Question

A river flowing steadily at a rate of 175 m3 /s is considered for hydroelectric power generation. it is determined that a dam can be built to collect water and release it from an elevation difference of 80 m to generate power. determine how much power can be generated from this river water after the dam is filled.

Answer 1

137200000 watts or 137200 kilowatts The formula for power is P= dhrg Where P = Power in watts d = density of water (~1000 kg/m^3) h = height in meters r = flow rate in cubic meters per second, g = acceleration due to gravity of 9.8 m/s^2, Plugging in the known values, we get P = 1000 kg/m^3 * 80 m * 175 m^3/s * 9.8 m/s^2 P = 80000 kg/m^2 * 175 m^3/s * 9.8 m/s^2 P = 14000000 kg m/s * 9.8 m/s^2 P = 137200000 kg m^2/s^3 P = 137200000 watts or 137200 kilowatts The above figure assumes 100% efficiency which is impossible. A good efficiency would be 90% so the actual power available would be close to 0.90 * 137200 = 123480 kilowatts