Hydroelectric power plants

The hydropower plants represent 40 years of our history. They are majestic and modest as well. Sometimes they are artworks and sometimes thay are pure concentrates of technology: our passion since 1980.

Frosio Next progetta e realizza impianti idroelettrici ad acqua fluente. Consulenza su progettazioni e manutenzione di centrali idroelettriche.

General features

Caratteristiche, tipologie e le funzionalità degli impianti idroelettrici, la più antica fonte di energia rinnovabile. -1

Run-of-river hydropower plants

The run-of-river hydropower plants don’t have storage basins. This type of plant, very common for low costs and limited environmental impacts, uses the natural water course, without the opportunity to adapt the energy production to the market needs.

Caratteristiche, tipologie e le funzionalità degli impianti idroelettrici, la più antica fonte di energia rinnovabile. -2

Storage hydropower plants

Equipped with upstream storage basin, this type of plant is realized with a dam or using natural basins. The presence of the basin allows to regulate the derived discharges, independent of the water availability: it leads to energy production which fits the market needs.

Caratteristiche, tipologie e le funzionalità degli impianti idroelettrici, la più antica fonte di energia rinnovabile. -3

Pumped storage hydropower plants

The pumped storage hydropower plants are characterised by the presence of upstream and downstream storage basins which can invert the flow. They are strategic plant due to the fact that they are able to guarantee the stability of the electricity grid and they allow to quickly compensate for the fluctuations of other renewable resources.

Typical hydropower schemes

High head plants

High head plants

Hydropower installations with head above 100 m areconsidered high head plants. Traditionally, they consist of intake works, headrace channel, forebay, penstock and powerhouse. Theri constraction is generally easy and quite cheap, except for the presence of possible storage basins of hughe dimensions. The biggest construction issues are related to their typical position: generally, they are located in mountain areas, usually far from the urban centers and from the consumption areas.

Low head plants

Low head plants

They are characterised by heads below 100 m. They are common in Italy and worldwide. Thanks to their versatility, they are usuallty inserted in mixed schemes. A standard scheme doesn’t exist and, especially for small capacity, several plant solutions can be adopted to limit the construction costs related to the construction of the derivation and headrace works. In fact, they derive high flows which are typical of this kind of plant.

Hydropower plants accross existing weirs

Hydropower plants accross existing weirs

They are characterised by very low head (3-5 m) and they are built across existing weirs. In this type of plant, the intake coincides with the water restitution, reducing the environmental impact related to the subtention of the riverbed. In the last few years, there has been a strong growth of this type of plant and several plant’s solutions have been developed with the aim of reducing the costs (especially the costs of the civil works) guaranteeing high efficiency.

Hydropower plants on environmental flow

Hydropower plants on environmental flow

This type of plant refers to very small hydopower plants inserted in existing schemes, with the aim of exploiting the residual hydropower potential in aqueducts, irrigation channles or greater hydropower plants. These plants are site specific and they are characterized by unique layout due to the fact that they have to coexist with existing works.

Typical components of a hydropower plant

Intake

The intake is the interface between the river and the headrace channel.

Headrace works

Its aim is to bring the derived water from the intake to the beginning of the penstock, in the high head schemes, or directly to the powerhouse, in the low head schemes.

Penstock

The penstock is a typical hydraulic work of the high head schemes, made up of pipes which bring pressurised water to the turbines.

Powerhouse

In a hydropower plant, the powerhouse hosts the generation groups and other electromechanical equipment.

Tailrace

After passing through the turbine the water returns to the river trough a canal called a tailrace.

Types of turbines

PELTON

Pelton turbines are impulse turbines where one or more jets convert the water pressure into kinetic energy.

BANKI/CROSS FLOW

This impulse turbine is used for a wide range of flows (between 20 l/s and 10 m3/s). It can operate with heads between 10 and 200 m.

FRANCIS

Francis turbines are reaction turbines, with fixed runner blades and adjustable guide vanes, used for medium heads. In this turbine the admission is always radial. This type of turbine is the most widespread and holds the record of unitary installed capacity.

KAPLAN

Kaplan turbines are axial-flow reaction turbines; generally used for low heads.

COCLEE

These turbines are used for very low heads and small capacities. They are characterised by quite low costs thanks to their easy construction.

Other areas of expertise

Hydraulic engeenering works

The importance of the hydraulic engineering works is now undeniable and there are various solutions that can ensure the safety of our towns and our areas.
Thanks to our experience in the field, we propose the solution that best suits the context.

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Dams and civil works

Arch, gravity, concrete, earth or rockfill dams: they are some of the many types of dams! The dams are the type of works that best reflect the level of competence achieved.
They are the perfect example of multidisciplinarity and a concentrate of the various civil works we are able to realize.

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