SPS (Stand-alone Power System)

Written and checked by the Energy Merchants desk · Reviewed 3 October 2026

SPS stands for stand-alone power system. It is a self-contained supply, normally solar panels, a battery and often a backup generator, that powers a property without a connection to the distribution grid. The older name was remote area power supply.

There are two main versions. A customer who has never had grid power may buy a privately owned SPS. In the second version, a network operator replaces an ageing section of rural poles and wires with an SPS it owns and maintains for the customer, which can be cheaper than rebuilding the line. Victoria and Western Australia have been active in this area.

In practice

Installers meet SPS in off-grid homes, farms and remote tourism sites. Design is different from a grid-connected job because the battery is not an optional extra. It carries the load overnight and the generator fills the gaps in a long cloudy spell. Sizing starts with the load, in kilowatt-hours a day, and the worst weather you must cover.

For certificates, solar panels on an off-grid system can still be eligible for STCs, because the Small-scale Renewable Energy Scheme is about the generation equipment, not whether the site has a grid connection. Eligible small generation units are covered under small generation unit (SGU). Battery STCs under the Cheaper Home Batteries Program work differently, and a stand-alone battery without VPP capability or CEC approval does not qualify. Check eligibility against the program rules and the CEC approved battery list before you quote on an off-grid battery.

Common confusion

An SPS is not a backup system on a grid-connected house. A backup power gateway lets a connected home island during a blackout. An SPS never had the grid to begin with, or has given it up.

It is also not the same as a microgrid, which serves several customers and is closer to an embedded network.

Read more on STC trading and in the glossary.