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Major schemes under construction[edit]

Bureya Dam is finished, all generators operating. Burger81 (talk) 08:18, 21 January 2010 (UTC)

There are several very large hydroelectric dams currently under construction in Brazil which are not listed in this section. These are

- UHE Santo Antonio Usina Hidrelétrica Santo Antônio of 3,150 MW of installed capacity, construction started in 2008 with generation starting in 2013. - UHE Jirau Usina Hidrelétrica de Jirau of 3,450 MW of installed capacity, construction started in 2008 with generation starting in 2013. - UHE Belo Monte Belo Monte Dam of 11,233 MW of installed capacity, construction started in 2010 with generation starting in 2016.

X mark.svg Not done Please provide reliable sources to back up the statements. ~ Matthewrbowker Say hi! 03:03, 2 April 2011 (UTC)
Yes check.svg Done Their construction is pretty easy to verify with a quick internet search. Articles for first two are Santo Antônio Dam and Jirau Dam. Thanks for heads up about those two.--NortyNort (Holla) 04:37, 2 April 2011 (UTC)

Addition of Cragside[edit]

Hi, not sure what to do, but would like to add Cragside as the first hydroelectricity plant (1870). Cheers. —Preceding unsigned comment added by (talk) 21:54, 31 May 2010 (UTC)

Done. The section still needs some expanding though.--NortyNort (talk) 02:10, 1 June 2010 (UTC)
The Norwegian town of Hamn i Senja claims to have had the world's first industrial hydro plant, opened in 1882. —Preceding unsigned comment added by (talk) 15:38, 20 June 2010 (UTC)

how many mw of cragside i dont know — Preceding unsigned comment added by (talk) 12:06, 15 August 2011 (UTC)


The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Hello. I propose a merge of Small hydro, Micro hydro and Pico hydro to this article. The articles share the same subject, and could be summarized enough to fit into this article. If no one opposes, I will carry out the task in a day or two. Kind regards. Rehman(+) 16:39, 25 June 2010 (UTC)

I have no problem and can help out. The length should be a problem. The history section is due for an expansion which will make the article longer too.--NortyNort (talk) 20:45, 25 June 2010 (UTC)
I thought about the size; as the article needs expansion, I have also noticed that some topics needs summarizing (or completely removed). So I believe we should be able to manage the size just within the limits. I will create a temporary userspace here, where I will start working on the new version of the article. And then depending on the users' comments, we can then move it here. You are most welcome in assisting. Kind regards. Rehman(+) 01:12, 26 June 2010 (UTC)
Hello. The merge is somewhat complete, along with many other changes. Please do compare the old version with the new, and feel free to edit the userpage. Also note that a bit more things (expand history section, etc) are left to do. You may also notice that considerable amount of text from the small, micro and pico articles are not included in this merged version, that is because those facts are already mentioned somewhere in the article. But please do add them if I missed any. Thanks. Kind regards. Rehman(+) 06:31, 26 June 2010 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── Oppose merger of Small hydro, Micro hydro and Pico hydro to Hydroelectricity.

Hydroelectricity is a big topic, with a big article. Micro hydro is a much smaller scope, but still distinct from hydroelectricity and worthy of a good article in its own right. Merging it into the single huge article would swamp its content. I can see some scope for merging Small hydro, Micro hydro and Pico hydro together into one article, but this should be something like Small hydro or micro hydro and stand-alone from the main hydroelectricity.

I'm also concerned at the speed with which some of these merges have been carried out, relative to the pasting of discussion templates, to the lack of any discussion template at all, and for the use of delete and redirect rather than a merge that preserves useful content. This is not good editing practice. Andy Dingley (talk) 10:04, 26 June 2010 (UTC)

Hello Andy. If you see the merged article (which is not yet complete), it seems like the merge perfectly fits in. We could always split it back out if it shows that there are things to put it. So based on the current contents, I believe this is the right move in terms of accessibility. Rehman(+) 11:08, 26 June 2010 (UTC)
I'm still against the merge of "small scale hydro" into hydroelectricity. This is mostly because small scale hydro warrants its own article (WHY merge it at all?) and mostly because hydroelectricity is such a huge topic. If hydro is huge, and the article size is to be kept manageable, then that suggests separate articles for topics like small-scale, turbine design etc. Otherwise they'll inevitably end up either inadequately covered or, as here, WP:UNDUE in the size of the overall article. The current hydroelectricity article isn't well balanced to begin with, but this is a push in the wrong direction. Imagine if the same merge was done for turbines - the size of a resultant article, with each topic in proportion, would be massive. Andy Dingley (talk) 10:03, 27 June 2010 (UTC)
Hello Andy. I understand your points. As you can see (discussed below), I have now removed my proposal in the merge; the articles will be left as it is. The article update going on now is just mere cleanup and re-arrangement. Kind regards. Rehman(+) 10:30, 27 June 2010 (UTC)


Hello. It seem that all key changes in the new version are complete; I believe any further changes can be done within the article namespace itself. I intend to update the article within a few hours. Please share your views. Kind regards. Rehman(+) 13:36, 26 June 2010 (UTC)

Looks much more organized and simple too. The only comment I have is in the disadvantage section below on this talk page where a summary of the unique problems that dams pose should be included as well.--NortyNort (talk) 14:05, 26 June 2010 (UTC)
Agreed. Lets add that after we move it to the article namespace, as I dont exactly know how the history merge function works. :) Rehman(+) 14:13, 26 June 2010 (UTC)
And per the comment above, I think it would be a good idea to wait a little in case other editors have input. Like those that made or worked on the articles you are about to delete.--NortyNort (talk) 14:26, 26 June 2010 (UTC)
Seems reasonable. Would you agree if I carry out the task tomorrow same time? Also, just to clarify, the current article will not be deleted. I intend to request a history merge to save the edit history of both pages, or worse case, a simple cut-paste in a single edit. Rehman(+) 14:36, 26 June 2010 (UTC)
Wikipedia doesn't specify a time (from what I can tell) but I usually wait three days between a discussion and major change. But like you said, it can be reversed. Side note: I will be out of pocket for a week or so but I want to expand that history section. I did a little work a few weeks ago.--NortyNort (talk) 15:03, 26 June 2010 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── Will then carry out the move in about nine hours (to cover the above three-day waiting period) to see if anyone objects. Worse case, if anyone disagrees after the move, it can always be changed or reverted. Kind regards. Rehman(+) 04:08, 27 June 2010 (UTC)

NO. I don't agree with the move. And the explanation here is not in line with the idea of having seperate article, for such seperate worthy subjects. --CyclePat (talk) 04:24, 27 June 2010 (UTC)
Hi CyclePat. Actually, to be honest, I am too having second thoughts about this. Would you (or everyone, for that matter), agree if the new version be updated without turning the three other articles into a redirect? That wouldn't do any harm to any articles would it? Rehman(+) 04:32, 27 June 2010 (UTC)
T<is water under the bridge... (meuh anyways). Well, this is after all an Encyclopedia... It wouldn't be that if we didn't "cycle" around the many subject matters, which are quite similar. POV though, etc... I don't even want to think about it. I'm just giving you my opinion. Do what you want... edit away. good luck! --CyclePat (talk) 02:28, 29 June 2010 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

4 Month Semi-Protection?[edit]

Any reason this page has been semi-protected for four months now? I will request it is unprotected unless someone know why it was protected indefinitely. Maybe I missed something...--NortyNort (talk) 21:02, 25 June 2010 (UTC)

Oh yes, let's fling open the doors and let the children play in the article again. Of the last 500 edits before protection, 138 of them used "revert" or "rv" in the edit description, which means that 55% at least of the preceding 500 edits were due to vandalism, not improving the article. But we Wikipedia editors are so numerous and energetic that we like nothing better than to increase our edit counts reverting Randy from Boise and his idiot cohorts. --Wtshymanski (talk) 21:36, 25 June 2010 (UTC)
... and in the 9 months covered by those 500 edits, 3 months were spent semi-protected. --Wtshymanski (talk) 21:50, 25 June 2010 (UTC)
Ok, no need for the emotion, I didn't know and that is why I brought it up for discussion.--NortyNort (talk) 22:08, 25 June 2010 (UTC)
Yeah, Wiki admins are always sticking protection tags on articles for the hell of it, you were right to complain about this. And looking at the edit history for the reason for a protection tag is *such* a drag. After all, some anon from Outer Beluchistan can no longer inform us here on which of his class mates are gay. This is the encyclopedia that *anyone* can edit, after all. --Wtshymanski (talk) 03:51, 26 June 2010 (UTC)
Got ya. I didn't watch this page too much back in February. Thanks for the insight, makes sense now.--NortyNort (talk) 13:56, 26 June 2010 (UTC)

Relay setting error not a hydro problem[edit]

Much as I appreciate the instructions on how to make a little hole in both ends and suck the yolk out, a relay setting error is nothing to do with the hydroelectric nature of the plant. That's a problem with failure modes of large interconnected networks, a field of study still rich with opportunities for dissertations today. The '65 backout was no more a hydroelectric failure than the 2003 blackout. --Wtshymanski (talk) 03:51, 26 June 2010 (UTC)

I agree, just when I read the list and saw the context that blackouts were in "...failure to the dam itself, or the connections and substations,", I remembered the 65' black out.--NortyNort (talk) 13:45, 26 June 2010 (UTC)


Hello editors. In the disadvantages section, I believe that, "Failure hazard", "Large power outages caused by dam failures", and "Limited service life", does not make sense. Because, these points are the same with nearly all types of power stations;

  • Failure: Take a nuclear, coal, gas-fired or any other plant for example, it has a great failure risk too.
  • Power outage: All, absolutely all, large power stations are at a risk of large power outages.
  • Limited life: As you already know, every power station would someday need to be closed, due to wear-and-tear, or other safety or economical reasons.

I believe these are better off in a power station or similar article. I would be glad to hear your points of whether or not to keep or remove them. Kind regards. Rehman(+) 04:25, 26 June 2010 (UTC)

Agreed. None of these are peculiar to hydroelectric plants. ( If Pointe du Bois makes it another 18 months or so, it'll be 100 years old...there are no 100-year old steam plants. ) I've taken out the dubious additions. --Wtshymanski (talk) 04:31, 26 June 2010 (UTC)
I agree those factors apply to all power stations and quite frankly, the specifics that are unique to my hydroelectric power stations apply to their accompanied dams. Silting of the reservoir and failure of the dams are unique and should be described as disadvantages of hydroelectric power. Maybe a new short subsection under the disadvantages "Dams" w/ limited service life, failure hazard and maybe the low flow/drought section included? --NortyNort (talk) 13:53, 26 June 2010 (UTC)

Good article. Shouldn't the effects on fisheries be included under the disadvantages?   Will Beback  talk  23:16, 16 July 2010 (UTC)

It is under the 'Damage and loss of land' (regarding Salmon and cold water) and under the see also "Environmental_impacts_of_reservoirs#Fragmentation_of_river_ecosystems". I don't think there should be much more expansion within this article.--NortyNort (talk) 00:08, 17 July 2010 (UTC)
I've changed the heading to "Ecosystem damage and loss of land" to make that clearer.   Will Beback  talk  00:40, 17 July 2010 (UTC)

Keep which version?[edit]

The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

  • Please discuss here whether to keep page Hydroelectricity, or whether to replace it with page User:Rehman/Hydroelectricity. Anthony Appleyard (talk) 18:38, 28 June 2010 (UTC)
  • Hello. Being the editor who created the new version, let me share more about it. The new version was created after I proposed a merger; proposing the merge of Small hydro, Micro hydro, and Pico hydro, into this article. As discussions progressed, turning the three articles to completely point at this article turned out to be somewhat controversial, which then made me to drop the merge, after completing the merge to some extent. The new version now holds the following key changes:
    • The different methods of hydroelectric generation is more clearly explained
    • The different sizes of hydro facilities are explained
    • Advantages/disadvantages of hydroelectricity is much more simplified
    • Added new charts and did some cleanup to World hydroelectric capacity
    • Removed long lists of power stations (thats already included in: this, this and/or other regional articles or lists) that unnecessarily increased file size.
    • Rearranged overall article arrangement.
    • --Rehman(+) 11:32, 29 June 2010 (UTC)
  • The change in size is due to the removal of large duplicated lists and the agreed removal of parts of the disadvantages section. And also probably due to the fact that categories/inter-wiki links are temporary excluded. Rehman(+) 06:42, 3 July 2010 (UTC)
  • I compared both versions and have a few comments. Overall, I think Rehman's version is better organized and flows better but the Small/Mirco/Pico articles shouldn't be deleted.. The whole article needs work/references though. I am willing to help with any of these changes.
    • In the "Sizes and capacities of hydroelectric facilities" section, a main article link like Main article: Pico hydro should be inserted to bring readers to each article. After seeing some of the comments here, I don't think the small, pico and micro articles should be deleted, especially if they have been around for awhile.
    • With the main article links, the sections and subsections for each type, ec. "Turbine types" could be removed. They confuse me anyway when I read though. It may confuse other readers.
    • Under the "Disadvantages" secton, the "Failure Hazard" section should be readded and renamed "Dam Failure Hazard". Rewording it to discuss the unique problems the associated dams poses, ie failure whether structural or from silt, storms, etc.
    • In the "Comparison with other methods of power generation", I think it was good to remove that paragraph about Hydro in Canada, it didn't really belong there. That is 893 bytes.
    • Most of the "Old hydro-electric power stations" section was referenced and if true should be intertwined in the history section. The "Claverack Creek" is "believed to be the oldest in the U.S." Most sources believe the Niagara was. That was 3,400 bytes.
    • On the main pic, that Hoover Dam image is the same as that for the article on dams. Maybe we could find a different one?--NortyNort (talk) 11:31, 3 July 2010 (UTC)
  • Agreed to all comments above. I have made the following edits (here) in respect to the above:
    • Removed/shortened paragraphs (i.e. Turbine types) and added main article links to parent articles.
    • Added short Failure hazard topic in the Disadvantages; to be expanded.
    • Seems like facts relating to Canadian hydro are already removed.
    • History section needs some work; for now, I have just tagged {{expand-sect}}.
    • Changed the main image; it can always be changed later.
    • Please do feel free to edit the userspace if you feel like it. :) Rehman(+) 14:24, 3 July 2010 (UTC)
  • This IP above seems suspicious. I had commented that I thought the removal of the Canadian hydro was a good idea. Is there a consensus?--NortyNort (talk) 09:01, 8 July 2010 (UTC)

More opinions please[edit]

  • So far most arguments and all alterations are by User:Rehman. User:NortyNort raises a few points; he put a new section in Hydroelectricity but has not edited User:Rehman/Hydroelectricity. User: put in one 8-word short comment. I await an opinion from someone independent. Anthony Appleyard (talk) 16:01, 10 July 2010 (UTC)
  • What are your comments? I haven't seen any here or in edits, aside from reverting. Do you oppose or are you just supervising the process?--NortyNort (talk) 06:25, 11 July 2010 (UTC)
  • I am supervising the process. Anthony Appleyard (talk) 16:50, 11 July 2010 (UTC)
  • User:Rehman/Hydroelectricity looks to be a definite improvement. It should be accepted as an improvement, and to maintain momentum in the editing process. --SmokeyJoe (talk) 12:16, 12 July 2010 (UTC)
  • New Zealand also produces the majority of its electricity from hydro. —Preceding unsigned comment added by (talk) 02:40, 13 July 2010 (UTC)
  • Thank you for that.--NortyNort (talk) 03:09, 13 July 2010 (UTC)
  • I view the User:Rehman/Hydroelectricity as preferable, largely due to the superior organizational structure of the page.--E8 (talk) 05:55, 13 July 2010 (UTC)
  • A complication is that 10 edits (not counting those by me) have been made to page Hydroelectricity (see [1] this difference) since page User:Rehman/Hydroelectricity was started. (18 edits have been made to page User:Rehman/Hydroelectricity.) Anthony Appleyard (talk) 05:34, 15 July 2010 (UTC)
  • I Prefer the version by User:Rehman for its more logical layout and more focussed approach. However, the longer this debate goes on, the more edits will be made to both versions making comparison increasingly more difficult. I would propose being bold and making the switch with immediate effect - this debate has been going quite long enough for anybody with a real issue to have commented by now.  Velela  Velela Talk   07:48, 15 July 2010 (UTC)
  • Strongly agree with Velela; the more we wait, the more edits needs to be deleted. So far, there were no opposes by any editors commenting on the topic. And this is going too far for an uncontroversial cleanup. Worst case, if someone does oppose the move so strongly, s/he could simply restore to the old version. Rehman(+) 09:09, 15 July 2010 (UTC)
  • I agree as well, let's get r' done!--NortyNort (talk) 10:14, 15 July 2010 (UTC)
  • Strongly agree with Rehman. This process has needlessly bogged down a normal editing process. --SmokeyJoe (talk) 23:11, 15 July 2010 (UTC)

History merge not done[edit]

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Hydroelectricity (article) - Large Hydro (topic)[edit]

[This is -- suggestion to add a section]:

Large Hydro is an arbitrary designation (meaning it has different definitions, in different settings, or by different agencies). For example, US DOE identifies Large Hydro as being larger than 30 MW. Yet, it is still included under the Renewable umbrella.(A) However, CA excludes Large Hydro from the definition of renewable energy resource.(B)(C) Such exclusion is based on politics, not science. Such assertion is because Large Hydro is the epitome of renewable. It takes the mechanical energy, of the pressure of water onto the wheels, the rotation of which creates a magnetic field, across which electrons jump, to create electricity.[insert - link to Hydro Power article]

Specifically, back when the CA renewables program was in its inception, the intent was to earmark funds to develop (underlined) alternate forms of power. If Large Hydro was then included, funds would of course be directed toward this proven and workable technology. But now, we are in a fully different construct. Namely, the state wants to install (underlined) more renewable power. So, now is the appropriate time to return Large Hydro to the defintion. The alternative forms of power have been developed. For benefit of the customers, the most cost-effective solutions should be able to viewed with parity. If not, this could set CA up to be in a deficit position, such as in the marketing of emssion credits, against other US states or other countries that indeed do recognize Large Hydro as "renewable".

Some argue that such an action would mean that the RES (Renewable Electricity Standard) would therefore need to be increased. So be it. At least it would be accurate representation. For instance, per CEC (California Energy Commission), thru year-end 2007, in-state generation was 14% renewables, but if include Large Hydro, it was 25%.(D) Likewise, if projects slated to meet the previous targets come to fruition (20% in 0202, 30% in 2030), CA would actually attain closer to 30% in 2020, 43% in 2030. And the CA governor spoke to this very figure, in his speech at dedication of the Renewable Transmission Project (May 4, 2010):

[indent] - And I want to also tell you that I will negotiate tirelessly to get our renewable policy set for the rest of this decade so we reach the 33 percent. And when I talk about 33 percent, that's a watered-down 33 percent, because in reality, when you add hydro, it's actually 43 percent.(E)

And Large Hydro is not just green power. It is now used for firming-up the electricy grid, such as when the demand from customers varies over the course of a day (called "load following"). And Large Hydro can respond in mere minutes.(F) Such is a straight-forward application of the concept of supply and demand. Large Hydro also has the capcity to provide Energy Storage, such as behind "intermittant" renewables (such as, when the wind doesn't blow, or the sun doesn't shine). These actions ensure power "reliability" (when hitting the switch, the power goes on). Large Hydro can help with all these energy problems. It thus seems far too good a resource for CA to contiue to ignore.

(A) (B)Public Resources Code Section 25741(a)(1) (C)Public Utilities Code Section 399.12(a)(3) (D) (E) (F)(there was a website that this, can't find it now) —Preceding unsigned comment added by (talk) 19:49, 24 September 2010 (UTC)

I think including the DOE threshold in the large hydro section is reasonable. It would be great to have the given large hydro threshold for another country's department or company. Such as HydroQuebec? --NortyNort (Holla) 23:26, 24 September 2010 (UTC)
[reply] - in Canada, small hydro definition goes to 50-MW.
[reply] - also, Vermont includes within its definition of renewable the hydro from Quebec.
[reply] - the US DOE secretary Steven Chu has said MANY times that he supports increased use of hydro for electricity. Most telling was an MOU signed with the Army Corps of Engineers and Dept of the Interior, to increase hydro.(March.2010) So, it shouldn't be only government lands that can count hydro as renewable. States need to (also) be given that latitude. (see second article, Sep.2010)

"Large and specialized industrial facilities" (misnomer)[edit]

Sub-section for "Large Hydro" is missing from "Sizes and capacities of hydroelectric facilities". The title of the existing sub-section is a misnomer, as it discusses ultra-large (GW size) and industry specific. Suggestion - put each of those under its own heading, and add a third, such as Specialized Industrial, Ultra Large, Large Hydro (followed by existing Small, Micro, Pico). —Preceding unsigned comment added by (talk) 19:03, 27 September 2010 (UTC)

Add a dam to the list of dams that have destroyed major cultural/historical sites.[edit]

The Dalles dam on the Columbia River should be added to the short list of dams that have damaged major cultural/historical sites. The dam inundated Celilo Falls. This destroyed a fishing ground and fishing village that had existed in some form for approximately 15,000 years. —Preceding unsigned comment added by (talk) 08:57, 13 October 2010 (UTC)

Hello, good comment. I think the significance of the relocation in the "Relocation" section is what you are talking about. The Grand Coulee Dam had a very similar impact as well. Each dam in that sentence had/or is going to have a significant impact on relocation, with maybe the exception of the Clyde Dam which I am not too familiar with. Three Gorges relocated around 1.1 million people, Ilisu will around 40k and part of Hasankeyf, while the Ataturk Dam (not even listed) already relocated about 40k as well and flooded an ancient city as well. Other dams could certainly be in there but those are just a few extreme examples. I don't think we should make the sentence too long.--NortyNort (Holla) 10:12, 13 October 2010 (UTC)

Banqiao and Shimantan Dams[edit]

Electrical power capacity of the dam - anyone know. — Preceding unsigned comment added by Engineman (talkcontribs) 12:02, 23 January 2011 (UTC)

Caption under first picture[edit]

I believe the phrase should be "conventionally dammed hydro facility." Conventional(ly) modifies dammed; both modify hydro facility. "Dammed-hydro" is not a compound adjective. (talk) 16:58, 6 February 2011 (UTC)

Yes check.svg Done, by Wtshymanski. Rehman 02:28, 7 February 2011 (UTC)

Brazilian Hydro plants database for Google Maps and Google Earth[edit]

Hi all, I would like to sugest an External Link:

Power calculation[edit]

The current calculation for power is:

  • A simple formula for approximating electric power production at a hydroelectric plant is: P = ρhrgk, where
  • P is Power in watts,
  • ρ is the density of water (~1000 kg/m3),
  • h is height in meters,
  • r is flow rate in cubic meters per second,
  • g is acceleration due to gravity of 9.8 m/s2,
  • k is a coefficient of efficiency ranging from 0 to 1. Efficiency is often higher (that is, closer to 1) with larger and more modern turbines.

I suggest using standard units:

  • A simple formula for approximating electric power production at a hydroelectric plant is: P = ρhrgk, where
  • P is Power in watts,
  • ρ is the density of water (~1 kg/L),
  • h is height in meters,
  • r is flow rate in liter per second,
  • g is acceleration due to gravity of 9.8 m/s2,
  • k is a coefficient of efficiency ranging from 0 to 1. Efficiency is often higher (that is, closer to 1) with larger and more modern turbines. —Preceding unsigned comment added by (talk) 18:16, 28 April 2011 (UTC)
Cubic meters is standard in engineering applications, and considering of the magnitude of the volumes, is more appropriate in this application.--E8 (talk) 19:17, 28 April 2011 (UTC)
Where the dam is big enough to send power to more than one cusomter, yes, the usual measure is cubic metres per second (or cubic feet per second in inch-pound literature). The hydrology department may measure leakage in litres/second. --Wtshymanski (talk) 19:24, 28 April 2011 (UTC)
The formula works pretty well. Here's an example with data taken from the Robert-Bourassa generating station (including LG-2-A).
1,000 kg/m³ × 137.16 m × 5,920 m³/s × 9.80665 m/s² × 0.97 = 7,723,988,046 W or 7,724 MW
Actual values are: 5,616 + 2,106 = 7,722 MW.
However, the calculation assumes nominal parameters: maximum head, flow and water at 3.98 °C. I'm also guessing k to be at a value around 0.97. Bouchecl (talk) 17:14, 17 May 2011 (UTC)
Temperature influence

I supose that temperature has really a low influence to output power due to really really low compression rate of water. There is true that water has the biggest density at nearly +4 degree, but the "loss" of efficiency due to lower density at higher temps is nearly nothing. There are so mutch other and bigger influences then temp (for example perfect coupling between network impedance to generators impedance and therfore losses in absolute active power due to non-ideal networks (let us say resulting impedance from network including all consumers) --Cosy-ch (talk) 15:36, 3 September 2012 (UTC)

Some small edits[edit]

The section "Flow Shortage" under "Advantages and Disadvantages has some minor typos:

1. The font on the double "f"s in run-off is strange.

2. Brazil has a heavy reliance, not a "heaving" reliance.

3. There is an unnecessary comma after "regime." Really, that sentence is poorly written. I would rewrite it:

Brazil is particularly vulnerable due to its heavy reliance on hydroelectricity. Increasing temperatures, lower water flow and alterations in the rainfall regime could reduce annual energy population by 7% by the end of the century. — Preceding unsigned comment added by (talk) 17:36, 1 November 2011 (UTC)

Edit request from , 23 November 2011[edit]

The figures given in the statement "Worldwide, an installed capacity of 1,010 GW supplied hydroelectricity in 2010. This was approximately 16% of the world's electricity, and accounted for about 76% of electricity from renewable sources" do not match those given in the quoted reference.

16% of the world's electricity is from renewables. 21% of this is from hydroelectricity, which is 3.4% of the world's total.

This needs to be changed as there is clearly a striking difference between the two figures which skews the reader's perception and understanding of hydroelectricity and its contribution to global energy. MegWhiteIII (talk) 01:11, 23 November 2011 (UTC)

Yes check.svg Done Thanks for the correction, CTJF83 01:47, 23 November 2011 (UTC)

Edit request from , 13 March 2012[edit]

Edit request: "Depending on the location, water exiting from turbines is typically much warmer than the pre-dam water" does not make sense: 1 kg of water falling for 1000m (HUGE assumption) would generate an energy of ~ 10000J, total. At an 80% efficiency, that leaves 20% on the table. Assuming half of that (10%, which is HUGE) goes into heating the water, that leaves 1000J on the table. Which, for 1 kg of water, rises the temperature by a spectacular... 0.25 degrees vs. the pre-dam water. Hence, the statement does not make sense.

Hmm, this might need to be fixed, but it's not the movement of the water that warms it up, it's the holding of the water in a sunny reservoir that affects its termperature. ( Haven't calculated it yet but the heat energy stored in the reservoir is probably an order of magnitude more than the gravitational potential energy in the water.) 1 kg of water falling 1000 metres in Earth gravity would produce 9810 joules - that's only enough energy to warm 1 kg of water by 2.3 degrees C. --Wtshymanski (talk) 19:47, 13 March 2012 (UTC)
---and a 1977 New Scientist article on Google Books says that a Russian dam was going to *drop* the temperature of the water, since it was discharging water from deeper, cooler layers of a resevoir. --Wtshymanski (talk) 19:50, 13 March 2012 (UTC)
I thought the major temperature change concern of dams was cooler than normal water being discharged downstream because of where it is drawn from the reservoir. That is a major problem downstream of Hoover Dam which is in a hot area of the world, but maybe warmer water is a problem at a large dam in a cold area like Sayano–Shushenskaya Dam. I couldn't find a good source to back up a warmer-water claim but agree its plausible, if only a few degrees. I made some tweaks to the sentence.--NortyNort (Holla) 20:13, 13 March 2012 (UTC)
My recollection is that it was not a problem with the Hoover Dam, but became a problem when the Glen Canyon Dam#Environmental impact upstream was built. Delphi234 (talk) 06:52, 25 December 2012 (UTC)
It certainly is not ubiquitous. Water leaving the turbines at Nant y Moch dam, Llyn Brianne and many other reservoirs which generate hydroelectricity in Wales is generally very much colder than expected as the water is drawn from the Hypolimnion.  Velella  Velella Talk   14:19, 25 December 2012 (UTC)

I propose to completely remove this argument from the text bevause it is unrelated and the effects definitly unreal and not measurable. Worlds biggest (most powerfull) pelton turbines in swiss area (see for [[2]])shows that water coming from turbine is mostly too cold (it keeps the temperature of mutch higher altitudes and becomes not warm enougth while falling)So absolutely no problem about warming --Cosy-ch (talk) 15:50, 3 September 2012 (UTC)

Mistakes about figure "Ten of the largest hydroelectric producers as at 2009"[edit]

There are some mistakes or errors in your text: You mention "annual power" in the text what is named in the table column as "production [TWh]. Production is ok, annual power is wrong, power stands for TW or MW.. not for Work [TWh]. The term "capacity" for the column about installed peak power is completely confusing. Capacity is physicaly indicated by for example TWh, never as MW!!! Please correct and name the column as follow: ¦ annual avg production [TWh] ¦ installed peak power [MW] ¦ Power to Energy ratio ¦ REM *) Hydro power percentage to countrywide installed power ¦

  • I sugest this definition. it is not yet clear how the figures are related in this part of the table!!

--Cosy-ch (talk) 15:29, 3 September 2012 (UTC)

Major Projects in Ethiopia and Rest of Africa Omitted[edit]

The following major projects have been omitted: Gilgel Gibe IV 2,000 MW - Ethiopia Grant Ethiopia Renaissance Dam 5,250MW - Ethiopia

This information is on this webpage (talk) 08:29, 6 January 2013 (UTC)

Not done: please provide reliable sources that support the change you want to be made. Wikipedia isn't a reliable source. - a boat that can float! (watch me float) 18:18, 11 January 2013 (UTC)
Grand Ethiopian added. I don't think Gilgel Gibe IV construction has begun yet. Can't find a source... Gibe III appears to be behind schedule.--NortyNort (Holla) 13:57, 1 May 2013 (UTC)


One major disadvantage is not mentioned: the risk that a hydroelectric dam generates far less power than expected as other hydrolectric hydroelectric dams are being built on that river by other countries and as these are not calculated in. This has been documented by the document submitted by R. Edward Grumbine and Maharaj K. Pandit. See

Include in article KVDP (talk) 11:53, 1 May 2013 (UTC)

It can go both ways. Upstream dams can regulate the flow of a river, allowing for a better capacity factor, or they can restrict flow during periods of drought, decreasing generation. I am thinking of a way to include both.--NortyNort (Holla) 13:53, 1 May 2013 (UTC)

Semi-protected edit request on 23 February 2014[edit]

can I edit the research that you people have added i am a professor at Harvard with new research. (talk) 23:27, 23 February 2014 (UTC)

Not done: this is not the right page to request additional user rights. You may reopen this request with the specific changes to be made and someone will add them for you, or if you have an account, you can wait until you are autoconfirmed and edit the page yourself. Jackmcbarn (talk) 00:21, 24 February 2014 (UTC)

Update Largest dams list[edit]

Xilodou Dam is now fully operational it should be added to the top 5 list kicking off the Grande Coulee... — Preceding unsigned comment added by (talk) 03:45, 4 August 2014 (UTC)

  • Yes check.svg Done Thank you, IP. Iselilja (talk) 19:01, 15 October 2014 (UTC)


Is "Underground" a method for developing hydroelectricity or rather an engineering consideration when selection the location of a hydroelectric power station? I am wonder if it belongs elsewhere in the article.--NortyNort (Holla) 21:09, 3 November 2014 (UTC)

Specific Countries[edit]

I have noticed that several countries have pages discussing Hydroelectricity specifically within their borders. Hydroelectricity_in_Canada, Hydroelectricity_in_Romania, Hydroelectric_power_in_New_Zealand, Hydroelectric_power_in_the_United_States, Hydroelectric_power_in_India, Hydroelectricity_in_Italy, Hydroelectricity_in_the_United_Kingdom, Hydroelectric_power_in_Kenya, for example. It seems like this information should at least be linked from this page, but I don't see that anywhere. Is there reasoning behind this? --Geneocide (talk) 19:51, 23 February 2015 (UTC)

In a nutshell, the pages you have linked above are largely about local hydroelectric power stations, policies, market share, etc of the respective country, whereas this article explains about hydroelectric power in general (methods of generation, efficiencies, advantages, etc etc. At least that's how it should be. :) Rehman 13:19, 24 February 2015 (UTC)
We have [[Category:Hydroelectricity by country]] which I've linked - a list would be the usual form but categories are easier to maintain. --Wtshymanski (talk) 15:59, 24 February 2015 (UTC)
Yes check.svg Done I'm satisfied. Great list. --Geneocide (talk) 16:48, 24 February 2015 (UTC)