# Estimating hydro power station water usage

Hi all,
I'm trying to estimate the water used/released by a hydro power station using data from another station but I'm not sure if I'm
estimating it correctly.
The data that I've from Station 1 (which I'm trying to estimate) are: Weekly Generation = 2300MWh Discharge Capacity = 1000m3/s
Data from Station 2 (which I'm using to help with the estimate) are: Weekly Generation = 30000MWh Weekly Water Used = 16GL Discharge Capacity = 200m3/s
From Station 2 data, the generation per GL = 1875MWh/GL Using Station 1 generation data, the water used = 2300/1875 = 1.23GL However, since Station 1 has a larger discharge capacity, the water used should be adjusted by 1.23x1000/200 = 6.1GL Therefore, the weekly water used by Station 1 is 6.1GL
I'm not sure if my rough estimates make sense or are there some fundamental flaws in the approach. Any feedback is very much appreciated.
Thank you.
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snipped-for-privacy@hotmail.com pretended :

I would assume water pressure would have to be included...
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** Generally, hydro power stations are not water users at all - cos all the water is used for agriculture etc after it passes through the turbines.
PLUS - in many cases, the used water is regularly pumped back UP into the holding damn for later re-use.
This way, multi-level damns and hydo generators act as temporary energy storage systems for excess power generated by coal and nuke stations during periods of low demand, releasing it during times of high electricity demand.
..... Phil
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snipped-for-privacy@hotmail.com wrote:

The energy produced depends on head (as Arlowe indicated) as well as flow. Without information with regard to head-one cannot make a comparison. In addition, since the discharge capacity doesn't measure the actual discharge but is merely an upper limit- it isn't particularly useful unless you know that both plants are operating at full capacity. Plant 2 is not at full capacity on average and the energy to flow ratio implies that it is at a much higher head than unit 1.
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Don Kelly
snipped-for-privacy@shawcross.ca
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" snipped-for-privacy@hotmail.com" wrote:

Assuming that these two units are running for approximately the same amount of time per week, you can figure it out. If this assumption cannot be made, then you don't have enough data to solve the problem. The stations' MWh outputs and flow rates suggest that they are not similar in other respects.
Since you know the flow rate of Station 2 and the total water volume used, how many hours was it flowing?
--
Paul Hovnanian mailto: snipped-for-privacy@Hovnanian.com
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If this is homework, make (and state) some assumptions that others have suggested at, and calculate an answer.
Energy per unit time is actually all you need for a rough estimate of power here. Actually calculating energy will probably put you on the path.
If this is professional, assumptions are not good enough. Get some further info. You have some (gross) fundamental flaws in your analysis (that others here have suggested at). If you are told some further info is not available, and you are required do this analysis, tell them nothing or tell them whatever, and leave. This is a deal breaker.
j
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The relative efficiencies and characteristics of the various types of turbines are also involved. Pelton, Francis, Kaplan spring to mind. Head of water is the major factor in turbine selection and orientation.
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operator jay wrote:

There is insufficient information. Energy per unit time (a week) is given but without other information, it is not of any use. Design flow rates are given. Actual load variations are not given nor is the all important head information. You may have a 200Mw plant operating full time at 27 m^3/s, a 1360Mw plant operating 22 hours a week at 200m^3/s or anything in between. Head would be in the 680m range (bloody high). For plant1 - take a guess-even less information.
The best estimate of the water usage is plant 1 using 5 times as much water per week based on rated discharge capacities and equal time at any given % of rated discharge (a questionable assumption ). The energy per GL will be much lower than that of plant 2 so the plant 2. MW/Gl value is useless. it appears that the comparison is between a smaller low head plant and a very large high head plant- apples and oranges.
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Don Kelly
snipped-for-privacy@shawcross.ca