April and May, it’s starting to shade!

Tesla Straya Logo

It’s been about 6 weeks since I have posted here. It’s been a busy time at work for me unfortunately. I’ve been eagerly keeping track of when Australia will finally get Model 3 deliveries!

So, what has April and May delivered in terms of solar output and what effect has that had on my power bills? Well, for a start the days are definitely getting shorter and the sun is much lower in the sky. This means peak output is getting lower and lower each day.

As you can see in the images above, I was seeing weekly generation of up to 280 kWh on April however that dropped to around 230 kWh in May. The good news is there is still surplus solar and battery storage to supply all house loads.

The raw figures probably paint a more obvious picture. House usage has remained pretty much the same, averaging around 18 kWh per day. We are starting to see a little more battery usage, this is primarily due to the days getting shorter and battery usage kicking in during evening meal preparation. Heating is also starting to get a little more usage as the weather gets colder.

As always, the self-powered ratio remains very high. We achieved 100% efficiency in April and 99% in May. I’m definitely happy with that! Below, I will aggregate power usage and final dollar figures over the April and May billing period.

April/May Energy figures without Solar and Powerwall 2

Daily Supply Charge – $0.924 per day * 61 = $56.36
Power Usage (from grid) – $0.3179 per kWh * 1099.3 = $349.47
Total bill = $405.83

April/May Energy figures with Solar and Powerwall 2

Daily Supply Charge – $0.924 per day * 61 = $56.36
Power Usage (from grid) – $0.3179 per kWh * 7.3 = $2.32
Solar Credits (to grid) – $0.20 per kWh * 761 – ($152.20)
Total bill = ($93.52) – that’s a little better!

That gives me a saving of $499.35 for the last 2 months alone and brings my total solar and battery savings to $1876.80 for the last 6 months alone. I’m very happy with that!

Powerwall 2 Efficiency and Utilisation

For the past 2 months, I’m seeing the below efficiency and utilization rates for my two Tesla Powerwall 2’s:

  • Efficiency: 85.9% – up by 0.6% since last report
  • Utilization: 36.3% – down by 2.6% since last report.

As always, I wanted to thank you for reading. I hope that the data I look to provide you helps with your decision to move towards a sustainable household for you, your family and your friends.


Author: Adam

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