Is it worth going 100% off grid?

With a combination of PV and battery storage it is technically feasible to become independent from the grid. However, for the next few years at least, it would not make financial sense to do so when there is a grid connection available.

Using a typical Australian home as an example, we can investigate what it would take to become independent to the power grid and the costs involved.

The average Australian home uses approximately 16 kWh (units) with a peak load close to 1.2 kW. The way that power is used throughout the day is shown below. As can be seen, peak load occurs in the evening between 6pm and 8pm, whilst solar peak generation occurs at midday.

off grid

To meet the whole day’s energy requirements, the orange area in the graph above must equal the area under the green curve. However, this is not strictly true since inefficiencies in storing and then removing power from batteries means that the orange area must actually be about 10% more than the area under the green curve.

This scenario works if we assume that we get optimum sunlight everyday, but as we know ,there are days when there is intermittent cloud cover or even overcast the whole day. Therefore, the battery storage and PV should actually be designed to cover multiple days in the event that there is no generation available tomorrow. Typically stand alone systems are designed with 3 days of backup generation.

For a typical Australian home, the stand alone system specifications to make sure power is available around 90% of the year would be:

  • Approximately 9 kW of Solar Panels (some variation depending on location in Australia)
  • 96 kWh of Battery Storage
  • Approximately 4 kW Solar PV Inverter that is off grid capable and battery charging capable
  • Battery Charge controller if not included in selected inverter

This setup makes sure that even in winter, the solar system will produce enough power to charge the batteries to give 3 days worth of backup. Lead acid batteries were chosen since at the moment they are the most widely used in the market place, though this is likely to change over time. Since we are using lead acid the storage capacity was doubled to allow a 7-8 year lifecycle on the battery storage units.

The total cost of this system using current market prices is approximately $29,000. The shortest lived component are the batteries and will need to be replaced every 7-8 years, they represent $16,300 of the original $29,000 price tag.

At current battery storage costs, an off-grid system would not pay for itself ever since the batteries would need to be replaced before they’ve paid or themselves. Even then the reliability of this system would be far less than the reliability of grid supply in most areas of Australia. At present there is currently no advantage to going off grid when there is a good grid supply given the high cost, low reliability and large amount of physical space required to operate an off-grid system.

Where in your solar journey are you?

Download Your FREE Beginner’s Guide To Solar Power!

Beginners Guide to Solar Power

If you’re considering solar for your property or just looking to maximise the savings for your solar system, download a FREE copy of our "Beginner’s Guide To Solar Power".

Become an expert and better understand the ins and outs of solar power and solar PV systems for your property.

Includes detailed explanations and diagrams of the various types of solar systems and their parts, solar battery storage systems, Government incentives, expected ROI periods, finance, energy saving tips and more!

Download Your Free Copy Now!

Words From Our Customers

Latest news & blog


Please provide your email address so that we can send your free copy of "Beginner’s Guide To Solar Power".

Yes please, I would like to receive updates from Solar Market. Click to view our Privacy Policy.

Thank you

We have emailed your copy of "Beginner’s Guide To Solar Power".

If your guide does not appear in your inbox ensure that you have provided the correct email address or check your junk/spam folder.

This message will close in 10 seconds or

Close and back to page

Understanding Batteries

Off-Grid Systems

For some households a battery system can be of great benefit and minimise a home’s reliance on the grid. However, it’s important to understand for a battery to be useful your solar system needs to be generating excess energy for the battery to store, which you can then use at night or when the sun is not out.

When selecting a battery, you’ll want to invest in a system that is most suited to your home and can drive the best return on investment (ROI). Despite a larger upfront cost, a higher quality battery may significantly increase your ROI.

    Battery systems start from $6,000 and costs can vary greatly based on the following factors:

  1. Cycle Life-Time

    The number of times a battery can fully charge and discharge.

  2. Battery Power (kW)

    How fast it can be charged or discharged.

  3. Storage Capacity (kWh)

    The maximum amount of energy a battery system can store.

  4. Battery Management System (BMS)

    An electronic ‘smart’ system that gathers data and manages the battery ensuring it does not overload or operate outside of its safe functioning zone..

  5. Inverter

    Battery systems require their own inverter if your solar system does not have a hybrid inverter.

  6. 'All-In-One Unit’

    A system which includes the battery, BMS and an inverter all in one unit.

  7. Warranty

    Length of time or cycles the battery system is under guarantee.

  8. Blackout Protection/Backup

    It’s important to note this is not a common feature of a battery system and could cost thousands of dollars to include. Blackout protection not only requires additional components but also a specialised installation and rewiring. For grid-connected homes, the cost for blackout protection can outweigh the benefit.

Additionally, if your purpose for adding battery is to go Off-Grid and become completely independent from the grid you will need to ensure your solar system can generate enough energy to power your home and your battery system is large enough to store this energy. For homes in metro areas going Off-grid is not cost effective and is only recommended for those in remote areas with limited access to the grid. Off-grid solar systems with battery start at approximately $30,000.