# Energy balance for a system

A hydropower plant uses a river to generate electrical energy. It has a drop of $107m$ and the flow rate of water is $275$ $m^3$/$s$. The flow rate of the water is the same in and out of the system.

I was asked to determine whether the system is open or closed. Ans: open

And to simplify the general energy balance for the system

$Q + W = ΔH + ΔE_k + ΔE_p$

here is where I am a bit uncertain as to how to simplify it, I think that only $ΔH$ can be removed from the equation since the enthalpy won't change. Is that correct?

And so if $Q + W =ΔE_k + ΔE_p$ how can I use that to calculate the maximum amount of electrical energy that can be generated?

• Why won't the formula for (gravitational) potential energy do $E=m*g*h$? That'd yield 289MW.
– Bart
Jan 24 '18 at 23:20