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Understanding your solar savings


So now you have solar, and your electricity bill has arrived. This is a bit exciting! How much did your solar save you? You flip over the bill and see over the last quarter you’ve saved a massive …

80 bucks?! What the …!?
Honey, our solar system has only saved us a measly eighty dollars! At this rate it will take us 25 years to pay the system off! We’ve been scammed!!!

Calm down, I’ve got some good news for you. You’re wrong.
A common misconception when getting your first bill after installing your solar panels is that many see their ‘solar credit’ on their bill and assume that’s all they’ve saved from their solar. For example, look at this comment on a Whirlpool forum.

I’ve looked at my bills but still paying $300+, but getting around $200 credit, so is that my saving each quarter? $200 during Winter? Sorry, I’m a noob, and I just jumped into this Solar thing because of hype last year, but wanting to know a bit more about it so I can get the wife off my back!

In this video, the first of our MC Electrical ‘How to’ series, we first look at understanding tariffs on your power bill, and then explain how not to understand your solar savings off your bill.

T33 and T33 Explained

Before looking at your solar feed in, I’ll quickly explain tariff 31 and 33.

In Queensland, we generally don’t have “Time Of Use” (TOU) tariffs. TOU is where you pay more for power at peak times and less at shoulder and off-peak times. Tariff 31 and 33 is different. This is called a controlled tariff, where Energex sends a signal down the power line to turn off your power at peak times. In exchange for this, you are charged a lesser rate for power on these tariffs. Clearly, T33 and T31 is not suitable for your power points and lights. Energex requires that the appliance is “hard wired”.

T33 is about 22c/kWh (inc GST). Energex will guarantee you a minimum of 18 hours supply, and they will often turn off the electricity around dinner time. T33 is suitable for small hot water systems and pools. It also works well for bedroom air-conditioners and your clothes dryer.

T31 is about 16c/kWh (inc GST). Energex only guarantee 8 hours of supply a day, which is almost always around midnight. T31 is suitable only for large hot water systems.

Tariffs and solar

However, appliances on T31 and T33 do not use power from your solar.  This power is measured with a different electricity meter from your T11 meter. So when we install solar, we would often move your T33 and T31 appliances to tariff 11, and control your hot water and pool to run with excess solar power. This is explained better in the Fronius smart meter blog.

How to read your solar savings from your electricity bill

It’s important to understand that your electricity bill does not show you your full savings generated from your solar system.

Here’s Kellee’s analogy.

Think of your electricity as m&m’s – if you eat half the bag (electricity) before sharing the leftovers (excess electricity) with others (your energy provider), they won’t ever know how much you ate first, only the amount that you gave them. This amount ”given’ to ‘them’ is your ‘feed-in’, and registers on your bill as credit. The amount you save is the amount you consumed directly (the m&m’s you ate).

Confused much? Just watch the video.

Stay tuned, or subscribe to our blog (via the orange button along the right of the page) for more videos that will explain various ways to calculate your actual savings.

Continue to our next blog to learn how to calculate your savings using a Fronius Smart Meter.

Mark Cavanagh

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4 Comments on How to read your Solar Electricity Bill

Tom said :Guest Report 8 months ago

Great job on your blog post! The information you shared was relevant and up-to-date. I appreciated the links to additional resources and references you provided. click here to explore more on this subject.

    Jeremy Gill said :Guest Report 2 years ago

    Hi folks, I recently watched your iSolar video on youtube so i thought id reach out with you about a issue i have. I recently got a 10kw solar system installed by another retailer on the green energy councill approved list here on the sunshine coast. I have an issue you may be able to provide guidance on. As of 2 nights we received our 1st bill since our solar install and initially was happy as it was a $117 bill but then i realised it was only that low because of the one off $175 credit from the government. It looking at the comparative data from what I see in the iSolar app (used for my sungrow inverter) to that shown on my origin bill the energy we are taking from the grid is very different. As an example over a 20 day period origin say i took 301 kwh from the grid yet the app says 194 which is vastly different. Similarly the excess I export shows different data also. So with that said here are the potential outcomes as i see it. 1. Im interpreting the data wrong and its all correct on both sides and there should be no concern 2. The data i see from iSolar is inaccurate and not reflective of actual usage 3. The data and records from origin aren't correct and i need to follow up with them 4. The is something wrong the the installation or configuration at my house. Any advice would be appreciated. Cheers, Jeremy

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    Ben Neville said :administrator Report 5 years ago

    HI Paul, Yes, our advice has changed since this article was written. We would still recommend putting the pool on T11, but hot water is going to be far better off on T31 or T33 in the current electricity market. Once feed in tariff's and electricity prices change, we'll perform the calculation again.

      Paul said :Guest Report 5 years ago

      Has the following advice in your article now changed? i.e. "when we install solar, we would often move your T33 and T31 appliances to tariff 11, and control your hot water and pool to run with excess solar power." Reason I ask is that I was advised by MC Electrical for my new house build with solar that I should connect my electric hot water system to T33 or T31. I keep finding conflicting information on this topic.

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