4. Environment

4.1 Drive turbines

• The highest falls (several hundred meters) are equipped with Pelton turbines. Originally, these turbines, whose ancestor was the mill wheel, had a horizontal axis and a single jet. The number of jets then multiplied as power levels increased, and today these turbines are generally vertical-axis, with the number of jets reaching 5 or 6 at the highest power levels (of the order of 200 MW).

• Francis turbines are used on a wide range of medium-sized...