Hydro turbine Efficiency

Actually the turbine method is very efficient. The Turgo turbine is as much as 90per cent efficient at removing the energy from liquid. Large-scale hydro plants using Francis Turbines can be as large as 95percent effective (see here).

Electrical generators typically utilize high RPMs, so you need rate also torque to operate a vehicle it round. Minimal RPM generators tend to be feasible also, but less efficient. Energy available in hydro energy originates from the 'head' (level drop) while the 'flow' (amount of liquid per second). So in low-head circumstances, you will need alot more flow to get the exact same energy. In such cases, you won't get high pressures (and for that reason large speeds) without gearing (performance losings there too), so a water-wheel method is feasible. In fact there are low-head generators like the way you describe - the bucket-and-belt strategy - along with more conventional low-head turbines.

Low-head circumstances tend to be harder to engineer (economically), because high flows are expected and so the whole set up (networks, bearings, generators, etc.) needs to be much more resilient and bigger. It is cheaper (per kW of generating capacity) to utilize high-head circumstances with smaller/faster turbine tires at greater pressures.