There are two types of photovoltaic plants: those that are connected to the grid and those that are not. Within the former there are two sub-classes:
Photovoltaic power plants: all the energy produced by the panels is fed into the electricity grid.
Generator with self-consumption: part of the electricity generated is consumed by the producer (in a dwelling, for example) and the rest is discharged onto the grid. In addition, the producer takes from the grid the energy needed to meet their demands when the unit does not supply enough.
These grid-connected installations have three basic elements:
Photovoltaic panels: these are groups of photovoltaic cells mounted between layers of silicon that capture solar radiation and transform the light (photons) into electrical energy (electrons).
Inverters: they convert the direct electrical current produced by the panels into alternating current, suitable for consumption.
Transformers: the alternating current generated by the inverters is low voltage (380-800 V), so a transformer is used to raise it to medium voltage (up to 36 kV).
Off-grid facilities operate in isolation and are often located in remote locations and on farms to meet lighting demands, support telecommunications and run pumps in irrigation systems. These isolated plants require two additional elements to function:
Batteries: to store the energy produced by the panels that is not used when it is generated, the stored energy can then be used when needed.
Controllers: to protect the battery from overcharging and prevent inefficient use of the battery.