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Elastic Energy

I'd be really interested to see [Elastic_energy] added to the list. What is the energy density of a metal spring? Of an rubber band? Compressed air? They're all are used to store energy, but how good are they?

Wired had an article recently about rubber bands. — Preceding unsigned comment added by 2001:8003:2FEA:AE00:34BD:5B2D:DEED:A92C (talk) 02:07, 25 March 2018 (UTC)[reply]

Dubious

I removed the following text from a {{citation needed}} template and replace it with a new {{dubious}} template that points to this discussion. The reason parameter of the template is far too long and includes characters that break the template. Plus, the reason had grown into a discussion (edits: edit 79.182.119.9, edit 140.239.58.226, among others)

Seems high, please check. Using a density of anthracite coal of 1.4g/cc and a specific energy of 32.5MJ/kg, you get 45.5MJ/L instead. - re: yes, correct it please. See wiki Coal_assay#Relative_density. Ideally for most materials we list the highest possible number, the record, then porosity is a separate issue, giving any low value you wish. However as coal above 91% C is classed anthracite, or even 88% C, the rest of the impurities, whether H,S or heavy minerals, affect the sp. gr up or down. Anthracite burns without much flame, not much H or CO or CS2 to pyrolyze out of it. So it depends on your definition of anthracite, if 100%C mineral graphite being excluded from it, then you may still find mined anthracite out there that's well above 1.8 sp.gr., and even mineral graphite may have internal porosity to get listed at <2.1 sp. gr., when ideally it's 2.23-2.26, the difference being attributed to porosity. Listing the highest, the record value and saying everything less is due to porosity or contamination may not be ideal. You can fix it to a more representative, average value. Lignite and bituminous coal by definition are vague compounds containing H, 0, N, etc, and porosity, and listing the "record" lignite or bituminous compounds, and saying the rest is due to porosity would not make sense, so for anthracite we should list the most representative average value from global coals classed as anthracite, as long as graphite is included and listed separately from anthracite. I think using a sp.gr. of 1.5 would be better than 1.4, (and better than 1.8-1.9 which is very high grade but very rare anthracite of relatively low porosity) all these cited values being still very far from 2.2 originally used.

((New Comment : 1.4g/cc is low. even decent bitumunous coal such as Newcastle or Richards Bay standard contract coals get to 27.5Mj/kg at SG's of 1.6g/cc. These coals have excellent volatile contents and hence burn very easily, so their Mj/L ratings should comfortably reach 40 and higher. The energy rating for Bitumunous Coal in the main article is misleading. The quality of coal used there is a low quality power station coal, typically referred to as Run of Mine (RoM) coal, which has not been treated in a wash plant or is the deliberate product of a wash plant set to generate two streams of coal : one for export and one for a power station. Typical Run of Mine coals contain significant amounts of ash (de facto rock) which means that RoM coal seldom has an SG of less than 1.8. Hence RoM coal at 22Mj/kg and an SG of 1.8 results in a Mj/L of close to 40. So the SG used in the main article used for bituminous coal is also dubious.)) — Preceding unsigned comment added by Historiese huise (talk • contribs) 11:42, 4 July 2015

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Ethanol

Could somebody please extent the list with ethanol?

I don't know how to do it technically (how to expand a list in Wikipedia).

26.8 MJ/kg, 21.2 MJ/L

https://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/storage.pdf

Thank you. — Preceding unsigned comment added by 94.114.202.121 (talk) 09:21, 23 May 2018 (UTC)[reply]

Hydrogen

Can someone please verify the energy density of liqufied Hydrogen per Liter? It looks a bit asymetric to me, could be that's for gaseous H₂?

(changing IP) 2003:DE:4F05:3800:D428:F5DA:EEF:7AF2 (talk) 20:10, 12 August 2018 (UTC)[reply]

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