Stand-alone power systems (SPS) generate and store electricity without being connected to the network.
They use a combination of decentralised generation and a battery to provide enough electricity to supply a single household. Currently the common configuration of SPS involves solar panels, a battery, an inverter (to convert DC to AC) and a diesel generator.
Solar panels generate the electricity from the sun, which is either used by the household at the time or stored in the battery to be used when it is dark or when demand exceeds what is being produced by the panels. The inverter converts the DC electricity from the solar panel and battery to AC which can be used by the household. In some cases when the battery has been completely discharged and the sun is not shining, the generator will start up to cover the household needs. The size of the system can be matched to the use of the household, so that most days of the year the battery and panels meet the electricity needs of the household, only on rare occasions would the generator be required.
SPS are a good solution in instances where the household is isolated and serviced by very long transmission and distribution electricity lines. Long lines in country areas are more exposed to wind, rain, vegetation and lightning, and are more likely to experience interference and customers to have a less reliable service. While the cost of an SPS is still quite high, in remote locations, they can be cheaper than more traditional methods of supplying electricity.
A Western Power led pilot project is currently underway in the Ravensthorpe area of Western Australia. Six systems were installed with rural customers in mid-2016 to investigate the costs and benefits of SPS. Please refer to the Stand-alone Power Systems Pilot project page for more information.