Increasing the Power Output of a Turbine

[Caledonian14]

I have a hydro turbine spinning at 62.746RPM and it produces 170.195Nm of torque.
It generates 1.1183kW but ideally, I would like to step it up to at least 4.5kW.
Is this possible using a gearbox and if so how can it be done?

 

[Baluncore]

Welcome to PF.
First you must identify the factors that limit power now.
Power is torque * RPM. A gearbox changes the ratio of torque to RPM, but it will probably not change the power output.
To get 4 times the power you need to increase the flow or the height by a factor of 4, or the water speed by a factor of 2.
You might also consider 4 separate systems.

 

[CWatters]

You can't do it with just a gearbox as that would violate conservation of energy. Gearboxes can never be more than 100% efficient, they always have losses.