An overview of Photovoltaic systems

Photovoltaic (PV) technology converts one form of energy (sunlight) into another form of energy (electricity).  PV systems consume no conventional fossil fuels, create no pollution, use no moving parts and last for more than 25 years with very little maintenance.  Photovoltaics can utilize both direct and diffused solar radiation and convert it into electricity.

A single conventional PV cell produces only about 1.5 Watts, so to obtain more power, groups of cells are usually connected together to form modules, and modules connect together to form arrays.  Photovoltaic systems have the capacity to generate anything from a few Watts to several Mega Watts.

PV systems can be placed onto roofs, on building facades, as well as in open spaces. 

Reasons for choosing a PV system

Ecological reasons

Photovoltaic is now a proven technology which is inherently safe, unlike some other forms of electricity generating technologies.  Over its estimated life, a photovoltaic module will produce much more electricity than used in its production – a 100W module will prevent the emission of over two tons of CO₂.  Photovoltaic systems make no noise and cause no pollution in operation, so is a clean and silent technology.  The PV system can be used for either centralized or distributed power generation.

Economic reasons

PV system prices decreased from around 3500 €/kWp in 2010 to 1450 €/kWp in 2020.  Cost reductions result from economies of scale and progress in research. The price of a photovoltaic system depends on the desired performance. This is measured in kilowatt peak (kWp). A system with an output of around 4 to 5 kWp is usually installed to supply a single-family home. Regardless of any location in the world, the PV system is an economically viable way to generate electricity from solar energy.  Even in cloudy conditions, PV systems have proven their reliability.

Major system components of a PV

• PV module –  converts sunlight into direct current (DC) electricity.
• Solar charge controller – regulates the voltage and current that comes from the PV panels into a battery. Also prevents the battery from overcharging, extending its lifetime.
• Inverter – An electrical device that changes DC to alternating current (AC).
• Battery storage – stores energy for supplying to electrical appliances when it is needed.
• The mounting system – is used to fasten the solar modules to the roof. There are two options for rooftop installations, on-roof installation and in-roof installation.  On-roof involves the solar modules being installed above the roof, while in-roof installation integrates the modules into the roofs surface.  PV systems can also be mounted on vertical façades or as a free-standing installation at ground level.
• Monitoring system – the performance of the PV system can be monitored. There are several options ranging from simple displays to wireless monitors and web-based data access.