What is solar PV?
Solar PV (photovoltaic) refers to the collection of photons from the sun that are then converted into energy by a process called the photovoltaic effect.
This particular solar technology utilises solar cells generally constructed of silicon acting as a semiconductor. Sandwiched between conductive layers, the silicon atoms are bonded in such a way that prohibits the flow of current. By having two separate layers within the silicon cell, the electron movement leaves one layer positively charged, and one negatively charged.
As photons hit the silicon cells, they can knock electrons loose. An electric field between the silicon layers then directs the electrons through thin metal conductor strips.
This part of a solar energy system is referred to as the solar module.
From this point, a more standard or traditional system organises the available energy into usable and distributable electricity.
The main components of a solar energy system
To make up a full solar PV system, the linking of solar modules creates capacity.
Solar panels, or modules, are linked together by wires in what is called a string. At this point, junction boxes are used to combine all the wires from the string, before the main cable then runs to an inverter.
The inverter converts the electrical voltage from DC to AC and passes it through to a low voltage switchboard.
In the case of larger systems and solar farms, a HV switchyard then steps up the voltage with the use of transformers, and distributes the power into the electrical grid.
Efficiency and system losses
Solar photovoltaic (PV) systems are becoming more prevalent across Australia and the world, and efficiencies and technologies continue to develop however, most commercial solar cells are only about 15-20% efficient.
This does not necessarily constitute 80% lost energy, as the systems are designed with this in mind. It does however highlight the need to ensure peak capacity within the designed system itself.
So where can losses and inefficiencies occur? The answer is right across the system from the cells themselves to the electrical distribution system, both being susceptible to degradation and things going wrong.
These include damage to panels that may or may not be seen by the naked eye, poor wiring, bad connections, inverter component break down, switchboard and circuit breaker connections, SCADA monitoring issues, transformer oil degradation, and transformer wiring. All these can succumb to harsh Australian conditions.