A hydroelectric power generating facility depends on the energy from water flow to create the energy it delivers to the electric power grid. Typically this energy is described in units
of kilowatts, that is, thousands of joules delivered per second. Louisville Gas and Electric has a hydro power station on the Ohio River that supplies a fraction of the area's power
needs. Its capability now is 100 MW, $10^8$ watts, when there is sufficient water flow. You can read about it here
Upgrades at LG&E and KU's Ohio Falls Hydroelectric Generating Station now complete
Following the idea of conservation of energy, the electrical electrical energy that the station produces must come from the kinetic energy of the water. That in turn comes from the high
difference, simply the potential energy of water dipping a height "h" is mgh. The output energy is always less than energy available because the transfer of the kinetic energy of
the water after it drops to the rotating turbine and then to generate electricity is not 100% efficient.
This is a low-head dam, holding back the river where the Falls of the Ohio once dropped about 36 feet. That's the operating "head" of this dam. It is typically 36 feet, 11 meters.
How many kilograms of water per second must flow through the dam to generate 100 MW of power?
$10^8$ kg/s
$1.1 \times 10^{10}$ kg/s
930,000 kg/s
280,000 kg/s
