16. REVISION OF POWER/ENERGY FROM A DAM
• Hydro (Potential) Energy available in a Dam 𝑃. 𝐸ℎ= 𝑚𝑔ℎ = 𝛒Vgh ;
where 𝛒 = 𝑑𝑒𝑛𝑠𝑖𝑡𝑦 𝑜𝑓 𝑤𝑎𝑡𝑒𝑟 = 1000 (𝐾𝑔
𝑚3), V= 𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑅𝑒𝑠𝑒𝑟𝑣𝑖𝑟𝑒 (𝑚3
), h= 𝐻𝑒𝑎𝑑 𝑜𝑓 𝐷𝑎𝑚 (m)
• Hydro-Power Available in a Dam (Joul or N-m)………… 𝑃ℎ =
𝛒Vgh
𝑡
= 𝛒gh∗Q
Where 𝑄 = 𝑉𝑜𝑙𝑢𝑚𝑒
𝑡 = 𝐷𝑖𝑠𝑐ℎ𝑎𝑟𝑔𝑒 𝑜𝑓 𝑊𝑎𝑡𝑒𝑟 𝑓𝑟𝑜𝑚 𝑎 𝐷𝑎𝑚 (unit; 𝑚3
𝑠)
• Mechanical / Turbine Power available / Produced From a Hydroelectric Station (in Watts) ;……….
• 𝑃𝑚 = 𝛒gh∗Q∗𝜼𝑡 = 1000 ∗ 9.8h∗Q∗𝜼𝑡
Where 𝜼𝑡 = 𝑇𝑢𝑟𝑏𝑖𝑛𝑒 𝐸𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦
17. .
• Mechanical/Turbine Power available / Produced From a Hydroelectric Station (in metric-
horsepower);
𝑃𝑚 =
𝛒hQ∗𝜼𝑡
75
Where 𝜼𝑡 = 𝑇𝑢𝑟𝑏𝑖𝑛𝑒 𝐸𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦
• Electrical Power Generated From a Hydroelectric Station (in KW);
𝑃𝑒 =
736 ∗ 𝛒hQ∗𝜼𝑡 ∗ 𝜼𝑒
75 ∗ 1000
Where 𝜼𝑒 = 𝐸𝑙𝑒𝑐𝑡𝑟𝑖𝑐𝑎𝑙/𝐺𝑒𝑛𝑒𝑟𝑎𝑡𝑜𝑟 𝐸𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 of Generating units of Power House
𝜼𝑡 = 𝑇𝑢𝑟𝑏𝑖𝑛𝑒 𝐸𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦
One metric horsepower as the power to raise a mass of 75 kilograms against the Earth's gravitational force over a distance of one metre in on1e second:[19] 75 kg × 9.80665 m/s2 × 1 m / 1 s = 735.49875 W
1 metric horsepower = 75 Kg*m/s = 736 W
1 metric horsepower = 0.736 KW
1 mechanical horsepower = 746 W
Note: In this formula for calculating the
power in metric horsepower there is no
“g” Note: In this formula
for calculating the
power in Watts there
is no “g” as
736
75
=
9.81 = 𝑔 hence
indirectly “g” is there
18. • Electrical Energy Generated From a Hydroelectric Station (in KWh);
𝐸𝑒 =
𝛒ghV∗𝜼𝑜𝑣𝑒𝑟𝑎𝑙𝑙
1000 ∗ 3600
Where V= 𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑅𝑒𝑠𝑒𝑟𝑣𝑖𝑜𝑟
• Electrical Power Generated From a Hydroelectric Station (in KW);
𝑃𝑒 = 𝛒ghQ∗𝜼𝑜𝑣𝑒𝑟𝑎𝑙𝑙
Where ;𝜼𝑜𝑣𝑒𝑟𝑎𝑙𝑙 = 𝜼𝑡 ∗ 𝜼𝑒
