Photovoltaic installations connected to mains
The electric current generated by a photovoltaic installation can be discharged to the electricity grid as if it were a power station. The electricity consumption is independent of the energy generated by the photovoltaic panels. In these cases, the user continues to buy the electric energy that consumes the distributor company at the established price and also owns an electric power generating facility.
The most common powers are 2.5 and 5 kW or multiples of 5 to 100 kW. There are larger facilities, but only by companies or research centers, as they are amortized over longer periods.
Some applications of these systems are as follows:
- Installations on roofs, terraces, etc. Of dwellings that have a connection to the electrical distribution network: The roof surface is used to install modular systems with easy installation.
- Integration in buildings: It consists of the replacement of conventional architectural elements by new architectural elements that include the photovoltaic element, and that therefore are power generators (façade coverings, curtain walls, parasols, pergolas, etc.)
Production plants: These are industrial applications that can be installed in rural areas not used for other uses ("solar farms", "energy cooperatives") or superimposed on large decks of urban areas (car parks, commercial areas, etc.) Eur-lex.europa.eu eur-lex.europa.eu
Elements of a grid-connected photovoltaic solar system
Photovoltaic cells, usually of black or dark blue color, are associated in groups and protected from the elements, forming photovoltaic modules. Several photovoltaic modules together with the electrical cables that connect them and with the elements of support and fixation, constitute what is known as photovoltaic generator.
The photovoltaic generator is the element in charge of transforming solar radiation into electrical energy. This electricity is produced in direct current, and its characteristics depend on the energy intensity of the solar radiation and the ambient temperature.
The inverter is the element that transforms the electrical energy (direct current) produced by the panels in alternating current of the same characteristics as the one of the electric network. There are different types of inverters, but it is advisable to choose it depending on the size of the installation to be made.
The photovoltaic generator needs two meters located between the inverter and the grid, one to quantify the energy generated and injected into the network for billing, and another to quantify the small consumption (<2 kWh / year) of the PV inverter in Absence of solar radiation, as well as guarantee for the electric company of possible consumptions that the owner of the installation could do.
The electricity consumption of the building will be made from the grid, with its own meter, this being an independent installation of the photovoltaic system.
Last review: March 21, 2017