How Solar Power Works
Most Australians are connected to the National Electricity Grid, a network of electric cables and transformers that links power generating stations to your home. A Grid-Connect Solar Photovoltaic (PV) System acts as a mini power station on your roof, feeds power to your home, and surplus power back to the Grid. Solar systems for domestic homes generally consist of solar panels, an inverter and a metering system.
Most solar power systems use PV modules (panels) installed on a rooftop to create and collect energy from sunlight. An inverter converts the Direct Current (DC) electricity generated by solar panels into Alternating Current (AC), the form of electricity conventionally used in homes. The system is connected through a meter to the grid. Solar systems allow you to use your solar power when it is generating electricity during the day and put any excess back into the grid. As soon as you need more electricity than your system can generate, your electricity will automatically be supplied from the grid. At night, your house draws energy from the grid.
Solar panels
Solar cells are produced from thin wafers of silicon. When light falls on the cells an electric current is produced. A collection of solar cells connected together forms a module.
Most homes or commercial buildings will need around 10 square metres of unshaded, north-facing roof space to mount the modules for a 1kW solar system. Ideally the modules should be tilted towards the sun at around 30 degrees to maximise the solar collection.
Inverters
You will need an inverter to convert the direct current (DC) power collected by the solar panels into power for your home, or power to send back to the electricity grid. It can be placed inside or outside your home and can give you information about the amount of electricity being produced by your system.
Meters and the grid
You still need to be connected to the electricity grid to ensure that you have electricity at night-time when no solar energy is being collected. A meter will also enable you to sell back excess electricity. A new digital smart meter will be fitted to your system as part of the solar installation.
For safety reasons, when your electricity supply from the grid is interrupted, your solar PV system must automatically and immediately turn off.
Greenhouse gas savings
Solar power is a zero-emission electricity source. One megawatt hour (MWh) of solar-derived electricity avoids approximately one tonne of CO2.
In Australia
As at the end of July 2009, more than 41,000 homes across Australia have solar PV installed. At the end of 2008 we have over 100 megawatts (MW) of solar PV capacity installed nation-wide. This is almost 0.7% of the global installed capacity.
Solar PV has a long history of supplying reliable ‘off grid’ power to remote and regional Australian communities. Around 70 percent of all PV installations are currently off-grid. However, with the introduction of recent government incentives, the number of grid-connected solar PV installations has grown and now accounts for about 30 percent of Australia’s total installed capacity.