Fuel cell

Fuel cell

Overview
A fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol
Methanol
Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...

 are sometimes used. Fuel cells are different from batteries
Battery (electricity)
An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...

 in that they require a constant source of fuel and oxygen to run, but they can produce electricity continually for as long as these inputs are supplied.

Welsh Physicist William Grove
William Robert Grove
Sir William Robert Grove PC QC FRS was a judge and physical scientist. He anticipated the general theory of the conservation of energy, and was a pioneer of fuel cell technology.-Early life:...

 developed the first crude fuel cells in 1839.
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Encyclopedia
A fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol
Methanol
Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...

 are sometimes used. Fuel cells are different from batteries
Battery (electricity)
An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...

 in that they require a constant source of fuel and oxygen to run, but they can produce electricity continually for as long as these inputs are supplied.

Welsh Physicist William Grove
William Robert Grove
Sir William Robert Grove PC QC FRS was a judge and physical scientist. He anticipated the general theory of the conservation of energy, and was a pioneer of fuel cell technology.-Early life:...

 developed the first crude fuel cells in 1839. The first commercial use of fuel cells was in NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

 space programs to generate power for probes, satellites and space capsules. 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 used to power fuel cell vehicle
Fuel cell vehicle
A Fuel cell vehicle or Fuel Cell Electric Vehicle is a type of hydrogen vehicle which uses a fuel cell to produce electricity, powering its on-board electric motor...

s, including automobiles, buses, forklifts, airplanes, boats, motorcycles and submarines.

There are many types of fuel cells, but they all consist of an anode
Anode
An anode is an electrode through which electric current flows into a polarized electrical device. Mnemonic: ACID ....

 (negative side), a cathode
Cathode
A cathode is an electrode through which electric current flows out of a polarized electrical device. Mnemonic: CCD .Cathode polarity is not always negative...

 (positive side) and an electrolyte
Electrolyte
In chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....

 that allows charges to move between the two sides of the fuel cell. Electrons are drawn from the anode to the cathode through an external circuit, producing direct current
Direct current
Direct current is the unidirectional flow of electric charge. Direct current is produced by such sources as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through...

 electricity. As the main difference among fuel cell types is the electrolyte, fuel cells are classified by the type of electrolyte
Electrolyte
In chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....

 they use. Fuel cells come in a variety of sizes. Individual fuel cells produce very small amounts of electricity, about 0.7 volts, so cells are "stacked", or placed in series or parallel circuits, to increase the voltage and current output to meet an application’s power generation requirements. In addition to electricity, fuel cells produce water, heat and, depending on the fuel source, very small amounts of nitrogen dioxide
Nitrogen dioxide
Nitrogen dioxide is the 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. This reddish-brown toxic gas has a characteristic sharp, biting odor and is a prominent...

 and other emissions. The energy efficiency of a fuel cell is generally between 40-60%, or up to 85% efficient if waste heat is captured for use.

History




The principle of the fuel cell was discovered by German scientist Christian Friedrich Schönbein
Christian Friedrich Schönbein
Christian Friedrich Schönbein was a German-Swiss chemist who is best known for inventing the fuel cell and his discoveries of guncotton and ozone.- Life :...

 in 1838 and published in one of the scientific magazines of the time. Based on this work, the first fuel cell was demonstrated by Welsh scientist and barrister Sir William Robert Grove
William Robert Grove
Sir William Robert Grove PC QC FRS was a judge and physical scientist. He anticipated the general theory of the conservation of energy, and was a pioneer of fuel cell technology.-Early life:...

 in the February 1839 edition of the Philosophical Magazine and Journal of Science and later sketched, in 1842, in the same journal. The fuel cell he made used similar materials to today's phosphoric-acid fuel cell
Phosphoric-acid fuel cell
Phosphoric acid fuel cells 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 significantly in stability, performance, and cost...

.

In 1955, W. Thomas Grubb, a chemist working for the General Electric Company (GE
Gê are the people who spoke Ge languages of the northern South American Caribbean coast and Brazil. In Brazil the Gê were found in Rio de Janeiro, Minas Gerais, Bahia, Piaui, Mato Grosso, Goias, Tocantins, Maranhão, and as far south as Paraguay....

), 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
Project Gemini was the second human spaceflight program of NASA, the civilian space agency of the United States government. Project Gemini was conducted between projects Mercury and Apollo, with ten manned flights occurring in 1965 and 1966....

. This was the first commercial use of a fuel cell. In 1959, British engineer Francis Thomas Bacon
Francis Thomas Bacon
Francis Thomas Bacon OBE FREng F.R.S. was an English engineer who developed the first practical hydrogen–oxygen fuel cell.- Life and works :...

 successfully developed a 5 kW stationary fuel cell. In 1959, a team led by Harry Ihrig built a 15 kW fuel cell tractor for Allis-Chalmers which was demonstrated across the US at state fairs. This system used potassium hydroxide as the electrolyte and compressed hydrogen
Compressed hydrogen
Compressed hydrogen is the gaseous state of the element hydrogen kept under pressure. Compressed hydrogen in hydrogen tanks at 350 bar and 700 bar is used for mobile hydrogen storage in hydrogen vehicles...

 and oxygen as the reactants. Later in 1959, Bacon and his colleagues demonstrated a practical five-kilowatt unit capable of powering a welding machine. In the 1960s, Pratt and Whitney licensed Bacon's U.S. patents for use in the U.S. space program to supply electricity and drinking water (hydrogen and oxygen being readily available from the spacecraft tanks). In 1991, the first hydrogen fuel cell automobile was developed by Roger Billings.

United Technologies Corporation
United Technologies Corporation
United Technologies Corporation is an American multinational conglomerate headquartered in the United Technologies Building in Hartford, Connecticut...

's UTC Power
UTC Power
- About :UTC Power is a fuel cell company based in South Windsor, Connecticut. It is part of United Technologies Corporation and has been in business for over 50 years. The company has experience in all five major fuel cell technologies. The company specializes in fuel cells for buildings, buses ...

 subsidiary was the first company to manufacture and commercialize a large, stationary fuel cell system for use as a co-generation power plant in hospitals, universities and large office buildings. UTC Power continues to market this fuel cell as the PureCell 200, a 200 kW system (although soon to be replaced by a 400 kW version, expected for sale in late 2009). UTC Power continues to be the sole supplier of fuel cells to NASA for use in space vehicles, having supplied fuel cells for the Apollo missions, and the Space Shuttle program
Space Shuttle program
NASA's Space Shuttle program, officially called Space Transportation System , was the United States government's manned launch vehicle program from 1981 to 2011...

, and is developing fuel cells for automobiles, buses, and cell phone towers; the company has demonstrated the first fuel cell capable of starting under freezing conditions with its proton exchange membrane
Proton exchange membrane
A proton exchange membrane or polymer electrolyte membrane is a semipermeable membrane generally made from ionomers and designed to conduct protons while being impermeable to gases such as oxygen or hydrogen...

.

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 segments which are sandwiched together: the anode
Anode
An anode is an electrode through which electric current flows into a polarized electrical device. Mnemonic: ACID ....

, the electrolyte
Electrolyte
In chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....

, and the cathode
Cathode
A cathode is an electrode through which electric current flows out of a polarized electrical device. Mnemonic: CCD .Cathode polarity is not always negative...

. 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 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.
The most important design features in a fuel cell are:
  • The electrolyte substance. The electrolyte substance usually defines the type of fuel cell.
  • The fuel that is used. The most common fuel is hydrogen.
  • The anode catalyst, which breaks down the fuel into electrons and ions. The anode catalyst is usually made up of very fine platinum powder.
  • The cathode catalyst, which turns the ions into the waste chemicals like water or carbon dioxide. The cathode catalyst is often made up of nickel
    Nickel
    Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...

    .


A typical fuel cell produces a voltage from 0.6 V to 0.7 V at full rated load. Voltage decreases as current increases, due to several factors:
  • Activation loss
    Overpotential
    Overpotential is an electrochemical term which refers to the potential difference between a half-reaction's thermodynamically determined reduction potential and the potential at which the redox event is experimentally observed. The term is directly related to a cell's voltage efficiency...

  • Ohmic loss (voltage drop
    Voltage drop
    Voltage drop is the reduction in voltage in the passive elements of an electrical circuit. Voltage drops across conductors, contacts, connectors and source internal resistances are undesired as they reduce the supplied voltage while voltage drops across loads and other electrical and electronic...

     due to resistance of the cell components and interconnects)
  • 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 and parallel circuits
Series and parallel circuits
Components of an electrical circuit or electronic circuit can be connected in many different ways. The two simplest of these are called series and parallel and occur very frequently. Components connected in series are connected along a single path, so the same current flows through all of the...

, where series yields higher voltage
Voltage
Voltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...

, and parallel allows a higher current
Electric current
Electric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...

 to be supplied. Such a design is called a fuel cell stack. The cell surface area can be increased, to allow stronger current
Electric current
Electric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...

 from each cell.

Proton exchange membrane fuel cells


In the archetypical hydrogen–oxygen proton exchange membrane fuel cell
Proton exchange membrane fuel cell
Proton exchange membrane fuel cells, also known as polymer electrolyte membrane fuel cells , are a type of fuel cell being developed for transport applications as well as for stationary fuel cell applications and portable fuel cell applications. Their distinguishing features include lower...

 (PEMFC) design, a proton-conducting polymer membrane, (the electrolyte
Electrolyte
In chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....

), separates the anode
Anode
An anode is an electrode through which electric current flows into a polarized electrical device. Mnemonic: ACID ....

 and cathode
Cathode
A cathode is an electrode through which electric current flows out of a polarized electrical device. Mnemonic: CCD .Cathode polarity is not always negative...

 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 "polymer electrolyte membrane" and "proton exchange mechanism" result in the same acronym.)

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 is 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
Molecule
A molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...

s react with the electrons (which have traveled through the external circuit) and protons to form water — in this example, the only waste product, either liquid
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

 or vapor
Water vapor
Water vapor or water vapour , also aqueous vapor, is the gas phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Under typical atmospheric conditions, water vapor is continuously...

.

In addition to this pure hydrogen type, there are hydrocarbon
Hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....

 fuels for fuel cells, including diesel, methanol
Methanol
Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...

 (see: direct-methanol fuel cell
Direct-methanol fuel cell
Direct-methanol fuel cells or DMFCs are a subcategory of proton-exchange fuel cells in which methanol is used as the fuel. Their main advantage is the ease of transport of methanol, an energy-dense yet reasonably stable liquid at all environmental conditions.Efficiency is presently quite low for...

s and indirect methanol fuel cells) and chemical hydrides. The waste products with these types of fuel are carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

 and water.

The different components of a PEMFC are (i) bipolar plates, (ii) electrode
Electrode
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit...

s, (iii) catalyst, (iv) membrane, and (v) the necessary hardwares. 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
The mineral graphite is one of the allotropes of carbon. It was named by Abraham Gottlob Werner in 1789 from the Ancient Greek γράφω , "to draw/write", for its use in pencils, where it is commonly called lead . Unlike diamond , graphite is an electrical conductor, a semimetal...

, flexible graphite, C–C composite
Composite material
Composite materials, often shortened to composites or called composition materials, are engineered or naturally occurring materials made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct at the macroscopic or...

, carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...

polymer
Polymer
A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...

 composites etc. The membrane electrode assembly
Membrane electrode assembly
A membrane electrode assembly is an assembled stack of proton exchange membranes or alkali anion exchange membrane , catalyst and flat plate electrode used in a fuel cell.-PEM-MEA:...

 (MEA), is referred as the heart of the PEMFC and usually made of a proton exchange membrane sandwiched between two catalyst coated carbon paper
Carbon paper
Carbon paper is paper coated on one side with a layer of a loosely bound dry ink or pigmented coating, usually bound with wax. It is used for making one or more copies simultaneous with the creation of an original document...

s.
Platinum
Platinum
Platinum is a chemical element with the chemical symbol Pt and an atomic number of 78. Its name is derived from the Spanish term platina del Pinto, which is literally translated into "little silver of the Pinto River." It is a dense, malleable, ductile, precious, gray-white transition metal...

 and/or similar type of noble metals are usually used as the catalyst for PEMFC. The electrolyte could be a polymer membrane
Artificial membrane
An artificial membrane, or synthetic membrane, is a synthetically created membrane which is usually intended for separation purposes in laboratory or in industry. Synthetic membranes have been successfully used for small and large-scale industrial processes since the middle of twentieth century. A...

.

Proton exchange membrane fuel cell design issues

  • Costs. In 2002, typical fuel cell systems were projected to cost per kilowatt of electric power output, assuming high-volume production of contemporary designs. At lower production volumes that do not incorporate economies of scale or a well-developed supply chain, costs are roughly one order of magnitude higher. In 2009, the Department of Energy reported that 80-kW automotive fuel cell system costs in volume production (projected to 500,000 units per year) are per kilowatt. The goal is per kilowatt. Cost reduction over a ramp-up period of about 20 years is needed in order for PEM fuel cells to compete with current market technologies, including gasoline internal combustion engines. 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
    Ballard Power Systems , located in Burnaby, British Columbia -- a suburb of Vancouver -- is a company that designs, develops, and manufactures zero emission proton-exchange-membrane fuel cells. This company has made a bus that uses only hydrogen fuel cells. These fuel cells combine hydrogen and...

     has experiments with a catalyst enhanced with carbon silk which allows a 30% reduction (1 mg/cm² to 0.7 mg/cm²) in platinum usage without reduction in performance. Monash University
    Monash University
    Monash University is a public university based in Melbourne, Victoria. It was founded in 1958 and is the second oldest university in the state. Monash is a member of Australia's Group of Eight and the ASAIHL....

    , Melbourne
    Melbourne
    Melbourne is the capital and most populous city in the state of Victoria, and the second most populous city in Australia. The Melbourne City Centre is the hub of the greater metropolitan area and the Census statistical division—of which "Melbourne" is the common name. As of June 2009, the greater...

     uses PEDOT
    Poly(3,4-ethylenedioxythiophene)
    Poly or PEDOT is a conducting polymer based on 3,4-ethylenedioxylthiophene or EDOT monomer. Advantages of this polymer are optical transparency in its conducting state, high stability and moderate band gap and low redox potential...

     as a cathode
    Cathode
    A cathode is an electrode through which electric current flows out of a polarized electrical device. Mnemonic: CCD .Cathode polarity is not always negative...

    . A 2011 published study documented the first metal-free electrocatalyst using relatively inexpensive doped carbon nanotubes that are less than 1% the cost of platinum and are of equal or superior performance.
  • 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 pump
    Electroosmotic pump
    An electroosmotic pump , or EO pump, is used for generating flow or pressure by use of an electric field. One application of this is removing liquid flooding water from channels and gas diffusion layers and direct hydration of the proton exchange membrane in the membrane electrode assembly of the...

    s 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
    Service life
    A product's service life is its expected lifetime, or the acceptable period of use in service. It is the time that any manufactured item can be expected to be 'serviceable' or supported by its manufacturer....

    , and special requirements for some type of cells. Stationary fuel cell applications 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 150000 miles) under extreme temperatures. Current service life
    Service life
    A product's service life is its expected lifetime, or the acceptable period of use in service. It is the time that any manufactured item can be expected to be 'serviceable' or supported by its manufacturer....

     is 7,300 hours under cycling conditions. 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 per liter).
  • Limited carbon monoxide
    Carbon monoxide
    Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...

     tolerance of some (non-PEDOT) cathodes.

SOFC


Solid oxide fuel cells use a solid material, most commonly a ceramic material called yttria-stabilized zirconia
Yttria-stabilized zirconia
Yttria-stabilized zirconia is a zirconium-oxide based ceramic, in which the particular crystal structure of zirconium oxide is made stable at room temperature by an addition of yttrium oxide...

 (YSZ), as the electrolyte
Electrolyte
In chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....

. 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 temperatures (800°C to 1000°C) and can be run on a variety of fuels including natural gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...

.

SOFCs are unique in that negatively charged oxygen ion
Ion
An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...

s travel from the cathode
Cathode
A cathode is an electrode through which electric current flows out of a polarized electrical device. Mnemonic: CCD .Cathode polarity is not always negative...

 (negative side of the fuel cell) to the anode
Anode
An anode is an electrode through which electric current flows into a polarized electrical device. Mnemonic: ACID ....

 (positive side of the fuel cell) instead of positively charged hydrogen ions travelling 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 reacts with 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 + 2O–2 → 2H2O + 4e
Cathode Reaction: O2 + 4e → 2O–2
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. In order 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 (natural gas), propane and butane. Heavier hydrocarbons including gasoline, diesel, jet fuel and biofuels can serve as fuels in a SOFC system, but an external reformer is required.

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 slow start-up time, 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
Ionic conductivity
Ionic conduction is the movement of an ion from one site to another through defects in the crystal lattice of a solid. Ionic conduction is one aspect of current....

 of YSZ. Therefore, to obtain optimum performance of the fuel cell, a high operating temperature is required. According to their website, Ceres Power
Ceres Power
Ceres Power is a UK-based company that is developing a fuel-cell boiler for the UK domestic CHP market.The boiler produces both heat and electricity. The design is small enough to be wall-mounted and is therefore compatible with the layout of most central heating systems in the UK.At the heart of...

, 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.

MCFC



Molten carbonate fuel cells (MCFCs) require a high operating temperature (650°C), similar to (SOFCs). MCFCs use lithium potassium carbonate salt as an electrolyte, and at high temperatures, this salt melts into a molten state that allows for the movement of charge (in this case, negative carbonate ions) within the cell.

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 CO2 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: CO3-2 + H2 → H2O + CO2 + 2e-
Cathode Reaction: CO2 + ½O2 + 2e- → CO3-2
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 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
Cogeneration is the use of a heat engine or a power station to simultaneously generate both electricity and useful heat....

 (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%.

Comparison of fuel cell types

! Fuel cell name
! Electrolyte
! Qualified power
Electric power
Electric power is the rate at which electric energy is transferred by an electric circuit. The SI unit of power is the watt.-Circuits:Electric power, like mechanical power, is represented by the letter P in electrical equations...

 (W)
! Working temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...

 (°C)
! Efficiency (cell)
! Efficiency (system)
! Status
! Cost (USD/W)
|-
||Metal hydride fuel cell
Metal hydride fuel cell
Metal hydride fuel cells are a subclass of alkaline fuel cells that are currently in the research and development phase. A notable feature is their ability to chemically bond and store hydrogen within the cell. This feature is shared with direct borohydride fuel cells, although the two differ in...


|Aqueous alkali
Alkali
In chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal element. Some authors also define an alkali as a base that dissolves in water. A solution of a soluble base has a pH greater than 7. The adjective alkaline is commonly used in English as a synonym for base,...

ne solution
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||Electro-galvanic fuel cell
Electro-galvanic fuel cell
An electro-galvanic fuel cell is an electrical device, one form of which is commonly used to measure the concentration of oxygen gas in scuba diving and medical equipment....


|Aqueous alkaline solution
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||Direct formic acid fuel cell
Formic acid fuel cell
Direct-formic acid fuel cells or DFAFCs are a subcategory of proton exchange membrane fuel cells where, the fuel, formic acid, is not reformed, but fed directly to the fuel cell...

  (DFAFC)
|Polymer membrane (ionomer)
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||Zinc-air battery
Zinc-air battery
Zinc–air batteries , and zinc–air fuel cells, are electro-chemical batteries powered by oxidizing zinc with oxygen from the air. These batteries have high energy densities and are relatively inexpensive to produce...


|Aqueous alkaline solution
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|Mass production
Mass production
Mass production is the production of large amounts of standardized products, including and especially on assembly lines...


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||Microbial fuel cell
Microbial fuel cell
A microbial fuel cell or biological fuel cell is a bio-electrochemical system that drives a current by mimicking bacterial interactions found in nature....


|Polymer membrane or humic acid
Humic acid
Humic acid is a principal component of humic substances, which are the major organic constituents of soil , peat, coal, many upland streams, dystrophic lakes, and ocean water. It is produced by biodegradation of dead organic matter...


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||Regenerative fuel cell
|Polymer membrane (ionomer
Ionomer
An ionomer is a polymer that comprises repeat units of both electrically neutral repeating units and a fraction of ionized units...

)
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||Direct borohydride fuel cell
Direct borohydride fuel cell
Direct borohydride fuel cells are a subcategory of alkaline fuel cells which are directly fed by sodium borohydride or potassium borohydride as a fuel and either air/oxygen or hydrogen peroxide as the oxidant...


|Aqueous alkaline solution
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||Alkaline fuel cell
Alkaline fuel cell
The alkaline fuel cell , also known as the Bacon fuel cell after its British inventor, is one of the most developed fuel cell technologies. NASA has used alkaline fuel cells since the mid-1960s, in Apollo-series missions and on the Space Shuttle. AFCs consume hydrogen and pure oxygen producing...


|Aqueous alkaline solution
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||Direct methanol fuel cell
|Polymer membrane (ionomer)
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|125
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||Reformed methanol fuel cell
Reformed methanol fuel cell
Reformed Methanol Fuel Cell or Indirect Methanol Fuel Cell systems are a subcategory of proton-exchange fuel cells where, the fuel, methanol , is reformed, before being fed into the fuel cell...


|Polymer membrane (ionomer)
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||Direct-ethanol fuel cell
Direct-ethanol fuel cell
Direct-ethanol fuel cells or DEFCs are a subcategory of Proton-exchange fuel cells where the fuel, ethanol, is fed directly to the fuel cell.-Advantages:...


|Polymer membrane (ionomer)
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||Proton exchange membrane fuel cell
Proton exchange membrane fuel cell
Proton exchange membrane fuel cells, also known as polymer electrolyte membrane fuel cells , are a type of fuel cell being developed for transport applications as well as for stationary fuel cell applications and portable fuel cell applications. Their distinguishing features include lower...


|Polymer membrane (ionomer)
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| 30–35
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||RFC - Redox
|Liquid electrolytes with redox
Redox
Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....

 shuttle and polymer membrane (Ionomer)
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||Phosphoric acid fuel cell
|Molten phosphoric acid
Phosphoric acid
Phosphoric acid, also known as orthophosphoric acid or phosphoric acid, is a mineral acid having the chemical formula H3PO4. Orthophosphoric acid molecules can combine with themselves to form a variety of compounds which are also referred to as phosphoric acids, but in a more general way...

 (H3PO4)
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| 4–4.50
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||Molten carbonate fuel cell
|Molten alkaline carbonate
Carbonate
In chemistry, a carbonate is a salt of carbonic acid, characterized by the presence of the carbonate ion, . The name may also mean an ester of carbonic acid, an organic compound containing the carbonate group C2....

 
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||Tubular solid oxide fuel cell (TSOFC)
|O2--conducting ceramic oxide
Oxide
An oxide is a chemical compound that contains at least one oxygen atom in its chemical formula. Metal oxides typically contain an anion of oxygen in the oxidation state of −2....

 
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||Protonic ceramic fuel cell
Protonic ceramic fuel cell
The Protonic ceramic fuel cell or PCFC is a fuel cell based on a ceramic electrolyte material that exhibits high protonic conductivity at elevated temperatures....


|H+-conducting ceramic oxide
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||Direct carbon fuel cell
Direct carbon fuel cell
A Direct Carbon Fuel Cell is a fuel cell that uses a carbon rich material as a fuel. The cell produces energy by combining carbon and oxygen, which releases carbon dioxide as a by-product.The total reaction of the cell is C + O2 → CO2....


|Several different
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||Planar Solid oxide fuel cell
|O2--conducting ceramic oxide
Oxide
An oxide is a chemical compound that contains at least one oxygen atom in its chemical formula. Metal oxides typically contain an anion of oxygen in the oxidation state of −2....

 
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||Enzymatic Biofuel Cells
Enzymatic Biofuel Cells
An Enzymatic Biofuel Cell is a specific type of fuel cell which uses biocatalysts to convert energy stored within chemicals into electrical energy. Enzymes are used to catalytically oxidise the fuel at the anode and reduce the ensuing oxidant at the cathode...


|Any that will not denature the enzyme
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||Magnesium-Air Fuel Cell
Magnesium-air fuel cell
A Magnesium-Air Fuel Cell is a type of fuel cell which uses a magnesium anode, oxygen from air as a cathode and a salt water electrolyte.Research and commercialization of the technology by has shown an efficiency of 90% and an operating range of -20 to 55 degrees Celsius....


|salt water
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Efficiency of leading fuel cell types


Glossary of Terms in table:
  • Anode
    Anode
    An anode is an electrode through which electric current flows into a polarized electrical device. Mnemonic: ACID ....

    : 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
    Aqueous solution
    An aqueous solution is a solution in which the solvent is water. It is usually shown in chemical equations by appending aq to the relevant formula, such as NaCl. The word aqueous means pertaining to, related to, similar to, or dissolved in water...

    : a: of, relating to, or resembling water b : made from, with, or by water.
  • Catalyst: 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
    Cathode
    A cathode is an electrode through which electric current flows out of a polarized electrical device. Mnemonic: CCD .Cathode polarity is not always negative...

    :
    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
    Electrolyte
    In chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....

    : A substance that conducts charged ions from one electrode to the other in a fuel cell, battery, or electrolyzer.
  • 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
    Membrane (selective barrier)
    A membrane is a layer of material which serves as a selective barrier between two phases and remains impermeable to specific particles, molecules, or substances when exposed to the action of a driving force...

    : 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 (CO3-2) are transported from the cathode to the anode. Operating temperatures are typically near 650°C.
  • Phosphoric Acid Fuel Cell (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°C–220°C.
  • Polymer Electrolyte Membrane (PEM)
    Proton exchange membrane fuel cell
    Proton exchange membrane fuel cells, also known as polymer electrolyte membrane fuel cells , are a type of fuel cell being developed for transport applications as well as for stationary fuel cell applications and portable fuel cell applications. Their distinguishing features include lower...

    : 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°C–100°C.
  • Solid Oxide Fuel Cell (SOFC): A type of fuel cell in which the electrolyte is a solid, nonporous metal oxide, typically zirconium oxide (ZrO2) treated with Y2O3, and O-2 is transported from the cathode to the anode. Any CO in the reformate gas is oxidized to at the anode. Temperatures of operation are typically 800°C–1,000°C.
  • Solution
    Solution
    In chemistry, a solution is a homogeneous mixture composed of only one phase. In such a mixture, a solute is dissolved in another substance, known as a solvent. The solvent does the dissolving.- Types of solutions :...

    :
    a: an act or the process by which a solid, liquid, or gaseous substance is homogeneously mixed with a liquid or sometimes a gas or solid, b : a homogeneous mixture formed by this process; especially : a single-phase liquid system, c : the condition of being dissolved


For more information see Glossary of fuel cell terms
Glossary of fuel cell terms
The Glossary of fuel cell terms lists the definitions of many terms used within the fuel cell industry. The terms in this fuel cell glossary may be used by fuel cell industry associations, in education material and fuel cell codes and standards to name but a few. –...


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 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 40–60% 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. In combined heat and power (CHP) systems, the heat produced by the fuel cell 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 rarely 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 maximum theoretical energy efficiency of a fuel cell is 83%, operating at low power density and using pure hydrogen and oxygen as reactants (assuming no heat recapture) According to the World Energy Council, this compares with a maximum theoretical efficiency of 58% for internal combustion engines. While these efficiencies are not approached in most real world applications, high temperature fuel cells (solid oxide fuel cells or molten carbonate fuel cells) can theoretically be combined with gas turbines to allow stationary fuel cells to come closer to the theoretical limit. A gas turbine would capture heat from the fuel cell and turn it into mechanical energy to increase the fuel cell’s operational efficiency. This solution has been predicted to increase total efficiency to as much as 70%.

In practice


The tank-to-wheel efficiency of a fuel cell vehicle
Fuel cell vehicle
A Fuel cell vehicle or Fuel Cell Electric Vehicle is a type of hydrogen vehicle which uses a fuel cell to produce electricity, powering its on-board electric motor...

 is greater than 45% at low loads and shows average values of about 36% when a driving cycle like the NEDC (New European Driving Cycle
New European Driving Cycle
The New European Driving Cycle is a driving cycle consisting of four repeated ECE-15 driving cycles and an Extra-Urban driving cycle . The NEDC is supposed to represent the typical usage of a car in Europe, and is used, among other things, to assess the emission levels of car engines...

) 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) 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
Liquid hydrogen 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 pressurized above and cooled below hydrogen's Critical point. However, for hydrogen to be in a full liquid state without boiling off, it needs to be...

. 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
Wind power is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electricity, windmills for mechanical power, windpumps for water pumping or drainage, or sails to propel ships....

, they are combined with electrolyzers
Electrolysis
In chemistry and manufacturing, electrolysis is a method of using a direct electric current to drive an otherwise non-spontaneous chemical reaction...

 and storage systems to form an energy storage system. Most hydrogen, however, is produced by steam methane reforming, and so most hydrogen production 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. While a much cheaper lead–acid battery might return about 90%, the electrolyzer/fuel cell system can store indefinite quantities of hydrogen, and is therefore better suited for long-term storage.

Solid-oxide fuel cells produce exothermic 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 journal Interface in 2008, wrote, "While fuel cells are efficient relative to combustion engines, they are not as efficient as batteries, due primarily to the inefficiency of the oxygen reduction reaction (and ... the oxygen evolution reaction, should the hydrogen be formed by electrolysis of water). ... [T]hey 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 [PEM fuel cell] is becoming an increasingly attractive choice [if exchanging batteries is inconvenient]".

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 cellelectrolyzer 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. 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 produced, compared to 25 pounds of pollutants generated by conventional combustion systems. Fuel Cells also produce 97% less nitrogen oxide emissions then conventional coal-fired power plants.

Coca-Cola, Google, Sysco, FedEx, UPS, Ikea, Staples, Whole Foods, Gills Onions, Nestle Waters, Pepperidge Farm, Sierra Nevada Brewery, Super Store Industries, Brigestone-Firestone, Nissan North America, Kimberly-Clark, Michelin and more have installed fuel cells to help meet their power needs. 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 500 gallons (1,892.7 l) at 200 pound per square inches (1,378,951.5 Pa), and runs a ReliOn fuel cell to provide full electric back-up to the off-the-grid residence.

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
Home fuel cell
A home fuel cell, also called micro combined heat and power and microgeneration, is a residential-scaled clean energy system. A home fuel cell is an alternative energy technology that increases efficiency by simultaneously generating power and heat from one unit, on-site within a home...

), office building and factories. These stationary fuel cells are already in the mass production phase. 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
Waste heat sometimes called Secondary heat or Low-grade heat refers to heat produced by machines, electrical equipment and industrial processes for which no useful application is found. Energy is often produced by a heat engine, running on a source of high-temperature heat...

. MicroCHP is usually less than 5 kWe for a home fuel cell
Home fuel cell
A home fuel cell, also called micro combined heat and power and microgeneration, is a residential-scaled clean energy system. A home fuel cell is an alternative energy technology that increases efficiency by simultaneously generating power and heat from one unit, on-site within a home...

 or small business.

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 + 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 effciences around 60%.

Fuel Cell Electric Vehicles (FCEVs)







Automobiles


Although there are currently no Fuel cell vehicle
Fuel cell vehicle
A Fuel cell vehicle or Fuel Cell Electric Vehicle is a type of hydrogen vehicle which uses a fuel cell to produce electricity, powering its on-board electric motor...

s available for commercial sale, over 20 FCEVs prototypes and demonstration cars have been released since 2009. Demonstration models include the Honda FCX Clarity, Toyota FCHV-adv, and Mercedes-Benz F-Cell
Mercedes-Benz F-Cell
The F-Cell is a hydrogen fuel cell 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 generation F-Cell was introduced in 2002, and had a range of , with...

. As of June 2011 demonstration FCEVs had driven more than 3000000 miles, with more than 27,000 refuelings. Demonstration fuel cell vehicles have been produced with "a driving range of more than 250 miles between refueling". They can be refueled in less than 5 minutes. The U.S. Department of Energy's Fuel Cell Technology Program claims that, as of 2011, fuel cells achieved 53–59% efficiency at ¼ power and 42–53% vehicle efficiency at full power, and a durability of over 75000 miles with less than 10% degradation, double that achieved in 2006. In a Well-to-Wheels simulation analysis, that "did not address the economics and market constraints", General Motors and its partners estimated that per mile traveled, 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. A lead engineer from the Department of Energy whose team is testing fuel cell cars said in 2011 that the potential appeal is that "these are full-function vehicles with no limitations on range or refueling rate so they are a direct replacement for any vehicle. For instance, if you drive a full sized SUV and pull a boat up into the mountains, you can do that with this technology and you can't with current battery-only vehicles, which are more geared toward city driving."

Some experts believe that fuel cell cars will never become economically competitive with other technologies or that it will take decades for them to become profitable. In July 2011, the Chairman and CEO of General Motors
General Motors
General Motors Company , commonly known as GM, formerly incorporated as General Motors Corporation, is an American multinational automotive corporation headquartered in Detroit, Michigan and the world's second-largest automaker in 2010...

, Daniel Akerson
Daniel Akerson
Daniel Francis "Dan" Akerson, is the current Chairman and CEO of General Motors. Akerson succeeded Edward Whitacre as CEO on September 1, 2010, and became Chairman of the Board on January 1, 2011. Akerson was a Managing Director of The Carlyle Group and head of global buyout prior to joining...

, stated that while the cost of hydrogen fuel cell cars is decreasing: "The car is still too expensive and probably won't be practical until the 2020-plus period, I don't know." Analyses cite the lack of an extensive hydrogen infrastructure
Hydrogen infrastructure
A hydrogen infrastructure is the infrastructure of pipes and stations for distribution and sale of hydrogen fuel.-Hydrogen pipeline transport:Hydrogen pipeline transport is a transportation of hydrogen through a pipe as part of the hydrogen infrastructure...

 in the U.S. as an ongoing challenge to Fuel Cell Electric Vehicle commercialization. In 2006, a study for the IEEE showed that for hydrogen produced via electrolysis of water: "Only about 25% of the power generated from wind, water, or sun is converted to practical use." The study further noted that "Electricity obtained from hydrogen fuel cells appears to be four times as expensive as electricity drawn from the electrical transmission grid. ... Because of the high energy losses [hydrogen] cannot compete with electricity." Furthermore, the study found: "Natural gas reforming is not a sustainable solution". "The large amount of energy required to isolate hydrogen from natural compounds (water, natural gas, biomass), package the light gas by compression or liquefaction, transfer the energy carrier to the user, plus the energy lost when it is converted to useful electricity with fuel cells, leaves around 25% for practical use." Despite this, several major car manufacturers have announced plans to introduce a production model of a fuel cell car in 2015. Toyota has stated that it plans to introduce such a vehicle at a price of around . In June 2011, Mercedes-Benz announced that they would move the scheduled production date of their fuel cell car from 2015 up to 2014, asserting that "The product is ready for the market technically. ... The issue is infrastructure."

In 2003 US President George Bush proposed the Hydrogen Fuel Initiative (HFI). This aimed at further developing hydrogen fuel cells and infrastructure technologies with the goal of producing commercial fuel cell vehicles. By 2008, the U.S. had contributed 1 billion dollars to this project. The Obama Administration has sought to reduce funding for the development of fuel cell vehicles, concluding that other vehicle technologies will lead to quicker reduction in emissions in a shorter time. Steven Chu
Steven Chu
Steven Chu is an American physicist and the 12th United States Secretary of Energy. Chu is known for his research at Bell Labs in cooling and trapping of atoms with laser light, which won him the Nobel Prize in Physics in 1997, along with his scientific colleagues Claude Cohen-Tannoudji and...

, the US Secretary of Energy, stated that hydrogen vehicles "will not be practical over the next 10 to 20 years". He told MIT's Technology Review
Technology Review
Technology Review is a magazine published by the Massachusetts Institute of Technology. It was founded in 1899 as "The Technology Review", and was re-launched without the "The" in its name on April 23, 1998 under then publisher R. Bruce Journey...

that he is skeptical about hydrogen's use in transportation because of four problems: "the way we get hydrogen primarily is from reforming [natural] gas. ... You're giving away some of the energy content of natural gas. ... [For] transportation, we don't have a good storage mechanism yet. ... The fuel cells aren't there yet, and the distribution infrastructure isn't there yet. ... In order to get significant deployment, you need four significant technological breakthroughs. Critics disagree. Mary Nichols, Chairwoman of California's Air Resources Board, said: "Secretary Chu has firmly set his mind against hydrogen as a passenger-car fuel. Frankly, his explanations don’t make sense to me. They are not based on the facts as we know them."

Buses


In total there are over 100 fuel cell bus
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....

es deployed around the world today. Most buses are produced by UTC Power, Toyota, Ballard, Hydrogenics, and Proton Motor. UTC Buses have already accumulated over 600000 miles of driving. Fuel cell buses have a 30-141% higher fuel economy than diesel buses and natural gas buses. Fuel cell buses have been deployed around the world including in Whistler Canada, San Francisco USA, Hamburg Germany, Shanghai China, London England, São Paulo Brazil as well as several others. The Fuel Cell Bus Club
Fuel Cell Bus Club
The Fuel Cell Bus Club comprises the participants of the projects CUTE, ECTOS and STEP. Their website title says "the first fuel cell bus fleet"....

 is a global cooperative effort in trial fuel cell buses. Notable Projects Include:
  • 12 Fuel cell buses are being deployed in the Oakland and San Francisco Bay area of California.
  • Daimler AG, with thirty-six experimental buses powered by Ballard Power Systems
    Ballard Power Systems
    Ballard Power Systems , located in Burnaby, British Columbia -- a suburb of Vancouver -- is a company that designs, develops, and manufactures zero emission proton-exchange-membrane fuel cells. This company has made a bus that uses only hydrogen fuel cells. These fuel cells combine hydrogen and...

     fuel cells completed a successful three-year trial, in eleven cities, in January 2007.
  • A fleet of Thor buses with UTC Power
    United Technologies Corporation
    United Technologies Corporation is an American multinational conglomerate headquartered in the United Technologies Building in Hartford, Connecticut...

     fuel cells was deployed in California, operated by SunLine Transit Agency.


The first Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

ian hydrogen
Hydrogen vehicle
A hydrogen vehicle is a vehicle that uses hydrogen as its onboard fuel for motive power. Hydrogen vehicles include hydrogen fueled space rockets, as well as automobiles and other transportation vehicles...

 fuel cell bus prototype in Brazil was deployed in São Paulo
São Paulo
São Paulo is the largest city in Brazil, the largest city in the southern hemisphere and South America, and the world's seventh largest city by population. The metropolis is anchor to the São Paulo metropolitan area, ranked as the second-most populous metropolitan area in the Americas and among...

. The bus was manufactured in Caxias do Sul
Caxias do Sul
Caxias do Sul is a city in Rio Grande do Sul, Southern Brazil, situated in the state's mountainous Serra Gaúcha region. Coordinates: 29°10′0″ S, 51°11′0″ W....

 and the hydrogen fuel will be produced in São Bernardo do Campo
São Bernardo do Campo
São Bernardo do Campo is a municipality in the state of São Paulo, in southern Metropolitan São Paulo and São Paulo microregion. The municipality's total area is 408.45 km ² and a population estimated at 1 July 2009, according to the IBGE, was 810,979 inhabitants, which results in a population...

 from water through electrolysis
Electrolysis
In chemistry and manufacturing, electrolysis is a method of using a direct electric current to drive an otherwise non-spontaneous chemical reaction...

. The program, called "Ônibus Brasileiro a Hidrogênio" (Brazilian Hydrogen Autobus), includes three additional buses.

Forklifts


Fuel cell powered forklifts are one of the largest sectors of fuel cell applications in the industry. Most fuel cells used for material handling purposes are powered by PEM fuel cells, although some direct methanol fuel forklifts are coming onto the market. Fuel cell fleets are currently being operated by a large number of companies, including Sysco Foods, FedEx Freight, GENCO (at Wegmans, Coca-Cola, Kimberly Clark, Sysco Foods, and Whole Foods), and H-E-B Grocers.

Fuel cell powered forklifts provide significant benefits over both petroleum and battery powered forklifts as they produce no local emissions, can work for a full 8 hour shift on a single tank of hydrogen, can be refueled in 3 minutes and have a lifetime of 8–10 years. Fuel cell powered forklifts are often used in refrigerated warehouses as their performance is not degraded by lower temperatures. Many companies do not use petroleum powered forklifts, as these vehicles work indoors where emissions must be controlled and instead are turning towards electric forklifts. Fuel cell forklifts offer green house gas, product lifetime, maintenance cost, refueling and labor cost benefits over battery operated fork lifts.

Motorcycles and bicycles


In 2005 the British firm Intelligent Energy produced the first ever working hydrogen run motorcycle
Motorcycle
A motorcycle is a single-track, two-wheeled motor vehicle. Motorcycles vary considerably depending on the task for which they are designed, such as long distance travel, navigating congested urban traffic, cruising, sport and racing, or off-road conditions.Motorcycles are one of the most...

 called the ENV
ENV
The ENV is an electric motorcycle prototype powered by an hydrogen fuel cell. It is being developed by Intelligent Energy, a British company.-Specifications:...

 (Emission Neutral Vehicle). The motorcycle holds enough fuel to run for four hours, and to travel 100 miles in an urban area, at a top speed of 50 mph (80 km/h). In 2004 Honda
Honda
is a Japanese public multinational corporation primarily known as a manufacturer of automobiles and motorcycles.Honda has been the world's largest motorcycle manufacturer since 1959, as well as the world's largest manufacturer of internal combustion engines measured by volume, producing more than...

 developed a fuel-cell motorcycle which utilized the Honda FC Stack. There are other examples of bikes and bicycles with a hydrogen fuel cell engine.

Airplanes


Boeing
Boeing
The Boeing Company is an American multinational aerospace and defense corporation, founded in 1916 by William E. Boeing in Seattle, Washington. Boeing has expanded over the years, merging with McDonnell Douglas in 1997. Boeing Corporate headquarters has been in Chicago, Illinois since 2001...

 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
Battery (electricity)
An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...

. The Fuel Cell Demonstrator Airplane, as it was called, used a Proton Exchange Membrane (PEM) fuel cell/lithium-ion battery hybrid system to power an electric motor, which was coupled to a conventional propeller.
In 2003, the world's first propeller driven airplane to be powered entirely by a fuel cell was flown. The fuel cell was a unique FlatStackTM stack design which allowed the fuel cell to be integrated with the aerodynamic surfaces of the plane.

There have been several fuel cell powered unmanned aerial vehicles (UAV). A Horizen fuel cell UAV set the record distance flow for a small UAV in 2007. The military is especially interested in this application because of the low noise, low thermal signature and ability to attain high altitude. 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. Boeing is completing tests on the Phantom Eye, a high-altitude, long endurance (HALE) to be used to conduce research and surveillance flying at 65000 ft (19,812 m) for up to four days at a time. Fuel cells are also being used to provide auxiliary power power aircraft, replacing fossil fuel generators that were previously used to start the engines and power on board electrical needs. Fuel cells can help airplanes reduce and other pollutant emissions and noise.

Boats


The world's first Fuel Cell Boat HYDRA
Hydra (ship)
The Hydra is a 22 person hydrogen ship, power-assisted by an electric motor that gets its electricity from a fuel cell. The debut was in June 2000 on the Rhine near Bonn, Germany....

 used an AFC system with 6.5 kW net output. Iceland has committed to converting its vast fishing fleet to use fuel cells to provide auxiliary power by 2015 and, eventually, to provide primary power in its boats. Amsterdam recently introduced its first fuel cell powered boat that ferries people around the city's famous and beautiful canals.

Submarines


The Type 212 submarine
Type 212 submarine
The German Type 212 class, also Italian Todaro class, is a highly advanced design of non-nuclear submarine developed by Howaldtswerke-Deutsche Werft AG and Fincantieri S.p.a. for the German and Italian Navy. It features diesel propulsion and an additional air-independent propulsion system using...

s of the German and Italian navies use fuel cells to remain submerged for weeks without the need to surface.

The latest in fuel cell submarines is the U212A—an ultra-advanced non-nuclear sub developed by German naval shipyard Howaldtswerke Deutsche Werft, who claim it to be "the peak of German submarine technology." The system consists of nine PEM (polymer electrolyte membrane) fuel cells, providing between 30 kW and 50 kW each. The ship is totally silent giving it a distinct advantage in the detection of other submarines. Fuel cells offer some distinct advantages to submarines, in addition to being completely silent, and can be distributed throughut a ship to improve balance and require far less air to run, allowing ships to be submerged for longer periods of time. Fuel cells offer a good alternative to nuclear fuels.

Other applications

  • Providing power for base station
    Base station
    The term base station can be used in the context of land surveying and wireless communications.- Land surveying :In the context of external land surveying, a base station is a GPS receiver at an accurately-known fixed location which is used to derive correction information for nearby portable GPS...

    s or cell site
    Cell site
    A cell site is a term used to describe a site where antennas and electronic communications equipment are placed, usually on a radio mast, tower or other high place, to create a cell in a cellular network...

    s
  • Off-grid
    Electric power transmission
    Electric-power transmission is the bulk transfer of electrical energy, from generating power plants to Electrical substations located near demand centers...

     power supply
  • Distributed generation
    Distributed generation
    Distributed generation, also called on-site generation, dispersed generation, embedded generation, decentralized generation, decentralized energy or distributed energy, generates electricity from many small energy sources....

  • Fork Lifts
  • Emergency power systems 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 hospital
    Hospital
    A hospital is a health care institution providing patient treatment by specialized staff and equipment. Hospitals often, but not always, provide for inpatient care or longer-term patient stays....

    s, scientific laboratories, data center
    Data center
    A data center is a facility used to house computer systems and associated components, such as telecommunications and storage systems...

    s, telecommunication
    Telecommunication
    Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...

     equipment and modern naval ships.
  • An uninterrupted power supply (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 plant
    Base load power plant
    Baseload is the minimum amount of power that a utility or distribution company must make available to its customers, or the amount of power required to meet minimum demands based on reasonable expectations of customer requirements...

    s
  • Fuel cell APU for Refuse Collection Vehicle
  • Electric
    Electric vehicle
    An electric vehicle , also referred to as an electric drive vehicle, uses one or more electric motors or traction motors for propulsion...

     and hybrid vehicle
    Hybrid vehicle
    A hybrid vehicle is a vehicle that uses two or more distinct power sources to move the vehicle. The term most commonly refers to hybrid electric vehicles , which combine an internal combustion engine and one or more electric motors.-Power:...

    s.
  • Notebook computers for applications where AC
    Alternating current
    In alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....

     charging may not be available for weeks at a time.
  • Portable charging docks for small electronics (e.g. a belt clip that charges your cell phone or PDA
    Personal digital assistant
    A personal digital assistant , also known as a palmtop computer, or personal data assistant, is a mobile device that functions as a personal information manager. Current PDAs often have the ability to connect to the Internet...

    ).
  • Smartphones with high power consumption due to large displays and additional features like GPS might be equipped with micro fuel cells.
  • Small heating appliances

Fueling stations




There are already over 85 hydrogen refueling stations in the U.S. The National Research Council estimated that creating the infrastructure to supply fuel for 10 million FCVs through 2025 would cost the government over 16 years.

The first public hydrogen refueling station was opened in Reykjavík
Reykjavík
Reykjavík is the capital and largest city in Iceland.Its latitude at 64°08' N makes it the world's northernmost capital of a sovereign state. It is located in southwestern Iceland, on the southern shore of Faxaflói Bay...

, Iceland
Iceland
Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...

 in April 2003. This station serves three buses built by DaimlerChrysler
DaimlerChrysler
Daimler AG is a German car corporation. By unit sales, it is the thirteenth-largest car manufacturer and second-largest truck manufacturer in the world. In addition to automobiles, Daimler manufactures buses and provides financial services through its Daimler Financial Services arm...

 that are in service in the public transport
Public transport
Public transport is a shared passenger transportation service which is available for use by the general public, as distinct from modes such as taxicab, car pooling or hired buses which are not shared by strangers without private arrangement.Public transport modes include buses, trolleybuses, trams...

 net of Reykjavík. The station produces the hydrogen it needs by itself, with an electrolyzing unit (produced by Norsk Hydro
Norsk Hydro
Norsk Hydro ASA is a Norwegian aluminium and renewable energy company, headquartered in Oslo. Hydro is the fourth largest integrated aluminium company worldwide. It has operations in some 40 countries around the world and is active on all continents. The Norwegian state holds a 43.8 percent...

), and does not need refilling: all that enters is electricity and water. Royal Dutch Shell
Royal Dutch Shell
Royal Dutch Shell plc , commonly known as Shell, is a global oil and gas company headquartered in The Hague, Netherlands and with its registered office in London, United Kingdom. It is the fifth-largest company in the world according to a composite measure by Forbes magazine and one of the six...

 is also a partner in the project. The station has no roof, in order to allow any leaked hydrogen to escape to the atmosphere.

As part of the California Hydrogen Highway initiative California has the most extensive hydrogen refueling infrastructure in the U.S.A. As of June 2011 California had 22 hydrogen refueling stations in operation. Honda announced plans in March 2011 to open the first station that would generate hydrogen through solar-powered renewable electrolysis. South Carolina
South Carolina
South Carolina is a state in the Deep South of the United States that borders Georgia to the south, North Carolina to the north, and the Atlantic Ocean to the east. Originally part of the Province of Carolina, the Province of South Carolina was one of the 13 colonies that declared independence...

 also has two hydrogen fueling stations, in Aiken and Columbia, SC. According to the South Carolina Hydrogen & Fuel Cell Alliance
South Carolina Hydrogen & Fuel Cell Alliance
The South Carolina Hydrogen & Fuel Cell Alliance is a Public-private collaborative with a mission of advancing the commercialization of hydrogen fuel cell technologies in the state of South Carolina. Government entities, in particular, the Department of Energy has funded SCHFCA with $188,788 for...

, the Columbia station has a current capacity of 120 kg a day, with future plans to develop on-site hydrogen production from electrolysis and reformation. The Aiken station has a current capacity of 80 kg. The University of South Carolina
University of South Carolina
The University of South Carolina is a public, co-educational research university located in Columbia, South Carolina, United States, with 7 surrounding satellite campuses. Its historic campus covers over in downtown Columbia not far from the South Carolina State House...

, a founding member of the South Carolina Hydrogen & Fuel Cell Alliance
South Carolina Hydrogen & Fuel Cell Alliance
The South Carolina Hydrogen & Fuel Cell Alliance is a Public-private collaborative with a mission of advancing the commercialization of hydrogen fuel cell technologies in the state of South Carolina. Government entities, in particular, the Department of Energy has funded SCHFCA with $188,788 for...

, received 12.5 million dollars from the United States Department of Energy
United States Department of Energy
The United States Department of Energy is a Cabinet-level department of the United States government concerned with the United States' policies regarding energy and safety in handling nuclear material...

 for its Future Fuels Program.

Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

 also has a hydrogen highway
Hydrogen highway (Japan)
Japan's hydrogen highway is a network of hydrogen filling stations placed along roadsides that provide fuel for hydrogen fuel cell vehicles . An HFCV is a vehicle that uses a fuel cell to convert hydrogen energy into electrical energy. Fuel cell technology is what allowed for the hydrogen highway...

, as part of the Japan hydrogen fuel cell project. Twelve hydrogen fueling stations
Hydrogen station
A hydrogen station is a storage or filling station for hydrogen, usually located along a road or hydrogen highway, or at home as part of the distributed generation resources concept. The stations are usually intended to power vehicles, but can also be used to power small devices. Vehicles use...

 have been built in 11 cities in Japan. Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

, Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....

 and Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

 also have hydrogen highway
Hydrogen highway
A hydrogen highway is a chain of hydrogen-equipped filling stations and other infrastructure along a road or highway which allow hydrogen powered cars to travel. It is an element of the hydrogen infrastructure that is generally assumed to be a pre-requisite for mass utilization of hydrogen cars....

s implemented.

Markets and economics


In 2010, fuel cell industry revenues exceeded a $750 million market value worldwide, although, as of 2010, no public company in the industry had yet become profitable. There were 140,000 fuel cell stacks shipped globally in 2010, up from 11 thousand shipments in 2007, and in 2010 worldwide fuel cell shipments had an annual growth rate of 115%. 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 remain the United States, Germany, Japan and South Korea. 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. Bloom Energy, a major fuel cell supplier, says its fuel cells will meet a return on investment in 3–5 years, as its fuel cells generate power at 9-11 cents per kilowatt-hour, including the price of fuel, maintenance, and hardware.

Low temperature fuel cell stacks proton exchange membrane fuel cell
Proton exchange membrane fuel cell
Proton exchange membrane fuel cells, also known as polymer electrolyte membrane fuel cells , are a type of fuel cell being developed for transport applications as well as for stationary fuel cell applications and portable fuel cell applications. Their distinguishing features include lower...

 (PEMFC), direct methanol fuel cell (DMFC) and phosphoric acid fuel cell (PAFC) use a platinum
Platinum
Platinum is a chemical element with the chemical symbol Pt and an atomic number of 78. Its name is derived from the Spanish term platina del Pinto, which is literally translated into "little silver of the Pinto River." It is a dense, malleable, ductile, precious, gray-white transition metal...

 catalyst. Impurities create catalyst poisoning
Catalyst poisoning
Catalyst poisoning refers to the effect that a catalyst can be 'poisoned' if it reacts with another compound that bonds chemically to its active surface sites. This effectively reduces the usefulness of the catalyst...

 (reducing activity and efficiency) in these low-temperature fuel cells, thus high hydrogen purity
Hydrogen purity
Hydrogen purity or hydrogen quality is a term to describe the lack of impurities in hydrogen as a fuel gas. The purity requirement varies with the application, for example a H2 ICE can tolerate low hydrogen purity where a hydrogen fuel cell requires high hydrogen purity to prevent catalyst...

 or higher catalyst densities are required. Although there are sufficient platinum resources for future demand, most predictions of platinum running out and/or platinum prices soaring do not take into account effects of reduction in catalyst loading and recycling. Recent research at Brookhaven National Laboratory
Brookhaven National Laboratory
Brookhaven National Laboratory , is a United States national laboratory located in Upton, New York on Long Island, and was formally established in 1947 at the site of Camp Upton, a former U.S. Army base...

 could lead to the replacement of platinum by a gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...

-palladium
Palladium
Palladium is a chemical element with the chemical symbol Pd and an atomic number of 46. It is a rare and lustrous silvery-white metal discovered in 1803 by William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired...

 coating which may be less susceptible to poisoning and thereby improve fuel cell lifetime considerably. Another method would use iron and sulphur instead of platinum. This is possible through an intermediate conversion by bacteria. This would lower the cost of a fuel cell substantially (as the platinum in a regular fuel cell costs around , and the same amount of iron costs only around ). The concept is being developed by a coalition of the John Innes Centre
John Innes Centre
The John Innes Centre located in Norwich, Norfolk, England is an independent centre for research and training in plant and microbial science...

 and the University of Milan-Bicocca. PEDOT
Pedot
Pedot is the eleventh album of the Finnish rock band CMX. "Pedot" means "Beasts" in Finnish.The opening track "Eteläisen tähtitaivaan kartoitus" breaks a CMX tradition of starting their albums with powerful rock songs. It is a minimalistic piano-based ballad with no drums...

 cathodes are immune to monoxide poisoning.

Current targets for a transport PEM fuel cells are 0.2 g/kW Pt – which is a factor of 5 decrease over current loadings – and recent comments from major original equipment manufacturer
Original Equipment Manufacturer
An original equipment manufacturer, or OEM, manufactures products or components that are purchased by a company and retailed under that purchasing company's brand name. OEM refers to the company that originally manufactured the product. When referring to automotive parts, OEM designates a...

s (OEMs) indicate that this is possible. Recycling of fuel cells components, including platinum, will conserve supplies. High-temperature fuel cells, including molten carbonate fuel cells (MCFC's) and solid oxide fuel cells (SOFC's), do not use platinum as catalysts, but instead use cheaper materials such as nickel and nickel oxide. They also do not experience catalyst poisoning by carbon monoxide, and so they do not require high-purity hydrogen to operate. They can use fuels with an existing and extensive infrastructure, such as natural gas, directly, without having to first reform it externally to hydrogen and CO followed by CO removal.

Research and development

  • August 2005: Georgia Institute of Technology
    Georgia Institute of Technology
    The Georgia Institute of Technology is a public research university in Atlanta, Georgia, in the United States...

     researchers use triazole
    Triazole
    Triazole refers to either one of a pair of isomeric chemical compounds with molecular formula C2H3N3, having a five-membered ring of two carbon atoms and three nitrogen atoms.The two isomers are:*1,2,3-Triazole 100px*1,2,4-Triazole 100px...

     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
    Monash University is a public university based in Melbourne, Victoria. It was founded in 1958 and is the second oldest university in the state. Monash is a member of Australia's Group of Eight and the ASAIHL....

    , Melbourne
    Melbourne
    Melbourne is the capital and most populous city in the state of Victoria, and the second most populous city in Australia. The Melbourne City Centre is the hub of the greater metropolitan area and the Census statistical division—of which "Melbourne" is the common name. As of June 2009, the greater...

     uses PEDOT
    Poly(3,4-ethylenedioxythiophene)
    Poly or PEDOT is a conducting polymer based on 3,4-ethylenedioxylthiophene or EDOT monomer. Advantages of this polymer are optical transparency in its conducting state, high stability and moderate band gap and low redox potential...

     as a cathode
    Cathode
    A cathode is an electrode through which electric current flows out of a polarized electrical device. Mnemonic: CCD .Cathode polarity is not always negative...

    .
  • 2009 Researchers at the University of Dayton
    University of Dayton
    The University of Dayton is a private Roman Catholic university operated by the Society of Mary located in Dayton, Ohio...

    , in Ohio, show that arrays of vertically grown carbon nanotubes could be used as the catalyst in fuel cells.
  • 2009: Y-Carbon
    Tunable nanoporous carbon
    Ultracapacitors may have the potential to become key components for energy storage in the industrial market with the rising push for environmental technology. There are several different approaches to creating ultracapacitors, as detailed here, and tunable nanoporous carbon is a relatively new...

     has begun to develop a carbide-derived-carbon-based ultracapacitor with high energy density which may lead to improvements in fuel cell technology.
  • 2009: A nickel bisdiphosphine-based catalyst for fuel cells is demonstrated.

See also



  • Bio-nano generator
  • Cryptophane
    Cryptophane
    Cryptophanes are a class of organic supramolecular compounds studied and synthesized primarily for molecular encapsulation and recognition. One possible noteworthy application of cryptophanes is encapsulation and storage of hydrogen gas for potential use in fuel cell automobiles...

  • Energy development
    Energy development
    Energy development is the effort to provide sufficient primary energy sources and secondary energy forms for supply, cost, impact on air pollution and water pollution, mitigation of climate change with renewable energy....

  • Fuel Cell Development Information Center
    Fuel Cell Development Information Center
    The Fuel Cell Development Information Center is a Japanese center established in July 1986 to exchange information among its members on fuel cell research, development and deployment to speed up the introduction and penetration of fuel cells into the market.The FCDIC consists of 154 organizations,...

  • Fuel Cells and Hydrogen Joint Technology Initiative (in Europe)
  • Glossary of fuel cell terms
    Glossary of fuel cell terms
    The Glossary of fuel cell terms lists the definitions of many terms used within the fuel cell industry. The terms in this fuel cell glossary may be used by fuel cell industry associations, in education material and fuel cell codes and standards to name but a few. –...

  • Grid energy storage
    Grid energy storage
    Grid energy storage refers to the methods used to store electricity on a large scale within an electrical power grid. Electrical energy is stored during times when production exceeds consumption and the stores are used at times when consumption exceeds production...

  • Hydrogen codes and standards
  • Hydrogen reformer
  • Hydrogen storage
    Hydrogen storage
    Hydrogen storage describes the methods for storing H2 for subsequent use. The methods span many approaches, including high pressures, cryogenics, and chemical compounds that reversibly release H2 upon heating...

  • Hydrogen technologies
    Hydrogen technologies
    Hydrogen technologies are technologies that relate to the production and use of hydrogen. Hydrogen technologies are applicable for many uses....

  • Microgeneration
    Microgeneration
    Microgeneration is the small-scale generation of heat and power by individuals, small businesses and communities to meet their own needs, as alternatives or supplements to traditional centralized grid-connected power...

  • Water splitting
    Water splitting
    Water splitting is the general term for a chemical reaction in which water is separated into oxygen and hydrogen. Efficient and economical water splitting would be a key technology component of a hydrogen economy. Various techniques for water splitting have been issued in water splitting patents in...


Further reading

  • Vielstich, W., et al. (eds.) (2009). Handbook of fuel cells: advances in electrocatalysis, materials, diagnostics and durability. 6 vol. Hoboken: Wiley, 2009.

External links