I compared my electricity plan after getting solar and a battery. Here's what I learned.

The three parts of your electricity bill (and why they all matter)

Most people focus on the rate that feels most relevant to their situation:

• No solar? You look at usage rates.
• Got solar? You zoom in on the feed-in tariff.
• Trying to cut costs? You notice the daily supply charge.

But your bill is the result of all three working together.

Usage rates. This is the cents per kWh you pay for the electricity you import from the grid. It applies when:

• The sun is not shining (or is not strong enough)
• Your battery is empty
• Your usage is higher than what your solar or battery can cover

Even with solar and a battery, most households still import some power, especially at night, on cloudy days, or when everyone is home cooking, heating, cooling and running appliances.

A difference of a few cents per kWh can add up quickly if you import a few hundred kWh each quarter.

Daily supply charges. This is the fixed daily amount you pay just to be connected to the grid. You pay it every day, whether you use 1 kWh or 1,000 kWh.

It covers things like:

• Grid connection
• Metering
• Administration and billing

Daily supply charges vary a lot by state, distributor and plan. Some are under a dollar a day. Others are well over $1.50. Over a year, that difference can be hundreds of dollars, regardless of how much solar you have.

Solar feed-in tariffs. Your feed-in tariff (FiT) is what your retailer pays you for the surplus solar you export to the grid.

Typical solar plans in Australia often sit around the mid-single digits per kWh, though this varies by state, retailer and plan type. Many plans with higher FiTs come with higher usage rates or supply charges, which can wipe out the benefit.

Importantly, you only get the FiT on the kWh you export. If you use most of your solar yourself (or store it in a battery), your export volume might be modest, so a slightly higher FiT will not move the needle much.

Why the highest feed-in tariff is not always the cheapest plan

Here is the trap I fell into: I saw a plan advertising a "high" solar feed-in tariff and assumed it would save us the most money. What I did not notice at first glance was that:

• Its usage rate was higher
• Its daily supply charge was higher
• Our export volume was not large enough to offset those extra costs

A simple illustrative example

These figures are not real advertised plans. They are just made-up numbers to show the principle.

Plan A – "High FiT" plan

• Daily supply charge: $1.40 per day
• Usage rate: 35c per kWh
• Solar feed-in tariff: 12c per kWh

Plan B – "Balanced" plan

• Daily supply charge: $0.95 per day
• Usage rate: 28c per kWh
• Solar feed-in tariff: 6c per kWh

Now imagine a typical solar and battery household over a year:

• Electricity imported from the grid: 2,500 kWh
• Solar exported to the grid: 3,000 kWh
• Daily supply charge applies every day (365 days)

Plan A annual cost:

• Supply: $1.40 × 365 = $511
• Usage: 2,500 kWh × $0.35 = $875
• FiT credit: 3,000 kWh × $0.12 = -$360

Estimated annual net cost: $511 + $875 - $360 = $1,026

Plan B annual cost:

• Supply: $0.95 × 365 = $347
• Usage: 2,500 kWh × $0.28 = $700
• FiT credit: 3,000 kWh × $0.06 = -$180

Estimated annual net cost: $347 + $700 - $180 = $867

Even though Plan A has double the feed-in tariff, Plan B is about $159 cheaper per year in this example, because its lower usage rate and lower daily supply charge more than offset the smaller FiT.

If your household imports more power, or exports less, the gap can be even bigger. If you export a lot more, the high-FiT plan might start to win, but only if the other charges do not climb too high.

The key takeaway: you cannot judge a solar plan by the feed-in tariff alone.

What changed when I compared properly

Once I stopped fixating on the FiT and started comparing plans on all three components, a few things became obvious:

My usage pattern matters more than I thought. We still import a fair bit in the evenings and on cloudy days. A lower usage rate saved us more than a slightly higher FiT ever could.

Daily supply charges are silent budget killers. A 40 to 50 cent difference per day looks small, but over a year it is $150 to $180, no matter how much solar or battery capacity you have.

Export volume is often smaller than people assume. With a battery, we store more of our solar for evening use instead of exporting it. That means fewer kWh earn the FiT, so a "big" FiT applies to a smaller pool of exports.

The cheapest plan is the one that matches your household. A plan that is great for a house that exports heaps of solar all day might be terrible for a house that uses most of its solar onsite or relies heavily on grid power at night.

When I ran the numbers properly, the "boring" plan with moderate FiT, lower usage rates and a lower daily supply charge came out clearly ahead for us.

How to compare solar electricity plans without getting tricked by headlines

If you are on solar (with or without a battery), here is a practical way to approach plan comparisons:

1. Gather your own data

From your last few bills, note:

• kWh imported (bought from the grid)
• kWh exported (solar sent to the grid)
• Daily supply charge
• Your current usage rate(s) and FiT

You do not need perfect data. Recent bills are enough to see your pattern.

2. Look at all three numbers together

For each plan you are considering, write down:

• Daily supply charge (cents or dollars per day)
• Usage rate(s) (cents per kWh). Check if there are peak, shoulder or off-peak rates.
• Solar feed-in tariff (cents per kWh), and whether it is capped or uncapped

Then ask:

• If I import X kWh at this usage rate, how much does that cost?
• If I export Y kWh at this FiT, how much credit do I get?
• What does the daily supply charge add up to over a year?

You are aiming for an estimated annual net cost, not just a "looks good" headline rate.

3. Think about your solar and battery behavior

Consider:

• Do you export a lot in the middle of the day, or do you use most of your solar onsite?
• Does your battery shift your exports to different times?
• Are you home during the day, or is the house mostly empty while the sun is shining?

Households that export a lot may benefit more from a higher FiT. Households that import more, or store solar in a battery, often benefit more from lower usage rates and supply charges.

4. Use a tool that shows the whole picture

This is exactly why I built the Money Detective Solar Energy Plan Comparer. You can upload a monthly or quarterly electricity bill and the comparer will automatically fill in your usage rates from the bill. It then calculates how much you would pay if your usage stayed the same, and shows what your bill would be at the end of each period under different plans with the same household usage.

That way, you can see side by side how different combinations of usage rates, daily supply charges and feed-in tariffs affect your total cost, without having to do the math yourself or guess what your usage might be.

It is not a replacement for checking current offers in your area, but it is a practical way to understand which type of plan structure is likely to suit your household.

You can try it here: Money Detective Solar Energy Plan Comparer

The mindset shift that actually saves money

The biggest lesson from my own experience was not about finding some secret "hack". It was about changing how I compare:

From: "Which plan has the highest feed-in tariff?"

To: "Which plan gives me the lowest overall cost, given how my household actually uses and exports power?"

Once I started thinking in terms of total annual cost, not just one standout rate, the choices became much clearer. And the savings were real, without changing our lifestyle or second-guessing every appliance.

If you have recently got solar or a battery (or you are thinking about it), do not stop at the headline FiT. Pull out a recent bill, look at all three components, and run a few simple scenarios. You might be surprised which plan actually comes out on top for your home.

About the author

Alex Buhot is the founder of Money Detective, an Australian household money website focused on making everyday finances easier to understand and manage. She creates practical tools and resources to help households compare their bills, organize their money and make more informed decisions about everyday expenses.