The capacity benefit of hydro
Since the hydro’s energy is limited to 2,400 MWh, if it’s base loaded it must run at (2,400 MWh) / 24h = 100 MW.
So the production cost for base loading the hydro around-the-clock is C(2,000 - 100) x 8h + C(600 - 100) x 8h x 2 = {0.1 x (1,900)2 - 100 x 1,900 + 85,000} x 8h + {0.1 x (500)2 - 100 x 500 + 85,000} x 8h x 2 = 256 k$/h x 8h + 60 k$/h x 16h = 2.048 M$ + 0.960 M$ = 3.008 M$.
So the base-loaded hydro saves 248 k$.