Energy return on investment
Ratio of usable energy delivered to energy invested.
Last updated
Energy return on investment (EROI) is the ratio of usable energy delivered from a resource to the energy used to obtain it.[1] An energy source becomes a net "energy sink" and cannot be used as an energy source when its EROI is less than or equal to one.[2]
Quick Facts
- Field
- Energy economics, ecological energetics
- Known for
- Ratio of energy delivered to energy required to deliver that energy
- Minimum viable eroi
- 3:1
- Break even point
- EROI of 1 or net energy gain of 0
- Related measure
- Energy stored on energy invested (ESOEI)
Facts from the source article.
Key facts and history
Charles Hall, an ecologist at the State University of New York, is credited with creating the EROI measure.[3] Arithmetically, EROI is defined as energy delivered divided by energy required to deliver that energy.[4] A fuel must have an EROI ratio of at least 3:1 to be considered a viable prominent fuel or energy source.[5] Hydropower plants operated for about 100 years have an average EROI of approximately 110.[6]
What the cited sources add
A report prepared for Western Resource Advocates by Dr. Cutler Cleveland indicates oil shale may not produce more energy than is consumed to turn it into fuel.[7] Dr. Cleveland’s analysis shows oil shale has an EROI considerably less than conventional crude oil at both wellhead and refined fuel stages.[7] The report states that should oil shale ever be commercially developed, it would be a poor energy source.[7] Inman explains that the "external energy ratio" only counts energy society puts in, not what comes from the resource itself.[8]
For oil sands, the "net energy ratio" counts all inputs including the resource itself, while the "external energy ratio" is always higher.[8] Hall argues that at some EROI—he guesses 5:1 or 6:1—it does not work anymore to run society.[3]
References
- Wikipedia, "Energy return on investment" (CC BY-SA 4.0), which cites: Murphy, "Year in review EROI or energy return on (energy) invested", Annals of the New York Academy of Sciences, 2010, p. 102–118 (original not read by us) en.wikipedia.org
- Wikipedia, "Energy return on investment" (CC BY-SA 4.0), which cites: "Why energy storage is a dead-end industry - Energy Storage Report", 15 October 2014; Barnhart, "The energetic implications of curtailing versus storing solar- and wind-generated electricity", Energy Environ. Sci., 2013, p. 2804–10 (original not read by us) en.wikipedia.org
- "Will Fossil Fuels be Able to Maintain Economic Growth? A Q&A with Charles Hall", Scientific American, April 2013. facts only, no text reused. scientificamerican.com
- Wikipedia, "Energy return on investment" (CC BY-SA 4.0), which cites: Hall, "EROI of different fuels and the implications for society", Energy Policy, 2013, p. 141–52 (original not read by us) en.wikipedia.org
- Wikipedia, "Energy return on investment" (CC BY-SA 4.0), which cites: Atlason, "Ideal EROI (energy return on investment) deepens the understanding of energy systems", Energy, 2014, p. 241–45; Hall, "EROI of different fuels and the implications for society", Energy Policy, 2013, p. 141–52 (original not read by us) en.wikipedia.org
- Wikipedia, "Energy return on investment" (CC BY-SA 4.0), which cites: Atlason, "Energy return on investment of hydroelectric power generation calculated using a standardised methodology", Renewable Energy, 2014-06-01, p. 364–370 (original not read by us) en.wikipedia.org
- "An Assessment of Energy Return on Investment of Oil Shale", Western Resource Advocates. facts only, no text reused. westernresourceadvocates.org
- Mason Inman. Behind the Numbers on Energy Return on Investment. Scientific American, April 1, 2013. Archive. facts only, no text reused. scientificamerican.com
Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Energy return on investment (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.
More in Miscellaneous
Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Energy return on investment (CC BY-SA 4.0).
- Word definitions: the Codexery glossary, each quoted from its Wikipedia article.
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