Enel - Visita alle Centrali

Basin

It is a water harvesting infrastructure intended to make this natural "fuel" technically exploitable for the production of electricity. It is generally of limited storage capacity.

Dam

It is a water harvesting infrastructure intended to make this natural "fuel" technically exploitable for the production of electricity. It is generally of large capacity and allows a seasonal deferral of water use by planning the hydro production capacities so as to minimize the costs of use of nuclear power plants.

Valve

Head-conduct (testa condotta) valves stop the water flow in case of over speed, for instance because the conduct itself brakes, and the valves are auto-triggering. Turbine safety valves, at (piede condotta) foot-conduct, intervene either automatically or manually to safeguard the integrity of the machine in case of abnormal operating conditions.

Penstock

The penstock is a large pressurized pipe carrying the water out of the upstream retention and into the downstream turbine, with the aim of transforming the potential energy held by water at a certain altitude, into kinetic energy used to spin the turbine placed at a lower altitude.

Transformer

The electricity produced by the alternator is sent to the transformer which has the function of heightening the tension and lowering the current, before sending it to the transmission network, to minimize power losses in the network depending on the square of the current.

Restitution Infrastructures

The purpose of the restitution infrastructures is to restore the river water taken for hydroelectric use.

Turbine

The turbine converts the potential energy of water into mechanical rotation energy. The rotational energy is transferred from the turbine to the alternator, mounted on the same axis of the turbine, which transforms it into electricity.

Alternator

The alternator transforms the rotation energy, transmitted by the turbine, into electricity. From the alternator, the electrical energy is transferred through appropriate cables (made of copper or aluminium) to the transformer.


	Hydroelectric

	Basin
	Dam
	Turbine
	Penstock
	Valves
	Restitution Infrastructure
	Transformer
	Alternator

A hydroelectric power plant converts the hydraulic energy of a watercourse, be it natural or artificial, into electricity. Generally, the functional scheme includes the infrastructure barrier, a dam or crossbar, which intercepts the stream, creating a tank or basin, where a layer of water is created.
Through works of abduction, canals and junction tunnels the water is piped into lading tanks and, through the penstocks, into the turbines through inlet (safety) valves and flow regulators (distributors), according to the energy demand. The water activates the turbines and flows out, ending up into the spillway channel through which it is returned to the river. In direct connection with the turbine, according to a vertical or horizontal axis provision, there is the alternator, which is a rotating electric machine capable of converting the mechanical energy provided by the turbine into electricity. The power thus obtained must be transformed, if it is to be transmitted over long distances. Therefore, before being fed into transmission lines, electricity passes through the transformer which lowers the intensity of the current produced by the alternator, but raises the voltage to thousands of volts. Once arrived at its intended destination, before it can be used the energy must pass into a transformer once more, only this time it’s intensity of current is raised and the tension lowered, so as to make it suitable for domestic purposes.

The term “small hydro” is conventionally used for hydroelectric systems with a capacity up to 10 MW, which differ from plants with a higher capacity. In fact, while the latter require large barrages (dams) and extended artificial lakes for water accumulation, small hydro systems practically work like the old wind mills (obviously as a high-tech version), without almost any environmental impact.
On the contrary, they offer several environmental advantages. First of all they supply energy without emitting polluting substances, dust particles, heat and greenhouse gasses, thus helping to reduce local pollution and global warming.
From the point of view of energy, even if small hydro plants do have a limited individual capacity, they can be installed in arrays that include several systems, thus making a significant contribution to the national electricity production. In fact, this is an energy source that is considered essential to achieve European emissions reduction targets by increasing the amount of renewables that is deployed.