A Stand Alone Power System (SAPS or SPS) is an electric system that works independently, without needing external power from the main electrical grid. SAPS can refer to either small systems designed to power a single household, or microgrids designed to power a small community. SAPS are also referred to as simply ‘off-grid’ electrical systems. SAPS are usually connected to a generator as a backup for increased energy consumption or extended bad weather.
Instead of paying huge connection fees and ongoing electricity costs, many people are now making the move to off-grid, particularly in regional areas.
Not all off-grid systems are in the middle of the Aussie outback, though; extended outages from bushfires, a growing desire to be green and a need to save money in the long term are all driving Australians to either choose hybrid systems or completely off-grid setups.
“Extended outages from bushfires, a growing desire to be green and a need to save money in the long term are all driving Australians to either choose hybrid systems or completely off-grid setups.”
How do off-grid SAPS work?
The system is made up of solar panels, an inverter, and one or more batteries, with most installations having backup power in the form of a diesel generator. This type of system is self contained, meaning it will create electricity during the day and store any excess energy in batteries for use at night time or on rainy days.
Your installer will work with you to create a system that is the right size to store enough energy to power your home around the clock.
What are the limitations of off-grid SAPS?
Modern off-grid systems can support the same electrical needs as a grid connected home. You can run air conditioning, normal appliances and cook, just as you would in a suburban home.
The only limitations come down to battery size; if there are visitors or long periods of bad weather, batteries may be fully drained. This is why generator backup is usually attached to off-grid systems, for the rare cases where additional power is needed.
You could install a battery bank big enough to cover all the power you would ever use, but the cost would be prohibitive. Like most things, economics and common sense come into play.
How much do off-grid SAPS cost?
The price of an off-grid system will vary based on a range of factors, including the number of people in your household, how many days of energy you want to store, and how long of a design lifetime you’re willing to pay for. Prices can range anywhere from $25,000 to $60,000 for the average installation.
Most people consider an off-grid system because it will be cheaper than the grid connector or a grid connection, or a grid connected system may not even be possible. Remember with an off-grid system there are no ongoing electricity bills. The only additional costs are for cleaning and maintenance, which are minimal for most quality systems.
How are off-grid solar system sizes calculated?
Your solar installer will look at your current usage, or in cases of installations on new buildings, will calculate usage based on industry standard usage of the appliances you’re planning to use. An important part of designing an off grid solar installation is ensuring the solar panels, inverter, and batteries cover all your needs, while still having spare capacity for night time and a rainy day.
While off grid batteries once offered enough storage for up to seven days of power, many systems now only include 24 hours of backup storage. One of the reasons for this is that older lead acid battery systems couldn’t have additional batteries added after installation; with modern lithium batteries, additional batteries can be added whenever a property owner either needs them, or feels it’s a financially viable option. Another reason is, in the past, seven days of power would be running one fridge and two small lights, so seven days of power was not a huge requirement. Todays’ Modern off grid systems are often expected to run the entire load of a modern but very different type of home.
Should your off grid system be roof or ground mounted?
The location where the system should be placed will vary based on a range of factors, including roof space, roof direction and budget.
Roof mounted systems are generally less expensive, as they make use of your existing roof surface. Ground mounted panels take up more space on your property, but provide easier access for installation and repairs, as well as more choices for the panel orientation to optimise your production.
Is orientation and angle more important for off-grid? Simply put, yes. It is preferable in off-grid to have a steeper angle than normal and face north to maximise winter production, although there are other options.
What ongoing maintenance do off-grid systems need?
If your property has wi-fi, smart monitoring can be installed to track the system’s production and consumption. Monitoring allows you to see how well your system is producing in real time, and identify most issues before they have a big impact on your production.
While older systems required monthly maintenance, especially for the battery bank, modern off grid systems require minimal upkeep. Cleaning the panels every six to twelve months and regular maintenance checks every two years will keep most off grid systems running optimally.
What are the next steps?
If you’re ready to create an off grid system, or simply have more questions about the process, Proven Energy’s CEC Accredited Installers can help. Proven Energy has many years of experience in designing and installing off grid systems to help our customers achieve energy independence.