If you’ve got a home battery or you’re thinking of installing one, you’ve probably heard about Time-of-Use tariffs—often referred to as TOU tariffs. These are electricity pricing structures where the cost of power changes throughout the day depending on demand. And while that might sound a bit complicated, it’s actually a big opportunity. When paired with solar and a battery, TOU tariffs can help us slash our energy bills, improve our battery’s value, and shift even further away from grid reliance.

Let’s unpack how TOU works in Australia, how to take advantage of it, and how your battery can play a major role in reducing your power costs.

Understanding Time-of-Use Tariffs

Unlike flat-rate electricity plans, Time-of-Use tariffs break the day into different pricing periods. Most commonly, it looks something like this:

• Peak (when demand is highest, usually in the late afternoon and evening)
• Shoulder (moderate demand, typically morning or early afternoon)
• Off-peak (overnight or weekends, when demand is lowest)

Energy used during peak periods is the most expensive, while off-peak power is much cheaper. If we’re smart about when we use grid electricity—or better yet, store cheaper power and use it when prices spike—we can get far more value out of our battery system.

Charging With Cheap Power, Discharging When It Counts

One of the best ways to take advantage of TOU tariffs is through energy arbitrage. That’s a fancy term for a simple idea: charge your battery when electricity is cheap (off-peak) and use it when electricity is expensive (peak).

If you’ve got solar panels, you’re probably already doing part of this. You’re storing excess solar energy during the day and using it in the evening. But on cloudy days or in winter, your solar might not generate enough. In that case, you can program your battery to top up from the grid during off-peak hours—say, 2 am to 6 am—when rates are low. Then your battery can supply that power later in the day when the cost of electricity jumps.

Even if you don’t have solar, this setup still works. Some Australians are installing batteries specifically to load up on cheap overnight power and use it during peak periods. It’s not as green, but it’s still effective in reducing bills and reducing reliance on high-cost electricity.

Let Automation Do the Heavy Lifting

Modern batteries and hybrid inverters are smart. Many of them let you set schedules or rules that align your battery use with TOU pricing.

For example, with inverters from brands like Fronius, SolarEdge, or Sungrow, you can program the system to:

• Only discharge between 5 pm and 9 pm (peak window)
• Reserve a portion of battery capacity for emergency backup
• Avoid discharging during shoulder or off-peak periods

Some platforms go a step further and make those decisions automatically. They use algorithms that learn your household’s usage patterns, weather forecasts, and price signals to make real-time decisions. Systems like Tesla Powerwall with “Time-Based Control” or Enphase’s Ensemble energy management can help squeeze every dollar out of your setup.

If you’re using a battery with a user-friendly app, you can often change these settings yourself, so you’re in control. Just keep in mind that automatic modes usually need a few weeks to learn your habits properly.

Maximising Solar Self-Consumption

Solar panels produce the most energy during the middle of the day, but that’s not when most of us use the most power. TOU tariffs tend to give us lower feed-in rates, too—so if you’re exporting solar to the grid during the day, you might only get 5 to 10 cents per kilowatt-hour. But when you’re buying that energy back during peak time, it might cost 40 to 50 cents.

That’s where batteries come in.

By storing your excess solar and using it when grid prices are highest, you’re effectively increasing the value of every unit of energy your system produces. You’re not just avoiding buying expensive power—you’re avoiding sending cheap power back to the grid.

This strategy, often called “solar shifting,” is the single most important way to reduce your energy bills if you’ve got solar and TOU pricing.

Balancing Backup and Savings

One thing to be aware of: if you rely on your battery for backup power during outages, you may not want to drain it all during peak pricing windows. Most batteries let you reserve a percentage of their capacity for backup—say, 20 or 30%. That way, if a blackout hits in the middle of the night, you’re not left in the dark.

The trade-off is that a higher backup reserve means you have less capacity available for arbitrage and TOU optimisation. You’ll need to find the balance that fits your needs—whether it’s maximum savings or maximum energy security.

Do TOU Strategies Really Pay Off?

Several Australian households have already shared their success stories.

For instance, homeowners with a 13.5 kWh battery system in Victoria found that simply switching from a flat-rate plan to a TOU tariff and enabling smart discharge scheduling cut their bills by over 50%. In some cases, this halved the estimated battery payback time—from over 14 years down to less than 9.

Those kinds of savings can vary, of course. It depends on your usage pattern, solar generation, the TOU structure in your area, and how well your battery is configured. But the general trend is clear: when your battery is aligned with your tariff, you get far more value from it.

A Few Tips for Fine-Tuning Your Setup

If you want to get the most from your battery under TOU pricing, here are a few practical steps:

First, check your current electricity plan. Not all TOU tariffs are the same. Some have a much higher peak rate but very cheap off-peak, while others are more balanced. You’ll want a plan with a decent spread between high and low pricing—that’s what creates the savings opportunity.

Second, review your energy usage. If you tend to use a lot of electricity in the evening (like running dishwashers or aircon), you’ll benefit more from TOU optimisation than someone who’s home all day.

Third, make sure your battery or inverter supports advanced scheduling. Not all systems do, so if you’re shopping for a new one, ask your installer about this feature.

And finally, don’t set and forget. Monitor your battery’s performance for a month or two. Use the app or portal to track when it’s charging, discharging, and how much money it’s saving you. That way, you can tweak the settings if needed.

Time-of-Use tariffs can turn your battery into a powerful money-saving tool. By charging during cheaper off-peak periods—whether from your solar system or even from the grid—and discharging when electricity is most expensive, you’re using energy smarter, not harder.

With the right configuration, TOU pricing makes your battery more valuable and brings you one step closer to energy independence. Whether you’ve got a Tesla Powerwall, an AlphaESS, or a Redback system, the key is aligning your battery behaviour with your electricity plan. And once that’s dialled in, the results speak for themselves.