Photovoltaico: What is it?

The photovoltaic effect discovered by Albert Einstein is the physical principle at the base of the functioning of the photovoltaic modules: those elements that stricken by the radiation produce electric power.
The photovoltaic technology allows to directly transform sunlight into electricity. It exploits the so called photovoltaic effect that is based on the properties of some semiconductor materials, among which the silicon, that, properly processed, are able to generate electricity if stricken by solar radiation, without using any kind of fuel.
The most elementary device able to carry out this conversion is the photovoltaic cell; more cells assembled together and connected in series in a single structure form the photovoltaic module. The tension in the clamps of a photovoltaic module is determined by the number of cells connected in series while the current is determined by the current supplied by every single cell.
A set of modules, electrically connected between them, forms the photovoltaic system that, together with other mechanical, electric and electronic components, creates a photovoltaic system.
There are two types of photovoltaic systems:

1.”Stand Alone” Systems, are autonomous systems, that means systems completely independent from the power grid and that rely only on solar power to meet the energy demand of any load and entity. They are usually built in remote areas where it could be difficult to connect to the power grid or where the connection would be too expensive.

2. "Grid Connected" Systems: system connected to the utility provider grid, able to exchange electric power with the grid. During daytime the system generates electricity for its own energy demand and in the moment in which it is not directly used, it supplies power to the public distribution network. In periods of lack of sun the energy produced is taken from the grid, generating a continuous interchange between the photovoltaic system and the grid, without any energy storage. It is possible to monitor this continuous exchange with a pair of meters, dividing the incoming energy from the outgoing.

This system is the only one that gives access to valuable financing.

Download the ENEA's informational brochure

Photovoltaic Energy - Sustainable development
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