Variable speed hydroelectricity: a new approach for small&𝛍-Hydro.

When it comes to hydroelectricity, the key points are easily identified: performance, reliability and the best possible price (cost/revenue). In this case study we tell how we used variable speed turbines to achieve the desired results.

Since water mills and the first turbines in the 17th century, humans have always used water to produce energy.

Over the centuries, the goal has remained the same: maximize energy production and minimize maintenance time and costs.

In certain contexts, particularly with very small water jumps, fixed speed turbines have no longer proven adequate to meet the efficiency standards required by the market.

We therefore used our know-how and resources to develop an alternative solution.


In 2003, we were able to closely follow the start-up of the first forge with permanent magnet motors and inverters developed by FICEP, which was a great success.

We have seen the possibility of transferring the new concept from the industrial field to the hydroelectric one.
In concrete terms, our idea was to reduce the mechanical components and move the regulation to the electronic part.
In 2008 we participated in the realization of the first Italian plant of energy production with asynchronous generator and AFE+ inverter system.


The technology we have developed is applicable to all types of existing hydraulic machines (e.g. Pelton, Francis, Kaplan, Coclee)
The wide power range of the inverters allows it to be used from a few kW up to 2MW.

The variable speed system realized by AFE+INVERTER, controls the speed and the torque of the generator: in this way, it reduces the mechanical stress and increases the productivity and the longevity of the system.
Combined with a dedicated software, the system allows you to work with maximum efficiency in a wide range of jump/flow rate.

Other advantages:

⦁ simplifies the start-up procedure
⦁ Reduces start-up time
⦁ Cos or variable
⦁ allows to compensate harmonics
⦁ facilitates stand-alone applications
⦁ allows you to control multiple generators with 1AFE
⦁ eliminates mechanical stress due to parallel operation
⦁ increases production thanks to the exploitation of a wide range of jump/flow rate
⦁ reduces maintenance times
⦁ enables braking even in the absence of a mains supply
⦁ improves plant reliability thanks to the use of components derived from the industrial sector.


Screw conveyor systems were the first to use variable speed because, on small jumps, even small changes in level result in a discrete variation in the power generated.
The one in La Thuille is the first screw plant equipped with a variable speed system in Italy.
The previous plant operated with a turbine that was stopped in November to be restarted in May, the current plant instead is able to produce an average of 15-20 Kw even during the winter period.

Typology: on stream
N° augers: 1
Rated generator power: 90Kw
Installation: 2008
Grid connection: no


Efficiency of variable speed: comparing the efficiency of the inverter switched on and off, significant differences in production have been identified.
First Italian plant equipped with grid connection.
Initially the customer was dubious, but was satisfied immediately after observing the tests and measurements performed during the first summer of activation. Today the plant is left to work automatically.
Typology: on channel
N° augers: 1
Rated generator power: 45 KW
Installation: 2008
Grid connection: yes


This plant is very special, because it was built near an old mill and is an example of TWO GENERATORS CONTROLLED BY A SINGLE INVERTER.
Typology: on stream
N° augers: 2
Rated generator power:200Kw
Installation: 2010
Grid connection: yes

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