Home battery storage
A battery lets you store solar electricity during the day and use it during the expensive evening peak. Here's what that means for your bills and your household.
What does a home battery do?
A home battery sits between your solar system and the grid. During the day, when your panels produce more than your house needs, the surplus charges the battery instead of exporting to the grid. In the evening, when the sun sets and electricity prices peak, the battery discharges to power your home — avoiding those expensive grid imports.
Think of it as a buffer that lets you time-shift your solar production to match when you actually need it.
How it works in practice
A typical day with solar and a battery looks like this:
- Morning (6am–9am) — Solar production is low and building. The house draws from the grid for any shortfall. The battery holds its charge for later.
- Midday (9am–3pm) — Solar production peaks. The house runs entirely on solar, and the surplus charges the battery. Once the battery is full, any remaining excess exports to the grid.
- Afternoon/evening (3pm–10pm) — Solar production drops and household demand rises (cooking, heating/cooling, lighting). The battery discharges to cover as much of this demand as possible, avoiding high peak-rate grid imports.
- Overnight (10pm–6am) — The battery is typically depleted. The house draws from the grid at the cheaper off-peak rate (if on a time-of-use tariff).
Typical battery sizes and costs
| Usable capacity | Typical cost* | Suits |
|---|---|---|
| 5 kWh | $5,000–$7,000 | Small household, covers 3–4 hours of evening usage |
| 10 kWh | $9,000–$13,000 | Average household, covers most of the evening peak |
| 13.5 kWh | $12,000–$16,000 | Tesla Powerwall size — larger home or blackout protection priority |
| 15+ kWh | $14,000–$20,000+ | High-usage household, full evening coverage, or off-grid aspirations |
* Fully installed prices as of late 2025. Costs are falling year on year. State rebates (where available) can reduce the upfront cost significantly.
Popular battery brands in Australia
Tesla Powerwall
13.5 kWh usable. The most recognisable brand, with strong software, weather-aware charging, and built-in backup gateway. Widely available but can have long wait times.
BYD
Modular systems from 5–22 kWh. Lithium iron phosphate (LFP) chemistry for long cycle life. Popular with installers for flexibility and competitive pricing.
Enphase
Modular 5 kWh units that stack to your needs. Pairs naturally with Enphase micro-inverter systems. AC-coupled, so easy to retrofit to existing solar.
Alpha ESS
Integrated battery and hybrid inverter systems. Competitive pricing and strong Australian distribution. Available in 5–20 kWh configurations.
When a battery makes sense
A battery isn’t automatically a good investment for every household. The payback depends heavily on your usage patterns and tariff structure.
Good candidates
- High evening electricity usage (cooking, heating, EV charging)
- On a time-of-use tariff with a big peak/off-peak price gap
- Want blackout protection (grid outages are a concern)
- Planning to add an EV and want to maximise solar self-consumption
- State battery rebate available (e.g. Victoria, South Australia)
- Future-proofing for time-varying tariffs and VPP income
Less compelling
- Already low electricity bills (less savings to harvest)
- On a flat-rate tariff with no peak/off-peak difference
- Limited solar production (small system or heavy shading)
- Low evening usage (already consuming most solar during the day)
- Expecting to move house within a few years
Honest payback assessment
Virtual Power Plants (VPPs)
A Virtual Power Plant is a network of home batteries that work together as if they were a single large power station. When the grid needs extra power (typically during evening peaks or heatwave demand surges), your battery can discharge into the grid — and you get paid for it.
VPP programs are offered by several Australian retailers and networks. The typical deal:
- You keep control — the VPP operator can only discharge your battery within limits you agree to, and your home’s needs always come first.
- You earn credits — typically $0.50–$2.00 per kWh discharged during VPP events (much more than a standard feed-in tariff), or a fixed monthly payment.
- Events are infrequent — most VPP events happen on a handful of extreme demand days per year, so the impact on your daily battery use is minimal.
VPPs represent a growing income stream for battery owners and help stabilise the grid during stress events. As battery uptake grows, VPP participation is becoming a significant factor in the financial case for batteries.
Next step
If you’re charging an EV, that’s likely your household’s single biggest new electricity load. Smart charging can slash the cost.
Next: EV Charging for Less →