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Chris Crocker-White's avatar

Nice work! I recently switched to agile purely from the point of view that I want the ability to take advantage of price changes - I don't need to be isolated from the uncertainties of the grid, as like yourself, we have no major consumers of electricity and in theory can move our usage around to fit. So far we're cutting 25% off the fixed tariff quite easily by timing our cooking and laundry appropriately.

I also will be writing about some home automation findings but have subscribed to you also - looking forward to more posts!

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Giordy Salvi's avatar

Thanks for the comment Chris. Since I wrote this, Octopus have introduced free 2 hour periods that you get emailed about and can opt into (as I write this, there's one tomorrow between 2pm and 4pm). I've written a little node red routine that switches on a Tuya switch I have plugged my immersion heater into between these times. I have a toggle helper that I turn on for any day with a free period that enables my node red routine. At the moment I can't see a way of completely automating this.

Looking forward to your writings.

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Chris Crocker-White's avatar

What tariff is that? Do they not expose the free 2 hour periods in the API? I've been using this integration [1] which provides fully automated sensors that toggle on when the cheapest period (using parameters you can define) is found for the day ahead - very cool stuff!

[1] https://github.com/BottlecapDave/HomeAssistant-OctopusEnergy

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Giordy Salvi's avatar

I've posted the following in the HA Ocotpus thread at https://community.home-assistant.io/t/octopus-agile-display-tariff-in-graphs-tables-best-import-export-periods-all-done-using-node-red-and-jsonata. The way Octopus do this free period is retrospective and not through a tariff.

Octopus have recently introduced “free periods” for their customers. I don’t know if it’s for every tariff or limited (I’m on Flexible Octopus). It works like this:

You get an email the day before asking if you want to opt in (why wouldn’t you?!)

You click on the link in the email and you go to a page where you opt in

To date it’s always been the same time: 2pm to 4pm

You will get credited on your bill for any electricity used in this free period

The last point is crucial. It’s not that your tariff is zero in the free period. Octopus’s billing system applies the credit retrospectively so you can’t write an automation to exploit this by looking at the tariff.

At the moment I do the following to make the most of this:

I have a toggle helper I manually set the day before to flag a free period is coming

I have a node red flow that checks at 2pm if this helper is set. If so, it switched on my immersion heater.

At 4pm it switches the immersion heater off and resets the helper.

I wonder if there’s any way of automating this fully? Reading the email and automatically opting in and setting my helper?

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Chris Crocker-White's avatar

Looks like you could do something based on seeing the email come in, depending on your email setup: https://www.home-assistant.io/integrations/imap/

I've never tried this but looks doable!

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Giordy Salvi's avatar

Hmmmm... looks interesting. I'll have to investigate!

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