Steam Turbine Power Output

Specific work is per kilogram, so multiply by the kilograms per second and you have watts. A machine passing 10 kg/s, which is 36,000 kg/h or about 79,000 lb/h, at 614 kJ/kg develops 6,140 kW at the shaft. That single multiplication is the bridge between the thermodynamics and the electrical single line, and it is also the bridge back: divide a required 5 MW by the same 614 kJ/kg and the boiler has to deliver 8.14 kg/s of steam at the throttle conditions, which is what actually sizes the plant.

Be clear about where the boundary sits. This is shaft power at the coupling, before the gearbox, before the generator and before the excitation. A generator at 96% and a gearbox at 98% turn that 6,140 kW into about 5,780 kW at the terminals, and nameplates are usually quoted at the terminals, so comparing a calculated shaft figure against a nameplate without accounting for the drivetrain will always make the machine look bad. The other thing to keep straight is which kind of turbine you are costing. A back-pressure machine exhausts into a process header, so its steam is not wasted and the work is nearly free, while a condensing machine dumps its exhaust latent heat into the cooling tower and only converts a fraction of the fuel into work. Same equation, completely different economics.