Introduction to solar electricity
Solar elecricty is electricity that has been generated by a solar pv (photovoltaic) system. Solar electricity is generated when particles of light energy called photos hit a photoelectric cell. These particles cause a chemical-physical reaction to take place within the material causing an electric charge to move through the photovoltaic cell. This electrical charge from the solar pv cell creates a voltage and a current flow resulting in useable electrical power. The solar cells which convert the light energy into solar electricity are connected together in a large number, normally around 60, in order to make a solar pv panel (sometimes called a solar module). These solar pv panels in turn are connected to other solar panels in a string in order to make a solar array.
Grid-connected solar electricity systems
In grid-connect solar pv systems these solar arrays will be connected to a solar inverter which will convert the direct current (DC) solar electricity into useful alternating current (AC) solar electricity. This AC solar electricity can then be utilised by electrical components within the property or exported back to the national grid.
Off-grid solar electricity systems
In off-grid solar pv systems there are two options. You can connect the solar array to a special type of off-grid solar inverter which will convert the DC solar eletricity into AC power that can be used by any AC appliances. However if you only have DC appliances, eg DC lights, you do not need to use a solar inverter and can draw DC electricity straight from the panels or battary. This saves on cost and is a bit more efficienct, however it makes the system a little less practical as most electrical appliances are designed to run off AC electrical supplies. You can have off-grid solar systems that have both DC and AC outputs.
Benefits of solar electricity systems
Solar electricity has a number of benefits over traditional types of electricity supply.