Stand-alone Photovoltaic Systems
Grid-connected Photovoltaic Systems
When the electricity grid is available but electricity from a clean source (solar) is desired, solar panels can be connected to the grid. Provided that sufficient panels are placed, the appliances in the house/building will then run on solar electricity. A grid-connected solar electricity system basically consists of one or more solar panels, an inverter, cables, the electric load and a support structure to mount the solar panels
Stand-alone photovoltaic systems (SPS) are used when no electricity grid is available. A battery is needed to ensure the availability of electricity at night or at periods with little bright sunlight. Stand-alone systems are often used to cover the electricity needs of a housedhold. Small systems cover the most basic needs (lighting and sometimes TV or radio), larger systems can also power a water pump, wireless phone, refrigerator, electric tools (drill, sewing machine, etc) and a VCR. The system consists of a solar panel, a control unit, battery storage, cables, the electric load and a support structure.
Hybrid Systems
Solar electricity back-up systems are used when electricity from the grid is available but unreliable. The solar electric back-up system can be used to provide electric power during periods when there is no electricity from the rid (blackouts). A small solar electric back up system can provide electric power to cover the most important needs such as lighting, computer and telecommunication (phone, radio, fax, etc) equipment. A larger system can be sized to power the fridge during a black out. The more power the appliances take and the longer the black outs normally last, the larger the solar electric system needs to be. Although a handy person can do much of the work, all electric connections must be made by a trained professional
