. ''Single-wall carbon na ...
s. It was shown by Girishkumar et al. that depositing nanotubes on electrode surfaces allows for substantially greater surface area increasing the oxygen reduction rate. Fuel cells for use in larger scale operations also show much promise. Portable power systems that use fuel cells can be used in the leisure sector (i.e. RVs, cabins, marine), the industrial sector (i.e. power for remote locations including gas/oil wellsites, communication towers, security, weather stations), and in the military sector. SFC Energy is a German manufacturer of direct methanol fuel cells for a variety of portable power systems. Ensol Systems Inc. is an integrator of portable power systems, using the SFC Energy DMFC. The key advantage of fuel cells in this market is the great power generation per weight. While fuel cells can be expensive, for remote locations that require dependable energy fuel cells hold great power. For a 72-h excursion the comparison in weight is substantial, with a fuel cell only weighing 15 pounds compared to 29 pounds of batteries needed for the same energy.


Other applications

* Providing power for
base station Base station (or base radio station) is – according to the International Telecommunication Union's (ITU) Radio Regulations (RR) – a "land station in the land mobile service." The term is used in the context of mobile telephony, wireless c ...
s or
cell site A cell site, cell tower, or cellular base station is a cellular-enabled mobile device site where antennas and electronic communications equipment are placed (typically on a radio mast, tower, or other raised structure) to create a cell, or adj ...
s *
Distributed generation Distributed generation, also distributed energy, on-site generation (OSG), or district/decentralized energy, is electrical generation and storage performed by a variety of small, grid-connected or distribution system-connected devices referred to ...
*
Emergency power systems An emergency power system is an independent source of electrical power that supports important electrical systems on loss of normal power supply. A standby power system may include a standby generator, batteries and other apparatus. Emergency p ...
are a type of fuel cell system, which may include lighting, generators and other apparatus, to provide backup resources in a crisis or when regular systems fail. They find uses in a wide variety of settings from residential homes to hospitals, scientific laboratories,
data center A data center (American English) or data centre (British English)See spelling differences. is a building, a dedicated space within a building, or a group of buildings used to house computer systems and associated components, such as telecommun ...
s, * Telecommunication equipment and modern naval ships. * An
uninterrupted power supply An uninterruptible power supply or uninterruptible power source (UPS) is an electrical apparatus that provides emergency power to a load when the input power source or mains power fails. A UPS differs from an auxiliary or emergency power syste ...
(''UPS'') provides emergency power and, depending on the topology, provide line regulation as well to connected equipment by supplying power from a separate source when utility power is not available. Unlike a standby generator, it can provide instant protection from a momentary power interruption. * Base load power plants *
Hybrid vehicle A hybrid vehicle is one that uses two or more distinct types of power, such as submarines that use diesel when surfaced and batteries when submerged. Other means to store energy include pressurized fluid in hydraulic hybrids. The basic princi ...
s, pairing the fuel cell with either an ICE or a battery. *
Notebook computers A laptop, laptop computer, or notebook computer is a small, portable personal computer (PC) with a screen and alphanumeric keyboard. Laptops typically have a clam shell form factor with the screen mounted on the inside of the upper li ...
for applications where AC charging may not be readily available. * Portable charging docks for small electronics (e.g. a belt clip that charges a cell phone or
PDA PDA may refer to: Science and technology * Patron-driven acquisition, a mechanism for libraries to purchase books *Personal digital assistant, a mobile device * Photodiode array, a type of detector * Polydiacetylenes, a family of conducting po ...
). *
Smartphones A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, whic ...
, laptops and tablets. * Small heating appliances *
Food preservation Food preservation includes processes that make food more resistant to microorganism growth and slow the oxidation of fats. This slows down the decomposition and rancidification process. Food preservation may also include processes that inhibit ...
, achieved by exhausting the oxygen and automatically maintaining oxygen exhaustion in a shipping container, containing, for example, fresh fish. *
Breathalyzer A breathalyzer or breathalyser (a portmanteau of ''breath'' and ''analyzer/analyser'') is a device for estimating blood alcohol content (BAC), or to detect viruses or diseases from a breath sample. The name is a genericized trademark of the Br ...
s, where the amount of voltage generated by a fuel cell is used to determine the concentration of fuel (alcohol) in the sample. *
Carbon monoxide detector A carbon monoxide detector or CO detector is a device that detects the presence of the carbon monoxide (CO) gas to prevent carbon monoxide poisoning. In the late 1990s Underwriters Laboratories changed the definition of a single station CO d ...
, electrochemical sensor.


Fueling stations

According to FuelCellsWorks, an industry group, at the end of 2019, 330 hydrogen refueling stations were open to the public worldwide. As of June 2020, there were 178 publicly available hydrogen stations in operation in Asia. 114 of these were in Japan. There were at least 177 stations in Europe, and about half of these were in Germany. There were 44 publicly accessible stations in the US, 42 of which were located in California.Alternative Fueling Station Counts by State
''Alternative Fuels Data Center'', accessed 31 August 2020
A hydrogen fueling station costs between $1 million and $4 million to build.


Markets and economics

In 2012, fuel cell industry revenues exceeded $1 billion market value worldwide, with Asian pacific countries shipping more than 3/4 of the fuel cell systems worldwide. However, as of January 2014, no public company in the industry had yet become profitable. There were 140,000 fuel cell stacks shipped globally in 2010, up from 11,000 shipments in 2007, and from 2011 to 2012 worldwide fuel cell shipments had an annual growth rate of 85%.
Tanaka Kikinzoku The Tanaka Kikinzoku Group, founded in 1885, is a Japanese manufacturer of precious metals materials focusing mainly on products for the electronics, semiconductor and automotive industries. Tanaka's European subsidiary is Tanaka Kikinzoku Inter ...
expanded its manufacturing facilities in 2011. Approximately 50% of fuel cell shipments in 2010 were stationary fuel cells, up from about a third in 2009, and the four dominant producers in the Fuel Cell Industry were the United States, Germany, Japan and South Korea.Adamson, Karry-Ann and Clint Wheelock
"Fuel Cell Annual Report 2011"
. 2Q 2011, Pike Research, accessed 1 August 2011
The Department of Energy Solid State Energy Conversion Alliance found that, as of January 2011, stationary fuel cells generated power at approximately $724 to $775 per kilowatt installed. In 2011, Bloom Energy, a major fuel cell supplier, said that its fuel cells generated power at 9–11 cents per kilowatt-hour, including the price of fuel, maintenance, and hardware. Industry groups predict that there are sufficient platinum resources for future demand, and in 2007, research at
Brookhaven National Laboratory Brookhaven National Laboratory (BNL) is a United States Department of Energy national laboratory located in Upton, Long Island, and was formally established in 1947 at the site of Camp Upton, a former U.S. Army base and Japanese internment c ...
suggested that platinum could be replaced by a gold-
palladium Palladium is a chemical element with the symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1803 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas, which was itself ...
coating, which may be less susceptible to poisoning and thereby improve fuel cell lifetime. Another method would use iron and sulphur instead of platinum. This would lower the cost of a fuel cell (as the platinum in a regular fuel cell costs around , and the same amount of iron costs only around ). The concept was being developed by a coalition of the John Innes Centre and the University of Milan-Bicocca.
PEDOT Poly(3,4-ethylenedioxythiophene) (PEDOT or PEDT; ''IUPAC'' name poly(2,3-dihydrothieno ,4-''b''1,4]dioxane-5,7-diyl)) is a conducting polymer based on 3,4-ethylenedioxythiophene or EDOT. It was first reported by Bayer AG in 1989. Polymer PEDOT p ...
cathodes are immune to monoxide poisoning. In 2016,
Samsung The Samsung Group (or simply Samsung) ( ko, 삼성 ) is a South Korean multinational manufacturing conglomerate headquartered in Samsung Town, Seoul, South Korea. It comprises numerous affiliated businesses, most of them united under the ...
"decided to drop fuel cell-related business projects, as the outlook of the market isn't good".


Research and development

* 2005:
Georgia Institute of Technology The Georgia Institute of Technology, commonly referred to as Georgia Tech or, in the state of Georgia, as Tech or The Institute, is a public research university and institute of technology in Atlanta, Georgia. Established in 1885, it is part ...
researchers used
triazole A triazole is a heterocyclic compound featuring a five-membered ring of two carbon atoms and three nitrogen atoms with molecular formula C2H3N3. Triazoles exhibit substantial isomerism, depending on the positioning of the nitrogen atoms within ...
to raise the operating temperature of PEM fuel cells from below 100 °C to over 125 °C, claiming this will require less carbon-monoxide purification of the hydrogen fuel. * 2008:
Monash University Monash University () is a public research university based in Melbourne, Victoria, Australia. Named for prominent World War I general Sir John Monash, it was founded in 1958 and is the second oldest university in the state. The university has ...
,
Melbourne Melbourne ( ; Boonwurrung/ Woiwurrung: ''Narrm'' or ''Naarm'') is the capital and most populous city of the Australian state of Victoria, and the second-most populous city in both Australia and Oceania. Its name generally refers to a metro ...
used
PEDOT Poly(3,4-ethylenedioxythiophene) (PEDOT or PEDT; ''IUPAC'' name poly(2,3-dihydrothieno ,4-''b''1,4]dioxane-5,7-diyl)) is a conducting polymer based on 3,4-ethylenedioxythiophene or EDOT. It was first reported by Bayer AG in 1989. Polymer PEDOT p ...
as a
cathode A cathode is the electrode from which a conventional current leaves a polarized electrical device. This definition can be recalled by using the mnemonic ''CCD'' for ''Cathode Current Departs''. A conventional current describes the direction in whi ...
. * 2009: Researchers at the
University of Dayton The University of Dayton (UD) is a private, Catholic research university in Dayton, Ohio. Founded in 1850 by the Society of Mary, it is one of three Marianist universities in the nation and the second-largest private university in Ohio. The univ ...
, in Ohio, showed that arrays of vertically grown
carbon nanotubes A scanning tunneling microscopy image of a single-walled carbon nanotube Rotating single-walled zigzag carbon nanotube A carbon nanotube (CNT) is a tube made of carbon with diameters typically measured in nanometers. ''Single-wall carbon na ...
could be used as the
catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
in fuel cells. The same year, a nickel bisdiphosphine-based catalyst for fuel cells was demonstrated. * 2013: British firm ACAL Energy developed a fuel cell that it said can run for 10,000 hours in simulated driving conditions. It asserted that the cost of fuel cell construction can be reduced to $40/kW (roughly $9,000 for 300 HP). * 2014: Researchers in
Imperial College London Imperial College London (legally Imperial College of Science, Technology and Medicine) is a public research university in London, United Kingdom. Its history began with Prince Albert, consort of Queen Victoria, who developed his vision for a cu ...
developed a new method for regeneration of hydrogen sulfide contaminated PEFCs. They recovered 95–100% of the original performance of a hydrogen sulfide contaminated PEFC. They were successful in rejuvenating a SO2 contaminated PEFC too. This regeneration method is applicable to multiple cell stacks.


See also

* Bio-nano generator * Cryptophane * Fuel Cell Development Information Center *
Fuel Cells and Hydrogen Joint Technology Initiative The Framework Programmes for Research and Technological Development, also called Framework Programmes or abbreviated FP1 to FP9, are funding programmes created by the European Union/ European Commission to support and foster research in the Europ ...
(in Europe) *
Grid energy storage Grid energy storage (also called large-scale energy storage) is a collection of methods used for energy storage on a large scale within an electrical power grid. Electrical energy is stored during times when electricity is plentiful and inex ...
*
Hydrogen reformer Steam reforming or steam methane reforming (SMR) is a method for producing syngas (hydrogen and carbon monoxide) by reaction of hydrocarbons with water. Commonly natural gas is the feedstock. The main purpose of this technology is hydrogen produc ...
* Hydrogen storage * Hydrogen technologies * List of fuel cell manufacturers *
Methanol reformer A methanol reformer is a device used in chemical engineering, especially in the area of fuel cell technology, which can produce pure hydrogen gas and carbon dioxide by reacting a methanol and water (steam) mixture. :\mathrm \Delta H_^0 = 49.2 ...
* PEM electrolysis


References


Further reading

* * * * * * * *


External links


Animation – how a fuel cell works



EERE: Hydrogen, Fuel Cells and Infrastructure Technologies Program


* ttp://www.doitpoms.ac.uk/tlplib/fuel-cells/index.php DoITPoMS Teaching and Learning Package: "Fuel Cells" {{Authority control 1838 introductions Bright green environmentalism Energy conversion Hydrogen economy Hydrogen technologies Energy storage