A time-of-use (TOU) tariff charges a different price per kilowatt-hour depending on when you use it — cheap overnight, expensive in the early-evening peak. Most NSW households are now on, or being moved toward, TOU pricing, and understanding how it's structured explains why solar and battery systems are increasingly sized and configured around timing, not just total generation.
<div class="tldr" style="border:1px solid #cbd5e1;background:#f8fafc;padding:16px 20px;border-radius:8px;margin:24px 0;"> <strong>Quick answer</strong> <ul> <li>TOU splits the day into peak, shoulder and off-peak bands.</li> <li>Peak (often ~2–8pm or 3–9pm weekdays) can run 40–60% above the flat rate; off-peak can be under half.</li> <li>Solar generates most at midday — the cheapest window — while peak hits after sunset.</li> <li>A battery captures midday surplus and discharges it during the peak, which is often a battery's biggest ROI driver.</li> </ul> <em>Updated August 2026 for NSW residents. Rates and windows vary by retailer and network — confirm your own plan.</em> </div>
Electricity networks are built to handle peak demand — the highest simultaneous draw across the grid, typically in the early evening as people get home, turn on air conditioning, cook dinner and run appliances, often while solar generation is already tapering off. Building and maintaining infrastructure for that peak is expensive, and that cost is recovered disproportionately from usage during peak windows.
Retailers and networks structure TOU tariffs to reflect this: cheaper when demand and wholesale cost are low, higher when demand is high. It aligns what you pay with what your usage actually costs the system to serve — and, deliberately, incentivises shifting flexible usage away from peak windows.
While exact windows and rates vary by retailer and network, a standard NSW plan is generally structured around three bands.
<div style="overflow-x:auto;"> <table style="border-collapse:collapse;width:100%;min-width:520px;"> <thead><tr style="background:#eef2f7;"> <th style="border:1px solid #cbd5e1;padding:8px;text-align:left;">Band</th> <th style="border:1px solid #cbd5e1;padding:8px;text-align:left;">Typical window (varies)</th> <th style="border:1px solid #cbd5e1;padding:8px;text-align:left;">Relative price</th> </tr></thead> <tbody> <tr><td style="border:1px solid #cbd5e1;padding:8px;">Peak</td><td style="border:1px solid #cbd5e1;padding:8px;">Late afternoon–evening (~2–8pm or 3–9pm weekdays)</td><td style="border:1px solid #cbd5e1;padding:8px;">Highest — often 40–60% above the flat rate</td></tr> <tr><td style="border:1px solid #cbd5e1;padding:8px;">Shoulder</td><td style="border:1px solid #cbd5e1;padding:8px;">Remaining daytime/early evening</td><td style="border:1px solid #cbd5e1;padding:8px;">Moderate</td></tr> <tr><td style="border:1px solid #cbd5e1;padding:8px;">Off-peak</td><td style="border:1px solid #cbd5e1;padding:8px;">Overnight (often ~10pm–7am)</td><td style="border:1px solid #cbd5e1;padding:8px;">Cheapest — sometimes under half the peak rate</td></tr> </tbody> </table> </div>
Some retailers also apply demand tariffs on top of, or instead of, TOU pricing — charging based on your single highest half-hour of demand in a billing period. These are becoming more common for higher-usage households and reward flattening peak demand, not just shifting it in time.
This is the crux of why batteries matter under TOU pricing. Solar panels generate most in the middle of the day — typically 10am to 3pm — which is exactly when TOU rates are lowest (or, at times of very high grid-wide solar penetration, even negative on the wholesale market). Peak pricing hits in the early evening, precisely when household solar is falling toward zero.
Without a battery, a solar-only household exports its midday surplus at a low feed-in tariff — now trending toward roughly 3–4c/kWh in NSW from 1 July 2026 — and then buys back power at peak rates a few hours later. That's the least favourable possible trade: selling cheap, buying expensive. (See Understanding Feed-in Tariffs.)
A battery lets a household store midday solar surplus — instead of exporting it for a few cents — and discharge it during the evening peak, substituting battery-stored solar for peak-rate grid electricity that might cost several times as much per kWh. This is sometimes called "tariff arbitrage," and under current NSW TOU structures, with the peak/off-peak spread as wide as it is, it's often the single biggest driver of a battery's return on investment — arguably larger than the value of self-consuming solar during the day alone.
Batteries can also charge from cheap off-peak grid power overnight if a household's usage pattern warrants it, and some inverter and retailer combinations allow more advanced strategies — charging ahead of a forecast high-price event, or participating in a Virtual Power Plant.
Because TOU pricing rewards timing as much as total generation, correctly sizing a battery (and configuring its charge/discharge schedule) against your household's actual peak-window usage matters as much as the size of your solar array. A battery too small to cover the evening peak, or configured to discharge at the wrong time, captures only a fraction of the available saving.
It depends. With a battery that shifts solar into the peak window, TOU can pay off substantially; without one, a household with inflexible evening usage may be worse off. Check your usage pattern before switching.
Storing cheap midday solar in a battery and using it during the expensive evening peak, avoiding peak-rate grid import — often a battery's largest single saving under TOU pricing.
See what your specific tariff structure and usage pattern mean for battery sizing and savings with Blue Energy Solar's savings tools, or call 0421 458 217.
