Solar system with battery

Solar systems only generate electricity during daylight hours which in Perth will normally average 8.8 hours but this varies seasonally and is a maximum amount of Sunshine. The Clean Energy Council endorses an average annual figure for Perth of 4.4 hours which is quite conservative but this is average sunshine hours over 12 months.


Any eligible surplus electricity generated from solar is fed-back into the electricity grid and the customer is paid a feed-in-tariff although the amount of the feed-in-tariff is relatively small. In Perth Synergy pays approximately 7 cents per kWh so there is minimal incentive to export the surplus generation and the economics of storage is now emerging as an real option to store that surplus electricity.


The objective for astute consumers must be to achieve energy self-sufficiency with battery-storage now becoming attractive as it becomes more affordable. Batteries simply store the surplus electricity generation from the solar system which is not consumed during the day which can then be used after sunset. While the cost of batteries remains relatively high, their cost is steadily reducing along with pay-back periods so the economics is tipping toward the time to buy phase. Industry watchers expect 70% of Australian households to have battery-storage by 2030.


Technology is enabling energy choices that will provide consumers with more control over their energy needs and electricity costs. It is relatively straightforward to install battery-storage to existing solar systems and many system owners are opting for Hybrid inverters so they are battery-ready once their cost reaches that cost-benefit tipping point. Battery-storage will be the next big wave for the solar sector, households and eventually businesses.


Electricity Flow Image from Rooftop Solar System to Battery and Grid in Day and Night

Battery storage advantage

Energy Self-Sufficiency - Reduced Grid Dependency

Battery-Storage will increase energy self-sufficiency, with batteries discharging the evening energy needs of households and businesses the surplus electricity generated during the day. Solar system size and battery-storage capacity are two factors that will determine the extent of energy self-sufficiency and assuming the adoption or uptake of batteries reflects the growth of solar in Australia, the figures will be impressive.


Monitoring devices provide information about electricity generation and are becoming integral to solar systems, with the data accessible via an app and your smart-phone. It provides a real-time summary of everything the system owner needs to know about their solar system operations during the day including energy demand or consumption as well as any surplus being diverted to battery-storage. This data will enable better management and control of energy demand and cost.

Power Black-Outs

In the event grid-supply electricity is interrupted, a blackout occurs and power is essentially cut-off, even if the residence or business premises have an existing solar system. A solar system that incorporates battery-storage will have access to stored electricity during power blackouts, they will have energy security.

Smart Plan Tariff Utilisation

If you are on a smart electricity plan which has off-peak tariffs, battery-storage can be of further benefit financially, providing additional electricity cost savings. Smart-Plans invariably have a higher electricity rate for specific time (peak or shoulder) periods and lower electricity rates referred to as off-peak. Battery-storage allows the system owner to plan when they make use of the stored electricity which of course would be when the cost of grid electricity is at the peak rate per unit or kWh.


In most parts of Australia, the feed-in-tariff or rate paid for surplus electricity fed-into the grid is relatively small and is unlikely to increase significantly in the future. Therefore, exporting surplus electricity into the grid should be minimised. Battery-storage solar systems will divert any surplus electricity generated once the energy load or demand has been met, achieving peak period tariff savings greater than feed-in tariff credits or revenue. It is all about maximising electricity self-consumption, which in turn maximises cost reduction.