Solar photovoltaic power. How a photovoltaic installation works
The name solar photovoltaic power is given to the method used to obtain electricity using photovoltaic panels. The photovoltaic panels, modules or collectors are formed by diode-type semi-conductor devices which, on receiving solar radiation, become excited and cause electronic triggers, which generate a small difference of potential at their ends. Coupling various photo-diodes in series allows higher voltages to be obtained in very simple configurations, suitable for powering small electronic devices.
On a larger scale, the direct electrical current provided by the photovoltaic modules can be converted to alternating current and fed onto the electricity grid, something which can be financially profitable itself and for which premiums are given in some countries to increase viability.
The process would be the following: the power is generated at low voltage (380-800 V) and in direct current. It is then converted into alternating current with an inverter. A transformer substation then converts the power to Medium Voltage and it is fed onto the grid of the utility company in the area.
In isolated environments, where little electricity is required and access to the grid is difficult, such as weather stations or communications repeaters, photovoltaic modules are used in combination with batteries or accumulators to provide an economically viable alternative.
Global sales of photovoltaic modules grew at an annual rate of 20% in the nineties. In the EU, the average annual growth rate is 30%, and Germany has 80% of the installed capacity.
Access to the electricity grid normally requires a series of permits from the administrative bodies and the authorisation of the utility company in the area. The utility company is obliged to provide a hook-up or connection point to the electricity grid.
PV Technology
The most important components of a PV system are the cells, which are the basic building blocks of the module and the elements which collect the sunlight; the modules, which bring a large number of cells together in one module; and for grid-connected installations, the inverters, used for converting the electricity generated into a form suitable for daily use.
Source:
Report “Solar electricity for over one billion people and two million jobs by 2020" EPIA.
