Very Low Head

Hydraulic turbines are bulky by nature. Indeed, to generate even relatively moderate output (on the order of some hundred  kW) under heads lower than 3 m, turbine flow rates can exceed 10 m3/s. This results, for water supply works, in large civil engineering structures proportioned to the collected flow rates.

To make their equipment more competitive, hydraulic turbine constructors have always endeavoured to optimize their product by increasing performances, in particular by a permanent research oriented towards the decrease of the runner diameters. This runner diameter decrease has led to water intake and outlet structures of a dimension such that their economical implementation is impossible when the head is too low.

The basic idea of the VLH concept goes against this tendency by aiming at decreasing, as much as possible, intake and outlet structures by increasing the size of the turbine runner diameter and by integrating therein a self-supporting structure which ensures all the functions of a conventional facility.




VLH Range

Since the VLH concept only addresses a relatively narrow range of heads and flow rates, it is perfectly well adapted to being totally standardized.

Range of products

A range of machines provided in 5 diameters (3,150-3,550- 4,000- 4,500- 5,000 mm) has thus been designed.

Net head range

The net head range addressed by the VLH concept extends from 1.5 to 3.4 m. (up to 4,5 m in customised reinforced version).
The reinforcing of the supporting structure has enabled to bring the acceptable net head up to more than 4.5 m for the three smallest models in the range.


Flow range

The range of flow rates of the equipments extends from 10 to 27 m3/s, and the addition of several units on a same site enables considering very high total equipment flow rates.

Power range

This results in a range of power per unit from 100 to 500 kW (at the network level). It is estimated that below 100 kW, the expected profitability will not be achieved, and the studies performed up to now demonstrate that above 500 kW, it is more profitable to install several smaller machines rather than a single large one.


Low Head

VLH is able to operate
with very low heads,
from 1,5 to 4,5 meters.

Civil work reduction

Allows a sensible reduction of civil works costs. The quantity of concrete is reduced and no external buildings are necessary.

Fish Friendly

Tests executed on eels, salmons, trouts and other species demonstrate unprecedent fish friendliness .

High Efficency

VLH achieves high efficiencies thanks to its modern design including direct driven generators and variable speed.

Environmental Impact

VLH displays submerged turbine and generator. There is no significant environmental impact. The turbine is noiseless and there are no vibrations.

Product Standardization

A standard product distributed on different sizes. The price is affordable. Low implementation and delivery schedules.