Going off-grid can be a tempting proposition. For some, it’s the thought of completely cutting out the electricity companies and never receiving another bill. For others, its the planet-friendly idea of reducing your household carbon footprint to practically nothing.
With energy-dense lithium-ion battery storage and smart energy management, going off-grid could be up to 80% cheaper than previous estimates based on older systems predicted. At these levels, off-grid solar and battery storage is close to competitive with diesel generation over the whole system lifetime.
So what is needed to go completely off-grid, and is it worthwhile today?
Completely off-grid requires overcapacity
While many Australian buildings use solar-plus-storage to produce most of their own electricity, the majority of them still maintain a grid connection. There are two key benefits – income from feeding excess electricity back into the grid and continued power when the sun doesn’t shine.
When going off-grid, it’s not enough to just have enough solar and battery storage to meet your household’s daily energy needs. Without grid backup, prolonged rainy periods and winter weather could leave your building in the lurch. If your household has a daily energy consumption of 10 kWh (quite low for a modern family home!), you would need around 30-40 kWh of energy storage to be safe off-grid.
Consider also the size of PV system that your property can support. While more expensive upfront, larger solar panel arrays keep your batteries topped up and ready to provide power. If you have limited roof space, outbuildings and sheds can be used to mount additional panels.
Location, Location, Location
Some places are just easier to be grid independent than others. Darwin naturally gets more hours of sunshine than Melbourne, and mounting your solar panels on a large open north-facing roof will produce far more juice than tree-crowded southern-facing property.
If you get a lot of sunshine and consume most of your electricity during the day, you won’t need as much storage capacity to go off-grid. Another factor to consider is seasonal variation. Some cities, such as Brisbane, have very similar levels of sunshine hours in both winter and summer. In comparison, Adelaide has over 50% less sunshine in winter. In the first case, your solar and storage system would be suitable year-round – in the second, the system would need to have extra capacity for the winter that would not be used in summer.
Regardless of falling equipment costs, a solar and storage system suitable for complete grid independence is a large upfront investment. Even a relatively modest daily consumption level of 8-10 kWh would require close to a 10 kW solar system and 30 kWh of storage – a far cry from the 3 kW, 4 kW and 5 kW PV systems that are most commonly chosen for residential use.
It’s true, solar panels have a long lifespan – 25 years for newer models – and it’s important to look at the whole lifetime cost. However, it’s unlikely you would recoup the value of investment in the case of a move.
At current levels of energy consumption and solar and storage prices, our opinion that going off-grid is not worthwhile for the majority of those in Australia, Australian Capital Territory and Canberra. Those with low daily energy consumption and consistent, year-round sunshine are a potential exception.
One important exception is in the case of rural or isolated properties – a solar-plus-storage is cost-competitive with diesel generation and much more planet friendly. While the off-grid dream is unlikely to be worth the cost, solar panels and battery storage are still an excellent way to slashing household electricity costs by reducing peak-time electricity consumption.
Want to know more about solar battery storage, going off-grid and reducing your electricity bills? Australian Smart Group install solar panels, battery energy storage and smart meters – and we’re always available to answer your questions.