What is the cost of daytime off peak power (controlled load) during solar production ?

[FredS]

"In New South Wales, from 1 July 2024 Ausgrid has both overnight and daytime operating windows as standard for controlled load 1 tariffs. An overnight-only option is no longer available."
This is a sample of a period from my AGL smart meter data 2-2.30pm, 1.38Kw to the grid ? 0.543Kw to my hot water ? General usage 0.

RateTypeDescription	StartDate	EndDate	ProfileReadValue Kw
Solar	31/01/2025 14:00	31/01/2025 14:29	1.388
Generalusage	31/01/2025 14:00	31/01/2025 14:29	0
Controlledload	31/01/2025 14:00	31/01/2025 14:29	0.543

When the Off peak tariff 1 is tuned on during the daytime and my solar is producing power, what am I being charged for MY power that is being used to heat MY hot water ?

Thank you anyone who can clarify.

[Lester]

Probably the same as my setup was Fred.

We got solar Nov 2023, and before we did the old analogue metering was single tariff with timed off peak for the HWS.

When we went solar, what our power supplier SAPN did was put in 2 meters, a regular TOU usage meter that also does the solar for grid feed in, AND a second CL meter for TOU on the HWS.

This was fairly unnecessary, but they just put in metering close to what we had before . . . well, AGL put us onto TOU without any consultation, but turns out TOU is probably no different for us that if we could have stayed on single tariff . . . maybe that wasn't an option either, some states it is / isn't, and retailers seem to want people on TOU tariffs.

Bottom line, I think the most likely scenario is the CL metering is separate for your HWS and not affected by your solar production.

If so, how to fix it . . . and note the last bit below that might mean you are better off leaving it as is !!.

You can get a sparky to take the HWS off CL metering, and onto the regular circuit.

Same time, you need to do one of two things to take advantage of solar . . .

1. Get a Solar Catch unit to work with your HWS.

or

2. Get a timer that you can manually set for the HWS to come on between say 1000 and 1500, or whatever you feel ample (what we did).

The advantage of Catch Power is it will sense excess production and only allow the HWS to come on when enough excess production, rather than sending to the grid, OR if Winter and a really rubbish solar day, it can be set to come on during the cheapest tariff period, if on TOU. 

They are around a grand + install cost.

If on a timer, you can time it manually to suit the season etc.

Eg. if producing enough for the HWS during the day, you can set for that.

If not, you can set for any cheaper tariff times.

I paid $380 total for change HWS to normal circuit, timer, and sparky install, he is a great bloke though and looked after us I'm sure.

Now, the big BUT . . . 1400 - 1429, you are producing just 2.76kwh or so (per hour) on a good summer day ???

Not knowing what your setup or usage etc is, you might not have enough solar to operate the HWS on solar alone.

Most use 3.6kw or so element, some 2 elements, if in peak summer solar time you are producing much less, you may end up using a lot more (especially out of summer time) to heat your water at a much DEARER cost.

Check the HWS specs on the fitted compliance plate, consider the figures carefully.

I would be tempted to leave the HWS on CL until you can do some sums, as it could be a fairly new change to solar ?

You will also have to check what the state regulations are for HWS heating, I think some might have rules for having HWS on CL circuits, then a Solar Catch unit could be the best option, they seem to be fitted in all states so they must have options to suit all situations.

Good luck with it.

[FredS]

Hi Lester, thank you for your input.

Bottom line, I think the most likely scenario is the CL metering is separate for your HWS and not affected by your solar production.

My question worded differently is, when my solar is producing and power going back to the grid, if CL is switch on some of that power is diverted to the HWS by the smart meter as it is the device that switches the CL on. No power is coming from the grid, so why am i being charge for CL power ?

I appreciate all the other information about catch relays etc, but this about not getting your feed in tariff for the solar that in then being used for CL and being charged CL tariff rate for it.

If i am correct then since this change by Ausgrid everyone with solar and CL is being disadvantaged.

[Lester]

Fred, power is obviously coming from CL for whenever it comes on, hard to say what times that should be, every state is somewhat different.

Do you have CL readings much through the whole 48 x 30 min intervals in a day ?

Are you saying that approx 2.76kwh production for an hour (based on a single 2 x the 30 min usage in the original table) is only part of what you are producing, and you think some is going to the HWS ?

Why I am recommending you check is I am fairly sure your HWS is not involved at all by the solar you make, it is being metered and charged at whatever the rate is for CL at the time of use, that could be single rate by the looks of your original table fields.

Your solar is being produced and used in the home while you use your appliances etc, and any extra going to the grid for your FIT rebate.

[FredS]

Hi Lester

I have full monitoring of CL times on and off and heating periods of my HWS logged.

"I am fairly sure your HWS is not involved at all by the solar you make"

"Your solar is being produced and used in the home while you use your appliances etc, and any extra going to the grid for your FIT rebate."

It is not possible that excess solar is going back to the gird and at the same time power is coming from the grid to supply my HWS. This is a physical impossibility. During this period my solar is the supplier of all the power, some used in the home, some going back the grid, so the HWS is getting power from where ?

[Lester]

"It is not possible that excess solar is going back to the grid and at the same time power is coming from the grid to supply my HWS. " - Yes, it is possible. Smart metering is that smart and can separate every 30 minute interval (or 15 minute from the supplier to the retailer), and put it to whatever power co wants as agreed in your plan.

"This is a physical impossibility." - I found it is possible, as CL is treated separately to your normal usage circuit, which also does your feed in. 

During this period my solar is the supplier of all the power" - Not necessarily.

"some used in the home, some going back the grid" - As said, you can have a completely stand alone CL circuit, that is treated 24/7 as it's own usage from the grid. Your data shows this for that 30 minute interval.

"so the HWS is getting power from where ?" - The grid, whenever it comes on.

Fred, I have seen one 30 min interval from your AGL data.

If you look through your typical days data, does it show OTHER intervals clocking kwh to that CL reading ?

What times are they showing ?

You gave a small window of a days usage, so it's not easy to see what else there might be going on at various times.

Before I ended up changing the HWS to the normal circuit, and timing that as I please, I was getting CL data during shoulder in solar soak hours, charged at that TOU tariff on my data / bill, for 12 months before I did the circuit change.

It also came on during off peak, about 2 or 3 in the morning briefly and charged at our medium priced TOU tariff, but mostly during shoulder CL which is our cheapest rate here.

I won't bother you again if you really think your HWS CL isn't being charged to you at a CL rate for whatever you plan is, and that nothing should be charged anywhere when you are producing solar during the day.

Remember, if you are making 2.76kwh production for an hour of a typical summers day sun, and you are using more than that, you will then make the balance up from the grid, not sure if that is what's happening in your case . . . if the HWS is supposed to be on your normal circuit (which it isn't as a CL item), a typical HWS will use 3.6kw or more when heating, so it's possible if it's coming on for an hour say (that alone would push you into a grid usage vs your estimated 2.76kwh production from that 30 min example), but especially while also using some extra power in the home.

[FredS]

Hi Lester

"It is not possible that excess solar is going back to the grid and at the same time power is coming from the grid to supply my HWS. " - Yes, it is possible.

Lester this statement is not about the smart meter it is about physics, the supply cable coming from the street (grid) to my house can not be carrying power in both directions at the same time, this is not possible. It must be flow in or out, do you agree ?

[Lester]

"this statement is not about the smart meter it is about physics, the supply cable coming from the street (grid) to my house can not be carrying power in both directions at the same time, this is not possible. It must be flow in or out, do you agree ?"

Yes. Sort of. When you are only drawing, it's coming into the meter box / home, then as your solar comes online in the morning and increasing gradually, the meter simply takes your solar feed and applies it to a diminishing usage inwards, until it switches from draw to feed in.

It's ALL to do with your smart metering, how AGL or any retailers takes the power suppliers meter data, and applies it to usage and feed in, and other such as CL, all recorded by the smart meter(s)*.

* We had 2 smart meters, one for general usage and solar feed in, and the other for CL to the HWS, but there are meters which CAN do both . . . do you have 1 or 2 meters, and what brand / models are they ?

Example . . .

Your home is using 1.5kw of power, your solar is producing 2kw of power, you will use 1.5kw of that in the home, the 0.5kw will go to the grid, and your fit.

Keeping the figures above constant for say an hour, say your HWS *IS* on the same circuit (not separate CL), it comes on using 3.6kw, and stays on for a full hour, then you will be using 3.1kw from the grid.

Using the first lot of figures above, and you are sending 0.5kw to the grid for an hour, you will get 0.5kwh of FIT credit.

Now, if your CL is on a separate CL circuit (and it is) that records that 3.6kwh as a separate figure, it is likely outside the normal usage meter on its own tariff, not affected by your solar production, and it is charged at say 34c / kwh for that time it's used, you will get charged 3.6kwh x $0.34 = $1.22 . . .

Say you get 10c FIT, you would get 5c for your 0.5kwh, and the bill would be $1.17 higher.

Even though you are producing more power than the home is using, you are using more for the HWS when it comes on, so you are drawing from the grid, the smart meter(s) is splitting it all up though to where it's alloted.

I can't say definitively that is what's happened in your example table 30 min data in your first post, but that's my best guess.

You bill will tell you, or your plan details.

Your plan rates will possibly show the following, not knowing if you are on single or TOU tariff.

Let's say it's single tariff with CL.

You will have a rate for usage in the home (not inc CL HWS).

You will have a solar FIT rate.

You will have a CL rate.

If on TOU, you will have up to 4 or so blocks of times for those for BOTH regular usage, AND for CL usage.

You may also have various TOU FITs in some states, but those for us in SA are a flat rate.

If your plan shows a CL rate single or TOU rate, I am fairly sure you are going to find the HWS not included in being covered by your solar production.