Plug-In Solar for NSW: Solar Sponge Tariffs + Battery Arbitrage
How the NSW Solar Sponge (super-cheap 10am–3pm) tariff transforms the economics of a small plug-in + battery setup.
NSW retailers introduced Solar Sponge tariffs in 2023 — a super-cheap daytime rate (typically 6–10c/kWh from 10am–3pm) designed to soak up midday solar surplus on the network. For a household with a portable battery, this is a massive arbitrage opportunity: buy cheap at 10am, sell back to yourself at 34c during peak evening.
The tariff basics
Typical NSW time-of-use tariff (Ausgrid network) in 2026:
| Period | Rate |
|---|---|
| Peak (5-8 PM) | 55–65c/kWh |
| Shoulder (7-5 AM, 8-10 PM) | 25c/kWh |
| Off-peak (10 PM-7 AM) | 20c/kWh |
| Solar Sponge (10 AM-3 PM) | 6-10c/kWh |
That 6-10c mid-day rate is often cheaper than typical FiT export rates. Households with a battery can charge from grid during the sponge window, then discharge into evening peak.
The plug-in + battery play
- 1kWh portable battery (EcoFlow DELTA 2, Anker SOLIX): $600–$800
- 400W portable panel: $250–$400
- Solar Sponge daily charge: 1 kWh × ~8c = 8c cost
- Peak displacement: 1 kWh × 60c = 60c value
- Net daily arbitrage: ~50c
- Annual saving: ~$180 from arbitrage + ~$100 from solar self-consumption = $280/year
Payback: ~3 years on the combined kit. This is the strongest economic case for portable solar-battery combos in AU.
Retailers currently offering Solar Sponge in NSW
Amber, OVO Energy AU, Origin (with add-on request), AGL EVo (for EV owners), Powershop.
For AS/NZS 4777 context see the regulatory plain English guide.
- portable power station lifepo4 — current AU inventory
- LiFePO4 batteries, CEC-recognised panels, MC4 hardware
- Fast AU warehouse shipping via Amazon Prime
See how much plug-in solar could save you — with real data for your postcode.