View source for Fuel cell

{{Short description|Device that converts the chemical energy from a fuel into electricity}}
{{Other uses}}
{{Update|date=February 2021}}{{Use dmy dates|date=June 2020}}
[[File:Fuel cell NASA p48600ac.jpg|thumb|250px|right|Demonstration model of a direct methanol fuel cell (black layered cube) in its enclosure]]
[[File:Solid oxide fuel cell protonic.svg|thumb|Scheme of a proton-conducting fuel cell]]

A '''fuel cell''' is an [[electrochemical cell]] that converts the [[chemical energy]] of a fuel (often [[hydrogen fuel|hydrogen]]) and an [[oxidizing agent]] (often oxygen)<ref>{{cite book |last1=Saikia |first1=Kaustav |title=Recent Advancements in Biofuels and Bioenergy Utilization |last2=Kakati |first2=Biraj Kumar |last3=Boro |first3=Bibha |last4=Verma |first4=Anil |date=2018 |publisher=Springer |isbn=978-981-13-1307-3 |location=Singapore |pages=303–337 |chapter=Current Advances and Applications of Fuel Cell Technologies |doi=10.1007/978-981-13-1307-3_13}}</ref> into electricity through a pair of [[redox]] reactions.<ref>{{cite book |last=Khurmi |first=R. S. |title=Material Science |url=https://www.biblio.com/book/materials-science-rs-khurmirs-sedha/d/436308472|publisher=S. Chand & Company |year=2014 |isbn=9788121901468 }}</ref> Fuel cells are different from most [[battery (electricity)|batteries]] in requiring a continuous source of fuel and oxygen (usually from air) to sustain the chemical reaction, whereas in a battery the chemical energy usually comes from substances that are already present in the battery.<ref>{{Cite journal|title=What Are Batteries, Fuel Cells, and Supercapacitors?|first1=Martin|last1=Winter|first2=Ralph J.|last2=Brodd|date=28 September 2004|journal=Chemical Reviews|volume=104|issue=10|pages=4245–4270 |doi=10.1021/cr020730k|pmid=15669155 |s2cid=3091080 |doi-access=free}}</ref> Fuel cells can produce electricity continuously for as long as fuel and oxygen are supplied.
 	
The first fuel cells were invented by Sir [[William Robert Grove|William Grove]] in 1838. The first commercial use of fuel cells came almost a century later following the invention of the hydrogen–oxygen fuel cell by [[Francis Thomas Bacon]] in 1932. The [[alkaline fuel cell]], also known as the Bacon fuel cell after its inventor, has been used in [[NASA]] space programs since the mid-1960s to generate power for [[satellites]] and [[space capsule]]s. Since then, fuel cells have been used in many other applications. Fuel cells are used for primary and backup power for commercial, industrial and residential buildings and in remote or inaccessible areas. They are also used to power [[fuel cell vehicle]]s, including forklifts, automobiles, buses,<ref>{{Cite web |title=Bronx Hydrogen Fuel Cell Bus |url=https://www.empirecleancities.org/ktc.html |access-date=2024-04-13 |website=Empire Clean Cities |language=en}}</ref> trains, boats, motorcycles, and submarines.

There are many types of fuel cells, but they all consist of an [[anode]], a [[cathode]], and an [[electrolyte]] that allows ions, often positively charged hydrogen ions (protons), to move between the two sides of the fuel cell. At the anode, a catalyst causes the fuel to undergo oxidation reactions that generate ions (often positively charged hydrogen ions) and electrons. The ions move from the anode to the cathode through the electrolyte. At the same time, electrons flow from the anode to the cathode through an external circuit, producing [[direct current]] electricity. At the cathode, another catalyst causes ions, electrons, and oxygen to react, forming water and possibly other products. Fuel cells are classified by the type of electrolyte they use and by the difference in start-up time ranging from 1 second for [[proton-exchange membrane fuel cell]]s (PEM fuel cells, or PEMFC) to 10 minutes for [[solid oxide fuel cell]]s (SOFC). A related technology is [[Flow battery|flow batteries]], in which the fuel can be regenerated by recharging. Individual fuel cells produce relatively small electrical potentials, about 0.7 volts, so cells are "stacked", or placed in series, to create sufficient voltage to meet an application's requirements.<ref>Nice, Karim and Strickland, Jonathan. [https://auto.howstuffworks.com/fuel-efficiency/alternative-fuels/fuel-cell.htm#pt2 "How Fuel Cells Work: Polymer Exchange Membrane Fuel Cells"]. How Stuff Works, accessed 4 August 2011</ref> In addition to electricity, fuel cells produce water vapor, heat and, depending on the fuel source, very small amounts of [[nitrogen dioxide]] and other emissions. PEMFC cells generally produce fewer nitrogen oxides than SOFC cells: they operate at lower temperatures, use hydrogen as fuel, and limit the diffusion of nitrogen into the anode via the proton exchange membrane, which forms NOx. The [[Efficient energy use|energy efficiency]] of a fuel cell is generally between 40 and 60%; however, if waste heat is captured in a [[cogeneration]] scheme, efficiencies of up to 85% can be obtained.<ref name=Types1/>
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==History==
[[File:AllByYear-2023-10-24.png|thumb|800x800px|The number of patent families (solid lines) and non-patent publications about different electrochemical powersources by year. Also shown as the magenta line is the inflation-adjusted oil price in US$/liter in linear scale.|center]]
{{Main|Timeline of hydrogen technologies}}
[[File:1839 William Grove Fuel Cell.jpg|thumb|right|Sketch of Sir [[William Robert Grove|William Grove]]'s 1839 fuel cell]]
The first references to [[hydrogen]] fuel cells appeared in 1838. In a letter dated October 1838 but published in the December 1838 edition of ''The London and Edinburgh Philosophical Magazine and Journal of Science'', Welsh physicist and barrister Sir [[William Robert Grove|William Grove]] wrote about the development of his first crude fuel cells. He used a combination of sheet iron, copper, and porcelain plates, and a solution of sulphate of copper and dilute acid.<ref>{{cite journal | last1 = Grove | first1 = W. R. |title=On a new voltaic combination |journal=The London and Edinburgh Philosophical Magazine and Journal of Science |series= 3rd series | volume = 13 | issue = 84| pages = 430–431 | year=1838 |access-date=2 October 2013 |url=https://archive.org/details/londonedinburghp13lond/page/430/mode/2up | doi=10.1080/14786443808649618}}</ref><ref>{{cite journal | last1 = Grove | first1 = William Robert | year = 1839 | title = On Voltaic Series and the Combination of Gases by Platinum | url = https://zenodo.org/record/1431021| journal = Philosophical Magazine and Journal of Science |series= 3rd series | volume = 14 | issue = 86–87| pages = 127–130 | doi=10.1080/14786443908649684}}</ref> In a letter to the same publication written in December 1838 but published in June 1839, German physicist [[Christian Friedrich Schönbein]] discussed the first crude fuel cell that he had invented. His letter discussed the current generated from hydrogen and oxygen dissolved in water.<ref>{{cite journal |last1= Schœnbein |title= On the voltaic polarization of certain solid and fluid substances |journal= The London and Edinburgh Philosophical Magazine and Journal of Science |series= 3rd series |volume= 14 |issue = 85 |pages=43–45 |year= 1839 |access-date=2 October 2013 |url=https://www.biodiversitylibrary.org/item/53521#page/63/mode/1up |archive-url=https://web.archive.org/web/20131005022402/http://electrochem.cwru.edu/estir/hist/hist-14-Schoenbein.pdf |archive-date= 5 October 2013 }}</ref> Grove later sketched his design, in 1842, in the same journal. The fuel cell he made used similar materials to today's [[phosphoric acid fuel cell]].<ref>{{cite journal | last1 = Grove | first1 = William Robert | year = 1842 | title = On a Gaseous Voltaic Battery | url = https://zenodo.org/record/1431031| journal = The London, Edinburgh and Dublin Philosophical Magazine and Journal of Science |series=3rd series | volume = 21 | issue = 140| pages = 417–420 | doi=10.1080/14786444208621600}}</ref><ref>{{cite book |last1=Larminie |first1=James |last2=Dicks |first2=Andrew |title=Fuel Cell Systems Explained |url=https://87eb298c-a-62cb3a1a-s-sites.googlegroups.com/site/senthilvssc/Home/fuel-cells/FuelCellSystemsExplained_Second.Edition_Wiley2003_.pdf?attachauth=ANoY7crX_IkVIPQ-acr5K0O8seJelGPHSyLjN0WxCGzldpUgBnBfXrPV2bzNvA7s8HDmRMeqPO5Okjy7ysDnw5-lT1tAidw1fwf8LULLQT98hybocX63JkBhjgIEDl_2v-GLGFkD5YebdMUrHjb-IwiM3okL2sGmqOMGQt514PAYjAiktAv1uHuh4izkW4R8-PjEXMD1lKTf1sH76F8Oy44uV1n2J0gDxtwd_HcLZhrzc86kzjcLfygo_hXPDdwCpI3kvb9gI-gPTMRjFTc-6S1upFRfxcBEMIG5Jn4osQqAgzO2BAseRjw%3D&attredirects=0 }}{{Dead link|date=December 2021 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

In 1932, English engineer [[Francis Thomas Bacon]] successfully developed a 5&nbsp;kW stationary fuel cell.<ref name="BBC"/>  [[NASA]] used the [[alkaline fuel cell]] (AFC), also known as the Bacon fuel cell after its inventor, from the mid-1960s.<ref name="BBC">{{cite news |title=The Brits who bolstered the Moon landings |url=https://www.bbc.co.uk/archive/the-brits-who-bolstered-the-moon-landings/zfcrscw |access-date=7 August 2019 |agency=BBC}}</ref><ref>{{cite news |title=Apollo 11 mission 50 years on: The Cambridge scientist who helped put man on the moon |url=https://www.cambridgeindependent.co.uk/news/apollo-11-mission-50-years-on-the-cambridge-scientist-who-helped-put-man-on-the-moon-9077166/ |access-date=7 August 2019 |work=Cambridge Independent}}</ref>

In 1955, W. Thomas Grubb, a chemist working for the [[General Electric]] Company (GE), further modified the original fuel cell design by using a sulphonated polystyrene ion-exchange membrane as the electrolyte. Three years later another GE chemist, Leonard Niedrach, devised a way of depositing platinum onto the membrane, which served as a catalyst for the necessary hydrogen oxidation and oxygen reduction reactions. This became known as the "Grubb-Niedrach fuel cell".<ref>{{Cite web|url=https://americanhistory.si.edu/fuelcells/pem/pem2.htm|title=Fuel Cell Project: PEM Fuel Cells photo #2|website=americanhistory.si.edu}}</ref><ref>{{Cite web|url=https://americanhistory.si.edu/fuelcells/pem/pemmain.htm|title=Collecting the History of Proton Exchange Membrane Fuel Cells|website=americanhistory.si.edu}}</ref> GE went on to develop this technology with NASA and McDonnell Aircraft, leading to its use during [[Project Gemini]]. This was the first commercial use of a fuel cell. In 1959, a team led by Harry Ihrig built a 15&nbsp;kW fuel cell tractor for [[Allis-Chalmers]], which was demonstrated across the U.S. at state fairs. This system used potassium hydroxide as the electrolyte and [[compressed hydrogen]] and oxygen as the reactants. Later in 1959, Bacon and his colleagues demonstrated a practical five-kilowatt unit capable of powering a welding machine. In the 1960s, [[Pratt & 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).

[[UTC Power]] was the first company to manufacture and commercialize a large, stationary fuel cell system for use as a [[cogeneration]] power plant in hospitals, universities and large office buildings.<ref>{{cite web|title=The PureCell Model 400 – Product Overview |publisher=UTC Power |url=http://www.utcpower.com/products/purecell400 |access-date=2011-12-22 |url-status=dead |archive-url=https://web.archive.org/web/20111211055124/http://www.utcpower.com/products/purecell400 |archive-date=11 December 2011}}</ref>

In recognition of the fuel cell industry and America's role in fuel cell development, the United States Senate recognized October 8, 2015 as [[National Hydrogen and Fuel Cell Day]], passing S. RES 217. The date was chosen in recognition of the atomic weight of hydrogen (1.008).<ref>{{cite web |url=https://www.congress.gov/bill/114th-congress/senate-resolution/217/text |title=S.Res.217 – A resolution designating October 8, 2015, as "National Hydrogen and Fuel Cell Day" |website=Congress.gov |date= 29 September 2015}}</ref>

==Types of fuel cells; design==
Fuel cells come in many varieties; however, they all work in the same general manner. They are made up of three adjacent segments: the [[anode]], the [[electrolyte]], and the [[cathode]]. 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]] ionizes the fuel, 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 an 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.

[[File:Fuel Cell Block Diagram.svg|thumb|upright=1.35|A block diagram of a fuel cell]]
Design features in a fuel cell include:
* The electrolyte substance, which usually defines the ''type'' of fuel cell, and can be made from a number of substances like potassium hydroxide, salt carbonates, and phosphoric acid.<ref>{{Cite news| url=http://www.energygroove.net/technologies/fuel-cells| title=Fuel Cells - EnergyGroove.net|work=EnergyGroove.net|access-date=2018-02-06}}</ref>
* The most common fuel that is used is hydrogen.
* The anode catalyst, usually fine platinum powder, breaks down the fuel into electrons and ions.
* The cathode catalyst, often nickel, converts ions into waste chemicals, with water being the most common type of waste.<ref name=TTI>{{Cite news|url=https://textechindustries.com/high-performance-materials| title=Reliable High Performance Textile Materials| work=Tex Tech Industries|access-date=2018-02-06}}</ref>
* Gas diffusion layers that are designed to resist oxidization.<ref name=TTI/>

A typical fuel cell produces a voltage from 0.6 to 0.7&nbsp;V at a full-rated load. Voltage decreases as current increases, due to several factors:
* [[Overpotential|Activation loss]]
* Ohmic loss ([[voltage drop]] due to resistance of the cell components and interconnections)
* Mass transport loss (depletion of reactants at catalyst sites under high loads, causing rapid loss of voltage).<ref name="Larminie2003">{{Cite book| last = Larminie | first = James | title = Fuel Cell Systems Explained, Second Edition | publisher = [[Society of Automotive Engineers|SAE International]] | date=1 May 2003| isbn = 978-0-7680-1259-0}}</ref>

To deliver the desired amount of energy, the fuel cells can be combined in [[series and parallel circuits|series]] to yield higher [[voltage]], and in parallel to allow a higher [[Electric current|current]] to be supplied. Such a design is called a ''fuel cell stack''. The cell surface area can also be increased, to allow higher current from each cell.

===Proton-exchange membrane fuel cells===
{{main|Proton-exchange membrane fuel cell}}
[[File:PEM fuelcell.svg|thumb|upright=1.75|Construction of a high-temperature [[proton-exchange membrane fuel cell|PEMFC]]: Bipolar plate as [[electrode]] with in-milled gas channel structure, fabricated from conductive [[composite material|composites]] (enhanced with [[graphite]], [[carbon black]], [[carbon fiber]], and/or [[carbon nanotube]]s for more conductivity);<ref>{{cite journal | last1 = Kakati | first1 = B. K. | last2 = Deka | first2 = D. | year = 2007 | title = Effect of resin matrix precursor on the properties of graphite composite bipolar plate for PEM fuel cell | journal = Energy & Fuels | volume = 21 | issue = 3| pages = 1681–1687 | doi=10.1021/ef0603582}}</ref> [[Porous]] carbon papers; reactive layer, usually on the [[polymer]] membrane applied; polymer membrane.]] 
[[File:condensation.jpg|upright=1.55|thumb|Condensation of water produced by a PEMFC on the air channel wall. The gold wire around the cell ensures the collection of electric current.<ref>{{cite web|url=http://perso.ensem.inpl-nancy.fr/Olivier.Lottin/Ourfuelcells.html |title=LEMTA – Our fuel cells |publisher=Perso.ensem.inpl-nancy.fr |access-date=2009-09-21 |url-status=dead |archive-url=https://web.archive.org/web/20090621084543/http://perso.ensem.inpl-nancy.fr/Olivier.Lottin/Ourfuelcells.html |archive-date=21 June 2009 }}</ref>]]
[[File:SEM micrograph of an MEA cross section.jpg|thumb|SEM micrograph of a PEMFC MEA cross-section with a non-precious metal catalyst cathode and Pt/C anode.<ref>{{cite journal |last1=Yin |first1=Xi |last2=Lin |first2=Ling |last3=Chung |first3=Hoon T |last4=Komini Babu |first4=Siddharth |last5=Martinez |first5=Ulises |last6=Purdy |first6=Geraldine M |last7=Zelenay |first7=Piotr |title=Effects of MEA Fabrication and Ionomer Composition on Fuel Cell Performance of PGM-Free ORR Catalyst |journal=ECS Transactions |date=4 August 2017 |volume=77 |issue=11 |pages=1273–1281 |doi=10.1149/07711.1273ecst|bibcode=2017ECSTr..77k1273Y |osti=1463547 }}</ref> False colors applied for clarity.]]
In the archetypical hydrogen–oxide [[proton-exchange membrane fuel cell]] (PEMFC) design, a proton-conducting polymer membrane (typically [[nafion]]) contains the [[electrolyte]] solution that separates the [[anode]] and [[cathode]] sides.<ref>Anne-Claire Dupuis, Progress in Materials Science, Volume 56, Issue 3, March 2011, pp. 289–327</ref><ref>{{Cite web|url=http://personal.cityu.edu.hk/~kwanshui/Paper/IJHE2.pdf|archive-url=https://web.archive.org/web/20131105234936/http://personal.cityu.edu.hk/~kwanshui/Paper/IJHE2.pdf|url-status=dead|title=Measuring the relative efficiency of hydrogen energy technologies for implementing the hydrogen economy 2010|archive-date=5 November 2013}}</ref> This was called a ''solid polymer electrolyte fuel cell'' (''SPEFC'') in the early 1970s, before the proton-exchange mechanism was well understood. (Notice that the synonyms ''polymer electrolyte membrane'' and ''proton-exchange mechanism'' result in the same [[acronym]].)

On the anode side, hydrogen diffuses to the anode catalyst where it later dissociates into protons and electrons. These protons often react with oxidants causing them to become what are commonly referred to as multi-facilitated proton membranes. The protons are conducted through the membrane to the cathode, but the electrons are forced to travel in an external circuit (supplying power) because the membrane is electrically insulating. On the cathode catalyst, oxygen [[molecule]]s react with the electrons (which have traveled through the external circuit) and protons to form water.

In addition to this pure hydrogen type, there are [[hydrocarbon]] fuels for fuel cells, including [[diesel fuel|diesel]], [[methanol]] (''see:'' [[direct-methanol fuel cell]]s and [[indirect methanol fuel cell]]s) and chemical hydrides. The waste products with these types of fuel are [[carbon dioxide]] and water. When hydrogen is used, the CO{{sub|2}} is released when methane from natural gas is combined with steam, in a process called [[steam reforming|steam methane reforming]], to produce the hydrogen. This can take place in a different location to the fuel cell, potentially allowing the hydrogen fuel cell to be used indoors—for example, in forklifts.

The different components of a PEMFC are
# bipolar plates,
# [[electrode]]s,
# [[catalyst]],
# membrane, and
# the necessary hardware such as current collectors and gaskets.<ref>{{cite journal | last1 = Kakati | first1 = B. K. | last2 = Mohan | first2 = V. | year = 2008 | title = Development of low cost advanced composite bipolar plate for P.E.M. fuel cell | journal = Fuel Cells | volume = 08 | issue = 1| pages = 45–51 | doi=10.1002/fuce.200700008| s2cid = 94469845 }}</ref>

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]], flexible graphite, C–C [[composite material|composite]], [[carbon]]–[[polymer]] composites etc.<ref>{{cite journal | last1 = Kakati | first1 = B. K. | last2 = Deka | first2 = D. | year = 2007 | title = Differences in physico-mechanical behaviors of resol and novolac type phenolic resin based composite bipolar plate for proton exchange membrane (PEM) fuel cell | journal = Electrochimica Acta | volume = 52 | issue = 25| pages = 7330–7336 | doi=10.1016/j.electacta.2007.06.021}}</ref> The [[membrane electrode assembly]] (MEA) is referred to as the heart of the PEMFC and is usually made of a proton-exchange membrane sandwiched between two [[catalyst]]-coated [[carbon paper]]s. Platinum and/or similar types of [[noble metal]]s are usually used as the catalyst for PEMFC, and these can be contaminated by [[carbon monoxide]], necessitating a relatively pure hydrogen fuel.<ref name=WGS>Coletta, Vitor, ''et al.'' [https://hal.archives-ouvertes.fr/hal-03132190/document/#page=3 "Cu-Modified SrTiO 3 Perovskites Toward Enhanced Water-Gas Shift Catalysis: A Combined Experimental and Computational Study" ], ''ACS Applied Energy Materials'' (2021), vol. 4, issue 1, pp. 452–461</ref> The electrolyte could be a polymer [[artificial membrane|membrane]].

====Proton-exchange membrane fuel cell design issues====
; Cost: In 2013, the Department of Energy estimated that 80&nbsp;kW automotive fuel cell system costs of {{USD|67}} per kilowatt could be achieved, assuming volume production of 100,000 automotive units per year and {{USD|55}} per kilowatt could be achieved, assuming volume production of 500,000 units per year.<ref>
Spendelow, Jacob and Jason Marcinkoski. [http://www.hydrogen.energy.gov/pdfs/13012_fuel_cell_system_cost_2013.pdf "Fuel Cell System Cost – 2013"] {{webarchive|url=https://web.archive.org/web/20131202225059/http://www.hydrogen.energy.gov/pdfs/13012_fuel_cell_system_cost_2013.pdf |date= 2 December 2013 }}, DOE Fuel Cell Technologies Office, 16 October 2013 ([https://web.archive.org/web/20131202225059/http://www.hydrogen.energy.gov/pdfs/13012_fuel_cell_system_cost_2013.pdf archived version])
</ref> 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]] has experimented with a catalyst enhanced with carbon silk, which allows a 30% reduction (1.0–0.7&nbsp;mg/cm<sup>2</sup>) in platinum usage without reduction in performance.<ref>
{{Cite news
 | title = Ballard Power Systems: Commercially Viable Fuel Cell Stack Technology Ready by 2010
 | date = 29 March 2005
 | url = http://www.fuelcellsworks.com/Supppage2336.html
 | access-date = 2007-05-27
 | archive-url = https://web.archive.org/web/20070927050617/http://www.fuelcellsworks.com/Supppage2336.html
 | archive-date = 27 September 2007
 | url-status=dead
}}</ref> [[Monash University]], [[Melbourne]] uses [[poly(3,4-ethylenedioxythiophene)|PEDOT]] as a [[cathode]].<ref name="Online">
{{cite web
 |last=Online |first=Science
 |url=http://www.abc.net.au/news/stories/2008/08/02/2322139.htm
 |archive-url=https://web.archive.org/web/20080806174903/http://www.abc.net.au/news/stories/2008/08/02/2322139.htm
 |url-status=dead
 |archive-date=6 August 2008
 |title=2008 – Cathodes in fuel cells
 |publisher=Abc.net.au
 |date=2 August 2008
 |access-date=2009-09-21
}}</ref> A 2011-published study<ref>
{{cite journal
 | doi=10.1021/ja1112904
 | pmid=21413707
 | volume=133 | issue=14
 | title=Polyelectrolyte Functionalized Carbon Nanotubes as Efficient Metal-free Electrocatalysts for Oxygen Reduction
 | journal=Journal of the American Chemical Society
 | pages=5182–5185
 | last1 = Wang | first1 = Shuangyin
 | s2cid=207063759
 | year=2011
 | bibcode=2011JAChS.133.5182W
 }}</ref> documented the first metal-free electrocatalyst using relatively inexpensive doped [[carbon nanotube]]s, which are less than 1% the cost of platinum and are of equal or superior performance. A recently published article demonstrated how the environmental burdens change when using carbon nanotubes as carbon substrate for platinum.<ref>
{{cite journal
 |last1=Notter|first1=Dominic A.
 |last2=Kouravelou|first2=Katerina
 |last3=Karachalios|first3=Theodoros
 |last4=Daletou|first4=Maria K.
 |last5=Haberland|first5=Nara Tudela
 |title=Life cycle assessment of PEM FC applications: electric mobility and μ-CHP
 |journal=Energy Environ. Sci.
 |date=2015
 |volume=8|issue=7|pages=1969–1985
 |doi=10.1039/C5EE01082A
|bibcode=2015EnEnS...8.1969N
 }}</ref>
; Water and air management<ref>{{cite web|url=http://www.ika.rwth-aachen.de/r2h/index.php/Water_and_Air_Management_for_Fuel_Cells |title=Water_and_Air_Management |publisher=Ika.rwth-aachen.de |access-date=2009-09-21 |url-status=dead |archive-url=https://web.archive.org/web/20090114182615/http://www.ika.rwth-aachen.de/r2h/index.php/Water_and_Air_Management_for_Fuel_Cells |archive-date=14 January 2009}}</ref><ref>{{Cite journal|last1=Andersson|first1=M.|last2=Beale|first2=S. B.|last3=Espinoza|first3=M.|last4=Wu|first4=Z.|last5=Lehnert|first5=W.|date=2016-10-15|title=A review of cell-scale multiphase flow modeling, including water management, in polymer electrolyte fuel cells|journal=Applied Energy|volume=180|pages=757–778|doi=10.1016/j.apenergy.2016.08.010|bibcode=2016ApEn..180..757A }}</ref> (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, the 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]]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 2H<sub>2</sub> + O<sub>2</sub> → 2H<sub>2</sub>O reaction is highly exothermic, so a large quantity of heat is generated within the fuel cell.
; Durability, [[service life]], 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 {{convert|-35|to|40|C|F}}, while automotive fuel cells require a 5,000-hour lifespan (the equivalent of {{convert|150000|miles|km|abbr=on|sigfig=2|order=flip|disp=or}}) under extreme temperatures. Current [[service life]] is 2,500 hours (about {{convert|75,000|mi|km|abbr=on|sigfig=2|order=flip|disp=or}}).<ref>{{cite web |url=http://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/accomplishments.pdf |title=Progress and Accomplishments in Hydrogen and Fuel Cells |access-date=2015-05-16 |url-status=dead |archive-url=https://web.archive.org/web/20151123185414/http://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/accomplishments.pdf |archive-date=23 November 2015}}</ref> Automotive engines must also be able to start reliably at {{convert|-30|°C|°F|abbr=on}} and have a high power-to-volume ratio (typically 2.5&nbsp;kW/L).
; Limited [[carbon monoxide]] tolerance of some (non-PEDOT) cathodes.<ref name=WGS />

=== Phosphoric acid fuel cell ===
{{Main|Phosphoric acid fuel cell}}
Phosphoric acid fuel cells (PAFCs) were first designed and introduced in 1961 by [[G. V. Elmore]] and [[H. A. Tanner]]. In these cells, phosphoric acid is used as a non-conductive electrolyte to pass protons from the anode to the cathode and to force electrons to travel from anode to cathode through an external electrical circuit. These cells commonly work in temperatures of 150 to 200&nbsp;°C. This high temperature will cause heat and energy loss if the heat is not removed and used properly. This heat can be used to produce steam for air conditioning systems or any other thermal energy-consuming system.<ref name="americanhistory.si.edu">{{Cite web|url=https://americanhistory.si.edu/fuelcells/phos/pafcmain.htm|title=Collecting the History of Phosphoric Acid Fuel Cells|website=americanhistory.si.edu}}</ref> Using this heat in [[cogeneration]] can enhance the efficiency of phosphoric acid fuel cells from 40 to 50% to about 80%.<ref name="americanhistory.si.edu"/> Since the proton production rate on the anode is small, platinum is used as a catalyst to increase this ionization rate. A key disadvantage of these cells is the use of an acidic electrolyte. This increases the corrosion or oxidation of components exposed to phosphoric acid.<ref>{{cite web|url=http://scopewe.com/phosphoric-acid-fuel-cells|title=Phosphoric Acid Fuel Cells|website=scopeWe - a Virtual Engineer|access-date=28 June 2013|archive-date=10 November 2013|archive-url=https://web.archive.org/web/20131110071945/http://scopewe.com/phosphoric-acid-fuel-cells/|url-status=usurped}}</ref>

=== Solid acid fuel cell ===
{{Main|Solid acid fuel cell}}

Solid acid fuel cells (SAFCs) are characterized by the use of a solid acid material as the electrolyte. At low temperatures, [[solid acid]]s have an ordered molecular structure like most salts. At warmer temperatures (between 140 and 150{{nbsp}}°C for CsHSO<sub>4</sub>), some solid acids undergo a phase transition to become highly disordered "superprotonic" structures, which increases conductivity by several orders of magnitude. SAFC systems use cesium dihydrogen phosphate (CsH<sub>2</sub>PO<sub>4</sub>) and have demonstrated lifetimes in the thousands of hours.<ref>{{Cite journal|last1=Haile|first1=Sossina M.|last2=Chisholm|first2=Calum R. I.|last3=Sasaki|first3=Kenji|last4=Boysen|first4=Dane A.|last5=Uda|first5=Tetsuya|date=2006-12-11|title=Solid acid proton conductors: from laboratory curiosities to fuel cell electrolytes|journal=Faraday Discussions| volume=134|doi=10.1039/B604311A|pmid=17326560|issn=1364-5498|pages=17–39|bibcode=2007FaDi..134...17H|url=https://authors.library.caltech.edu/7019/1/HAIfd07.pdf |archive-url=https://web.archive.org/web/20170815181049/http://authors.library.caltech.edu/7019/1/HAIfd07.pdf |archive-date=2017-08-15 |url-status=live}}</ref>

===Alkaline fuel cell===
{{Main|Alkaline fuel cell|Alkaline anion exchange membrane fuel cell}}
The alkaline fuel cell (AFC) or hydrogen-oxygen fuel cell was designed and first demonstrated publicly by Francis Thomas Bacon in 1959. It was used as a primary source of electrical energy in the Apollo space program.<ref>{{Cite journal|title = Francis Thomas Bacon. 21 December 1904 – 24 May 1992|last = Williams|first = K.R.|s2cid = 71613260|date = 1 February 1994|journal = Biographical Memoirs of Fellows of the Royal Society|doi = 10.1098/rsbm.1994.0001|volume = 39|pages = 2–9|doi-access = free}}</ref> The cell consists of two porous carbon electrodes impregnated with a suitable catalyst such as Pt, Ag, CoO, etc. The space between the two electrodes is filled with a concentrated solution of [[Potassium hydroxide|KOH]] or [[Sodium hydroxide|NaOH]] which serves as an electrolyte. H<sub>2</sub> gas and O<sub>2</sub> gas are bubbled into the electrolyte through the porous carbon electrodes. Thus the overall reaction involves the combination of hydrogen gas and oxygen gas to form water. The cell runs continuously until the reactant's supply is exhausted. This type of cell operates efficiently in the temperature range 343–413{{nbsp}}K (70 -140&nbsp;°C) and provides a potential of about 0.9{{nbsp}}V.<ref>Srivastava, H. C. ''Nootan ISC Chemistry'' (12th) Edition 18, pp. 458–459, Nageen Prakashan (2014) {{ISBN|9789382319399}}</ref> [[Alkaline anion exchange membrane fuel cell]] (AAEMFC) is a type of AFC which employs a solid polymer electrolyte instead of aqueous potassium hydroxide (KOH) and it is superior to aqueous AFC.

===High-temperature fuel cells===

====Solid oxide fuel cell====
{{Main|Solid oxide fuel cell}}
[[Solid oxide fuel cell]]s (SOFCs) use a solid material, most commonly a ceramic material called [[yttria-stabilized zirconia]] (YSZ), as the [[electrolyte]]. Because SOFCs are made entirely of solid materials, they are not limited to the flat plane configuration of other types of fuel cells and are often designed as rolled tubes. They require high [[operating temperature]]s (800–1000&nbsp;°C) and can be run on a variety of fuels including natural gas.<ref name=Types1>[http://www1.eere.energy.gov/hydrogenandfuelcells/fuelcells/fc_types.html "Types of Fuel Cells"] {{webarchive|url=https://web.archive.org/web/20100609041046/http://www1.eere.energy.gov/hydrogenandfuelcells/fuelcells/fc_types.html |date= 9 June 2010 }}. Department of Energy EERE website, accessed 4 August 2011</ref>

SOFCs are unique because negatively charged oxygen [[ion]]s travel from the [[cathode]] (positive side of the fuel cell) to the [[anode]] (negative side of the fuel cell) instead of [[proton]]s travelling vice versa (i.e., from the anode to the cathode), as is the case in all other types of fuel cells. Oxygen gas is fed through the cathode, where it absorbs electrons to create oxygen ions. The oxygen ions then travel through the electrolyte to react with hydrogen gas at the anode. The reaction at the anode produces electricity and water as by-products. Carbon dioxide may also be a by-product depending on the fuel, but the carbon emissions from a SOFC system are less than those from a [[fossil fuel]] combustion plant.<ref>{{cite journal | last1 = Stambouli | first1 = A. Boudghene | year = 2002 | title = Solid oxide fuel cells (SOFCs): a review of an environmentally clean and efficient source of energy | journal = Renewable and Sustainable Energy Reviews | volume = 6 | issue = 5| pages = 433–455 | doi=10.1016/S1364-0321(02)00014-X| bibcode = 2002RSERv...6..433S }}</ref> The chemical reactions for the SOFC system can be expressed as follows:<ref>[http://www.fctec.com/fctec_types_sofc.asp "Solid Oxide Fuel Cell (SOFC)"]. FCTec website', accessed 4 August 2011 {{webarchive |url=https://web.archive.org/web/20120108053109/http://www.fctec.com/fctec_types_sofc.asp |date=8 January 2012 }}</ref>

:''Anode reaction'': 2H<sub>2</sub> + 2O<sup>2−</sup> → 2H<sub>2</sub>O + 4e<sup>−</sup>
:''Cathode reaction'': O<sub>2</sub> + 4e<sup>−</sup> → 2O<sup>2−</sup>
:''Overall cell reaction'': 2H<sub>2</sub> + O<sub>2</sub> → 2H<sub>2</sub>O

SOFC systems can run on fuels other than pure hydrogen gas. However, since hydrogen is necessary for the reactions listed above, the fuel selected must contain hydrogen atoms. For the fuel cell to operate, the fuel must be converted into pure hydrogen gas. SOFCs are capable of internally [[Fossil fuel reforming|reforming]] light hydrocarbons such as [[methane]] (natural gas),<ref name=uva20130213>{{cite web|title=Methane Fuel Cell Subgroup|url=http://artsandsciences.virginia.edu/cchf/research/fuelcells.html|publisher=University of Virginia|access-date=2014-02-13|date=2012|archive-date=22 February 2014|archive-url=https://web.archive.org/web/20140222181513/http://artsandsciences.virginia.edu/cchf/research/fuelcells.html|url-status=dead}}</ref> propane, and butane.<ref>{{cite journal|author1=A Kulkarni |author2=FT Ciacchi |author3=S Giddey |author4=C Munnings |author5=SPS Badwal |author6=JA Kimpton |author7=D Fini |title=Mixed ionic electronic conducting perovskite anode for direct carbon fuel cells|journal=International Journal of Hydrogen Energy|year=2012| volume=37|issue=24|pages=19092–19102| doi=10.1016/j.ijhydene.2012.09.141|bibcode=2012IJHE...3719092K }}</ref> These fuel cells are at an early stage of development.<ref>{{cite journal|author1=S. Giddey |author2=S.P.S. Badwal |author3=A. Kulkarni |author4=C. Munnings |title=A comprehensive review of direct carbon fuel cell technology|journal=Progress in Energy and Combustion Science| year=2012| volume=38|issue=3|pages=360–399|doi=10.1016/j.pecs.2012.01.003|bibcode=2012PECS...38..360G }}</ref>

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.<ref>Hill, Michael. [http://www.ceramicindustry.com/Articles/Feature_Article/10637442bbac7010VgnVCM100000f932a8c0____ "Ceramic Energy: Material Trends in SOFC Systems"] {{Webarchive|url=https://web.archive.org/web/20110928023507/http://www.ceramicindustry.com/Articles/Feature_Article/10637442bbac7010VgnVCM100000f932a8c0____ |date=28 September 2011 }}. ''Ceramic Industry'', 1 September 2005.</ref> Another disadvantage of SOFC systems is the long start-up, making SOFCs less useful for mobile applications. Despite these disadvantages, a high operating temperature provides an advantage by removing the need for a precious metal catalyst like platinum, thereby reducing cost. Additionally, waste heat from SOFC systems may be captured and reused, increasing the theoretical overall efficiency to as high as 80–85%.<ref name=Types1/>

The high operating temperature is largely due to the physical properties of the YSZ electrolyte. As temperature decreases, so does the [[ionic conductivity (solid state)|ionic conductivity]] of YSZ. Therefore, to obtain the optimum performance of the fuel cell, a high operating temperature is required. According to their website, [[Ceres Power]], 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.<ref>[http://www.cerespower.com/Technology/TheCeresCell/ "The Ceres Cell"] {{webarchive|url=https://web.archive.org/web/20131213064702/http://www.cerespower.com/Technology/TheCeresCell/ |date=13 December 2013 }}. ''Ceres Power website'', accessed 4 August 2011</ref>

====Molten-carbonate fuel cell====
{{Main|Molten carbonate fuel cell}}
[[Molten carbonate fuel cell]]s (MCFCs) require a high operating temperature, {{convert|650|°C|abbr=on|-1}}, similar to [[Solid oxide fuel cell|SOFCs]]. MCFCs use lithium potassium carbonate salt as an electrolyte, and this salt liquefies at high temperatures, allowing for the movement of charge within the cell – in this case, negative carbonate ions.<ref name=moltencarb>[http://www.fossil.energy.gov/programs/powersystems/fuelcells/fuelcells_moltencarb.html "Molten Carbonate Fuel Cell Technology"]. U.S. Department of Energy, accessed 9 August 2011</ref>

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.<ref name=moltencarb/> The chemical reactions for an MCFC system can be expressed as follows:<ref>[http://www.fctec.com/fctec_types_mcfc.asp "Molten Carbonate Fuel Cells (MCFC)"]. FCTec.com, accessed 9 August 2011 {{webarchive |url=https://web.archive.org/web/20120303125426/http://www.fctec.com/fctec_types_mcfc.asp |date=3 March 2012 }}</ref>

:''Anode reaction'': CO<sub>3</sub><sup>2−</sup> + H<sub>2</sub> → H<sub>2</sub>O + CO<sub>2</sub> + 2e<sup>−</sup>
:''Cathode reaction'': CO<sub>2</sub> + ½O<sub>2</sub> + 2e<sup>−</sup> → CO<sub>3</sub><sup>2−</sup>
:''Overall cell reaction'': H<sub>2</sub> + ½O<sub>2</sub> → H<sub>2</sub>O

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.<ref name=Types1/>

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 [[Fossil fuel reforming|reforming]] process. Therefore, carbon-rich fuels like gases made from coal are compatible with the system. The United States Department of Energy claims that coal, itself, might even be a fuel option in the future, assuming the system can be made resistant to impurities such as sulfur and particulates that result from converting coal into hydrogen.<ref name=Types1/> 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 [[cogeneration|combined heat and power]] (CHP) system.<ref name=moltencarb/>

FuelCell Energy, a Connecticut-based fuel cell manufacturer, develops and sells MCFC fuel cells. The company says that their MCFC products range from 300&nbsp;kW to 2.8&nbsp;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%.<ref>[http://www.fuelcellenergy.com/products.php "Products"]. FuelCell Energy, accessed 9 August 2011 {{webarchive |url=https://archive.today/20130111041426/http://www.fuelcellenergy.com/products.php |date=11 January 2013 }}</ref>

===Electric storage fuel cell===
The electric storage fuel cell is a conventional battery chargeable by electric power input, using the conventional electro-chemical effect. However, the battery further includes hydrogen (and oxygen) inputs for alternatively charging the battery chemically.<ref>''{{US patent|8354,195}}''</ref>

===Biofuel cell===
{{Main article|Microbial fuel cell|Enzymatic biofuel cell}}
A biofuel cell converts chemical energy from biological substances into electrical energy using biological catalysts, such as enzymes or microorganisms. The process involves the oxidation of a fuel, like glucose, at the anode, releasing electrons and protons. The electrons travel through an external circuit to generate electrical current, while at the cathode, oxygen is typically reduced to water or hydrogen peroxide, completing the circuit.<ref>{{cite journal |last1=Huang |first1=Wengang |last2=Zulkifli |first2=Muhammad Yazid Bin |last3=Chai |first3=Milton |last4=Lin |first4=Rijia |last5=Wang |first5=Jingjing |last6=Chen |first6=Yuelei |last7=Chen |first7=Vicki |last8=Hou |first8=Jingwei |title=Recent advances in enzymatic biofuel cells enabled by innovative materials and techniques |journal=Exploration |date=August 2023 |volume=3 |issue=4 |doi=10.1002/EXP.20220145|pmid=37933234 |pmc=10624391 }}</ref> Applications include wastewater treatment and renewable energy production.<ref>{{cite journal |last1=Babanova |first1=Sofia |title=Biofuel Cells – Alternative Power Sources |journal=International Scientific Conference (FMNS2013), Blagoevgrad (Bulgaria) |date=2009 |url=https://inis.iaea.org/records/4884q-dkm61 |language=en}}</ref> Conductive polymers may be used to improve electron transfer between enzymes and electrodes.
<ref>{{cite journal |last1=Kižys |first1=Kasparas |last2=Zinovičius |first2=Antanas |last3=Jakštys |first3=Baltramiejus |last4=Bružaitė |first4=Ingrida |last5=Balčiūnas |first5=Evaldas |last6=Petrulevičienė |first6=Milda |last7=Ramanavičius |first7=Arūnas |last8=Morkvėnaitė-Vilkončienė |first8=Inga |title=Microbial Biofuel Cells: Fundamental Principles, Development and Recent Obstacles |journal=Biosensors |date=3 February 2023 |volume=13 |issue=2 |pages=221 |doi=10.3390/bios13020221|doi-access=free |pmid=36831987 |pmc=9954062 }}</ref>

The integration of nanomaterials, such as carbon nanotubes and metal nanoparticles, are used to enhance the performance of BFCs. These materials increase the surface area of electrodes and facilitate better electron transfer, resulting in higher power densities. Three-dimensional porous structures and graphene-based materials, have been used to improve conductivity and stability, and hybrid biofuel cells that combine BFCs with supercapacitors or secondary batteries are being developed to provide stable and continuous energy output.<ref>{{cite journal |last1=Kwon |first1=Cheong Hoon |last2=Ko |first2=Yongmin |last3=Shin |first3=Dongyeeb |last4=Kwon |first4=Minseong |last5=Park |first5=Jinho |last6=Bae |first6=Wan Ki |last7=Lee |first7=Seung Woo |last8=Cho |first8=Jinhan |title=High-power hybrid biofuel cells using layer-by-layer assembled glucose oxidase-coated metallic cotton fibers |journal=Nature Communications |date=26 October 2018 |volume=9 |issue=1 |page=4479 |doi=10.1038/s41467-018-06994-5|pmid=30367069 |pmc=6203850 |bibcode=2018NatCo...9.4479K }}</ref> BFCs are being explored as power sources for implantable devices like pacemakers and biosensors.to potentially eliminate the need for traditional batteries, and fiber-type EBFCs show potential in implantable applications.<ref>{{cite journal |last1=Cai |first1=Jingsheng |last2=Shen |first2=Fei |last3=Zhao |first3=Jianqing |last4=Xiao |first4=Xinxin |title=Enzymatic biofuel cell: A potential power source for self-sustained smart textiles |journal=iScience |date=February 2024 |volume=27 |issue=2 |pages=108998 |doi=10.1016/j.isci.2024.108998|pmid=38333690 |pmc=10850773 |bibcode=2024iSci...27j8998C }}</ref> The power density of BFCs, however, is generally lower than that of conventional energy sources, the stability of enzymes and microorganisms over extended periods is another concern, and scalability and commercial viability also pose hurdles.<ref>{{cite journal |last1=Wang |first1=Linlin |last2=Wu |first2=Xiaoge |last3=Su |first3=B. S. Qi-wen |last4=Song |first4=Rongbin |last5=Zhang |first5=Jian-Rong |last6=Zhu |first6=Jun-Jie |title=Enzymatic Biofuel Cell: Opportunities and Intrinsic Challenges in Futuristic Applications |journal=Advanced Energy and Sustainability Research |date=August 2021 |volume=2 |issue=8 |doi=10.1002/aesr.202100031|doi-access=free |bibcode=2021AdESR...200031W }}</ref>

===Comparison of fuel cell types===
{| class="wikitable sortable plainrowheaders" style="text-align:center;"
 ! rowspan=2 | Fuel cell name
 ! rowspan=2 | Electrolyte
 ! rowspan=2 | Qualified [[electric power|power]] (W)
 ! rowspan=2 | Working temperature (°C)
 ! colspan=2 | [[Electrical efficiency|Efficiency]]
 ! rowspan=2 | Status
 ! rowspan=2 | Cost (USD/W)
|-
 ! Cell
 ! System
|-
 ! scope="row" |Electro-galvanic fuel cell
 |Aqueous alkaline solution<!--e.g., potassium hydroxide-->
 |
 |{{Good|{{Sort|39|< 40}}}}
 | ||
 |{{Partial|Commercial / Research}}
 |3-7
|-
 ! scope="row" |[[Formic acid fuel cell|Direct formic acid fuel cell]] (DFAFC)
 |Polymer membrane (ionomer)
 |{{Okay|{{Sort|49|< 50 W}}}}
 |{{Good|{{Sort|39|< 40}}}}
 | ||
 |{{Okay|Commercial / Research}}
 |10-20
|-
 ! scope="row" |[[Alkaline fuel cell]]
 |Aqueous alkaline solution <!--e.g., potassium hydroxide-->
 |{{Okay|{{Sort|10000|10–200 kW}}}}
 |{{Good|{{Sort|79|< 80}}}}
 |{{Good|{{Sort|65%|60–70%}}}} || {{Good|62%}}
 |{{Partial|Commercial / Research}}
 |50-100
|-
 ! scope="row" |[[Proton-exchange membrane fuel cell]]
 |Polymer membrane (ionomer) <!--e.g. [[Nafion]] or [[Polybenzimidazole fiber]]-->
 |{{Good|{{Sort|100|1 W – 500 kW}}}}
 |{{Okay|{{Sort|125|50–100 (Nafion)<ref>{{cite web |url=http://www1.eere.energy.gov/hydrogenandfuelcells/fuelcells/pdfs/fc_comparison_chart.pdf |title=Fuel Cell Comparison Chart |access-date=2013-02-10 |url-status=dead |archive-url=https://web.archive.org/web/20130301120203/http://www1.eere.energy.gov/hydrogenandfuelcells/fuelcells/pdfs/fc_comparison_chart.pdf |archive-date=1 March 2013}}</ref><br />120–200 (PBI)}}}}<ref>{{Cite journal| title = Thermal management strategies for a 1 kWe stack of a high temperature proton exchange membrane fuel cell | journal=Applied Thermal Engineering | date = 15 December 2012 | doi = 10.1016/j.applthermaleng.2012.04.041 | author = E. Harikishan Reddy | volume = 48| pages = 465–475 | last2 = Jayanti | first2 = S| bibcode=2012AppTE..48..465H }}</ref>
 |{{Okay|{{Sort|60%|50–70%}}}} || {{Okay|{{Sort|40%|30–50%<ref name="BadwalGiddey"/>}}}}
 |{{Partial|Commercial / Research}}
 | 50–100
|-
 !scope=row|[[Metal hydride fuel cell]]
 |[[Aqueous]] [[alkali]]ne solution
 |
 |{{Okay|{{Sort|0|> −20<br />(50% P<sub>peak</sub> @ 0&nbsp;°C)}}}}
 |  || 
 |{{Partial|[[Research and development|Commercial / Research]]}}
 |30-200
|-
 !scope=row|[[Zinc–air battery]]
 |Aqueous alkaline solution<!--e.g., potassium hydroxide-->
 |
 |{{Good|{{Sort|39|< 40}}}} ||
 |
 |{{yes2}}[[Mass production]]
 |150-300
|-
 ! scope="row" |[[Direct carbon fuel cell]]
 |Several different
 |
 |{{Bad|{{Sort|775|700–850}}}}
 |{{Good|80%}} || {{Good|70%}}
 |{{Partial|Commercial / Research}}
 |18
|-
 ! scope="row" |[[Direct borohydride fuel cell]]
 |Aqueous alkaline solution<!--e.g., potassium hydroxide-->
 |
 |{{Good|70}}
 | ||
 |{{yes2|Commercial}}
 |400-450
|-
 !scope=row|[[Microbial fuel cell]]
 |Polymer membrane or [[humic acid]]
 |
 |{{Good|{{Sort|39|< 40}}}}
 |  || 
 |{{Beta|Research}}
 |10-50
|-
 !scope=row|Upflow microbial fuel cell (UMFC)
 |
 |
 |{{Good|{{Sort|39|< 40}}}}
 |  || 
 |{{Beta|Research}}
 |1-5
|-
 !scope=row|[[Regenerative fuel cell]]
 |Polymer membrane ([[ionomer]])
 |
 |{{Good|{{Sort|49|< 50}}}}
 |  || 
 |{{Partial|Commercial / Research}}
 |200-300
|-
 !scope=row|[[Direct methanol fuel cell]]
 |Polymer membrane (ionomer)
 |{{Okay|{{Sort|0.1|100 mW – 1 kW}}}}
 |{{Okay|{{Sort|105|90–120}}}}
 |{{Bad|{{Sort|25%|20–30%}}}} || {{Bad|{{Sort|15%|10–25%<ref name="BadwalGiddey">{{cite journal|last1=Badwal|first1=Sukhvinder P. S.|last2=Giddey|first2=Sarbjit S.|last3=Munnings|first3=Christopher|last4=Bhatt|first4=Anand I.|last5=Hollenkamp|first5=Anthony F.|title=Emerging electrochemical energy conversion and storage technologies|journal=Frontiers in Chemistry|date=24 September 2014|volume=2|pages=79|doi=10.3389/fchem.2014.00079|pmid=25309898|pmc=4174133|bibcode=2014FrCh....2...79B|doi-access=free}}</ref>}}}}
 |{{Partial|Commercial / Research}}
 |125
|-
 !scope=row|[[Reformed methanol fuel cell]]
 |Polymer membrane (ionomer)
 |{{Okay|{{Sort|5|5 W – 100 kW}}}}
 |{{Okay|{{Sort|200|250–300 (reformer)<br />125–200 (PBI)}}}}
 |{{Bad|{{Sort|55%|50–60%}}}} || {{Bad|{{Sort|33%|25–40%}}}}
 |{{Partial|Commercial / Research}}
 |8.50
|-
 !scope=row|[[Direct-ethanol fuel cell]]
 |Polymer membrane (ionomer)
 |{{Okay|{{Sort|0|< 140 mW/cm²}}}}
 |{{Okay|{{Sort|26|> 25<br />? 90–120}}}}
 |  || 
 |{{Beta|Research}}
 |12
|-
 !scope=row|[[Flow Battery#Classes of flow batteries|Redox fuel cell]]{{Broken anchor|date=2024-06-19|bot=User:Cewbot/log/20201008/configuration|target_link=Flow Battery#Classes of flow batteries|reason= The anchor (Classes of flow batteries) [[Special:Diff/655911549|has been deleted]].}} (RFC)
 |Liquid electrolytes with [[redox]] shuttle and polymer membrane (ionomer)
 |{{Good|{{Sort|1000|1 kW – 10 MW}}}}
 |  || 
 |
 |{{Beta|Research}}
 |12.50
|-
 !scope=row|[[Phosphoric acid fuel cell]]
 |Molten [[phosphoric acid]] (H<sub>3</sub>PO<sub>4</sub>)
 |{{Good|{{Sort|999999|< 10 MW}}}}
 |{{Bad|{{Sort|175|150–200}}}}
 |{{Okay|55%}} || {{Okay|{{Sort|40%|40%<ref name="BadwalGiddey"/><br />Co-gen: 90%}}}}
 |{{Partial|Commercial / Research}}
 | 4.00–4.50
|-
 !scope=row|[[Solid acid fuel cell]]
 |H<sup>+</sup>-conducting oxyanion salt (solid acid)
 |{{Okay|{{Sort|505|10 W – 1 kW}}}}
 |{{Bad|{{Sort|250|200–300}}}}
 |{{Okay|{{Sort|58|55–60%}}}}
 |{{Okay|{{Sort|42|40–45%}}}}
 |{{Partial|Commercial / Research}}
 |15
|-
 !scope=row|[[Molten carbonate fuel cell]]
 |Molten alkaline [[carbonate]] <!--e.g., [[sodium bicarbonate]] NaHCO<sub>3</sub>-->
 |{{Good|{{Sort|100000000|100 MW}}}}
 |{{Bad|{{Sort|625|600–650}}}}
 |{{Okay|55%}} || {{Okay|45–55%<ref name="BadwalGiddey"/>}}
 |{{Partial|Commercial / Research}}
 |1000
|-
 !scope=row|[[Tubular solid oxide fuel cell]] (TSOFC)
 |O<sup>2−</sup>-conducting ceramic [[oxide]] <!--e.g., [[zirconium dioxide]], ZrO<sub>2</sub>-->
 |{{Good|{{Sort|99999999|< 100 MW}}}}
 |{{Bad|{{Sort|975|850–1100}}}}
 |{{Good|{{Sort|63%|60–65%}}}} || {{Good|{{Sort|57%|55–60%}}}}
 |{{Partial|Commercial / Research}}
 |3.50
|-
 !scope=row|[[Protonic ceramic fuel cell]]
 |H<sup>+</sup>-conducting ceramic oxide
 |
 |{{Bad|700}}
 |  || 
 |{{Beta|Research}}
 |80
|-
 !scope=row|Planar [[solid oxide fuel cell]]
 |O<sup>2−</sup>-conducting ceramic [[oxide]] <!--e.g., [[zirconium dioxide]], ZrO<sub>2</sub> Lanthanum Nickel Oxide La<sub>2</sub>XO<sub>4</sub>, X = Ni, Co, Cu-->
 |{{Good|{{Sort|99999999|< 100 MW}}}}
 |{{Bad|{{Sort|975|500–1100}}}}
 |{{Good|{{Sort|63%|60–65%}}}} || {{Good|{{Sort|57%|55–60%<ref name="BadwalGiddey"/>}}}}
 |{{Partial|Commercial / Research}}
 |800
|-
 !scope=row|[[Enzymatic Biofuel Cells|Enzymatic biofuel cells]]
 |Any that will not denature the enzyme <!--usually aqueous [[buffer]]-->
 |
 |{{Good|{{Sort|39|< 40}}}}
 |  || 
 |{{Beta|Research}}
 |10
|-
 !scope=row|[[Magnesium-air fuel cell]]
 |Salt water
 |
 |{{Good|{{Sort|−20|−20 to 55}}}}
 |{{Good|{{Sort|90%|90%}}}}||
 |{{Partial|Commercial / Research}}
 |15
|}

Glossary of terms in table:
{{further|glossary of fuel cell terms}}
; [[Anode]]: 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.<ref name="fctpglossary"/>
; [[Aqueous solution]]<ref>[http://www.merriam-webster.com/dictionary/aqueous "Aqueous Solution"]. Merriam-Webster Free Online Dictionary</ref>{{defn|Of, relating to, or resembling water}}{{defn|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.<ref name="fctpglossary"/>
; [[Cathode]]: 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.<ref name="fctpglossary"/>
; [[Electrolyte]]: A substance that conducts charged ions from one electrode to the other in a fuel cell, battery, or electrolyzer.<ref name="fctpglossary">[http://www1.eere.energy.gov/hydrogenandfuelcells/glossary.html#c "Fuel Cell Technologies Program: Glossary"] {{webarchive|url=https://web.archive.org/web/20140223003718/http://www1.eere.energy.gov/hydrogenandfuelcells/glossary.html |date=23 February 2014 }}. Department of Energy Energy Efficiency and Renewable Energy Fuel Cell Technologies Program. 7 July 2011. Accessed 3 August 2011.</ref>
; Fuel cell stack: Individual fuel cells connected in a series. Fuel cells are stacked to increase voltage.<ref name="fctpglossary"/>
; Matrix: something within or from which something else originates, develops, or takes form.<ref>[http://www.merriam-webster.com/dictionary/matrix "Matrix"]. Merriam-Webster Free Online Dictionary</ref>
; [[Membrane (selective barrier)|Membrane]]: 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.<ref name="fctpglossary"/>
; [[Molten carbonate fuel cell]] (MCFC): A type of fuel cell that contains a molten carbonate electrolyte. Carbonate ions (CO<sub>3</sub><sup>2−</sup>) are transported from the cathode to the anode. Operating temperatures are typically near 650&nbsp;°C.<ref name="fctpglossary"/>
; [[Phosphoric acid fuel cell]] (PAFC): A type of fuel cell in which the electrolyte consists of concentrated phosphoric acid (H<sub>3</sub>PO<sub>4</sub>). Protons (H+) are transported from the anode to the cathode. The operating temperature range is generally 160–220&nbsp;°C.<ref name="fctpglossary"/>
; [[Proton-exchange membrane fuel cell]] (PEM): A fuel cell incorporating a solid polymer membrane used as its electrolyte. Protons (H+) are transported from the anode to the cathode. The operating temperature range is generally 60–100&nbsp;°C for Low Temperature Proton-exchange membrane fuel cell (LT-PEMFC).<ref name="fctpglossary"/> PEM fuel cell with operating temperature of 120-200&nbsp;°C is called [[High Temperature Proton Exchange Membrane fuel cell|High Temperature Proton-exchange membrane fuel cell]] (HT-PEMFC).<ref>{{Cite book|last=Araya|first=Samuel Simon|url=https://www.worldcat.org/oclc/857436369|title=High temperature PEM fuel cells - degradation & durability : dissertation submitted to the Faculty of Engineering and Science at Aalborg University in partial fulfillment of the requirements for the degree of Doctor of Philosophy|date=2012|publisher=Aalborg University, Department of Energy Technology|isbn=978-87-92846-14-3|location=Aalborg|oclc=857436369}}</ref> 
; [[Solid oxide fuel cell]] (SOFC): A type of fuel cell in which the electrolyte is a solid, nonporous metal oxide, typically zirconium oxide (ZrO<sub>2</sub>) treated with Y<sub>2</sub>O<sub>3</sub>, and O<sup>2−</sup> is transported from the cathode to the anode. Any CO in the reformate gas is oxidized to CO<sub>2</sub> at the anode. Temperatures of operation are typically 800–1,000&nbsp;°C.<ref name="fctpglossary"/>
; [[Solution (chemistry)|Solution]]<ref>[http://www.merriam-webster.com/dictionary/solution "Solution"]. Merriam-Webster Free Online Dictionary</ref>{{defn|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.}}{{defn|A homogeneous mixture formed by this process; especially : a single-phase liquid system.}}{{defn|The condition of being dissolved.}}

==Efficiency of leading fuel cell types==
===Theoretical maximum efficiency===
The energy efficiency of a system or device that converts energy is measured by the ratio of the amount of useful energy put out by the system ("output energy") to the total amount of energy that is put in ("input energy") or by useful output energy as a percentage of the total input energy. In the case of fuel cells, useful output energy is measured in [[electrical energy]] produced by the system. Input energy is the energy stored in the fuel. According to the U.S. Department of Energy, fuel cells are generally between 40 and 60% energy efficient.<ref>[http://www1.eere.energy.gov/hydrogenandfuelcells/fuelcells/pdfs/fc_comparison_chart.pdf "Comparison of Fuel Cell Technologies"] {{webarchive|url=https://web.archive.org/web/20130301120203/http://www1.eere.energy.gov/hydrogenandfuelcells/fuelcells/pdfs/fc_comparison_chart.pdf |date=1 March 2013 }}. U.S. Department of Energy, Energy Efficiency and Fuel Cell Technologies Program, February 2011, accessed 4 August 2011</ref> This is higher than some other systems for energy generation. For example, the internal combustion engine of a car can be about 43% energy efficient.<ref>{{cite web|url=https://www.epa.gov/sites/default/files/2020-08/documents/sae-2019-01-0249.pdf |title= Benchmarking a 2018 Toyota Camry 2.5-Liter Atkinson Cycle Engine with Cooled-EGR|publisher= SAE|accessdate= 2 April 2019}}</ref><ref>{{cite book|chapter-url=https://www.sae.org/publications/technical-papers/content/2021-01-1241/ |chapter= Development of 43% Brake Thermal Efficiency Gasoline Engine for BYD DM-i Plug-in Hybrid|publisher= SAE|doi= 10.4271/2021-01-1241|accessdate= 21 September 2021|title= SAE Technical Paper Series|date= 2021|last1= Yang|first1= Dongsheng|last2= Lu|first2= Guoxiang|last3= Gong|first3= Zewen|last4= Qiu|first4= An|last5= Bouaita|first5= Abdelhamid|volume= 1}}</ref> [[Steam power plant]]s usually achieve efficiencies of 30-40%<ref>{{Cite web|url=https://www.power-eng.com/news/new-benchmarks-for-steam-turbine-efficiency/|title=New Benchmarks for Steam Turbine Efficiency|date=August 2002|access-date=12 March 2022|archive-date=25 July 2021|archive-url=https://web.archive.org/web/20210725190441/https://www.power-eng.com/news/new-benchmarks-for-steam-turbine-efficiency/|url-status=dead}}</ref> while [[combined cycle]] gas turbine and steam plants can achieve efficiencies above 60%.<ref>{{Cite news |title=All Units of Nishi-Nagoya Thermal Power Station Now in Operation |url=https://www.toshiba-energy.com/en/info/info2018_0330.htm |date=2018-03-30 |agency=Toshiba Energy Systems & Solutions Corporation}}</ref><ref>{{Cite news |title=Chubu Electric Power's Nishi-Nagoya Thermal Power Station Unit 7-1 Recognized by Guinness World Records as World's Most Efficient Combined Cycle Power Plant: Achieved 63.08% Power Generation Efficiency |url=https://www.chuden.co.jp/english/corporate/releases/pressreleases/3267653_18939.html |work=Press Release 2018 |publisher=Chubu Electric |date=2018-03-27}}</ref> In [[combined heat and power]] (CHP) systems, the [[waste heat]] produced by the primary power cycle - whether fuel cell, nuclear fission or combustion - is captured and put to use, increasing the efficiency of the system to up to 85–90%.<ref name=Types1/>

The theoretical maximum efficiency of any type of power generation system is never reached in practice, and it does not consider other steps in power generation, such as production, transportation and storage of fuel and conversion of the electricity into mechanical power. However, this calculation allows the comparison of different types of power generation. The theoretical maximum efficiency of a fuel cell approaches 100%,<ref>{{Cite journal|date=3 May 2018|title=Maximum conversion efficiency of hydrogen fuel cells| url=https://www.sciencedirect.com/science/article/abs/pii/S0360319918308371| journal=International Journal of Hydrogen Energy|volume=43|issue=18|pages=9015–9021| doi=10.1016/j.ijhydene.2018.03.076| issn=0360-3199|last1=Haseli|first1=Y.|bibcode=2018IJHE...43.9015H |url-access=subscription}}</ref> while the theoretical maximum efficiency of internal combustion engines is approximately 58%.<ref>[http://www.worldenergy.org/focus/fuel_cells/377.asp "Fuel Cell Efficiency"] {{webarchive|url=https://web.archive.org/web/20140209080834/http://www.worldenergy.org/focus/fuel_cells/377.asp| date=9 February 2014}}. World Energy Council, 17 July 2007, accessed 4 August 2011</ref>

===In practice===
Values are given from 40% for acidic, 50% for molten carbonate, to 60% for alkaline, solid oxide and PEM fuel cells.<ref>{{cite web|title=Fuel Cells |date=November 2015 |url=https://www.energy.gov/sites/prod/files/2015/11/f27/fcto_fuel_cells_fact_sheet.pdf |access-date=2022-12-27}}</ref>

Fuel cells cannot store energy like a battery,<ref>{{cite web|url=https://www.loc.gov/rr/scitech/tracer-bullets/batteriestb.html#scope |title=Batteries, Supercapacitors, and Fuel Cells: Scope |access-date= 11 February 2009 |date=20 August 2007 |publisher=Science Reference Services }}</ref> except as hydrogen, but in some applications, such as stand-alone power plants based on discontinuous sources such as [[solar energy|solar]] or [[wind power]], they are combined with [[electrolysis|electrolyzers]] and storage systems to form an energy storage system. As of 2019, 90% of hydrogen was used for oil refining, chemicals and fertilizer production (where hydrogen is required for the [[Haber–Bosch process]]), and 98% of hydrogen is produced by [[steam methane reforming]], which emits carbon dioxide.<ref>[https://www.power-technology.com/comment/standing-at-the-precipice-of-the-hydrogen-economy "Realising the hydrogen economy"] {{Webarchive|url=https://web.archive.org/web/20191105054643/https://www.power-technology.com/comment/standing-at-the-precipice-of-the-hydrogen-economy/ |date=5 November 2019 }},''Power Technology'', 11 October 2019</ref> 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.<ref>{{Cite news| last=Garcia| first= Christopher P.| title = Round Trip Energy Efficiency of NASA Glenn Regenerative Fuel Cell System |date=January 2006 | publisher = Preprint |page=5 | display-authors=1| author2=<Please add first missing authors to populate metadata.>| hdl= 2060/20060008706}}</ref> The electrolyzer/fuel cell system can store indefinite quantities of hydrogen, and is therefore suited for long-term storage.

Solid-oxide fuel cells produce heat from the recombination of the oxygen and hydrogen. The ceramic can run as hot as {{cvt|800|C|F}}. 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, primarily due 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]".<ref name=Meyers1>Meyers, Jeremy P. [http://www.electrochem.org/dl/interface/wtr/wtr08/wtr08_p36-39.pdf "Getting Back Into Gear: Fuel Cell Development After the Hype"]. The Electrochemical Society ''Interface'', Winter 2008, pp. 36–39, accessed 7 August 2011</ref> In 2013 military organizations were evaluating fuel cells to determine if they could significantly reduce the battery weight carried by soldiers.<ref name="The fuel cell industry review 2013">{{cite web| url = http://www.fuelcelltoday.com/media/1889744/fct_review_2013.pdf| title = The fuel cell industry review 2013}}</ref>

==== In vehicles ====
In a [[fuel cell vehicle]] the tank-to-wheel efficiency is greater than 45% at low loads<ref name=RSC>Eberle, Ulrich and Rittmar von Helmolt. [https://www.researchgate.net/publication/224880220_Sustainable_transportation_based_on_electric_vehicle_concepts_a_brief_overview "Sustainable transportation based on electric vehicle concepts: a brief overview"]. Energy & Environmental Science, [[Royal Society of Chemistry]], 14 May 2010, accessed 2 August 2011</ref> and shows average values of about 36% when a driving cycle like the NEDC ([[New European Driving Cycle]]) is used as test procedure.<ref name="status2007">{{Cite journal| title = Fuel Cell Vehicles:Status 2007 | journal=Journal of Power Sources | date = 20 March 2007 | doi = 10.1016/j.jpowsour.2006.12.073 | author = Von Helmolt, R. | volume = 165 | pages = 833–843 | last2 = Eberle | first2 = U| issue = 2| bibcode = 2007JPS...165..833V }}</ref> 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.<ref>{{cite web| url=http://automobiles.honda.com/fcx-clarity/fuel-cell-comparison.aspx| title=Honda FCX Clarity – Fuel cell comparison| publisher=Honda| access-date=2009-01-02| archive-date=3 January 2009| archive-url=https://web.archive.org/web/20090103204930/http://automobiles.honda.com/fcx-clarity/fuel-cell-comparison.aspx| url-status=dead}}</ref>

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]].<ref>{{cite web|title=Efficiency of Hydrogen PEFC, Diesel-SOFC-Hybrid and Battery Electric Vehicles |date=15 July 2003 |url=http://www.efcf.com/reports/E04.pdf |access-date=2007-05-23 |url-status=dead |archive-url=https://web.archive.org/web/20061021051748/http://www.efcf.com/reports/E04.pdf |archive-date=21 October 2006 }}</ref>

==Applications==
[[File:U Boot 212 HDW 1.jpg|thumb|upright=1.3|[[Type 212 submarine]] with fuel cell propulsion. This example in dry dock is operated by the [[German Navy]].]]

===Power===
{{See also|Hydrogen fuel cell power plant}}
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.<ref name="Fuel Cell Basics Benefits">{{cite web|title=Fuel Cell Basics: Benefits |publisher=Fuel Cells 2000 |url=http://www.fuelcells.org/basics/benefits.html |access-date=2007-05-27 |url-status=dead |archive-url=https://web.archive.org/web/20070928225430/http://www.fuelcells.org/basics/benefits.html |archive-date=28 September 2007 }}</ref> This equates to less than one minute of downtime in a six-year period.<ref name="Fuel Cell Basics Benefits"/>

Since fuel cell electrolyzer systems do not store fuel in themselves, but rather rely on external storage units, they can be successfully applied in large-scale energy storage, rural areas being one example.<ref name="fuelcells.org">[http://www.fuelcells.org/basics/apps.html "Fuel Cell Basics: Applications"] {{webarchive |url=https://web.archive.org/web/20110515080800/http://www.fuelcells.org/basics/apps.html |date=15 May 2011 }}. Fuel Cells 2000. Accessed 2 August 2011.</ref> There are many different types of stationary fuel cells so efficiencies vary, but most are between 40% and 60% energy efficient.<ref name=Types1/> However, when the fuel cell's waste heat is used to heat a building in a cogeneration system this efficiency can increase to 85%.<ref name=Types1/> This is significantly more efficient than traditional coal power plants, which are only about one third energy efficient.<ref>[https://www.energy.gov/energysources/electricpower.htm "Energy Sources: Electric Power"]. U.S. Department of Energy. Accessed 2 August 2011.</ref> Assuming production at scale, fuel cells could save 20–40% on energy costs when used in cogeneration systems.<ref>[http://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/48219.pdf "2008 Fuel Cell Technologies Market Report"] {{webarchive|url=https://web.archive.org/web/20120904104908/http://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/48219.pdf |date=4 September 2012 }}. Bill Vincent of the Breakthrough Technologies Institute, Jennifer Gangi, Sandra Curtin, and Elizabeth Delmont. Department of Energy Energy Efficiency and Renewable Energy. June 2010.</ref> 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 {{CO2}}) for every 1,000&nbsp;kW·h produced, compared to 25 pounds of pollutants generated by conventional combustion systems.<ref>U.S. Fuel Cell Council Industry Overview 2010, p. 12. U.S. Fuel Cell Council. 2010.</ref> Fuel Cells also produce 97% less nitrogen oxide emissions than conventional coal-fired power plants.

One such pilot program is operating on [[Stuart Island (Washington)|Stuart Island]] in Washington State. There the Stuart Island Energy Initiative<ref>{{cite web |url=http://www.siei.org/ |title=Stuart Island Energy Initiative |publisher=Siei.org |access-date=2009-09-21 |archive-url=https://web.archive.org/web/20130618081052/http://siei.org/ |archive-date=18 June 2013 |url-status=dead }} – gives extensive technical details</ref> has built a complete, closed-loop system: Solar panels power an electrolyzer, which makes hydrogen. The hydrogen is stored in a {{convert|500|U.S.gal|L|adj=on}} tank at {{convert|200|psi}}, and runs a ReliOn fuel cell to provide full electric back-up to the off-the-grid residence. Another closed system loop was unveiled in late 2011 in Hempstead, NY.<ref>{{cite web|title=Town's Answer to Clean Energy is Blowin' in the Wind: New Wind Turbine Powers Hydrogen Car Fuel Station |url=http://townofhempstead.org/news/564-towns-answer-to-clean-energy-is-blowin-in-the-wind-new-wind-turbine-powers-hydrogen-car-fuel-station |publisher=Town of Hempstead |access-date=13 January 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120128114634/http://townofhempstead.org/news/564-towns-answer-to-clean-energy-is-blowin-in-the-wind-new-wind-turbine-powers-hydrogen-car-fuel-station |archive-date=28 January 2012}}</ref>

Fuel cells can be used with low-quality gas from landfills or waste-water treatment plants to generate power and lower [[methane emissions]]. A 2.8 MW fuel cell plant in California is said to be the largest of the type.<ref>[http://www.onlinetes.com/fuel-cell-energy-power-101612.aspx World's Largest Carbon Neutral Fuel Cell Power Plant] {{webarchive|url=https://web.archive.org/web/20130528160634/http://www.onlinetes.com/fuel-cell-energy-power-101612.aspx |date=28 May 2013 }}, 16 October 2012</ref> Small-scale (sub-5kWhr) fuel cells are being developed for use in residential off-grid deployment.<ref>[https://www.upstartpower.com/2020/12/investment-residential-fuel-cell/ Upstart Power Announces Investment for Residential Fuel Cell Technology from Clean Tech Leaders] {{Webarchive| url=https://web.archive.org/web/20210122122351/https://www.upstartpower.com/2020/12/investment-residential-fuel-cell/ |date=22 January 2021 }}, 16 December 2020</ref>

===Cogeneration===
{{See also|Combined cycle hydrogen power plant}}
Combined heat and power (CHP) fuel cell systems, including [[micro combined heat and power]] (MicroCHP) systems are used to generate both electricity and heat for homes (see [[home fuel cell]]), office building and factories. The system generates constant electric power (selling excess power back to the grid when it is not consumed), and at the same time produces hot air and water from the [[waste heat]]. As the result CHP systems have the potential to save primary energy as they can make use of waste heat which is generally rejected by thermal energy conversion systems.<ref>{{cite web|url=http://www.globalccsinstitute.com/publications/reduction-residential-carbon-dioxide-emissions-through-use-small-cogeneration-fuel-ce-7|title=Reduction of residential carbon dioxide emissions through the use of small cogeneration fuel cell systems – Combined heat and power systems|publisher=IEA Greenhouse Gas R&D Programme (IEAGHG)|date=11 November 2008|access-date=2013-07-01|archive-url=https://web.archive.org/web/20131203185449/http://www.globalccsinstitute.com/publications/reduction-residential-carbon-dioxide-emissions-through-use-small-cogeneration-fuel-ce-7|archive-date=3 December 2013|url-status=dead}}</ref> A typical capacity range of [[home fuel cell]] is 1–3&nbsp;kW<sub>el</sub>, 4–8&nbsp;kW<sub>th</sub>.<ref>{{cite web|url=http://www.globalccsinstitute.com/publications/reduction-residential-carbon-dioxide-emissions-through-use-small-cogeneration-fuel-c-20|title=Reduction of residential carbon dioxide emissions through the use of small cogeneration fuel cell systems – Scenario calculations|publisher=IEA Greenhouse Gas R&D Programme (IEAGHG)|date=11 November 2008|access-date=2013-07-01|archive-url=https://web.archive.org/web/20131026035842/http://www.globalccsinstitute.com/publications/reduction-residential-carbon-dioxide-emissions-through-use-small-cogeneration-fuel-c-20|archive-date=26 October 2013|url-status=dead}}</ref><ref>{{Cite web|url=https://cogen.org/|title=cogen.org – body shop in nassau county}}</ref> CHP systems linked to [[absorption chiller]]s use their waste heat for [[refrigeration]].<ref>{{Cite web|url=http://www.fchea.org/core/import/PDFs/CHP%20Fact%20Sheet.pdf|archive-url=https://web.archive.org/web/20120518094954/http://www.fchea.org/core/import/PDFs/CHP%20Fact%20Sheet.pdf|url-status=dead|title=Fuel Cells and CHP|archive-date=18 May 2012}}</ref>

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.<ref>{{cite web|title=Patent 7,334,406|url=http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=2&f=G&l=50&co1=AND&d=PTXT&s1=7,334,406&OS=7,334,406&RS=7,334,406|access-date=25 August 2011|archive-date=24 February 2021|archive-url=https://web.archive.org/web/20210224203754/http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=2&f=G&l=50&co1=AND&d=PTXT&s1=7,334,406&OS=7,334,406&RS=7,334,406|url-status=dead}}</ref><ref>{{cite web|title=Geothermal Heat, Hybrid Energy Storage System|url=http://www.license.umn.edu/Products/Hybrid-Geothermal-and-Fuel-Cell-System__Z04147.aspx|access-date=25 August 2011|archive-date=5 March 2012|archive-url=https://web.archive.org/web/20120305232421/http://www.license.umn.edu/Products/Hybrid-Geothermal-and-Fuel-Cell-System__Z04147.aspx|url-status=dead}}</ref>

Co-generation systems can reach 85% efficiency (40–60% electric and the remainder as thermal).<ref name=Types1/> Phosphoric-acid fuel cells (PAFC) comprise the largest segment of existing CHP products worldwide and can provide combined efficiencies close to 90%.<ref>{{cite web|url=http://www.globalccsinstitute.com/publications/reduction-residential-carbon-dioxide-emissions-through-use-small-cogeneration-fuel-c-12#tbl_4-7|title=Reduction of residential carbon dioxide emissions through the use of small cogeneration fuel cell systems – Commercial sector|publisher=IEA Greenhouse Gas R&D Programme (IEAGHG)|date=11 November 2008|access-date=2013-07-01|archive-url=https://web.archive.org/web/20180305202609/http://www.globalccsinstitute.com/publications/reduction-residential-carbon-dioxide-emissions-through-use-small-cogeneration-fuel-c-12#tbl_4-7|archive-date=5 March 2018|url-status=dead}}</ref><ref>[http://www.utcpower.com/products/purecell400 "PureCell Model 400: Overview"]  {{webarchive|url=https://web.archive.org/web/20110514111455/http://www.utcpower.com/products/purecell400 |date=14 May 2011 }}. UTC Power. Accessed 2 August 2011.</ref> Molten carbonate (MCFC) and solid-oxide fuel cells (SOFC) are also used for combined heat and power generation and have electrical energy efficiencies around 60%.<ref>[http://www1.eere.energy.gov/hydrogenandfuelcells/fuelcells/pdfs/fc_comparison_chart.pdf "Comparison of Fuel Cell Technologies"] {{webarchive|url=https://web.archive.org/web/20130301120203/http://www1.eere.energy.gov/hydrogenandfuelcells/fuelcells/pdfs/fc_comparison_chart.pdf |date=1 March 2013 }}. Department of Energy Energy Efficiency and Renewable Energy Fuel Cell Technologies Program. February 2011.</ref> Disadvantages of co-generation systems include slow ramping up and down rates, high cost and short lifetime.<ref>{{cite journal | last1 = Onovwiona | first1 = H.I. | last2 = Ugursal | first2 = V.I. | year = 2006 | title = Residential cogeneration systems: review of the current technology | journal = Renewable and Sustainable Energy Reviews | volume = 10 | issue = 5| pages = 389–431 | doi=10.1016/j.rser.2004.07.005| bibcode = 2006RSERv..10..389O }}</ref><ref>AD. Hawkes, L. Exarchakos, D. Hart, MA. Leach, D. Haeseldonckx, L. Cosijns and W. D’haeseleer. EUSUSTEL work package 3: Fuell cells, 2006.</ref> Also their need to have a hot water storage tank to smooth out the thermal heat production was a serious disadvantage in the domestic market place where space in domestic properties is at a great premium.<ref>{{cite web|url=http://www.globalccsinstitute.com/publications/reduction-residential-carbon-dioxide-emissions-through-use-small-cogeneration-fuel-c-31#Expert_Reviewers_Comments|title=Reduction of residential carbon dioxide emissions through the use of small cogeneration fuel cell systems|publisher=IEA Greenhouse Gas R&D Programme (IEAGHG)|date=11 November 2008|access-date=2013-07-01|archive-url=https://web.archive.org/web/20180504050857/http://www.globalccsinstitute.com/publications/reduction-residential-carbon-dioxide-emissions-through-use-small-cogeneration-fuel-c-31#Expert_Reviewers_Comments|archive-date=4 May 2018|url-status=dead}}</ref>

Delta-ee consultants stated in 2013 that with 64% of global sales the fuel cell micro-combined heat and power passed the conventional systems in sales in 2012.<ref name="The fuel cell industry review 2013"/> The Japanese ENE FARM project stated that 34.213 PEMFC and 2.224 SOFC were installed in the period 2012–2014, 30,000 units on [[LNG]] and 6,000 on [[liquefied petroleum gas|LPG]].<ref name="CalluxEn1">{{cite web|url=http://www.hyer.eu/2014/enfarm-enefield-eneware |title=HyER " Enfarm, enefield, eneware! |url-status=dead |archive-url=https://web.archive.org/web/20160215204028/http://www.hyer.eu/2014/enfarm-enefield-eneware |archive-date=15 February 2016 }}</ref>

===Fuel cell electric vehicles (FCEVs)===
{{main|Fuel cell vehicle|Hydrogen vehicle|List of fuel cell vehicles|hydrogen fuel cell train}}
[[File:Fuelcell.jpg|thumb|Configuration of components in a fuel cell car]]
[[File:Toyota mirai trimmed.jpg|thumb|[[Toyota Mirai]]]]
[[File:Element One.jpg|thumb|[[Element One]] fuel cell vehicle]]

====Automobiles====
Four [[fuel cell vehicle|fuel cell electric vehicle]]s have been introduced for commercial lease and sale: the [[Honda Clarity]], [[Toyota Mirai]], [[Hyundai ix35 FCEV]], and the [[Hyundai Nexo]]. By year-end 2019, about 18,000 FCEVs had been leased or sold worldwide.<ref>{{Cite web|date=2021-07-17|title=Hydrogen Fuel Cell - Designs, reactions, FCEV, Pros and Cons|url=https://bauaelectric.com/fuel-cell/hydrogen-fuel-cell-design-reaction-pros-and-cons/|access-date=2021-07-18|website=Bauaelectric|archive-date=18 July 2021|archive-url=https://web.archive.org/web/20210718193713/https://bauaelectric.com/fuel-cell/hydrogen-fuel-cell-design-reaction-pros-and-cons/|url-status=dead}}</ref><ref>{{Cite news|url=https://www.prnewswire.com/news-releases/global-market-for-hydrogen-fuel-cell-vehicles-forecasts-for-major-world-regions-to-2032-301063614.html/|title=Global Market for Hydrogen Fuel Cell Vehicles: Forecasts for Major World Regions To 2032|date=2020-05-21}}</ref> Fuel cell electric vehicles feature an average range of {{cvt|314|mi|km|order=flip}} between refuelings<ref>{{Cite news|url=http://www.cecsb.org/fcev/|title=Fuel Cell Electric Vehicles|work=Community Environmental Council|access-date=2018-03-26|archive-date=27 March 2018|archive-url=https://web.archive.org/web/20180327084403/http://www.cecsb.org/fcev/|url-status=dead}}</ref> and can be refueled in about 5 minutes.<ref>Wipke, Keith, Sam Sprik, Jennifer Kurtz and Todd Ramsden. [http://www.nrel.gov/hydrogen/pdfs/51564.pdf "National FCEV Learning Demonstration"] {{webarchive|url=https://web.archive.org/web/20111019173103/http://www.nrel.gov/hydrogen/pdfs/51564.pdf |date=19 October 2011}}. National Renewable Energy Laboratory, April 2011, accessed 2 August 2011</ref> The U.S. Department of Energy's Fuel Cell Technology Program states that, as of 2011, fuel cells achieved 53–59% efficiency at one-quarter power and 42–53% vehicle efficiency at full power,<ref name=progressreport>Garbak, John. [http://www.hydrogen.energy.gov/pdfs/progress10/viii_0_technology_validation_overview.pdf "VIII.0 Technology Validation Sub-Program Overview"] {{Webarchive|url=https://web.archive.org/web/20150924032047/http://www.hydrogen.energy.gov/pdfs/progress10/viii_0_technology_validation_overview.pdf |date=24 September 2015 }}. DOE Fuel Cell Technologies Program, FY 2010 Annual Progress Report, accessed 2 August 2011</ref> and a durability of over {{convert|75000|miles|sigfig=2|abbr=on|order=flip}} with less than 10% degradation.<ref name=Accomplishments>[http://www1.eere.energy.gov/hydrogenandfuelcells/accomplishments.html "Accomplishments and Progress"] {{webarchive|url=https://web.archive.org/web/20110821050300/http://www1.eere.energy.gov/hydrogenandfuelcells/accomplishments.html |date=21 August 2011}}. Fuel Cell Technology Program, U.S. Dept. of Energy, 24 June 2011</ref> In a 2017 Well-to-Wheels simulation analysis that "did not address the economics and market constraints", General Motors and its partners estimated that, for an equivalent journey, a fuel cell electric vehicle running on compressed gaseous hydrogen produced from natural gas could use about 40% less energy and emit 45% less greenhouse gasses than an internal combustion vehicle.<ref name=Lathia>{{Cite journal|last1=Lathia|first1=Rutvik Vasudev|last2=Dobariya|first2=Kevin S.|last3=Patel|first3=Ankit|title=Hydrogen Fuel Cells for Road Vehicles|journal=Journal of Cleaner Production|volume=141|date=10 January 2017|doi=10.1016/j.jclepro.2016.09.150|page=462|bibcode=2017JCPro.141..462L }}</ref>

In 2015, Toyota introduced its first fuel cell vehicle, the Mirai, at a price of $57,000.<ref>{{Cite web | url=http://driving.ca/toyota/mirai | title=Mirai – New and Used Car Reviews, Comparisons and News}}</ref> Hyundai introduced the limited production [[Hyundai ix35 FCEV]] under a lease agreement.<ref>{{cite news | url=http://www.autoblog.com/2012/09/27/hyundai-ix35-fuel-cell-paris-2012/ |title=Hyundai ix35 lays claim to world's first production fuel cell vehicle title |work=autoblog.com |first=Jeremy |last=Korzeniewski |date=27 September 2012 |access-date=2012-10-07}}</ref> In 2016, Honda started leasing the Honda Clarity Fuel Cell.<ref>{{Cite news|url=https://blog.caranddriver.com/hydro-dip-2017-honda-clarity-fuel-cell-leases-cheaper-than-initially-expected/|title=Hydro Dip: 2017 Honda Clarity Fuel-Cell Leases Cheaper Than Initially Expected|access-date=2018-03-26|archive-date=27 March 2018|archive-url=https://web.archive.org/web/20180327023719/https://blog.caranddriver.com/hydro-dip-2017-honda-clarity-fuel-cell-leases-cheaper-than-initially-expected/|url-status=dead}}</ref> In 2018, Hyundai introduced the [[Hyundai Nexo]], replacing the [[Hyundai ix35 FCEV]]. In 2020, Toyota introduced the second generation of its Mirai brand, improving [[fuel efficiency]] and expanding range compared to the original Sedan 2014 model.<ref>{{Cite news|url=https://www.h2bulletin.com/toyota-launches-second-generation-mirai-hydrogen-fuel-cell-vehicle/|title=Toyota launches second generation Mirai hydrogen fuel cell vehicle|access-date=2020-12-21}}</ref>

In 2024, Mirai owners filed a [[class action]] lawsuit against Toyota in California over the lack of availability of hydrogen for fuel cell electric cars, alleging, among other things, fraudulent concealment and misrepresentation as well as violations of California's false advertising law and breaches of implied warranty.<ref name=Martin2024>Martin, Polly. [https://www.hydrogeninsight.com/transport/toyota-sued-over-lack-of-hydrogen-availability-for-fuel-cell-cars-in-california/2-1-1676965 "Toyota sued over lack of hydrogen availability for fuel cell cars in California"], ''Hydrogen Insight'', July 15, 2024</ref> The same year, Hyundai recalled all 1,600 Nexo vehicles sold in the US to that time due to a risk of fuel leaks and fire from a faulty "pressure relief device".<ref name=Nexo2024>[https://www.boston.com/news/business/2024/10/18/hyundai-recalls-hydrogen-fuel-cell-vehicles-due-to-fire-risk-and-tells-owners-to-park-them-outdoors "Hyundai recalls hydrogen fuel cell vehicles due to fire risk and tells owners to park them outdoors"], Associated Press, via Boston.com, October 18, 2024</ref>

=====Criticism=====
Some commentators believe that hydrogen fuel cell cars will never become economically competitive with other technologies<ref name=Romm2014/><ref name=TechRev>{{cite web|url=https://www.technologyreview.com/2007/03/01/226486/hell-and-hydrogen |title=Hell and Hydrogen|date=March 2007 |publisher=Technologyreview.com |access-date=2011-01-31}}</ref><ref>{{cite web |url=https://www.slashgear.com/833231/heres-why-hydrogen-cars-were-doomed-to-fail |title=Here's Why Hydrogen Cars Were Doomed to Fail |last1=Fernandez |first1=Ray |date=April 14, 2022 |website=SlashGear |access-date=April 16, 2022}}</ref> or that it will take decades for them to become profitable.<ref name=Meyers1/><ref name=Lux2013/> Elon Musk, CEO of battery-electric vehicle maker [[Tesla Motors]], stated in 2015 that fuel cells for use in cars will never be commercially viable because of the inefficiency of producing, transporting and storing hydrogen and the flammability of the gas, among other reasons.<ref name=Musk1>[https://www.youtube.com/watch?v=Y_e7rA4fBAo "Elon Musk on why Hydrogen fuel cell is dumb (2015)"], YouTube, 14 January 2015, at 10:20 of the clip</ref> In 2012, Lux Research, Inc. issued a report that stated: "The dream of a hydrogen economy ... is no nearer". It concluded that "Capital cost ... will limit adoption to a mere 5.9 GW" by 2030, providing "a nearly insurmountable barrier to adoption, except in niche applications". The analysis concluded that, by 2030, PEM stationary market will reach $1 billion, while the vehicle market, including forklifts, will reach a total of $2 billion.<ref name=Lux2013>Brian Warshay, Brian. [http://www.luxresearchinc.com/news-and-events/press-releases/143.html "The Great Compression: the Future of the Hydrogen Economy"] {{Webarchive|url=https://web.archive.org/web/20130315140923/http://www.luxresearchinc.com/news-and-events/press-releases/143.html |date=15 March 2013 }}, Lux Research, Inc. January 2013</ref> Other analyses cite the lack of an extensive [[hydrogen infrastructure]] in the U.S. as an ongoing challenge to Fuel Cell Electric Vehicle commercialization.<ref name=RSC/>

In 2014, [[Joseph Romm]], the author of ''[[The Hype About Hydrogen]]'' (2005), said that FCVs still had not overcome the high fueling cost, lack of fuel-delivery infrastructure, and pollution caused by producing hydrogen. "It would take several miracles to overcome all of those problems simultaneously in the coming decades."<ref>Romm, Joseph. [http://thinkprogress.org/climate/2014/08/13/3467289/tesla-toyota-hydrogen-car/ "Tesla Trumps Toyota Part II: The Big Problem With Hydrogen Fuel Cell Vehicles"], CleanProgress.com, 13 August 2014</ref> He concluded that renewable energy cannot economically be used to make hydrogen for an FCV fleet "either now or in the future."<ref name=Romm2014>Romm, Joseph. [http://thinkprogress.org/climate/2014/08/05/3467115/tesla-toyota-hydrogen-cars-batteries/ "Tesla Trumps Toyota: Why Hydrogen Cars Can’t Compete With Pure Electric Cars"], CleanProgress.com, 5 August 2014</ref> [[Greentech Media]]'s analyst reached similar conclusions in 2014.<ref>Hunt, Tam. [http://www.greentechmedia.com/articles/read/should-california-reconsider-its-policy-support-for-fuel-cell-vehicles "Should California Reconsider Its Policy Support for Fuel-Cell Vehicles?"], GreenTech Media, 10 July 2014</ref> In 2015, ''[[CleanTechnica]]'' listed some of the disadvantages of hydrogen fuel cell vehicles.<ref>Brown, Nicholas. [http://cleantechnica.com/2015/06/26/hydrogen-cars-lost-much-support/ "Hydrogen Cars Lost Much of Their Support, But Why?"], ''Clean Technica'', 26 June 2015</ref> So did ''Car Throttle''.<ref>[https://www.carthrottle.com/post/engineering-explained-5-reasons-why-hydrogen-cars-are-stupid/ "Engineering Explained: 5 Reasons Why Hydrogen Cars Are Stupid"], ''Car Throttle'', 8 October 2015</ref> A 2019 video by ''Real Engineering'' noted that, notwithstanding the introduction of vehicles that run on hydrogen, using hydrogen as a fuel for cars does not help to reduce carbon emissions from transportation. The 95% of hydrogen still produced from fossil fuels releases carbon dioxide, and producing hydrogen from water is an energy-consuming process. Storing hydrogen requires more energy either to cool it down to the liquid state or to put it into tanks under high pressure, and delivering the hydrogen to fueling stations requires more energy and may release more carbon. The hydrogen needed to move a FCV a kilometer costs approximately 8 times as much as the electricity needed to move a BEV the same distance.<ref>Ruffo, Gustavo Henrique. [https://insideevs.com/features/373145/video-compares-bev-fcevs-energy-efficient "This Video Compares BEVs to FCEVs and the More Efficient Is..."], InsideEVs.com, 29 September 2019</ref>

A 2020 assessment concluded that hydrogen vehicles are still only 38% efficient, while battery EVs are 80% efficient.<ref>Baxter, Tom. [https://uk.news.yahoo.com/hydrogen-cars-wont-overtake-electric-111749065.html "Hydrogen cars won't overtake electric vehicles because they're hampered by the laws of science"], ''The Conversation'', 3 June 2020</ref> In 2021 ''[[CleanTechnica]]'' concluded that (a) hydrogen cars remain far less efficient than electric cars; (b) [[grey hydrogen]] – hydrogen produced with polluting processes – makes up the vast majority of available hydrogen; (c) delivering hydrogen would require building a vast and expensive new delivery and refueling infrastructure; and (d) the remaining two "advantages of fuel cell vehicles – longer range and fast fueling times – are rapidly being eroded by improving battery and charging technology."<ref>Morris, Charles. [https://cleantechnica.com/2021/10/14/why-are-3-automakers-still-hyping-hydrogen-fuel-cell-vehicles "Why Are 3 Automakers Still Hyping Hydrogen Fuel Cell Vehicles?"], CleanTechnica, October 14, 2021</ref> A 2022 study in ''[[Nature Electronics]]'' agreed.<ref>Plötz, Patrick. [https://doi.org/10.1038/s41928-021-00706-6 "Hydrogen technology is unlikely to play a major role in sustainable road transport"], ''[[Nature Electronics]]'', vol. 5, pp. 8–10, January 31, 2022</ref> A 2023 study by the [[Centre for International Climate and Environmental Research]] (CICERO) estimated that leaked hydrogen has a global warming effect 11.6 times stronger than CO₂.<ref name=CICERO>Bjørnæs, Christian. [https://cicero.oslo.no/en/hydrogen-leaks-add-to-global-warming "Global warming potential of hydrogen estimated"], [[Centre for International Climate and Environmental Research]], June 7, 2023. Retrieved June 15, 2023</ref>

====Buses====
[[File:TOYOTA FCHV Bus.jpg|thumb|right|[[Toyota FCHV-BUS]] at the [[Expo 2005]] ]]
{{as of|2011|08}}, there were about 100 [[fuel cell bus]]es in service around the world.<ref name="calstart.org">[http://www.calstart.org/projects/low-carbon-bus-program/National-Fuel-Cell-Bus-Program/National-Fuel-Cell-Bus-Program-Awards.aspx "National Fuel Cell Bus Program Awards"]. Calstart. Accessed 12 August 2011 {{webarchive|url=https://web.archive.org/web/20121031124915/http://www.calstart.org/projects/low-carbon-bus-program/National-Fuel-Cell-Bus-Program/National-Fuel-Cell-Bus-Program-Awards.aspx|date=31 October 2012}}</ref> Most of these were manufactured by [[UTC Power]], Toyota, Ballard, [[Hydrogenics]], and Proton Motor. UTC buses had driven more than {{convert|600000|miles|km|sigfig=2|abbr=on|order=flip}} by 2011.<ref>[http://www.utcpower.com/products/transportation/fleet-vehicles "Transportation Fleet Vehicles: Overview"] {{webarchive |url=https://web.archive.org/web/20111017062215/http://www.utcpower.com/products/transportation/fleet-vehicles |date=17 October 2011 }}. UTC Power. Accessed 2 August 2011.</ref> Fuel cell buses have from 39% to 141% higher fuel economy than diesel buses and natural gas buses.<ref name=Lathia/><ref>[http://www.hydrogen.energy.gov/pdfs/progress10/viii_0_technology_validation_overview.pdf "FY 2010 annual progress report: VIII.0 Technology Validation Sub-Program Overview"] {{Webarchive|url=https://web.archive.org/web/20150924032047/http://www.hydrogen.energy.gov/pdfs/progress10/viii_0_technology_validation_overview.pdf |date=24 September 2015 }}, John Garbak. Department of Energy Hydrogen Program.</ref>

{{As of|2019}}, [[National Renewable Energy Laboratory|the NREL]] was evaluating several current and planned fuel cell bus projects in the U.S.<ref>[https://www.nrel.gov/hydrogen/fuel-cell-bus-evaluation.html "Fuel Cell Electric Bus Evaluations"], U.S. Dept. of Energy, accessed 10 September 2019</ref>

====Trains====
Train operators may use hydrogen fuel cells in trains in an effort to save the costs of installing overhead electrification and to maintain the range offered by diesel trains. They have encountered expenses, however, due to fuel cells in trains lasting only three years, maintenance of the hydrogen tank and the additional need for batteries as a power buffer.<ref>{{Cite web |last=Hajek |first=Stefan |date=2023-08-17 |title=Wasserstoff- und Batterie-Züge: "Die Batterie setzt sich fast immer gegen den Wasserstoff durch |url=https://www.wiwo.de/unternehmen/dienstleister/wasserstoff-und-batterie-zuege-die-batterie-setzt-sich-fast-immer-gegen-den-wasserstoff-durch/29325672.html |access-date=2024-07-15 |website=www.wiwo.de |language=de}}</ref><ref>{{Cite web |last=Parkes |first=Rachel |date=2023-08-22 |title=Hydrogen will 'almost always' lose out to battery-electric in German rail transport: train manufacturer |url=https://www.hydrogeninsight.com/transport/hydrogen-will-almost-always-lose-out-to-battery-electric-in-german-rail-transport-train-manufacturer/2-1-1504868 |access-date=2024-07-15 |website=hydrogeninsight.com}}</ref> In 2018, the first fuel cell-powered trains, the [[Alstom Coradia Lint#iLint|Alstom Coradia iLint]] multiple units, began running on the Buxtehude–Bremervörde–Bremerhaven–Cuxhaven line in Germany.<ref>{{cite web |title=Fuel cell powered trains |url=https://www.alstom.com/solutions/rolling-stock/coradia-ilinttm-worlds-1st-hydrogen-powered-train |website=Alstom Coradia iLint}}</ref> Hydrogen trains have also been introduced in Sweden<ref>{{cite web |url=https://www.alstom.com/press-releases-news/2021/8/alstoms-coradia-ilint-hydrogen-train-runs-first-time-sweden |title=Alstom's Coradia iLint hydrogen train runs for the first time in Sweden|website=Alstom.com}}</ref> and the UK.<ref>{{cite web |title=Hydrogen trains in U.K. |url=https://rail.ricardo.com/campaigns/routes-to-railway-decarbonisation/hydrogen-traction/hydrogen-fuel-cell-rollingstock |website=HydroFlex}}</ref>

====Trucks====
In December 2020, [[Toyota]] and [[Hino Motors]], together with [[7-Eleven|Seven-Eleven (Japan)]], [[FamilyMart]] and [[Lawson (store)|Lawson]] announced that they have agreed to jointly consider introducing light-duty fuel cell electric trucks (light-duty FCETs).<ref>{{cite news|date=8 December 2020 |title=Toyota and Hino Launch Initiative with Seven-Eleven, FamilyMart, and Lawson to Introduce Light-Duty Fuel Cell Electric Trucks  |url=https://global.toyota/en/newsroom/corporate/34161251.html |work=[[Toyota]] |access-date=25 November 2021}}</ref> Lawson started testing for low temperature delivery at the end of July 2021 in Tokyo, using a [[Hino Dutro]] in which the [[Toyota Mirai]] fuel cell is implemented. FamilyMart started testing in [[Okazaki, Aichi|Okazaki city]].<ref>{{cite news|date=11 August 2021 |title=ローソンとファミマが燃料電池トラック導入、トヨタいすゞ日野が車両開発 |trans-title=Lawson and FamilyMart introduced fuell cell trucks developed by Toyota and Hino |url=https://monoist.itmedia.co.jp/mn/articles/2108/11/news043.html |work=IT media, Japan |access-date=25 November 2021}}</ref>

In August 2021, Toyota announced their plan to make fuel cell modules at its Kentucky auto-assembly plant for use in zero-emission big rigs and heavy-duty commercial vehicles. They plan to begin assembling the electrochemical devices in 2023.<ref>{{cite news|date=25 August 2021 |title=Toyota to Make Fuel Cell Modules for Hydrogen Big Rigs At Kentucky Plant |url=https://www.forbes.com/sites/alanohnsman/2021/08/25/toyota-to-make-fuel-cell-modules-at-kentucky-plant-for-hydrogen-big-rigs/?sh=72ef4804e54d |work=[[Forbes]] |access-date=25 November 2021}}</ref>

In October 2021, [[Daimler Truck]]'s fuel cell based truck received approval from German authorities for use on public roads.<ref name="DaimlerTruck">{{cite press release |url=https://media.daimlertruck.com/marsMediaSite/ko/en/51714040 |title=Daimler Truck's hydrogen-based fuel-cell truck receives license for road use |publisher=[[Daimler Truck]] |date=25 October 2021 |access-date=4 April 2022}}</ref>

====Forklifts====
A [[fuel cell forklift]] (also called a fuel cell lift truck) is a fuel cell-powered industrial [[forklift truck]] used to lift and transport materials. In 2013 there were over 4,000 fuel cell forklifts used in [[material handling]] in the US,<ref>{{Cite web|url=http://www.fuelcells.org/pdfs/FuelCellForkliftsGainGround.pdf|date=21 August 2013|archive-url=https://web.archive.org/web/20130821025808/http://www.fuelcells.org/pdfs/FuelCellForkliftsGainGround.pdf|archive-date=21 August 2013|title=再生医療専門クリニック リペアセルクリニック 東京院}}</ref> of which 500 received funding from [[United States Department of Energy|DOE]] (2012).<ref>{{Cite web| url=http://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/iea_hia_fctp_overview_oct12.pdf|archive-url=https://web.archive.org/web/20131203000519/http://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/iea_hia_fctp_overview_oct12.pdf|url-status=dead |title=Fuel cell technologies program overview|archive-date=3 December 2013}}</ref><ref>{{Cite web| url=http://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/economic_impacts_of_arra_fc.pdf|archive-url=https://web.archive.org/web/20131203004225/http://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/economic_impacts_of_arra_fc.pdf|url-status=dead |title=Economic Impact of Fuel Cell Deployment in Forklifts and for Backup Power under the American Recovery and Reinvestment Act|archive-date=3 December 2013}}</ref>  As of 2024, approximately 50,000 hydrogen forklifts are in operation worldwide (the bulk of which are in the U.S.), as compared with 1.2 million battery electric forklifts that were purchased in 2021.<ref>Barnard, Michael. [https://cleantechnica.com/2024/01/02/on-hydrogen-forklifts-bitcoin-mining-and-green-fertilizer "On Hydrogen Forklifts, Bitcoin Mining and Green Fertilizer"], ''CleanTechnica'', January 2, 2024</ref>

Most companies in Europe and the US do not use petroleum-powered forklifts, as these vehicles work indoors where emissions must be controlled and instead use electric forklifts.<ref name=Report>[http://www.prnewswire.com/news-releases/global-and-chinese-forklift-industry-report-2014-2016-281752401.html "Global and Chinese Forklift Industry Report, 2014-2016"], Research and Markets, 6 November 2014</ref><ref>{{Cite web|url=http://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/forklift_anl_esd.pdf|archive-url=https://web.archive.org/web/20130217104928/http://www2.eere.energy.gov/hydrogenandfuelcells/pdfs/forklift_anl_esd.pdf|url-status=dead|title=Full Fuel-Cycle Comparison of Forklift Propulsion Systems|archive-date=17 February 2013}}</ref> Fuel cell-powered forklifts can be refueled in 3 minutes and they can be used in refrigerated warehouses, where their performance is not degraded by lower temperatures. The FC units are often designed as drop-in replacements.<ref>{{cite web|url=http://www.still.co.uk/fuel-cell-technology-uk.0.0.html|title=Fuel cell technology|access-date=24 November 2013|archive-url=https://web.archive.org/web/20131203104905/http://www.still.co.uk/fuel-cell-technology-uk.0.0.html|archive-date=3 December 2013|url-status=dead}}</ref><ref>{{cite web|url=http://graftechaet.com/getattachment/065811d2-720e-40c6-b236-0440c4d90d76/OFCC-Forklift-Case-Study.aspx|title=Creating Innovative Graphite Solutions for Over 125 Years|website=GrafTech International|url-status=dead|archive-url=https://web.archive.org/web/20101206072419/http://www.graftechaet.com/getattachment/065811d2-720e-40c6-b236-0440c4d90d76/OFCC-Forklift-Case-Study.aspx|archive-date=6 December 2010}}</ref>

====Motorcycles and bicycles====
In 2005, a British manufacturer of hydrogen-powered fuel cells, [[Intelligent Energy]] (IE), produced the first working hydrogen-run motorcycle called the [[ENV]] (Emission Neutral Vehicle). The motorcycle holds enough fuel to run for four hours, and to travel {{convert|100|miles|km|abbr=on|sigfig=2|order=flip}} in an urban area, at a top speed of {{convert|50|mph|km/h|0|abbr=on|order=flip}}.<ref>{{cite web | title = The ENV Bike | publisher = Intelligent Energy | url = http://www.envbike.com/ | access-date = 2007-05-27 | archive-url = https://web.archive.org/web/20080306162946/http://www.envbike.com/ | archive-date = 6 March 2008 | url-status = dead}}</ref> In 2004 [[Honda]] developed a fuel cell motorcycle that utilized the Honda FC Stack.<ref>{{Cite news|title=Honda Develops Fuel Cell Scooter Equipped with Honda FC Stack |publisher=Honda Motor Co. |date=24 August 2004 |url=http://world.honda.com/news/2004/2040824_03.html |access-date=2007-05-27 |url-status=dead |archive-url=https://web.archive.org/web/20070402035611/http://world.honda.com/news/2004/2040824_03.html |archive-date= 2 April 2007 }}</ref><ref>{{cite web | title = Honda to offer fuel-cell motorcycle | last = Bryant | first = Eric | publisher = autoblog.com | date = 21 July 2005 | url = http://hybrids.autoblog.com/2005/07/21/honda-to-offer-fuel-cell-motorcycle/ | access-date = 2007-05-27 | url-status = dead | archive-url = https://archive.today/20120716185253/http://hybrids.autoblog.com/2005/07/21/honda-to-offer-fuel-cell-motorcycle/ | archive-date = 16 July 2012}}</ref>

Other examples of motorbikes<ref>{{cite web|author=15. Dezember 2007 |url=https://www.youtube.com/watch?v=B_Whbb_hlPs | archive-url=https://ghostarchive.org/varchive/youtube/20211030/B_Whbb_hlPs| archive-date=2021-10-30|title=Hydrogen Fuel Cell electric bike | date=15 December 2007 |publisher=Youtube.com |access-date=2009-09-21}}{{cbignore}}</ref> and bicycles<ref>[http://www.horizonfuelcell.com/mobility.htm "Horizon fuel cell vehicles: Transportation: Light Mobility"] {{webarchive|url=https://web.archive.org/web/20110722005838/http://www.horizonfuelcell.com/mobility.htm |date=22 July 2011 }}. Horizon Fuel Cell Technologies. 2010. Accessed 2 August 2011.</ref> that use hydrogen fuel cells include the Taiwanese company APFCT's scooter<ref>{{Cite web|url=http://www.apfct.com/article_cat.php|archive-url=https://archive.today/20130101222331/http://www.apfct.com/article_cat.php?act=view&no=26|archive-date=1 January 2013 |url-status=dead|title=Asia Pacific Fuel Cell Technologies, Ltd. --fuel cell systems and fuel cell powered vehicles}}</ref> using the fueling system from Italy's Acta SpA<ref>{{cite web| url = http://www.fuelcelltoday.com/media/1713685/fct_review_2012.pdf| title = The fuel cell industry review 2012}}</ref> and the [[Suzuki]] Burgman scooter with an [[Intelligent Energy|IE]] fuel cell that received EU [[Motor vehicle type approval|Whole Vehicle Type Approval]] in 2011.<ref>[http://www.globalsuzuki.com/Burgman_Fuel-Cell_Scooter/index.html Burgman_Fuel-Cell_Scooter]; {{cite web|title=Products History 2000s |url=http://www.globalsuzuki.com/motorcycle/history/products/products_2000s.html |website=Global Suzuki |publisher=Suzuki Motor Corporation |access-date=25 October 2013 |url-status=dead |archive-url=https://web.archive.org/web/20131024231820/https://www.globalsuzuki.com/motorcycle/history/products/products_2000s.html |archive-date=24 October 2013}}</ref> Suzuki Motor Corp. and IE have announced a joint venture to accelerate the commercialization of zero-emission vehicles.<ref>{{cite news|title=Eco energy firm in Suzuki deal|url=http://www.leicestermercury.co.uk/Eco-energy-firm-Suzuki-deal/story-15165957-detail/story.html|access-date=26 October 2013|newspaper=Leicester Mercury|date=6 February 2012|url-status=dead|archive-url=https://web.archive.org/web/20131029185618/http://www.leicestermercury.co.uk/Eco-energy-firm-Suzuki-deal/story-15165957-detail/story.html|archive-date=29 October 2013}}; {{cite news|title=Suzuki and IE to commercialize FC cars and bikes|url=http://www.gizmag.com/suzuki-ev-scooter/21380/|access-date=26 October 2013|newspaper=Gizmag|date=8 February 2012}}</ref>

====Airplanes====
In 2003, the world's first propeller-driven airplane to be powered entirely by a fuel cell was flown. The fuel cell was a stack design that allowed the fuel cell to be integrated with the plane's aerodynamic surfaces.<ref>{{Cite web|url=http://www.popularmechanics.com/technology/industry/1287561.html|archive-url=https://web.archive.org/web/20100106235805/http://www.popularmechanics.com/technology/industry/1287561.html|url-status=dead|title=First Fuel Cell Microaircraft|archive-date=6 January 2010}}</ref> Fuel cell-powered unmanned aerial vehicles (UAV) include a [[Horizon Fuel Cell Technologies|Horizon]] fuel cell UAV that set the record distance flown for a small UAV in 2007.<ref>[http://www.horizonfuelcell.com/file/Pterosoardistancerecord.pdf "Horizon Fuel Cell Powers New World Record in UAV Flight"] {{webarchive|url=https://web.archive.org/web/20111014121037/http://www.horizonfuelcell.com/file/Pterosoardistancerecord.pdf |date=14 October 2011 }}. Horizon Fuel Cell Technologies. 1 November 2007.</ref> [[Boeing]] researchers and industry partners throughout Europe conducted experimental flight tests in February 2008 of a manned airplane powered only by a fuel cell and lightweight batteries. The fuel cell demonstrator airplane, as it was called, used a proton-exchange membrane (PEM) fuel cell/[[lithium-ion battery]] hybrid system to power an electric motor, which was coupled to a conventional propeller.<ref>{{cite web|url=http://www.boeing.com/news/releases/2008/q2/080403a_nr.html |title=Boeing Successfully Flies Fuel Cell-Powered Airplane |url-status=dead |archive-url=https://web.archive.org/web/20130509091442/http://www.boeing.com/news/releases/2008/q2/080403a_nr.html |archive-date=9 May 2013 }}. Boeing. 3 April 2008. Accessed 2 August 2011.</ref>

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.<ref>[http://www.alternative-energy-news.info/fuel-cell-powered-uav-flight/ "Fuel Cell Powered UAV Completes 23-hour Flight"]. Alternative Energy: News. 22 October 2009. Accessed 2 August 2011.</ref> Fuel cells are also being tested and considered to provide auxiliary power in aircraft, replacing [[Auxiliary power unit|fossil fuel generators]] that were previously used to start the engines and power on board electrical needs, while reducing carbon emissions.<ref>{{Cite news| url=https://www.cnbc.com/2016/02/02/hydrogen-fuel-cells-on-a-plane.html|title=Hydrogen fuel cells… on a plane?|last=CNBC.com|first=Anmar Frangoul {{!}} Special to|date=2016-02-02|work=CNBC|access-date=2018-02-06}}</ref><ref name="theengineer.co.uk">[http://www.theengineer.co.uk/sectors/aerospace/news/hydrogen-powered-unmanned-aircraft-completes-set-of-tests/1009080.article "Hydrogen-powered unmanned aircraft completes set of tests"] {{Webarchive|url=https://web.archive.org/web/20151015230121/http://www.theengineer.co.uk/sectors/aerospace/news/hydrogen-powered-unmanned-aircraft-completes-set-of-tests/1009080.article |date=15 October 2015 }}.www.theengineer.co.uk. 20 June 2011. Accessed 2 August 2011.</ref>{{Failed verification|date=February 2012}} In 2016 a Raptor E1 drone made a successful test flight using a fuel cell that was lighter than the [[lithium-ion battery]] it replaced. The flight lasted 10 minutes at an altitude of {{Convert|80|m}}, although the fuel cell reportedly had enough fuel to fly for two hours. The fuel was contained in approximately 100 solid {{Convert|1|cm2}} pellets composed of a proprietary chemical within an unpressurized cartridge. The pellets are physically robust and operate at temperatures as warm as {{Convert|50|C|F}}. The cell was from Arcola Energy.<ref>{{Cite web|title = Drone flight powered by lightweight hydrogen-producing pellets|url = http://www.gizmag.com/cella-energy-fuel-cell-drone/41718|website = www.gizmag.com|access-date = 2016-02-09|date = 2016-02-08|last = Coxworth|first = Ben}}</ref>

[[Lockheed Martin Skunk Works Stalker]] is an electric UAV powered by solid oxide fuel cell.<ref>{{Cite web|url=https://defense-update.com/20110819_stalker-ex-mini-uav-set-for-eight-hour-endurance-missions-2.html|title=Stalker EX Mini-UAV Set for Eight Hour Endurance Missions|first=Tamir|last=Eshel|date=19 August 2011}}</ref>

====Boats====
[[File:Die Hydra in Leipzig I.jpg|thumb|Fuel cell boat ([[hydra (boat)|Hydra]]), in [[Leipzig]], Germany]]
The [[Hydra (boat)|Hydra]], a 22-person fuel cell boat operated from 1999 to 2001 on the [[Rhine]] river near [[Bonn]], Germany,<ref>[http://www.fuelcell.hu/fchu_engine/index.php/en/applications FC Applications]</ref> and was used as a ferry boat in [[Ghent]], Belgium, during an electric boat conference in 2000. It was fully certified by the [[Germanischer Lloyd]] for passenger transport.<ref>{{Cite web |url=http://www.gl-group.com/infoServices/rules/pdfs/gl_vi-3-11_e.pdf |title=GL- Rules for classification and construction |access-date=27 November 2023 |archive-date=3 December 2013 |archive-url=https://web.archive.org/web/20131203021725/http://www.gl-group.com/infoServices/rules/pdfs/gl_vi-3-11_e.pdf |url-status=dead }}</ref> The Zemship, a small passenger ship, was produced in 2003 to 2013. It used a 100&nbsp;kW [[Polymer Electrolyte Membrane Fuel Cell]]s (PEMFC) with 7 lead gel batteries. With these systems, alongside 12 storage tanks, fuel cells provided an energy capacity of 560&nbsp;V and 234&nbsp;kWh.<ref name=":02">{{Cite journal |last1=Sürer |first1=Meryem Gizem |last2=Arat |first2=Hüseyin Turan |date=2022-05-26 |title=Advancements and current technologies on hydrogen fuel cell applications for marine vehicles |url=https://www.sciencedirect.com/science/article/pii/S0360319921050552 |journal=International Journal of Hydrogen Energy |series=The Fifth International Hydrogen Technologies Congress |volume=47 |issue=45 |pages=19865–19875 |doi=10.1016/j.ijhydene.2021.12.251 |bibcode=2022IJHE...4719865S |s2cid=246104205 |issn=0360-3199|url-access=subscription }}</ref> Made in [[Hamburg]], Germany, the FCS Alsterwasser, revealed in 2008, was one of the first passenger ships powered by fuel cells and could carry 100 passengers. The hybrid fuel cell technology that powered this ship was produced by Proton Motor Fuel Cell GmbH.<ref>{{Cite journal |date=2008-10-01 |title=First fuel cell passenger ship unveiled in Hamburg |url=https://www.sciencedirect.com/science/article/pii/S1464285908703729 |journal=Fuel Cells Bulletin |volume=2008 |issue=10 |pages=4–5 |doi=10.1016/S1464-2859(08)70372-9 |bibcode=2008FCBu.2008SV..4. |issn=1464-2859|url-access=subscription }}</ref>

In 2010, the MF Vågen was first produced, utilizing 12&nbsp;kW fuel cells and 2- to 3-kilogram metal hydride hydrogen storage. It also utilizes 25&nbsp;kWh lithium batteries and a 10&nbsp;kW DC motor.<ref name=":02" />
The Hornblower Hybrid debuted in 2012. It utilizes a [[diesel generator]], batteries, [[photovoltaics]], [[wind power]], and fuel cells for energy.<ref name=":02" /> Made in [[Bristol]], a 12-passenger hybrid ferry, Hydrogenesis, has been in operation since 2012.<ref name=":02" /> The SF-BREEZE is a two-motor boat that utilizes 41 × 120&nbsp;kW fuel cells. With a type C storage tank, the pressurized vessel can maintain 1200&nbsp;kg of LH2. These ships are still in operation today.<ref name=":02" /> In Norway, the first ferry powered by fuel cells [[Hydrogen-powered ship|running on liquid hydrogen]] was scheduled for its first test drives in December 2022.<ref>{{Cite web|title=First Liquid Hydrogen Ferry equipped with Fuel Cells|url=https://ferrygogo.com/first-liquid-hydrogen-ferry-equipped-with-fuel-cells/ |date=28 November 2022 |access-date=28 November 2022 }}</ref><ref>{{Cite web |title=Fuel cells installed onboard the world's first liquid hydrogen-powered ferry |url=https://www.ballard.com/about-ballard/newsroom/market-updates/ballard-fuel-cells-installed-onboard-the-world-s-first-liquid-hydrogen-powered-ferry |date=18 November 2022 |access-date=28 November 2022 |archive-date=28 November 2022 |archive-url=https://web.archive.org/web/20221128094146/https://www.ballard.com/about-ballard/newsroom/market-updates/ballard-fuel-cells-installed-onboard-the-world-s-first-liquid-hydrogen-powered-ferry |url-status=dead }}</ref><!-- WAS IT EVER PRODUCED? -->

The [[Type 212 submarine]]s of the German and Italian navies use fuel cells to remain submerged for weeks without the need to surface.<ref>{{Cite web |date=2020-10-01 |title=A Revolution in Submarine Propulsion |url=https://www.usni.org/magazines/proceedings/2020/october/revolution-submarine-propulsion#:~:text=The%20third%20AIP%20option%20is%20the%20fuel%20cell.,212%20class%20is%20equipped%20with%20a%20fuel%20cell. |access-date=2024-12-03 |website=U.S. Naval Institute |language=en}}</ref> The U212A is a non-nuclear submarine developed by German naval shipyard Howaldtswerke Deutsche Werft.<ref>[http://articles.cnn.com/2011-02-22/tech/hybrid.submarine_1_submariners-aircraft-carrier-howaldtswerke-deutsche-werft?_s=PM:TECH "Super-stealth sub powered by fuel cell"] {{webarchive|url=https://web.archive.org/web/20110804181646/http://articles.cnn.com/2011-02-22/tech/hybrid.submarine_1_submariners-aircraft-carrier-howaldtswerke-deutsche-werft?_s=PM%3ATECH |date= 4 August 2011 }}. Frederik Pleitgen. CNN Tech: Nuclear Weapons. 22 February 2011. Accessed 2 August 2011.</ref> The system consists of nine PEM fuel cells, providing between 30&nbsp;kW and 50&nbsp;kW each. The ship is silent, giving it an advantage in the detection of other submarines.<ref>[http://www.naval-technology.com/projects/type_212/, "U212 / U214 Attack Submarines, Germany"]. Naval-Technology.com. Accessed 2 August 2011. {{webarchive |url=https://web.archive.org/web/20121003154509/http://www.naval-technology.com/projects/type_212/ |date=3 October 2012 }}</ref>

===Portable power systems===
Portable fuel cell systems are generally classified as weighing under 10&nbsp;kg and providing power of less than 5&nbsp;kW.<ref name="sciencedirect.com">{{cite journal|last1=Agnolucci|first1=Paolo|title=Economics and market prospects of portable fuel cells|journal=International Journal of Hydrogen Energy|date=December 2007|volume=32|issue=17|pages=4319–4328|doi=10.1016/j.ijhydene.2007.03.042|bibcode=2007IJHE...32.4319A |s2cid=98471675 }}</ref> The potential market size for smaller fuel cells is quite large with an up to 40% per annum potential growth rate and a market size of around $10 billion, leading a great deal of research to be devoted to the development of portable power cells.<ref name="ReferenceA">{{cite journal|last1=Dyer|first1=C.K>|title=Fuel cells for portable applications|journal=Journal of Power Sources|date=April 2002|volume=106|issue=1–2|pages=31–34|bibcode=2002JPS...106...31D|doi=10.1016/S0378-7753(01)01069-2}}</ref> Within this market two groups have been identified. The first is the microfuel cell market, in the 1-50 W range for power smaller electronic devices. The second is the 1-5&nbsp;kW range of generators for larger scale power generation (e.g. military outposts, remote oil fields).

Microfuel cells are primarily aimed at penetrating the market for phones and laptops. This can be primarily attributed to the advantageous [[energy density]] provided by fuel cells over a lithium-ion battery, for the entire system. For a battery, this system includes the charger as well as the battery itself. For the fuel cell this system would include the cell, the necessary fuel and peripheral attachments. Taking the full system into consideration, fuel cells have been shown to provide 530&nbsp;Wh/kg compared to 44&nbsp;Wh/kg for lithium-ion batteries.<ref name="ReferenceA"/> However, while the weight of fuel cell systems offer a distinct advantage the current costs are not in their favor. while a battery system will generally cost around $1.20 per Wh, fuel cell systems cost around $5 per Wh, putting them at a significant disadvantage.<ref name="ReferenceA"/>

As power demands for cell phones increase, fuel cells could become much more attractive options for larger power generation. The demand for longer on time on phones and computers is something often demanded by consumers so fuel cells could start to make strides into laptop and cell phone markets. The price will continue to go down as developments in fuel cells continues to accelerate. Current strategies for improving micro fuel cells is through the use of [[carbon nanotube]]s. It was shown by Girishkumar et al. that depositing nanotubes on electrode surfaces allows for substantially greater surface area increasing the oxygen reduction rate.<ref>{{cite journal|last1=Girishkumar|first1=G.|last2=Vinodgopal|first2=K.|last3=Kamat|first3=Prashant|title=Carbon Nanostructures in Portable Fuel Cells: Single-Walled Carbon Nanotube Electrodes for Methanol Oxidation and Oxygen Reduction|journal=J. Phys. Chem.|date=2004|volume=108|issue=52|pages=19960–19966|doi=10.1021/jp046872v|url=https://figshare.com/articles/journal_contribution/27622419 }}</ref>

Fuel cells for use in larger scale operations also show much promise. Portable power systems that use fuel cells can be used in the leisure sector (i.e. RVs, cabins, marine), the industrial sector (i.e. power for remote locations including gas/oil wellsites, communication towers, security, weather stations), and in the military sector. SFC Energy is a German manufacturer of [[direct methanol fuel cell]]s for a variety of portable power systems.<ref>{{Cite web|url=https://www.sfc.com/en/|title=SFC Energy AG - Clean energy everywhere|website=SFC Energy}}</ref> Ensol Systems Inc. is an integrator of portable power systems, using the SFC Energy DMFC.<ref>{{Cite web|url=https://www.ensolsystems.com/|title=ensol systems|first=ensol|last=systems|website=Ensol Systems}}</ref> The key advantage of fuel cells in this market is the great power generation per weight. While fuel cells can be expensive, for remote locations that require dependable energy fuel cells hold great power. For a 72-h excursion the comparison in weight is substantial, with a fuel cell only weighing 15 pounds compared to 29 pounds of batteries needed for the same energy.<ref name="sciencedirect.com"/>

===Other applications===
* Providing power for [[base station]]s or [[cell site]]s<ref>[http://fr.chfca.ca/itoolkit.asp?pg=BALLARD_07132009 "Ballard fuel cells to power telecom backup power units for motorola"] {{webarchive |url=https://web.archive.org/web/20110706172302/http://fr.chfca.ca/itoolkit.asp?pg=BALLARD_07132009 |date=6 July 2011 }}. Association Canadienne de l'hydrogene et des piles a combustible. 13 July 2009. Accessed 2 August 2011.</ref><ref>{{Cite web|url=http://cleantech.com/news/3674/india-telecom-get-fuel-cells|archive-url=https://web.archive.org/web/20101126130543/http://cleantech.com/news/3674/india-telecom-get-fuel-cells|url-status=dead|title=India telecoms to get fuel cell power|archive-date=26 November 2010}}</ref>
* [[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 hospitals, scientific laboratories, [[data center]]s,<ref>[http://www.t-systems.com/tsip/en/202342/home/publicsector/news/details/2011-03-21-rz-cottbus "Cottbus receives new local data center"] {{webarchive |url=https://web.archive.org/web/20110930144825/http://www.t-systems.com/tsip/en/202342/home/publicsector/news/details/2011-03-21-rz-cottbus |date=30 September 2011 }}. T Systems. 21 March 2011.</ref> <!-- THIS SHOULD BE DISCUSSED ABOVE UNDER POWER. Can anyone try to do that? -->
* Telecommunication<ref>[http://www.fuelcells.org/basics/apps.html "Fuel Cell Applications"] {{webarchive |url=https://web.archive.org/web/20110515080800/http://www.fuelcells.org/basics/apps.html |date=15 May 2011 }}. Fuel Cells 2000. Accessed 2 August 2011</ref> 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.
* [[Smartphones]], laptops and tablets for use in locations where [[Alternating current|AC]] charging may not be readily available.
* Portable charging docks for small electronics (e.g. a belt clip that charges a cell phone or [[Personal digital assistant|PDA]]).
* Small heating appliances<ref>[http://www.dvgw-cert.com/index.php?id=26 DVGW VP 119 Brennstoffzellen-Gasgeräte bis 70 kW] {{Webarchive|url=https://web.archive.org/web/20210226193610/http://www.dvgw-cert.com/index.php?id=26 |date=26 February 2021 }}. DVGW. (German)</ref>
* [[Food preservation]], achieved by exhausting the oxygen and automatically maintaining oxygen exhaustion in a shipping container, containing, for example, fresh fish.<ref name=ADN51813>{{cite news|title=Laine Welch: Fuel cell technology boosts long-distance fish shipping |url=http://www.adn.com/2013/05/18/2907670/laine-welch-fuel-cell-technology.html |access-date=19 May 2013 |newspaper=Anchorage Daily News |date=18 May 2013 |author=Laine Welch |url-status=dead |archive-url=https://web.archive.org/web/20130609190326/http://www.adn.com/2013/05/18/2907670/laine-welch-fuel-cell-technology.html |archive-date=9 June 2013 }}</ref>
* Sensors, including in [[Breathalyzer]]s, where the amount of voltage generated by a fuel cell is used to determine the concentration of fuel (alcohol) in the sample.<ref>{{cite web|title=Fuel Cell Technology Applied to Alcohol Breath Testing|url=http://www.intox.com/t-fuelcellwhitepaper.aspx|publisher=Intoximeters, Inc.|access-date=24 October 2013}}</ref>

===Fueling stations===
{{Main|Hydrogen station|Hydrogen highway}}
[[File:Hydrogen vehicle.jpg|thumb|right|[[Hydrogen station|Hydrogen fueling station]]]]

According to FuelCellsWorks, an industry group, at the end of 2019, 330 [[hydrogen station|hydrogen refueling stations]] were open to the public worldwide.<ref>{{Cite web|url=https://fuelcellsworks.com/news/in-2019-83-new-hydrogen-refuelling-stations-worldwide/|title=In 2019: 83 New Hydrogen Refuelling Stations Worldwide - FuelCellsWorks|date=19 February 2020 }}</ref> As of June 2020, there were 178 publicly available hydrogen stations in operation in Asia.<ref name=":0">{{cite web|url=https://fuelcellsworks.com/news/in-2019-83-new-hydrogen-refuelling-stations-worldwide/ |title=In 2019, 83 new hydrogen refuelling stations worldwide/ |date=19 February 2020 |access-date=10 June 2020}}</ref> 114 of these were in Japan.<ref name=":0"/> There were at least 177 stations in Europe, and about half of these were in Germany.<ref name="rws2020">{{cite web|url=https://h2.live/en |title=Filling up with H2|access-date=10 June 2020|date=2020-06-10}}</ref><ref>{{Cite web|url=https://h2me.eu/about/|title=About {{!}} Hydrogen Mobility Europe|website=h2me.eu|date=19 November 2015|access-date=2020-03-24}}</ref> There were 44 publicly accessible stations in the US, 42 of which were located in California.<ref name=afdc>[http://www.afdc.energy.gov/fuels/stations_counts.html Alternative Fueling Station Counts by State], ''Alternative Fuels Data Center'', accessed 31 August 2020</ref>

A hydrogen fueling station costs between $1 million and $4 million to build.<ref>{{cite journal|url=https://www.osti.gov/servlets/purl/1506613 |title=Review of Transportation Hydrogen Infrastructure Performance and Reliability |publisher=[[National Renewable Energy Laboratory]]|year=2019|doi=10.1016/j.ijhydene.2019.03.027 |access-date=7 October 2020|last1=Kurtz |first1=Jennifer |last2=Sprik |first2=Sam |last3=Bradley |first3=Thomas H. |journal=International Journal of Hydrogen Energy |volume=44 |issue=23 |pages=12010–12023 |s2cid=132085841 |doi-access=free |bibcode=2019IJHE...4412010K }}</ref>

=== Social Implications ===
As of 2023, technological barriers to fuel cell adoption remain.<ref>{{Cite web |title=Fuel Cells: Current Status and Future Challenges |url=https://nae.edu/7614/FuelCellsCurrentStatusandFutureChallenges |access-date=2023-12-02 |website=NAE Website}}</ref> Fuel cells are primarily for material handling in warehouses, distribution centers, and manufacturing facilities.<ref>{{Cite web |date=2023-01-19 |title=Fuel Cell Applications 101: Where Are Fuel Cells Used Today? - Plug Power |url=https://www.plugpower.com/fuel-cell-applications-101-where-are-fuel-cells-used-today/,%20https://www.plugpower.com/fuel-cell-applications-101-where-are-fuel-cells-used-today/ |access-date=2023-12-02 |website=www.plugpower.com }}{{Dead link|date=December 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> They are projected to be useful and sustainable in a wider range applications.<ref>{{Cite journal |last=İnci |first=Mustafa |date=2022-10-01 |title=Future vision of hydrogen fuel cells: A statistical review and research on applications, socio-economic impacts and forecasting prospects |url=https://www.sciencedirect.com/science/article/pii/S2213138822007871 |journal=Sustainable Energy Technologies and Assessments |volume=53 |pages=102739 |doi=10.1016/j.seta.2022.102739 |bibcode=2022SETA...5302739I |s2cid=252235918 |issn=2213-1388|url-access=subscription }}</ref> But current applications do not often reach lower-income communities,<ref>{{Cite journal |last1=Jessel |first1=Sonal |last2=Sawyer |first2=Samantha |last3=Hernández |first3=Diana |date=2019-12-12 |title=Energy, Poverty, and Health in Climate Change: A Comprehensive Review of an Emerging Literature |journal=Frontiers in Public Health |volume=7 |pages=357 |doi=10.3389/fpubh.2019.00357 |issn=2296-2565 |pmc=6920209 |pmid=31921733 |doi-access=free |bibcode=2019FrPH....7..357J }}</ref> though some attempts at inclusivity are being made, for example in accessibility.<ref>{{Cite web |title=Hydrogen Fuel Cell: Bus Technologies |url=https://www.zemo.org.uk/work-with-us/buses-coaches/low-emission-buses/technologies/hydrogen-fuel-cell.htm |access-date=2023-12-02 |website=www.zemo.org.uk}}</ref>

==Markets and economics==
{{Main|Hydrogen economy|Methanol economy}}
In 2012, fuel cell industry revenues exceeded $1 billion market value worldwide, with Asian pacific countries shipping more than 3/4 of the fuel cell systems worldwide.<ref>[http://www.greencarcongress.com/2013/08/navigant-20130812-1.html "Navigant: fuel cell industry passed $1-billion revenue mark in 2012"], Green Car Congress, 12 August 2013</ref> However, as of January 2014, no public company in the industry had yet become profitable.<ref>{{Cite web|title = Plug, FuelCell Climb as 'Experiments' Seen as Profitable|url = https://www.bloomberg.com/news/articles/2014-03-10/fuelcell-plug-surge-as-experiments-may-turn-profits|website = Bloomberg.com|date=10 March 2014|access-date = 28 December 2015|first = Christopher|last = Martin}}</ref> There were 140,000 fuel cell stacks shipped globally in 2010, up from 11,000 shipments in 2007, and from 2011 to 2012 worldwide fuel cell shipments had an annual growth rate of 85%.<ref>{{cite web|url=http://www.mmh.com/article/fuel_cell_report_highlights_continued_growth_in_material_handling_applicati|title=Fuel cell report highlights continued growth in material handling applications|date=20 November 2013}}</ref> [[Tanaka Kikinzoku]] expanded its manufacturing facilities in 2011.<ref>[http://www.fuelcelltoday.com/news-events/news-archive/2013/february/tanaka-precious-metals-constructs-dedicated-plant-for-the-development-and-manufacture-of-fuel-cell-catalysts "Tanaka precious metals constructs dedicated plant for the development and manufacture of fuel cell catalysts"], FuelCellToday.com, 26 February 2013, accessed 16 November 2013</ref> Approximately 50% of fuel cell shipments in 2010 were stationary fuel cells, up from about a third in 2009, and the four dominant producers in the Fuel Cell Industry were the United States, Germany, Japan and South Korea.<ref name=uploads>Adamson, Karry-Ann and Clint Wheelock. [http://www.pikeresearch.com/wordpress/wp-content/uploads/2011/05/FCAR-11-Executive-Summary.pdf "Fuel Cell Annual Report 2011"] {{webarchive |url=https://web.archive.org/web/20111017135343/http://www.pikeresearch.com/wordpress/wp-content/uploads/2011/05/FCAR-11-Executive-Summary.pdf |date=17 October 2011 }}. 2Q 2011, Pike Research, accessed 1 August 2011</ref> 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.<ref>[http://www.fossil.energy.gov/programs/powersystems/fuelcells/fuelcells_seca.html "Solid State Energy Conversion Alliance SECA Cost Reduction"]. U.S. Dept. of Energy, 31 January 2011, accessed 1 August 2011</ref> In 2011, Bloom Energy, a major fuel cell supplier, said that its fuel cells generated power at 9–11 cents per kilowatt-hour, including the price of fuel, maintenance, and hardware.<ref>[http://bloomenergy.com/benefits/lower-fix-energy-costs/ "Lower & Lock-In Energy Costs"] {{Webarchive|url=https://web.archive.org/web/20110803184841/http://www.bloomenergy.com/benefits/lower-fix-energy-costs/ |date=3 August 2011 }}, Bloom Energy, accessed 3 August 2011</ref><ref>Wesoff, Eric. [https://www.wired.com/epicenter/tag/bloom-energy/ "Bloom Energy Plays the Subsidy Game Like a Pro", 13 April 2011, accessed 1 August 2011] {{webarchive |url=https://web.archive.org/web/20120411145505/http://www.wired.com/epicenter/tag/bloom-energy/ |date=11 April 2012 }}</ref>

Industry groups predict that there are sufficient platinum resources for future demand.<ref>{{Cite web|url=http://www.ipa-news.com/pgm/faq/index.htm|archive-url=https://web.archive.org/web/20110419220753/http://www.ipa-news.com/pgm/faq/index.htm|url-status=dead|title=International Platinum Group Metals Association-FAQ|archive-date=19 April 2011}}</ref> [[PEDOT]] cathodes are immune to [[carbon monoxide]] poisoning.<ref>{{cite web|url=https://arstechnica.com/old/content/2008/07/fuel-cell-improvements-raise-hopes-for-clean-cheap-energy.ars|title=Fuel cell improvements raise hopes for clean, cheap energy |last=Timmer |first=John |website=Ars Technica |date=Aug 1, 2008 |access-date=Nov 1, 2024}}</ref>

In 2016, [[Samsung]] "decided to drop fuel cell-related business projects, as the outlook of the market isn't good".<ref>Yoo-chul, Kim. [https://www.koreatimes.co.kr/www/news/tech/2016/04/133_202485.html "Samsung to drop fuel cell business"], ''Korea Times'', 12 April 2016</ref>

==Research and development==
* 2013: British firm ACAL Energy developed a fuel cell that it said could run for 10,000 hours in simulated driving conditions.<ref>{{cite web|url=http://www.acalenergy.co.uk/news/release/acal-energy-system-breaks-the-10000-hour-endurance-barrier/en|title=Hydrogen Fuel Cell That's As Durable As A Conventional Engine|url-status=dead|archive-url=https://web.archive.org/web/20131016055850/http://www.acalenergy.co.uk/news/release/acal-energy-system-breaks-the-10000-hour-endurance-barrier/en|archive-date=16 October 2013}}</ref> It asserted that the cost of fuel cell construction can be reduced to $40/kW (roughly $9,000 for 300 HP).<ref>{{Cite web|url=http://www.acalenergy.co.uk/assets/common/0816_ACAL_Poster_1_Costs_v5.pdf|archive-url=https://web.archive.org/web/20131016055844/http://www.acalenergy.co.uk/assets/common/0816_ACAL_Poster_1_Costs_v5.pdf|url-status=dead|title=ACAL poster on Fuel Cell costs and efficiency|archive-date=16 October 2013}}</ref>
* 2014: Researchers in [[Imperial College London]] developed a new method for regeneration of [[hydrogen sulfide]] contaminated PEFCs.<ref>{{cite journal|last1=Kakati|first1=Biraj Kumar|last2=Kucernak|first2=Anthony RJ|title=Gas phase recovery of hydrogen sulfide contaminated polymer electrolyte membrane fuel cells|journal=Journal of Power Sources|date=15 March 2014| volume=252|pages=317–326|doi=10.1016/j.jpowsour.2013.11.077|bibcode=2014JPS...252..317K|doi-access=free}}</ref> They recovered 95–100% of the original performance of a hydrogen sulfide contaminated PEFC. They were successful in rejuvenating a SO<sub>2</sub> contaminated PEFC too.<ref>{{cite journal|last1=Kakati|first1=Biraj Kumar|last2=Unnikrishnan|first2=Anusree|last3=Rajalakshmi|first3=Natarajan|last4=Jafri|first4=RI|last5=Dhathathreyan|first5=KS|title=Kucernak|journal=Anthony RJ|volume=41|issue=12|pages=5598–5604|doi=10.1016/j.ijhydene.2016.01.077|hdl=10044/1/28872|year=2016|hdl-access=free}}</ref> This regeneration method is applicable to multiple cell stacks.<ref>{{cite news|last1=Kakati|first1=BK|title=In-situ O3 rejuvenation of SO2 contaminated Polymer Electrolyte Fuel Cell: Electrochemistry, single cell and 5-cells stack studies|url=http://www.efcf.com/fileadmin/EFCF-Pict-Logo/EFCF%202015/Download/5th_PEFC-H2-Forum_2015_30June-3July-FinAnnounc-Progr.pdf|access-date=14 July 2015|work=5th European PEFC & H2 Forum|archive-date=14 July 2015|archive-url=https://web.archive.org/web/20150714214241/http://www.efcf.com/fileadmin/EFCF-Pict-Logo/EFCF%202015/Download/5th_PEFC-H2-Forum_2015_30June-3July-FinAnnounc-Progr.pdf|url-status=dead}}</ref><!-- CAN ANYONE TRANSLATE THIS INTO ENGLISH? -->
* 2019: [[United States Army Research Laboratory|U.S. Army Research Laboratory]] researchers developed a two part in-situ hydrogen generation fuel cell, one for hydrogen generation and the other for electric power generation through an internal hydrogen/air power plant.<ref>{{Cite news |title=In Situ Hydrogen Generation Fuel Cell for Future Soldier Power Systems – HDIAC |newspaper=Hdiac |url=https://hdiac.org/articles/in-situ-hydrogen-generation-fuel-cell-for-future-soldier-power-systems/ |access-date=2023-02-07}}</ref>
* 2022: Researchers from [[University of Delaware]] developed a hydrogen-powered fuel cell projected to function at lower costs and operate at roughly $1.4/kW. This design removes [[carbon dioxide]] from the air feed of [[hydroxide exchange membrane fuel cells]].<ref>{{Cite journal |last1=Shi |first1=Lin |last2=Zhao |first2=Yun |last3=Matz |first3=Stephanie |last4=Gottesfeld |first4=Shimshon |last5=Setzler |first5=Brian P. |last6=Yan |first6=Yushan |date=March 2022 |title=A shorted membrane electrochemical cell powered by hydrogen to remove CO2 from the air feed of hydroxide exchange membrane fuel cells |url=https://www.nature.com/articles/s41560-021-00969-5 |journal=Nature Energy |volume=7 |issue=3 |pages=238–247 |doi=10.1038/s41560-021-00969-5 |s2cid=246585109 |issn=2058-7546|url-access=subscription }}</ref>

==See also==
{{Portal|Electronics|Energy|Renewable energy|Chemistry|Cars|Spaceflight|Trains}}
{{div col}}
* [[Bio-nano generator]]
* [[Cryptophane]]
* [[Fuel Cell Development Information Center]]
* [[Fuel Cells and Hydrogen Joint Technology Initiative]]
* [[Grid energy storage]]
* [[Hydrogen reformer]]
* [[Hydrogen storage]]
* [[Hydrogen technologies]]
* [[List of fuel cell manufacturers]]
* [[Methanol reformer]]
* [[PEM electrolysis]]
{{div col end}}

==References==
{{reflist}}

==Further reading==
* {{cite book |title= Handbook of fuel cells: advances in electrocatalysis, materials, diagnostics and durability |editor=Vielstich, W. |display-editors=etal |year=2009 |location=Hoboken |publisher=John Wiley and Sons}}
* {{Cite book|title = Fuel Cell Technology – Handbook | author=Gregor Hoogers | publisher=CRC Press|year=2003}}
* {{Cite book|title=Fuel Cell Systems Explained |edition=Second |author1=James Larminie |author2=Andrew Dicks |location=Hoboken |publisher=John Wiley and Sons|year=2003}}
* {{Cite book|title=High Temperature Solid Oxide Fuel Cells-Fundamentals, Design and Applications |publisher=Elsevier Academic Press |year=2003 | author1=Subash C. Singhal |author2=Kevin Kendall}}
* {{Cite book|title=PEM Fuel Cells-Theory and Practice |author=Frano Barbir |publisher=Elsevier Academic Press|year=2005}}
* {{Cite book|title=Fuel Cell Technology-Handbook, 7th Edition|author=EG&G Technical Services, Inc.|publisher=U.S. Department of Energy |year=2004}}
* {{Cite book|title=Fuel Cell Engines |author=Matthew M. Mench |location=Hoboken |publisher=John Wiley & Sons, Inc. |year=2008}}
* {{cite book|title=Fuel Cells: Current Technology Challenges and Future Research Needs |author=Noriko Hikosaka Behling |edition=First |location=Elsevier Academic Press |year=2012}}

==External links==
*[http://americanhistory.si.edu/fuelcells/origins/origins.htm Fuel Cell Origins: 1840–1890]
*[https://web.archive.org/web/20060102134744/http://www.eere.energy.gov/hydrogenandfuelcells/ EERE: Hydrogen, Fuel Cells and Infrastructure Technologies Program]
*[http://hyperphysics.phy-astr.gsu.edu/Hbase/thermo/electrol.html#c2 Thermodynamics of electrolysis of water and hydrogen fuel cells]
*[http://www.doitpoms.ac.uk/tlplib/fuel-cells/index.php DoITPoMS Teaching and Learning Package: "Fuel Cells"]

{{Fuel cells}}
{{Galvanic cells}}
{{Automobile configuration}}
{{Alternative propulsion}}
{{Authority control}}

[[Category:Fuel cells]]
[[Category:Energy storage]]
[[Category:1838 introductions]]
[[Category:Bright green environmentalism]]
[[Category:Energy conversion]]
[[Category:Hydrogen economy]]
[[Category:Hydrogen technologies]]