I switched from a flat electricity tariff to time-of-use pricing two years ago and it’s saved me about $350 per year extra — on top of my solar savings. And I didn’t change anything about my energy usage. I just matched my tariff to my existing consumption pattern.

If you’ve got solar (and especially if you’ve got a battery), time-of-use tariffs can be significantly cheaper than flat rates. But they can also be more expensive if you’re not careful. Let me explain.

What time-of-use means

A flat tariff charges you the same rate per kWh regardless of when you use power. Typically 28-35 cents/kWh in 2026.

A time-of-use (TOU) tariff varies the price based on when you consume:

• Peak: 38-52 cents/kWh (typically 2pm-8pm weekdays)
• Shoulder: 22-30 cents/kWh (7am-2pm and 8pm-10pm weekdays, daytime weekends)
• Off-peak: 15-22 cents/kWh (10pm-7am, all day weekends for some retailers)

The exact times and rates vary by distributor and retailer, so check your specific offer.

Why TOU works for solar owners

If you’ve got solar, you’re naturally consuming less grid power during the shoulder and peak periods because your panels are generating. Your remaining grid consumption is concentrated in the evening (peak) and overnight (off-peak).

With a battery, you can shift even more consumption away from peak. Charge the battery during solar hours, discharge during the evening peak, and buy off-peak power overnight for any remaining needs.

The maths works like this. Take a household using 20 kWh/day from the grid:

On a flat tariff at 32 cents/kWh: $6.40/day = $2,336/year

On TOU with solar and battery:

• 5 kWh at off-peak (20 cents): $1.00
• 8 kWh at shoulder covered by solar: $0
• 5 kWh at peak covered by battery: $0
• 2 kWh at peak from grid: $0.90
• Daily total: $1.90 = $694/year

That’s a saving of $1,642 compared to flat tariff. Even without a battery, shifting consumption to solar hours and off-peak still saves significantly.

When TOU doesn’t work

If you don’t have solar and you use a lot of power during the evening peak (cooking, air conditioning, entertainment, EV charging), a TOU tariff could be more expensive than flat. The peak rate is typically 40-50% higher than a flat rate.

Also, if you can’t or won’t change your consumption patterns, a flat tariff is safer. TOU rewards flexibility. If you’re inflexible, it penalises you.

How to check if TOU is right for you

Step 1: Get your smart meter data (most distributors provide half-hourly usage data through their website).

Step 2: Map your actual consumption against the TOU time periods.

Step 3: Calculate your cost under both flat and TOU tariffs.

Step 4: Factor in your solar production and any battery capacity.

If you’ve got solar and your evening consumption is moderate (or you’ve got a battery), TOU will almost certainly save money. If you’re a heavy evening user without solar, stick with flat.

The best comparison tool is the government’s Energy Made Easy website, which lets you input your usage profile and compare all available offers in your area. Takes 10 minutes and could save you hundreds.

The demand tariff option

Some networks now offer demand tariffs, which charge based on your peak demand (the highest rate you pull power at any given time) rather than total consumption. These can benefit solar-plus-battery households whose peak demand is very low, but they’re more complex to optimise and I’d only recommend them for people who actively monitor their energy usage.

My setup

I’m on AGL’s time-of-use plan in SEQ. My Powerwall charges from solar during the day and discharges during the 3pm-9pm peak. Any remaining overnight consumption is at off-peak rates. My average daily grid cost is about $1.20, compared to $2.80 before I switched.

If you’ve got solar and you’re not on a TOU tariff, at least run the numbers. The switch takes a single phone call and could be the easiest money you save all year.