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The usual definition of net energy gain compares the energy required to extract energy (that is, to find it, remove it from the ground, refine it, and ship it to the energy user) with the amount of energy produced and transmitted to a user from some (typically underground) energy resource. To better
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that are still underground, unextracted. To get to that energy, some of the extracted oil needs to be consumed in the extraction process to run the engines driving the pumps, therefore after extraction the net energy produced will be less than the amount of energy in the ground before extraction,
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were extracted for every barrel of crude used in the extraction and refining process. Today only 5 barrels (0.79 m) are harvested for every barrel used. When the net energy gain of an energy source reaches zero, then the source is no longer contributing energy to an economy.
488:(sometimes referred to as energy amortization) can be used instead, which is the time, usually given in years, a plant must operate until the running NEG becomes positive (i.e. until the amount of energy needed for the plant infrastructure has been harvested from the plant).
555:, energy resource planning, environmental impact assessments, meaningful energy statistics and forecasting of the direct natural energy resource or energyware inputs, technical energy system investments and the performed and expected future energy service outputs.
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In all energy extraction cases, the life cycle of the energy-extraction device is crucial for the NEG-ratio. If an extraction device is defunct after 10 years, its NEG will be significantly lower than if it operates for 30 years. Therefore, the
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Factors to consider when calculating NEG is the type of energy, the way energy is used and acquired, and the methods used to store or transport the energy. It is also possible to overcomplicate the equation by an infinite number of
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13602-1 provides methods to analyse, characterize and compare technical energy systems (TES) with all their inputs, outputs and risk factors. It contains rules and guidelines for the methodology for such analyses.
512:). The actual net energy of biofuel production is highly dependent on both the bio source that is converted into energy, how it is grown and harvested (and in particular the use of petroleum-derived
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is defined as "natural resource for which the ratio of the creation of the natural resource to the output of that resource from nature to the technosphere is equal to or greater than one".
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sources, because there is no bulk reserve to account for (other than the Sun's lifetime), but the energy continuously trickles, so only the energy required for extraction is considered.
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that refers to the difference between the energy expended to harvest an energy source and the amount of energy gained from that harvest. The net energy gain, which can be expressed in
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442:, the highly diffuse nature of the tar sands and low price of crude oil rendered them uneconomical to mine until the late 1950s (NEG<0). Since then, the
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The extraction energy can be viewed in one of two ways: profitable extractable (NEG>0) or nonprofitable extractable (NEG<0). For instance, in the
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The definition of an energy source is not rigorous. Anything that can provide energy to anything else can qualify. Wood in a stove is full of potential
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has risen and a new steam extraction technique has been developed, allowing the sands to become the largest oil provider in
Alberta (NEG>0).
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A net energy gain is achieved by expending less energy acquiring a source of energy than is contained in the source to be consumed. That is
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Thinking clearly about biofuels: ending the irrelevant net energy debate and developing better performance metrics for alternative fuels
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ISO 13602-1 describes a means of to establish relations between inputs and outputs (net energy) and thus to facilitate
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financial gain that may result from the energy harvesting process, in that various sources of energy (e.g.
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of gasoline, and the combustion of coal is converted from thermal to mechanical, and then to
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351:{\displaystyle NEG=Energy_{\hbox{Consumable}}-Energy_{\hbox{Expended}}.}
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ISO 13602-1:2002 Methods for analysis of technical energy systems
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understand this, assume an economy has a certain amount of finite
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The term net energy gain can be used in slightly different ways:
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The
Importance of ISO and IEC International Energy Standards
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87:. Unsourced material may be challenged and removed.
454:Further information on the EPBT for solar PV:
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670:"Technical Energy Systems - Methods for Analysis"
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500:has been a particular source of controversy for
407:Mechanical energy from wind, rivers, tides, etc.
677:International Organization for Standardization
520:article. Similar considerations also apply to
456:Crystalline silicon § Energy payback time
417:Heat from within the earth (geothermal energy)
578:During the 1920s, 50 barrels (7.9 m) of
399:Nuclear fuels (e.g., uranium and plutonium)
50:Learn how and when to remove these messages
212:Learn how and when to remove this message
147:Learn how and when to remove this message
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189:of all important aspects of the article.
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644:. Green World Solutions. Archived from
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390:. Examples of energy sources include:
185:Please consider expanding the lead to
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574:Net energy cliff with degrading EROI
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85:adding citations to reliable sources
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31:This article has multiple issues.
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617:Solar cells and energy payback
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679:. 2002-11-01. Archived from
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518:Ethanol fuel energy balance
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553:coefficient of performance
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720:Technical energy systems
642:"Biofuel vs Fossil Fuel"
224:Not to be confused with
410:Bio-fuels derived from
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403:Radiation from the sun
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558:In ISO 13602-1:2002,
382:is acquired from the
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81:improve this article
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440:Athabasca Oil Sands
246:, differs from the
622:Energy cannibalism
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560:renewable resource
462:sustainable energy
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524:and other fuels.
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450:Sustainables
444:price of oil
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395:Fossil fuels
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174:lead section
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79:Please help
74:verification
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33:Please help
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252:natural gas
690:2008-11-24
652:2008-11-24
628:References
608:Energyware
514:fertilizer
510:bioethanol
384:combustion
310:Consumable
107:newspapers
36:improve it
593:ISO 13600
580:crude oil
549:labelling
528:ISO 13602
522:biodiesel
316:−
195:June 2022
179:summarize
42:talk page
735:Category
587:See also
566:Examples
498:biofuels
492:Biofuels
340:Expended
545:marking
502:ethanol
412:biomass
121:scholar
547:, and
476:, and
244:joules
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684:(PDF)
673:(PDF)
474:solar
128:JSTOR
114:books
610:and
506:corn
470:wind
256:coal
100:news
533:ISO
248:net
236:NEG
83:by
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