Fuel cell - Revision history

Jmdonev: 1 revision imported

2021-12-20T19:47:11Z

1 revision imported

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energy>Jmdonev at 19:43, 15 October 2021

2021-10-15T19:43:02Z

← Older revision		Revision as of 19:43, 15 October 2021
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	[[~~File:fuelcell.png\|300px\|thumb\|Figure 1. A diagram of~~ a ~~hydrogen~~ fuel ~~cell. The hydrogen~~ and ~~oxygen combine to form water, while simultaneously producing~~ electricity.<~~Ref~~>~~Wikimedia Commons~~ [Online], Available: ~~https~~://~~commons~~.~~wikimedia~~.~~org~~/~~wiki~~/~~File:Solid_oxide_fuel_cell.svg#~~/~~media/File:Solid_oxide_fuel_cell~~.~~svg~~</ref>]]		<onlyinclude>'''Fuel cells''' are a type of [[energy conversion technology]] which take the [[chemical energy]] contained within a [[fuel]] and transform it into [[electricity]] along with certain by-products (depending on the fuel used).</onlyinclude> <ref name=hsw>How Stuff Works. (August 10, 2015). ''How Fuel Cells Work'' [Online], Available: http://auto.howstuffworks.com/fuel-efficiency/alternative-fuels/fuel-cell.htm</ref> It's important to note that fuel cells are not [[heat engine]]s, so they can have incredibly high efficiencies. However, when a heat engine is used to power a fuel cell, the heat engine still has a limiting [[thermal efficiency]].

	~~<onlyinclude>'''~~Fuel cells~~''' are a type of~~ [[energy ~~conversion technology~~]] ~~which take the~~ [[~~chemical~~ energy]] ~~contained within a~~ [[~~fuel~~]] and ~~transform it into~~ [[~~electricity~~]] ~~along with certain by-products~~ (~~depending on~~ the fuel ~~used~~).<~~/onlyinclude> <ref name~~=~~hsw~~>~~How Stuff Works~~. (~~August 10, 2015~~). '~~'How Fuel Cells Work~~'' [Online], Available: ~~http~~://~~auto~~.~~howstuffworks~~.~~com~~/~~fuel-efficiency~~/~~alternative-fuels~~/~~fuel-cell~~.~~htm~~</ref> It's ~~important~~ to ~~note that fuel cells are not~~ [[~~heat engine~~]]s, ~~so they can have incredibly high efficiencies~~. ~~However~~, ~~when a heat engine is used to power~~ a fuel cell, the ~~heat engine still has~~ a ~~limiting~~ [[~~thermal efficiency~~]].		Fuel cells can be seen as an [[energy storage]] device, as [[energy]] can be input to create [[hydrogen]] and [[oxygen]], which can remain in the cell until its use is needed at a later time. In this sense they work much like a [[battery]]. There are multiple types of fuel cells, but two common types are the solid oxide fuel cell (SOFC) and the polymer electrolyte membrane fuel cell (PEMFC).

			<gallery mode=packed heights=400px>
			File:fuelcell.png\|300px\|thumb\|Figure 1. A diagram of a '''solid oxide fuel cell (SOFC)'''. Molecular oxygen becomes oxide [[ion]]s (O<sup>2-</sup>) and combines with [[hydrogen]] to form [[water]], while simultaneously producing [[electricity]].<Ref>Wikimedia Commons [Online], Available: https://commons.wikimedia.org/wiki/File:Solid_oxide_fuel_cell.svg#/media/File:Solid_oxide_fuel_cell.svg</ref>
			File:PEM_fuel_cell.svg.png\|300px\|thumb\|Figure 2. A diagram of a '''polymer electrolyte membrane fuel cell (PEMFC)'''. Molecular hydrogen fuel becomes hydrogen [[ion]]s (H<sup>+</sup>) that travel through a polymer electrolyte. The hydrogen ions combine with [[oxygen]] to form [[water]], while simultaneously producing [[electricity]].<ref>Wikimedia Commons [Online], Available: https://commons.wikimedia.org/wiki/File:PEM_fuel_cell.svg</ref>
			</gallery>

			To produce [[electricity]] in a solid oxide fuel cell, [[oxygen]] in the air combines with free electrons to form oxide [[ion]]s. The oxide ions travel through a ceramic [[electrolyte]] and react with [[molecular hydrogen]] to form water. The reaction that makes water also releases [[electron]]s which travel through an external electrical [[circuit]], producing electricity.<ref name=fund>O'Hayre, Ryan, et al. Fuel Cell Fundamentals, John Wiley & Sons, Incorporated, 2016.</ref> This process can be seen in figure 1.

	~~Fuel cells can be seen as~~ an [[~~energy storage~~]] ~~device,~~ as [[~~energy~~]] ~~can be input to create~~ [[~~hydrogen~~]] and [[oxygen]]~~, which~~ can ~~remain in~~ the cell ~~until its use is needed at a later time~~. In this ~~sense they work much like~~ a ~~[[battery]]~~.		To produce [[electricity]] in a polymer electrolyte membrane fuel cell, a gaseous fuel is input and reacts with a catalyst made of [[platinum]] nanoparticles. When [[molecular hydrogen]] comes into contact with this, it splits into two H<sup>+</sup> ions and two [[electron]]s. The electrons are conducted through an [[electromotive force]] and electricity is produced. The hydrogen ions pass through a proton exchange membrane (also known as a polymer [[electrolyte]]) where it reaches the [[cathode]] and combines with [[oxygen]] to form water. This process can continue as long as there is hydrogen and oxygen supplied to the cell.<Ref name=hsw/> Figure 2 shows this process in a PEMFC.

	~~To produce electricity,~~ a ~~gaseous~~ fuel ~~is input and reacts with~~ a ~~catalyst made of [[platinum]] nanoparticles~~. ~~When [[molecular hydrogen]] comes into contact with this, it splits into two H~~<~~sup~~>+</~~sup> ions and two [[electron]]s~~. The electrons are conducted through an [[electromotive force]] and electricity is produced. The hydrogen ions pass through a proton exchange membrane where it reaches the cathode and combines with [[oxygen]] to form water. This process can continue as long as there is hydrogen and oxygen supplied to the cell.<~~Ref name=hsw~~/>		The video below from NASA illustrates how oxygen and hydrogen come together in a solid oxide fuel cell (SOFC) to release energy which can be snagged in a useful way.
			<html>
			<iframe width="600" height="340" src="https://www.youtube.com/embed/V3ChCroWttY" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
			</html>

	~~The video below from NASA illustrates how oxygen and hydrogen come together in a fuel cell to release energy which can be snagged in a useful way.~~
	<html>		<html>
	<iframe width="560" height="315" src="https://www.youtube.com/embed/~~V3ChCroWttY~~" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>		<iframe width="560" height="315" src="https://www.youtube.com/embed/KGkzLh14Sh0" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
	</html>		</html>

Jmdonev: 1 revision imported

2020-04-28T15:32:35Z

1 revision imported

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energy>Jmdonev at 19:21, 10 April 2020

2020-04-10T19:21:23Z

← Older revision		Revision as of 19:21, 10 April 2020
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	[[File:fuelcell.png\|300px\|thumb\|Figure 1. A diagram of a hydrogen fuel cell. The hydrogen and oxygen combine to form water, while simultaneously producing electricity.<Ref>Wikimedia Commons [Online], Available: https://commons.wikimedia.org/wiki/File:Solid_oxide_fuel_cell.svg#/media/File:Solid_oxide_fuel_cell.svg</ref>]]		[[File:fuelcell.png\|300px\|thumb\|Figure 1. A diagram of a hydrogen fuel cell. The hydrogen and oxygen combine to form water, while simultaneously producing electricity.<Ref>Wikimedia Commons [Online], Available: https://commons.wikimedia.org/wiki/File:Solid_oxide_fuel_cell.svg#/media/File:Solid_oxide_fuel_cell.svg</ref>]]

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	To produce electricity, a gaseous fuel is input and reacts with a catalyst made of [[platinum]] nanoparticles. When [[molecular hydrogen]] comes into contact with this, it splits into two H<sup>+</sup> ions and two [[electron]]s. The electrons are conducted through an [[electromotive force]] and electricity is produced. The hydrogen ions pass through a proton exchange membrane where it reaches the cathode and combines with [[oxygen]] to form water. This process can continue as long as there is hydrogen and oxygen supplied to the cell.<Ref name=hsw/>		To produce electricity, a gaseous fuel is input and reacts with a catalyst made of [[platinum]] nanoparticles. When [[molecular hydrogen]] comes into contact with this, it splits into two H<sup>+</sup> ions and two [[electron]]s. The electrons are conducted through an [[electromotive force]] and electricity is produced. The hydrogen ions pass through a proton exchange membrane where it reaches the cathode and combines with [[oxygen]] to form water. This process can continue as long as there is hydrogen and oxygen supplied to the cell.<Ref name=hsw/>

	~~[http~~://~~auto~~.~~howstuffworks~~.com/~~fuel~~-~~efficiency~~/~~alternative-fuels~~/~~fuel-cell2.htm Click here] to see an animation of a hydrogen fuel cell.~~		The video below from NASA illustrates how oxygen and hydrogen come together in a fuel cell to release energy which can be snagged in a useful way.
			<html>
			<iframe width="560" height="315" src="https://www.youtube.com/embed/V3ChCroWttY" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
			</html>

	===Hydrogen===		===Hydrogen===
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	[[File:Fuelcell.jpg\|300px\|thumb\|Figure 2. A fuel cell vehicle configuration.<Ref>Wikimedia Commons. "Fuelcell" by Welleman, [Online], Available: https://commons.wikimedia.org/wiki/File:Fuelcell.jpg#/media/File:Fuelcell.jpg</ref>]]		[[File:Fuelcell.jpg\|300px\|thumb\|Figure 2. A fuel cell vehicle configuration.<Ref>Wikimedia Commons. "Fuelcell" by Welleman, [Online], Available: https://commons.wikimedia.org/wiki/File:Fuelcell.jpg#/media/File:Fuelcell.jpg</ref>]]

	Many countries are spending enormous amounts of money into the development of hydrogen fuel cells~~, with the main reason being the future problems associated with an oil-dependent society~~. ~~Oil production is diminishing and it's~~ [[~~Hubbert's peak\|expected to continue this way~~]]~~—causing an increase in price for it and a greater need for imports of oil in places that do not have many oil resources. The burning of oil and~~ other fossil ~~fuels also~~ produces [[pollution]], which contributes to [[global warming]] and ultimately [[climate change\|changing climate]]~~. These reasons combined demonstrate a strong case for alternatives, with fuel cells being one of them~~.<Ref name=hsw/>		Many countries are spending enormous amounts of money into the development of hydrogen fuel cells. Burning [[oil product]]s (or any other [[fossil fuel]]s) produces [[pollution]]; most specifically, burning releases [[carbon dioxide]] which contributes to [[global warming]] and ultimately [[climate change\|changing climate]].<Ref name=hsw/>

	Uses of fuel cells range from large electricity generating plants to small devices like [[cell phone]]s or laptops.		Uses of fuel cells range from large electricity generating plants to small devices like [[cell phone]]s or laptops.

	===In vehicles===		===In vehicles===
	The most promising use for hydrogen as fuel (for the immediate future at least) are in vehicles—and there are already hydrogen based vehicles on the road today. The theoretical maximum efficiency of hydrogen fuel cells is 83%, ~~however, since theory is never accomplished in reality, a~~ realistic ~~efficiency is~~ around 60%.<ref name=wolf>R. Wolfson, "Toward a Hydrogen Economy?" in ''Energy, Environment, and Climate'', 2nd ed., New York, NY: W.W. Norton & Company, 2012, ch. 11, sec. 2, pp. 307-315</ref> Combined with an [[electric motor]] of 90% efficiency, the vehicles can achieve an efficiency of 54% before factoring in other [[energy loss]]es. This is around 2 - 2.5 times higher than a typical [[gasoline]]-powered vehicle.		The most promising use for hydrogen as fuel (for the immediate future at least) are in vehicles—and there are already hydrogen based vehicles on the road today. The theoretical maximum efficiency of hydrogen fuel cells is 83%, with realistic efficiencies around 60%.<ref name=wolf>R. Wolfson, "Toward a Hydrogen Economy?" in ''Energy, Environment, and Climate'', 2nd ed., New York, NY: W.W. Norton & Company, 2012, ch. 11, sec. 2, pp. 307-315</ref> Combined with an [[electric motor]] of 90% efficiency, the vehicles can achieve an efficiency of 54% before factoring in other [[energy loss]]es. This is around 2 - 2.5 times higher than a typical [[gasoline]]-powered vehicle.

	There is plenty of criticism for these types of vehicles, as many claim the cost of these vehicles will never be practical. The ~~cost of these~~ cells ~~is high as a result of the use of platinum and other valuable components—but~~ the price ~~would have to be less than half of what it currently is to be competitive~~.<ref name=hsw/> The durability and performance of such systems, along with the infrastructure necessary to accommodate them, is also under scrutiny.		There is plenty of criticism for these types of vehicles, as many claim the cost of these vehicles will never be practical. The platinum in the fuel cells has made them expensive, but advances are bringing the price down.<ref name=hsw/> The durability and performance of such systems, along with the infrastructure necessary to accommodate them, is also under scrutiny.

	==For Further Reading==		==For Further Reading==

Jmdonev: 1 revision imported

2018-06-25T14:30:25Z

1 revision imported

← Older revision	Revision as of 14:30, 25 June 2018
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Jmdonev at 19:39, 6 June 2018

2018-06-06T19:39:17Z

← Older revision		Revision as of 19:39, 6 June 2018
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	[[Category:Done ~~2015~~-08-21]]		[[Category:Done 2018-06-15]]
	[[File:fuelcell.png\|300px\|thumb\|Figure 1. A diagram of a hydrogen fuel cell. The hydrogen and oxygen combine to form water, while simultaneously producing electricity.<Ref>Wikimedia Commons [Online], Available: https://commons.wikimedia.org/wiki/File:Solid_oxide_fuel_cell.svg#/media/File:Solid_oxide_fuel_cell.svg</ref>]]		[[File:fuelcell.png\|300px\|thumb\|Figure 1. A diagram of a hydrogen fuel cell. The hydrogen and oxygen combine to form water, while simultaneously producing electricity.<Ref>Wikimedia Commons [Online], Available: https://commons.wikimedia.org/wiki/File:Solid_oxide_fuel_cell.svg#/media/File:Solid_oxide_fuel_cell.svg</ref>]]

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	Fuel cells can be seen as an [[energy storage]] device, as [[energy]] can be input to create [[hydrogen]] and [[oxygen]], which can remain in the cell until its use is needed at a later time. In this sense they work much like a [[battery]].		Fuel cells can be seen as an [[energy storage]] device, as [[energy]] can be input to create [[hydrogen]] and [[oxygen]], which can remain in the cell until its use is needed at a later time. In this sense they work much like a [[battery]].

	To produce electricity, a gaseous fuel is input and reacts with a catalyst made of platinum nanoparticles. When [[molecular hydrogen]] comes into contact with this, it splits into two H<sup>+</sup> ions and two [[electron]]s. The electrons are conducted through an [[electromotive force]] and electricity is produced. The hydrogen ions pass through a proton exchange membrane where it reaches the cathode and combines with [[oxygen]] to form water. This process can continue as long as there is hydrogen and oxygen supplied to the cell.<Ref name=hsw/>		To produce electricity, a gaseous fuel is input and reacts with a catalyst made of [[platinum]] nanoparticles. When [[molecular hydrogen]] comes into contact with this, it splits into two H<sup>+</sup> ions and two [[electron]]s. The electrons are conducted through an [[electromotive force]] and electricity is produced. The hydrogen ions pass through a proton exchange membrane where it reaches the cathode and combines with [[oxygen]] to form water. This process can continue as long as there is hydrogen and oxygen supplied to the cell.<Ref name=hsw/>

	[http://auto.howstuffworks.com/fuel-efficiency/alternative-fuels/fuel-cell2.htm Click here] to see an animation of a hydrogen fuel cell.		[http://auto.howstuffworks.com/fuel-efficiency/alternative-fuels/fuel-cell2.htm Click here] to see an animation of a hydrogen fuel cell.

	===Hydrogen===		===Hydrogen===
	An attractive fuel for use in fuel cells is [[hydrogen]], which is actively being researched and developed. The reasons for hydrogen use is not only because of its high [[energy density]] (121 [[joule\|MJ]]/[[kilogram\|kg]]),<ref>I. Hore-Lacy, "Future Energy Demand and Supply," in ''Nuclear Energy in the 21st Century'', 2nd ed., London, UK: WNUP, 2011, ch.1, sec.6, pp.9</ref> but ~~due to the fact that~~ the only by-product aside from electricity is [[water]].		An attractive fuel for use in fuel cells is [[hydrogen]], which is actively being researched and developed. The reasons for hydrogen use is not only because of its high [[energy density]] (121 [[joule\|MJ]]/[[kilogram\|kg]]),<ref>I. Hore-Lacy, "Future Energy Demand and Supply," in ''Nuclear Energy in the 21st Century'', 2nd ed., London, UK: WNUP, 2011, ch.1, sec.6, pp.9</ref> but because the only by-product aside from electricity is [[water]].

	Although hydrogen is the most abundant element in the universe, it doesn't exist in its elemental form on Earth. Therefore hydrogen must be manufactured by inputting energy into hydrogen compounds like [[hydrocarbon]]s or [[water]]. Depending on how this is done, the process may also release [[pollutant]]s. Around 96% of hydrogen produced is done by using [[natural gas]] and other [[fossil fuel]]s, resulting in considerable [[co2\|CO<sub>2</sub>]] emissions. However, for the future, cleaner methods of attaining hydrogen (ie. water) are preferred.<ref name=hsw/><ref name="E2">G. Aubrecht. "Fuel Cells," in ''Energy: Physical, Environmental, and Social Impact'', 3rd ed. San Francisco, CA, U.S.A.: Pearson, 2006, pp. 98-99</ref>		Although hydrogen is the most abundant element in the universe, it doesn't exist in its elemental form on Earth. Therefore hydrogen must be manufactured by inputting energy into hydrogen compounds like [[hydrocarbon]]s or [[water]]. Depending on how this is done, the process may also release [[pollutant]]s. Around 96% of hydrogen produced is done by using [[natural gas]] and other [[fossil fuel]]s, resulting in considerable [[co2\|CO<sub>2</sub>]] emissions. However, for the future, cleaner methods of attaining hydrogen (ie. water) are preferred.<ref name=hsw/><ref name="E2">G. Aubrecht. "Fuel Cells," in ''Energy: Physical, Environmental, and Social Impact'', 3rd ed. San Francisco, CA, U.S.A.: Pearson, 2006, pp. 98-99</ref>
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	[[File:Fuelcell.jpg\|300px\|thumb\|Figure 2. A fuel cell vehicle configuration.<Ref>Wikimedia Commons. "Fuelcell" by Welleman, [Online], Available: https://commons.wikimedia.org/wiki/File:Fuelcell.jpg#/media/File:Fuelcell.jpg</ref>]]		[[File:Fuelcell.jpg\|300px\|thumb\|Figure 2. A fuel cell vehicle configuration.<Ref>Wikimedia Commons. "Fuelcell" by Welleman, [Online], Available: https://commons.wikimedia.org/wiki/File:Fuelcell.jpg#/media/File:Fuelcell.jpg</ref>]]

	Many countries are spending enormous amounts of money into the development of hydrogen fuel cells, with the main reason being the future problems associated with an oil-dependent society. Oil production is [[Hubbert's peak\|expected to continue ~~to diminish~~]]~~, which comes along with increasing prices~~ for it and a greater need for imports of oil in places that do not have many oil resources. The burning of oil and other fossil fuels also produces [[pollution]], which contributes to [[global warming]] and ultimately [[climate change\|changing climate]]. These reasons combined demonstrate a strong case for alternatives, with fuel cells being one of them.<Ref name=hsw/>		Many countries are spending enormous amounts of money into the development of hydrogen fuel cells, with the main reason being the future problems associated with an oil-dependent society. Oil production is diminishing and it's [[Hubbert's peak\|expected to continue this way]]—causing an increase in price for it and a greater need for imports of oil in places that do not have many oil resources. The burning of oil and other fossil fuels also produces [[pollution]], which contributes to [[global warming]] and ultimately [[climate change\|changing climate]]. These reasons combined demonstrate a strong case for alternatives, with fuel cells being one of them.<Ref name=hsw/>

	Uses of fuel cells range from large electricity generating plants to small devices like [[cell phone]]s or laptops.		Uses of fuel cells range from large electricity generating plants to small devices like [[cell phone]]s or laptops.

	===In vehicles===		===In vehicles===
	The most promising use, for the immediate future at least~~, is~~ in ~~vehicles, and~~ there are already hydrogen based vehicles on the road today. The theoretical maximum efficiency of hydrogen fuel cells is 83%, however since theory is never accomplished in reality, a realistic efficiency is around 60%.<ref name=wolf>R. Wolfson, "Toward a Hydrogen Economy?" in ''Energy, Environment, and Climate'', 2nd ed., New York, NY: W.W. Norton & Company, 2012, ch. 11, sec. 2, pp. 307-315</ref> Combined with an [[electric motor]] of 90% efficiency, the vehicles can achieve an efficiency of 54% before factoring in other [[energy loss]]es. This is around 2 - 2.5 times higher than a typical [[gasoline]]-powered vehicle.		The most promising use for hydrogen as fuel (for the immediate future at least) are in vehicles—and there are already hydrogen based vehicles on the road today. The theoretical maximum efficiency of hydrogen fuel cells is 83%, however, since theory is never accomplished in reality, a realistic efficiency is around 60%.<ref name=wolf>R. Wolfson, "Toward a Hydrogen Economy?" in ''Energy, Environment, and Climate'', 2nd ed., New York, NY: W.W. Norton & Company, 2012, ch. 11, sec. 2, pp. 307-315</ref> Combined with an [[electric motor]] of 90% efficiency, the vehicles can achieve an efficiency of 54% before factoring in other [[energy loss]]es. This is around 2 - 2.5 times higher than a typical [[gasoline]]-powered vehicle.

	There is plenty of criticism for these types of vehicles, as many claim the cost of these vehicles will never be practical. The cost of these cells is high as a result of the use of platinum and other valuable ~~components, and~~ the price would have to be less than half of what it currently is to be competitive.<ref name=hsw/> The durability and performance of such systems, along with the infrastructure necessary to accommodate them, is also under scrutiny.		There is plenty of criticism for these types of vehicles, as many claim the cost of these vehicles will never be practical. The cost of these cells is high as a result of the use of platinum and other valuable components—but the price would have to be less than half of what it currently is to be competitive.<ref name=hsw/> The durability and performance of such systems, along with the infrastructure necessary to accommodate them, is also under scrutiny.

			==For Further Reading==
			*[[Thermal efficiency]]
			*[[Hydrogen]]
			*[[Alternative fuel vehicle]]
			*[[Hydrogen as an energy currency]]
			*Or explore a [[Special:Random\|random page]]

	==References==		==References==
	{{reflist}}[[Category:Uploaded]]		{{reflist}}[[Category:Uploaded]]

J.williams: 1 revision imported

2015-08-26T21:31:52Z

1 revision imported

← Older revision	Revision as of 21:31, 26 August 2015
(No difference)

J.williams at 18:50, 24 August 2015

2015-08-24T18:50:41Z

New page

[[category:371 topics]]
[[Category:Done 2015-08-21]]
[[File:fuelcell.png|300px|thumb|Figure 1. A diagram of a hydrogen fuel cell. The hydrogen and oxygen combine to form water, while simultaneously producing electricity.<Ref>Wikimedia Commons [Online], Available: https://commons.wikimedia.org/wiki/File:Solid_oxide_fuel_cell.svg#/media/File:Solid_oxide_fuel_cell.svg</ref>]]

<onlyinclude>'''Fuel cells''' are a type of [[energy conversion technology]] which take the [[chemical energy]] contained within a [[fuel]] and transform it into [[electricity]] along with certain by-products (depending on the fuel used).</onlyinclude> <ref name=hsw>How Stuff Works. (August 10, 2015). ''How Fuel Cells Work'' [Online], Available: http://auto.howstuffworks.com/fuel-efficiency/alternative-fuels/fuel-cell.htm</ref> It's important to note that fuel cells are not [[heat engine]]s, so they can have incredibly high efficiencies. However, when a heat engine is used to power a fuel cell, the heat engine still has a limiting [[thermal efficiency]].

Fuel cells can be seen as an [[energy storage]] device, as [[energy]] can be input to create [[hydrogen]] and [[oxygen]], which can remain in the cell until its use is needed at a later time. In this sense they work much like a [[battery]].

To produce electricity, a gaseous fuel is input and reacts with a catalyst made of platinum nanoparticles. When [[molecular hydrogen]] comes into contact with this, it splits into two H<sup>+</sup> ions and two [[electron]]s. The electrons are conducted through an [[electromotive force]] and electricity is produced. The hydrogen ions pass through a proton exchange membrane where it reaches the cathode and combines with [[oxygen]] to form water. This process can continue as long as there is hydrogen and oxygen supplied to the cell.<Ref name=hsw/>

[http://auto.howstuffworks.com/fuel-efficiency/alternative-fuels/fuel-cell2.htm Click here] to see an animation of a hydrogen fuel cell.

===Hydrogen===
An attractive fuel for use in fuel cells is [[hydrogen]], which is actively being researched and developed. The reasons for hydrogen use is not only because of its high [[energy density]] (121 [[joule|MJ]]/[[kilogram|kg]]),<ref>I. Hore-Lacy, "Future Energy Demand and Supply," in ''Nuclear Energy in the 21st Century'', 2nd ed., London, UK: WNUP, 2011, ch.1, sec.6, pp.9</ref> but due to the fact that the only by-product aside from electricity is [[water]].

Although hydrogen is the most abundant element in the universe, it doesn't exist in its elemental form on Earth. Therefore hydrogen must be manufactured by inputting energy into hydrogen compounds like [[hydrocarbon]]s or [[water]]. Depending on how this is done, the process may also release [[pollutant]]s. Around 96% of hydrogen produced is done by using [[natural gas]] and other [[fossil fuel]]s, resulting in considerable [[co2|CO<sub>2</sub>]] emissions. However, for the future, cleaner methods of attaining hydrogen (ie. water) are preferred.<ref name=hsw/><ref name="E2">G. Aubrecht. "Fuel Cells," in ''Energy: Physical, Environmental, and Social Impact'', 3rd ed. San Francisco, CA, U.S.A.: Pearson, 2006, pp. 98-99</ref>

An alternative way to produce hydrogen comes from [[nuclear power]]. During off-peak periods (when the [[electrical grid]] does not require as much electricity) [[nuclear power plant]]s may use their electricity for the production of hydrogen. The [[heat]] generated by the [[nuclear reactor]] could also be used for the production of hydrogen. [[combined heat and power|Combined cycle plants]] producing both hydrogen and electricity may reach an efficiency of 60%.<ref>I. Hore-Lacy, "Hydrogen Production and Use," in ''Nuclear Energy in the 21st Century'', 2nd ed., London, UK: WNUP, 2011, ch.7, sec.2, pp.75-78</ref> Many [[Generation IV nuclear reactors]] are being designed with the purpose of hydrogen production.

==Use of fuel cells==
[[File:Fuelcell.jpg|300px|thumb|Figure 2. A fuel cell vehicle configuration.<Ref>Wikimedia Commons. "Fuelcell" by Welleman, [Online], Available: https://commons.wikimedia.org/wiki/File:Fuelcell.jpg#/media/File:Fuelcell.jpg</ref>]]

Many countries are spending enormous amounts of money into the development of hydrogen fuel cells, with the main reason being the future problems associated with an oil-dependent society. Oil production is [[Hubbert's peak|expected to continue to diminish]], which comes along with increasing prices for it and a greater need for imports of oil in places that do not have many oil resources. The burning of oil and other fossil fuels also produces [[pollution]], which contributes to [[global warming]] and ultimately [[climate change|changing climate]]. These reasons combined demonstrate a strong case for alternatives, with fuel cells being one of them.<Ref name=hsw/>

Uses of fuel cells range from large electricity generating plants to small devices like [[cell phone]]s or laptops.

===In vehicles===
The most promising use, for the immediate future at least, is in vehicles, and there are already hydrogen based vehicles on the road today. The theoretical maximum efficiency of hydrogen fuel cells is 83%, however since theory is never accomplished in reality, a realistic efficiency is around 60%.<ref name=wolf>R. Wolfson, "Toward a Hydrogen Economy?" in ''Energy, Environment, and Climate'', 2nd ed., New York, NY: W.W. Norton & Company, 2012, ch. 11, sec. 2, pp. 307-315</ref> Combined with an [[electric motor]] of 90% efficiency, the vehicles can achieve an efficiency of 54% before factoring in other [[energy loss]]es. This is around 2 - 2.5 times higher than a typical [[gasoline]]-powered vehicle.

There is plenty of criticism for these types of vehicles, as many claim the cost of these vehicles will never be practical. The cost of these cells is high as a result of the use of platinum and other valuable components, and the price would have to be less than half of what it currently is to be competitive.<ref name=hsw/> The durability and performance of such systems, along with the infrastructure necessary to accommodate them, is also under scrutiny.

==References==
{{reflist}}[[Category:Uploaded]]