Introduction
When comparing solar plans, most households look at the feed-in tariff (FiT) rate first. But the daily supply charge can have an equal or even bigger impact on your bill. Understanding how these two charges interact helps you make better choices when comparing retailers.
Key Definitions
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Daily supply charge: A fixed fee (e.g. 90c/day) just to stay connected to the grid. It applies regardless of how much energy you use or export.
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Feed-in tariff (FiT): The credit you earn per kilowatt-hour (kWh) of unused solar energy exported back to the grid.
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Import tariff: The rate you pay for each kWh of electricity drawn from the grid when solar is not enough.
For an overview of FiTs by state, see Compare FiT by State.
Worked Example 1 — Low Daily Charge, Average FiT
Retailer A charges a 70c/day supply fee and pays 10c/kWh FiT.
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Daily fixed cost: $0.70 × 30 days = $21/month
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Exporting 300 kWh at 10c = $30 credit
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Net offset: $30 – $21 = $9 gain
Use the FiT Savings Calculator to run this against your household’s numbers.
Worked Example 2 — High Daily Charge, Higher FiT
Retailer B charges a $1.20/day supply fee but pays 15c/kWh FiT.
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Daily fixed cost: $1.20 × 30 = $36/month
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Exporting 300 kWh at 15c = $45 credit
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Net offset: $45 – $36 = $9 gain
Even though FiT is higher, the savings are the same as Example 1 because of the higher fixed charge. Check current Retailer Rates to see this trade-off.
Worked Example 3 — When Supply Charges Cancel Out FiT
Retailer C charges $1.50/day supply fee and pays 8c/kWh FiT.
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Daily fixed cost: $1.50 × 30 = $45/month
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Exporting 300 kWh at 8c = $24 credit
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Net impact: $24 – $45 = $21 extra cost
This shows why chasing the highest FiT without checking supply charges can backfire. The Rate Change Tracker helps you monitor when these conditions shift.
Why This Matters
FiTs can look attractive on paper, but a high daily supply charge can wipe out those credits quickly. The best plan balances a reasonable supply charge with a fair FiT and import tariff. To see which balance works for your location, try the Postcode Estimator or the Solar
FAQs
Q1. Why do supply charges vary so much between retailers?
Supply charges reflect both network costs and retailer pricing strategies.
Q2. Can low-usage households be worse off with solar?
Yes, if exports are small and supply charges are high, credits may not cover fixed costs.
Q3. Should I prioritise a low supply charge or a higher FiT?
It depends on your solar generation and usage. For many, a lower supply charge brings more stability.
Q4. How do TOU plans affect supply charges?
They usually don’t — supply charges are fixed, while TOU applies only to usage and FiTs.
Conclusion
When comparing solar plans, don’t just chase the highest FiT. Always weigh it against the daily supply charge, because fixed fees can outweigh export credits. By using the right calculators and comparing multiple retailers, you can find the plan that maximises your solar savings.