Hydropower Engineering past question

The mean monthly flows of a river in a typical year are as follows [table]. The gross available head is 229 m, and the average head loss in transition is 12m. The efficiencies of the turbines, gearboxes and generators are 94%, 92% and 99% respectively. 10 m³/s of water must be left in the river for downstream users. Other data: Fixed cost: US$1200×10⁶; Variable cost (present worth value): US$500/kW; Energy price: US$48/Mwh for primary and secondary energy; Interest rate: 12%; Economic life of the project: 50 years. Determine the best installed capacity, firm energy, secondary energy, total energy and plant factor of a run-of-river plant. [10]