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-- Main.MartinSevior - 10 Feb 2008
Estimate of annual water loss from Enhanced Geothermal energy.
Firstly we estimate the flow of water needed to maintain a 1 GW power station. We assume the water is extracted at 250 C and transfers 50 degrees C to heat exchangers. We further assume the efficiency of the heat engine used to convert the heat to electricity is 20% since the operating temperature (200 degrees C) is rather low.
The heat capacity of water is 4 Joules per degree C per gram.
The density of water is 1 gram per cubic centimeter.
Water Flow = 1x10
9x5/(50x4) = 2.5x10
7 cc/sec
This is 25,000 litres/sec
Of this we lose 5% so our water loss rate is 1,250 litres per second
Over the course of one full year this adds up to 1250*60*60*24*365 = 39420 MegaLitres
Which is approximately 40 GigaLitres
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