The term “solar panel” is used to describe two completely different technologies, both of which generate energy from sunlight, and both of which are packaged in the form of panels:
– a photovoltaic module is used to generate electricity
– a solar thermal collector is used to generate heat (generally hot water)
A solar cell or photovoltaic cell is a device that converts light energy into electrical energy. Sometimes the term “solar cell” is reserved for devices intended specifically to capture energy from sunlight, while the term photovoltaic cell is used when the light source is unspecified. The field of research related to solar cells is known as Photovoltaics.
Solar electric panels contain many photovoltaic cells electrically connected and packaged behind glass for mechanical protection and electrical insulation. The modules are usually connected together in an array and with other components such as a mounting frame and an electrical inverter (for on grid) or a charge controller and batteries (for off grid).
In addition to solar panels, a photovoltaic (PV) system requires a mounting structure to tilt panels toward the sun, an inverter to convert panel-generated direct current (DC) into appliance-friendly alternating current (AC), battery storage to compensate for unfavorable weather conditions, and a charge controller to regulate battery operation.
Renewable Energy Systems
Grid-tie or Grid Feed systems are interconnected to the utility grid. Wired with a synchronizing inverter, grid-tie systems can feed surplus electricity back into the local grid. This can act as an infinite storage system, eliminating the need for batteries. This system provides financial benefits as long as the government provides rebates (pay for) power supplied to the utility grid.
Stand-alone systems designed for remote areas, villas and resorts. Because they do not rely on the electrical grid, off-grid systems require batteries to offset lesser power production due to prolonged periods of inclement weather.
In Hybrid Power Systems the power is generated from a combination of power sources such as solar PV, wind generator, hydro generators and may use a LPG, petrol or diesel generator when the renewable energy generator is not meeting the power demand.
Supplemental systems are power systems that, as the name implies, supplement the utility grids supply by power generated from renewable energy sources. This results in a reduced power bill and in cases where the tariff increases as usage increases, the system may be designed to ensure higher tariffs are not incurred. These systems normally incorporate some form of UPS system.