Talk:EROEI
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[edit] Edits 12/24/2007
'Acceptance outside physics' section removed. This section, as written, is condescending and tautological in regard to all information presented other than opinion. For example, the statement "Geology and thermodynamics are much more fundamental to the world than economics." is not a factual statement given the lack of qualifiers inherent to the phrase 'more fundamental to the world' -- the question 'more fundamental to the world in what way?' is begged. In terms of describing how the world's economy works, neither geology nor thermodynamics, neither of which involve the study of the world's economy, would be likely to be 'more fundamental'.
[edit] Topics needing coverage
- Methodology
I think I have seen someone use the term energy accounting to mean measurement and disclosure of information that is useful in making energy resource allocation decisions. EROEI is a term that seem to be analogous to the accounting term ROI (return on investment). It seems to me that a methodology for determining EROEI should be somewhat similar to ROI accounting methods. - Another energy accounting issue
It is also important to know the complete energy usage required to perform a given task in a given way. For instance how much energy does it take to boil a liter of water on an electric stove as compared to a gas stove. That is similar to EROEI for energy delivered to the pan of water. - EROEI report
Using accounting-like methodology, EROEI would not be presented as a bottom-line number but would include some kind of detailed "income statement."
- References (I added one)
[edit] EROEI Values
Are these EROEI values given (3 for US and 10 for Saudi) supportable?
Cleveland and Kaufmann's latest work suggests an EROEI of around 10 for the US today, and Saudi Arabia will by extension by much higher. See the net energy page on www.oilanalytics.org, though the website appears to be down at present. 61.69.2.156 09:21, 26 November 2005 (UTC)
The values definitely seem low, but the language used is worse. I'm going to change it so it's a bit clearer.
[edit] Bad link
User:Renaissance Man removed a link to oilanalytics.org, once a legitimate site, but apparently now under new ownership. --C J Cowie 19:58, 10 December 2005 (UTC)
- I found a cache of the correct page and restored the link. Linkspro 01:25, 16 December 2005 (UTC)
[edit] Removed Sites Requiring Registration
Per WP:EL guidelines, removed 2 links that require registration to enter. Calltech 11:49, 25 November 2006 (UTC)
[edit] Fusion Power
Should the development of fusion power be mentioned? The focus of research in the field is to create an EROEI above one (currently only about 0.5). 71.103.22.71 01:28, 18 March 2007 (UTC)
- Yes, mention it. It would make an excellent example of why EROEI is so important to consider when developing new sources of energy. Some people wonder why we can't switch to fusion if it's physically possible to build a reactor and environmentally more friendly, and the low EROEI is the answer to this. —Preceding unsigned comment added by 212.146.47.250 (talk)
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- On the other hand the entire subject of Energy Return on Investment is totally irrelevent. For example, if you are burning wood to boil off maple syrup and you find that it takes you more energy to obtain the wood than you get from the wood, in other words your EROEI is less than one you certainly do not change from using wood to make maple syrup, because that would ruin the maple syrup, it simply means that you are actually getting your energy from something else other than wood, ultimately. For example if you cut the wood by hand and hauled it by draft horse the primary energy source for making maple syrup is not the wood that you burned but the food you and the horses ate. Since matter and energy and all forms of energy can be converted one to another what is most important is not how efficient your source of energy is but the damage that would be done along the way by using that source of energy. 199.125.109.18 02:43, 1 August 2007 (UTC)
[edit] Table of comparison
We need a handy table summarizing/comparing the EROEI ranges for solar, wind, etc energy sources, with references. We need better external links.-69.87.199.117 12:56, 18 June 2007 (UTC)
[edit] Historical evidence
Thomas Homer-Dixon in "The Upside of Down" suggests that EROI analysis provides a basis for the analysis of the rise and fall of civilisations. Looking at the maximum extent of the Roman Empire, (60 million) and its technological base the agrarian base of Rome was about 1:12 per hectare for wheat and 1:27 for alfalfa (giving a 1:2.7 production for oxen). One can then use this to calculate the population of the Roman Empire required at its height, on the basis of about 2,500-3,00 calories per day per person. It comes out roughly equal to the area of food production at its height. But ecological damage (deforestation, soil fertility loss particularly in southern Spain, southern Italy, Sicily and especially north Africa saw a collapse in the system beginning in the 2nd century, as EROI began to fall. It bottomed in 1084 when Rome's population, which had peaked under Trajan at 1.5 million, was only 15,000. Evidence also fits the cycle of Mayan and Cambodian collapse too. Perhaps some comment on this work could be included. Regards John D. Croft 03:03, 14 August 2007 (UTC)
[edit] Patent nonsense ?
Energy return on Energy invested does not take into account the factor of time. Energy invested in creating a solar panel may have consumed energy from a high power source like coal, but the return happens very slowly, i.e. over many years. If energy is increasing in relative value this should favour delayed returns.
That is patent nonsense. Generally, in financial terms, getting something now is almost always preferable to getting it later. (There's exceptions: if you could get a basket of strawberries in Canada in january, that'd be more worth than getting the same berries 6 months -earlier-)
Investing 1 GJ worth of coal now, and get 1GJ worth back out over the next 10 years may be beneficial if the price of energy rises, but this is only true if you ignore the fact that this coal could simply be -stored- and then used later for energy-generation.
There is no need to convert the coal to solar-cells if the point is simply to get the energy -later- rather than -now-. --Eivind Kjørstad (talk) 12:34, 7 February 2008 (UTC)
[edit] Citation of Rome's population contradicts History of Rome article
In this article (http://en.wikipedia.org/wiki/History_of_Rome), it seems that the population of Rome bottomed out sometime in the 1300s, not in 1084 as this article states. —Preceding unsigned comment added by 98.207.114.147 (talk) 16:07, 1 April 2008 (UTC)
