Efficiency - Revision history

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energy>Jmdonev at 05:41, 30 July 2026

2026-07-30T05:41:14Z

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	[[File:MWtMWe.png\|350px\|thumb\|Figure 1. The power input in a heat engine is measured as [[MWt]], and the output power obtained as electricity is measured as [[MWe]].<ref>''Made internally by a member of the Encyclopedia team''</ref> The ratio of power out over power in is the efficiency.]]		[[File:MWtMWe.png\|350px\|thumb\|Figure 1. The power input in a heat engine is measured as [[MWt]], and the output power obtained as electricity is measured as [[MWe]].<ref>''Made internally by a member of the Encyclopedia team''</ref> The ratio of power out over power in is the efficiency.]]

	A word ~~can have~~ multiple and ambiguous meanings in everyday language but ~~they have~~ precise meanings in science. <onlyinclude>'''Efficiency''' in physics (and often for chemistry) is a comparison of the [[energy]] output to the energy input in a given [[system]].</onlyinclude> It is defined as the [[percent]]age ratio of the output energy to the input energy, given by the equation:		The word efficiency has multiple and ambiguous meanings in everyday language but has a precise meanings in science. <onlyinclude>'''Efficiency''' in physics (and often for chemistry) is a comparison of the [[energy]] output to the energy input in a given [[system]].</onlyinclude> It is defined as the [[percent]]age ratio of the output energy to the input energy, given by the equation:

	<center><math>Efficiency = \frac{E_{out}}{E_{in}}\times 100\%</math></center>		<center><math>Efficiency = \frac{E_{out}}{E_{in}}\times 100\%</math></center>
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	This equation is commonly used in order to represent energy in the form of [[heat]] or [[power]].		This equation is commonly used in order to represent energy in the form of [[heat]] or [[power]].

	"Efficiency" is often confused with "effectiveness", and the two should be recognized as distinct from one another when analyzing [[energy system]]s. Energy efficiency measures how much a system is getting out of the [[fuel]] or [[primary energy flow]] it ~~is using~~. If the energy system is effective, it is making use of this energy towards the right goal. For example, a car is a very effective form of [[transportation]], since it is able to move people across long distances and to specific places. However, a car may not transport people very efficiently because of how it uses fuel.<ref>Diffen, ''Effectiveness vs Efficiency'' [Online], Available: http://www.diffen.com/difference/Effectiveness_vs_Efficiency</ref>		"Efficiency" is often confused with "effectiveness", and the two should be recognized as distinct from one another when analyzing [[energy system]]s. Energy efficiency measures how much a system is getting out of the [[fuel]] or [[primary energy flow]] it uses. If the energy system is effective, it is making use of this energy towards the right goal. For example, a car is a very effective form of [[transportation]], since it is able to move people across long distances and to specific places. However, a car may not transport people very efficiently because of how it uses fuel.<ref>Diffen, ''Effectiveness vs Efficiency'' [Online], Available: http://www.diffen.com/difference/Effectiveness_vs_Efficiency</ref>

	==Types of Efficiency==		==Types of Efficiency==
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	===Thermal Efficiency===		===Thermal Efficiency===

	~~Efficiency is very often used in~~ science ~~to describe how efficient~~ a [[heat engine]] is, and is referred to as [[thermal efficiency]].<ref name=wolf>R. Wolfson, "Entropy, Heat Engines, and the Second Law of Thermodynamics" in ''Energy, Environment, and Climate'', 2nd ed., New York, NY: W.W. Norton & Company, 2012, ch. 4, sec. 7, pp. 81-84</ref> This efficiency describes how much [[work]] an engine can get out of the fuel it is using. There are upper limits placed on how thermally efficient engines can be, due to the [[second law of thermodynamics]], known as the [[Carnot efficiency]]. This Carnot efficiency only depends on the [[temperature]] of the heat source and cold sink, and is for an ideal (impossible) engine that has no change in [[entropy]]. Although such an engine would maximize ''efficiency'', in terms of ''effectiveness'' it is terribly impractical since its idealized processes take so much time to output a significant amount of work. As Schroeder puts it, "don’t bother installing a Carnot engine in your car; while it would increase your gas mileage, you’d be passed by pedestrians".<ref>Hyperphysics, ''Carnot Cycle'' [Online], Available: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/carnot.html</ref><ref>McMaster Physics and Astronomy, ''Carnot Cycle'' [Online], Available: http://www.physics.mcmaster.ca/~morozov/3K03/Lecture9.pdf</ref>		In science efficiency usually describes what fraction of heat a [[heat engine]] turns into work, and is referred to as [[thermal efficiency]].<ref name=wolf>R. Wolfson, "Entropy, Heat Engines, and the Second Law of Thermodynamics" in ''Energy, Environment, and Climate'', 2nd ed., New York, NY: W.W. Norton & Company, 2012, ch. 4, sec. 7, pp. 81-84</ref> This efficiency describes how much [[work]] an engine can get out of the fuel it is using. There are upper limits placed on how thermally efficient engines can be, due to the [[second law of thermodynamics]], known as the [[Carnot efficiency]]. This Carnot efficiency only depends on the [[temperature]] of the heat source and cold sink, and is for an ideal (impossible) engine that has no change in [[entropy]]. Although such an engine would maximize ''efficiency'', in terms of ''effectiveness'' it is terribly impractical since its idealized processes take so much time to output a significant amount of work. As Schroeder puts it, "don’t bother installing a Carnot engine in your car; while it would increase your gas mileage, you’d be passed by pedestrians".<ref>Hyperphysics, ''Carnot Cycle'' [Online], Available: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/carnot.html</ref><ref>McMaster Physics and Astronomy, ''Carnot Cycle'' [Online], Available: http://www.physics.mcmaster.ca/~morozov/3K03/Lecture9.pdf</ref>

	===Electricity Transmission Efficiency===		===Electricity Transmission Efficiency===

Jmdonev: 1 revision imported

2021-09-27T00:02:48Z

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energy>Ethan.boechler at 16:30, 13 September 2021

2021-09-13T16:30:28Z

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			[[es:Eficiencia]]
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			[[fr:Rendement]]
	[[File:MWtMWe.png\|350px\|thumb\|Figure 1. The power input in a heat engine is measured as [[MWt]], and the output power obtained as electricity is measured as [[MWe]].<ref>''Made internally by a member of the Encyclopedia team''</ref> The ratio of power out over power in is the efficiency.]]		[[File:MWtMWe.png\|350px\|thumb\|Figure 1. The power input in a heat engine is measured as [[MWt]], and the output power obtained as electricity is measured as [[MWe]].<ref>''Made internally by a member of the Encyclopedia team''</ref> The ratio of power out over power in is the efficiency.]]

Jmdonev: 1 revision imported

2020-04-28T15:32:37Z

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energy>Jmdonev at 21:53, 10 April 2020

2020-04-10T21:53:06Z

← Older revision		Revision as of 21:53, 10 April 2020
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	[[Category:Done ~~2018~~-04-30]]		[[Category:Done 2020-02-29]]
	[[category:371 topics]]		[[category:371 topics]]
	[[File:MWtMWe.png\|350px\|thumb\|Figure 1. The power input in a heat engine is measured as [[MWt]], and the output power obtained as electricity is measured as [[MWe]].<ref>''Made internally by a member of the Encyclopedia team''</ref> The ratio of power out over power in is the efficiency.]]		[[File:MWtMWe.png\|350px\|thumb\|Figure 1. The power input in a heat engine is measured as [[MWt]], and the output power obtained as electricity is measured as [[MWe]].<ref>''Made internally by a member of the Encyclopedia team''</ref> The ratio of power out over power in is the efficiency.]]
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	This equation is commonly used in order to represent energy in the form of [[heat]] or [[power]].		This equation is commonly used in order to represent energy in the form of [[heat]] or [[power]].

	"Efficiency" is often confused with "effectiveness", and the two should be recognized as distinct from one another when analyzing [[energy system]]s. Energy efficiency measures how much a system is getting out of the [[fuel]] or [[flow]] it is using. If the energy system is effective, it is making use of this energy towards the right goal. For example, a car is a very effective form of [[transportation]], since it is able to move people across long distances and to specific places. However, a car may not transport people very efficiently because of how it uses fuel.<ref>Diffen, ''Effectiveness vs Efficiency'' [Online], Available: http://www.diffen.com/difference/Effectiveness_vs_Efficiency</ref>		"Efficiency" is often confused with "effectiveness", and the two should be recognized as distinct from one another when analyzing [[energy system]]s. Energy efficiency measures how much a system is getting out of the [[fuel]] or [[primary energy flow]] it is using. If the energy system is effective, it is making use of this energy towards the right goal. For example, a car is a very effective form of [[transportation]], since it is able to move people across long distances and to specific places. However, a car may not transport people very efficiently because of how it uses fuel.<ref>Diffen, ''Effectiveness vs Efficiency'' [Online], Available: http://www.diffen.com/difference/Effectiveness_vs_Efficiency</ref>

	==Types of Efficiency==		==Types of Efficiency==
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	==Implications==		==Implications==

	Efficiency is used to describe the energy that a certain system can extract and make useful from its energy source. Such systems include [[power plant]]s, [[engine]]s, and [[turbine]]s. ''Any'' system that uses energy from a [[fuel]] or [[flow]] has a certain efficiency associated with it.		Efficiency is used to describe the energy that a certain system can extract and make useful from its energy source. Such systems include [[power plant]]s, [[engine]]s, and [[turbine]]s. ''Any'' system that uses energy from a [[fuel]] or [[primary flow]] has a certain efficiency associated with it.

	The efficiency of [[coal]] and [[natural gas]] power plants range between 32% to 42%.<ref>Bright Hub Engineering, ''The Efficiency of Power Plants of Different types'' [Online], Available: http://www.brighthubengineering.com/power-plants/72369-compare-the-efficiency-of-different-power-plants/</ref> If a [[power plant]] has an efficiency of 35% then for every 100 [[joule\|J]] of heat from coal, about 35 J becomes electricity and the other 65 J becomes [[heat]]. This heat goes into making the [[atmosphere]] warmer, or perhaps a body of [[water]] like a river or lake.		The efficiency of [[coal]] and [[natural gas]] power plants range between 32% to 42%.<ref>Bright Hub Engineering, ''The Efficiency of Power Plants of Different types'' [Online], Available: http://www.brighthubengineering.com/power-plants/72369-compare-the-efficiency-of-different-power-plants/</ref> If a [[power plant]] has an efficiency of 35% then for every 100 [[joule\|J]] of heat from coal, about 35 J becomes electricity and the other 65 J becomes [[heat]]. This heat goes into making the [[atmosphere]] warmer, or perhaps a body of [[water]] like a river or lake.
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	[[Cogeneration]] plants make use of [[waste heat]] in power plants and other heat systems (like a car's engine running a [[heater]]) in order to power other parts of the system, thereby making the total efficiency higher.<ref>Forbes, ''The Most Efficient Power Plants'' [Online], Available: http://www.forbes.com/2008/07/03/energy-efficiency-cogeneration-biz-energy_cx_jz_0707efficiency_horror.html</ref>		[[Cogeneration]] plants make use of [[waste heat]] in power plants and other heat systems (like a car's engine running a [[heater]]) in order to power other parts of the system, thereby making the total efficiency higher.<ref>Forbes, ''The Most Efficient Power Plants'' [Online], Available: http://www.forbes.com/2008/07/03/energy-efficiency-cogeneration-biz-energy_cx_jz_0707efficiency_horror.html</ref>

			==For Further Reading==
			*[[Second law of thermodynamics]]
			*[[Conservation of energy]]
			*[[Energy transformations]]
			*[[Cogeneration]]
			*[[Carnot efficiency]]
			*Or explore a [[Special:Random\|random page]]

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

Jmdonev: 1 revision imported

2018-05-11T18:17:07Z

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Jmdonev at 22:08, 9 May 2018

2018-05-09T22:08:44Z

← Older revision		Revision as of 22:08, 9 May 2018
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	[[Category:Done ~~2017~~-07-01]]		[[Category:Done 2018-04-30]]
	[[category:371 topics]]		[[category:371 topics]]
	[[File:MWtMWe.png\|350px\|thumb\|Figure 1. The power input in a heat engine is measured as [[MWt]], and the output power obtained as electricity is measured as [[MWe]].<ref>''Made internally by a member of the Encyclopedia team''</ref> The ratio of power out over power in is the efficiency.]]		[[File:MWtMWe.png\|350px\|thumb\|Figure 1. The power input in a heat engine is measured as [[MWt]], and the output power obtained as electricity is measured as [[MWe]].<ref>''Made internally by a member of the Encyclopedia team''</ref> The ratio of power out over power in is the efficiency.]]

	~~As is often the case in science, words that~~ have ambiguous meanings in everyday language have precise meanings in science. <onlyinclude>'''Efficiency''' in physics (and often for chemistry) is a comparison of the [[energy]] output to the energy input in a given [[system]].</onlyinclude> It is defined as the [[percent]]age ratio of the output energy to the input energy, given by the equation:		A word can have multiple and ambiguous meanings in everyday language but they have precise meanings in science. <onlyinclude>'''Efficiency''' in physics (and often for chemistry) is a comparison of the [[energy]] output to the energy input in a given [[system]].</onlyinclude> It is defined as the [[percent]]age ratio of the output energy to the input energy, given by the equation:

	<center><math>Efficiency = \frac{E_{out}}{E_{in}}\times 100\%</math></center>		<center><math>Efficiency = \frac{E_{out}}{E_{in}}\times 100\%</math></center>
Line 9:		Line 9:
	This equation is commonly used in order to represent energy in the form of [[heat]] or [[power]].		This equation is commonly used in order to represent energy in the form of [[heat]] or [[power]].

	"Efficiency" is often confused with "effectiveness", and the two should be recognized as distinct from one another analyzing [[energy system]]s. Energy efficiency measures how much a system is getting out of the [[fuel]] or [[flow]] it is using. If the energy system is effective, it is making use of this energy towards the right goal. For example, a car is a very effective form of [[transportation]], able to move people across long distances and to specific places, ~~but~~ a car may not transport people very efficiently because of how it uses fuel.<ref>Diffen, ''Effectiveness vs Efficiency'' [Online], Available: http://www.diffen.com/difference/Effectiveness_vs_Efficiency</ref>		"Efficiency" is often confused with "effectiveness", and the two should be recognized as distinct from one another when analyzing [[energy system]]s. Energy efficiency measures how much a system is getting out of the [[fuel]] or [[flow]] it is using. If the energy system is effective, it is making use of this energy towards the right goal. For example, a car is a very effective form of [[transportation]], since it is able to move people across long distances and to specific places. However, a car may not transport people very efficiently because of how it uses fuel.<ref>Diffen, ''Effectiveness vs Efficiency'' [Online], Available: http://www.diffen.com/difference/Effectiveness_vs_Efficiency</ref>

	==Types of Efficiency==		==Types of Efficiency==
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	===Electricity Transmission Efficiency===		===Electricity Transmission Efficiency===

	[[Electricity]] tends to lose energy in the [[electrical grid]] as it is transmitted from one location to another, depending on the magnitude of [[current]], the specific [[conductor]]s, and the length of the [[electrical transmission\|transmission]] line. As [[voltage]]s increase these losses are reduced considerably due to its relationship with current. Typical losses from a [[power plant]] to a user in their home ranges from 8% to 15%.<ref>IEC, ''EFFICIENT ELECTRICAL ENERGY TRANSMISSION AND DISTRIBUTION'' [Online], Available: http://www.iec.ch/about/brochures/pdf/technology/transmission.pdf</ref>		[[Electricity]] tends to lose energy in the [[electrical grid]] as it is transmitted from one location to another, depending on the magnitude of [[electric current]], the specific [[conductor]]s, and the length of the [[electrical transmission\|transmission]] line. As [[voltage]]s increase these losses are reduced considerably due to its relationship with current. Typical losses from a [[power plant]] to a user in their home ranges from 8% to 15%.<ref>IEC, ''EFFICIENT ELECTRICAL ENERGY TRANSMISSION AND DISTRIBUTION'' [Online], Available: http://www.iec.ch/about/brochures/pdf/technology/transmission.pdf</ref>

	===Wind Turbine Efficiency===		===Wind Turbine Efficiency===
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	Efficiency is used to describe the energy that a certain system can extract and make useful from its energy source. Such systems include [[power plant]]s, [[engine]]s, and [[turbine]]s. ''Any'' system that uses energy from a [[fuel]] or [[flow]] has a certain efficiency associated with it.		Efficiency is used to describe the energy that a certain system can extract and make useful from its energy source. Such systems include [[power plant]]s, [[engine]]s, and [[turbine]]s. ''Any'' system that uses energy from a [[fuel]] or [[flow]] has a certain efficiency associated with it.

	The efficiency of [[coal]] and [[natural gas]] power plants range between 32% to 42%.<ref>Bright Hub Engineering, ''The Efficiency of Power Plants of Different types'' [Online], Available: http://www.brighthubengineering.com/power-plants/72369-compare-the-efficiency-of-different-power-plants/</ref> If a [[power plant]] has an efficiency of 35% then, for every 100 [[joule\|J]] of heat from coal, ~~only~~ about 35 J ~~become~~ electricity, the other 65 J ~~become~~ [[heat]]. This heat goes into making the [[atmosphere]] warmer, or perhaps a body of [[water]] like a river or lake.		The efficiency of [[coal]] and [[natural gas]] power plants range between 32% to 42%.<ref>Bright Hub Engineering, ''The Efficiency of Power Plants of Different types'' [Online], Available: http://www.brighthubengineering.com/power-plants/72369-compare-the-efficiency-of-different-power-plants/</ref> If a [[power plant]] has an efficiency of 35% then for every 100 [[joule\|J]] of heat from coal, about 35 J becomes electricity and the other 65 J becomes [[heat]]. This heat goes into making the [[atmosphere]] warmer, or perhaps a body of [[water]] like a river or lake.

	This isn't a failure of engineering, but rather a limit imposed by [[thermodynamics]], with the maximum efficiency of such plants given by the [[Carnot efficiency]]. The lower the efficiency of such plants ~~are~~, the more detrimental the effects of it are on the [[environment]] as more of these fuels need to be used in order to fulfill energy needs. The ability to increase efficiency is a topic with ongoing research, primarily due to the fact that the ability to increase efficiency will lessen environmental impacts of energy use and reduce [[resource]] needs in the future. Along with efficiency, it is important for both the environment and for people's health that the right fuels are [[access to non-solid fuel\|accessible]].		This isn't a failure of engineering, but rather a limit imposed by [[thermodynamics]], with the maximum efficiency of such plants given by the [[Carnot efficiency]]. The lower the efficiency of such plants, the more detrimental the effects of it are on the [[environment]] as more of these fuels need to be used in order to fulfill energy needs. The ability to increase efficiency is a topic with ongoing research, primarily due to the fact that the ability to increase efficiency will lessen environmental impacts of energy use and reduce [[resource]] needs in the future. Along with efficiency, it is important for both the environment and for people's health that the right fuels are [[access to non-solid fuel\|accessible]].

	[[Cogeneration]] plants ~~can~~ make use of [[waste heat]] in power plants and other heat systems (like a car's engine running a [[heater]]) in order to power other parts of the system, thereby making the total efficiency higher.<ref>Forbes, ''The Most Efficient Power Plants'' [Online], Available: http://www.forbes.com/2008/07/03/energy-efficiency-cogeneration-biz-energy_cx_jz_0707efficiency_horror.html</ref>		[[Cogeneration]] plants make use of [[waste heat]] in power plants and other heat systems (like a car's engine running a [[heater]]) in order to power other parts of the system, thereby making the total efficiency higher.<ref>Forbes, ''The Most Efficient Power Plants'' [Online], Available: http://www.forbes.com/2008/07/03/energy-efficiency-cogeneration-biz-energy_cx_jz_0707efficiency_horror.html</ref>

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

Jmdonev: 1 revision imported

2017-08-29T01:47:28Z

1 revision imported

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Jmdonev at 21:17, 17 August 2017

2017-08-17T21:17:15Z

← Older revision		Revision as of 21:17, 17 August 2017
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	~~As is often the case in science, words that have ambiguous meanings in everyday language have precise meanings in science~~. ~~<onlyinclude>'''Efficiency'''~~ in ~~physics (and often for chemistry)~~ is ~~a comparison of the~~ [[~~energy~~]] output ~~to the energy input in a given~~ [[~~system~~]].</~~onlyinclude~~> ~~It is defined as the percentage~~ ratio of the ~~output energy to the input energy, given by the equation:~~		[[File:MWtMWe.png\|350px\|thumb\|Figure 1. The power input in a heat engine is measured as [[MWt]], and the output power obtained as electricity is measured as [[MWe]].<ref>''Made internally by a member of the Encyclopedia team''</ref> The ratio of power out over power in is the efficiency.]]

	<center><m>Efficiency = \frac{E_{out}}{E_{in}}*100\%</~~m> </onlyinclude~~></center>		As is often the case in science, words that have ambiguous meanings in everyday language have precise meanings in science. <onlyinclude>'''Efficiency''' in physics (and often for chemistry) is a comparison of the [[energy]] output to the energy input in a given [[system]].</onlyinclude> It is defined as the [[percent]]age ratio of the output energy to the input energy, given by the equation:

			<center><math>Efficiency = \frac{E_{out}}{E_{in}}\times 100\%</math></center>

	This equation is commonly used in order to represent energy in the form of [[heat]] or [[power]].		This equation is commonly used in order to represent energy in the form of [[heat]] or [[power]].