Talk:Hydropower

message: I believe the section called "Hydroelectricity" has been misnamed.  It should be called "Hydroelectric Power," also a common term used for "Hydroelectric Power generation." In normal speaking, just; "hydroelectric," is often short for both terms. For example, see; "DINKEY CREEK HYDROELECTRIC PROJECT WATER RIGHTS DECISION." For example the first sentence is wrong: "Hydroelectricity is the application of hydropower to generate electricity."  But in fact; Hydroelectric Power (generation), or just "Hydroelectric" is the application of hydropower to generate electricity (or presumably; to generate "hydroelectricity"). 
However, the "Hydroelectricity can also be used to store energy..." is a correct usage, electricity is electricity when it comes to the end usage. Does the word; "hydroelectricity" even exist? Both www .merriam-webster.com/dictionary/hydroelectricity and en.oxforddictionaries.com/definition/us/hydroelectric#hydroelectric go to "hydroelectric." I write more arguments, with several URLs at Talk:Hydroelectricity#Merge. Thoughts? — Preceding unsigned comment added by 2602:306:CFCE:1EE0:1D6E:AFF9:2F27:2C4F (talk) 01:54, 21 March 2019 (UTC)
thread_title:  "Hydroelectricity" ?? 

message: https://amp.cnn.com/cnn/2019/07/04/us/alaska-record-heat-trnd-wxc/index.html
Could one include or refer to a List of countries on their installed Hydropower versus natural capacity? Wikistallion (talk) 09:29, 6 July 2019 (UTC)
thread_title:  Percentage of Installed Hydropower capacity and Natural potential by country 

message: — Assignment last updated by Ontarioeditor03 (talk) 20:00, 3 February 2023 (UTC)
replies: text: Hello, I will be editing and adding to this wiki article for an assignment. Today, I will be adding citations where I can and editing if required. Any editors that have worked on this page: do not hesitate to reach out about any concerns. Thank you. 65.95.186.89 (talk) 20:07, 10 February 2023 (UTC)
thread_title: Wiki Education assignment: ERTH 4303 Resources of the Earth

message: How does hydropower affect our world today? How often is it used? What is it used for? TrueLightMaster123 (talk) 19:16, 6 March 2023 (UTC)
replies: text: Would take several books to answer but you can start by reading the article. North8000 (talk) 21:11, 6 March 2023 (UTC)
thread_title:  How does hydropower affect our world today? 

message: As posted in "Calculating the amount of available power"
"The power available from falling water can be calculated from the flow rate and density of water, the height of fall, and the local acceleration due to gravity:
where
 (work flow rate out) is the useful power output (SI unit: watts)
 ("eta") is the efficiency of the turbine (dimensionless)
 is the mass flow rate (SI unit: kilograms per second)
 ("rho") is the density of water (SI unit: kilograms per cubic metre)
 is the volumetric flow rate (SI unit: cubic metres per second)
 is the acceleration due to gravity (SI unit: metres per second per second)
 ("Delta h") is the difference in height between the outlet and inlet (SI unit: metres)
To illustrate, the power output of a turbine that is 85% efficient, with a flow rate of 80 cubic metres per second (2800 cubic feet per second) and a head of 145 metres (476 feet), is 97 megawatts:"
----
Okay, you forgot to subtract the kinetic energy of the discharge flow.  For example, Hoover dam has a maximum head of 180 meters with a discharge flow of ~630 m^3/s at 140 kph.  140 kph = 38.9 m/s and using Ke = 1/2 mv^2, the discharge water needed to run the generators has a constant 1/2 * (38.9)^2 = 756 J/kg.  Doing the math on the 180 meter head,
A = 9.81 m/s^2
V = At
D = 1/2 At^2 = 180 m
Solving for t, t = ((180 m) * 2 / (9.81 m/s^2)) ^ (1/2) = 6.058 seconds
V = (6.058 s) * (9.81 m / s^2) = 59.43 m/s
and Ke/kg = 1765.8 J/kg
Subtracting the discharge energy of 756 J/kg max head energy leaves 1009.8 J/kg, meaning the discharge energy is 756/1765.8 = 42.8%  Unfortunately, it appears that 50% of the head divided by (100-42.8)% = 0.5 / 0.572 = 87.4% is being cited as the maximum efficiency vs the head for Hoover Dam, which is simply wrong.  Like any other heat engine, the maximum efficiency is 50%, and more like near 37% as with the various other power plant types.  Even with a discharge energy of 42.8%, I wouldn't expect the turbines to deliver more than that much power after losses in the pipes. Youjaes (talk) 08:17, 19 August 2023 (UTC)
thread_title:  Power calculation