Energy Management

Looking for tips or advice on energy efficiency around the home? See what others are doing or share your experience!

Looking for tips or advice on energy efficiency around the home? See what others are doing or share your experience!


Usage Data


I Think with all the tech knowledge & data that they have today on computers i think they should fix the problem with estimations of usage & get it right for all of their customers as they owe it especially the ones with solar as we try & do the right thing & it is not going without the cost ,so the least they ca do is get the readings right for all.Regards Paul


Re: Usage Data




Now the formulae is quite simple if you have a remotely readable meter.


Work out how much you have consumed from the grid (Current meter reading  MINUS previous meter reading from last bill ).


Do the same for all your meters (Solar and or Off Peak/Controlled load)


Calculate the number of days from your bill to the date of your latest reading.


Divide the figures you obtained from the above by the number of days.


(Say for interest sake 120kw consumed by 21 days = ‭5.715 kw per day)


Then multiply that by the number of days in your billing cycle (normally around 90 days).


This would give you ‭514.286 kw usage on your peak meter.


Multiply this by your cost per KW (lets say $0.36) for a figure of $‭‭185.14.


Do the same for each meter.


Remember that feed in is a Credit to you while usage is a debit.

Then you also have to factor in your supply charge (supply charge * no of days).


Meter          Amount

Peak             $185.14

Off Peak         $95.24

Supply            $90.00

Feed in         -$102.36


Current Prediction would be $‭268.02‬ payable using the above.


Looking at my AGL account right now states.

                               Updated 23 Mar 2020 using your last 30 days of data.

                                        Bill projection $-71.81

It says on my usage page Cbill.JPG

*** Note this figure above is perfectly correct, it shows my consumption and my feed in since my last billing date. The billing prediction is shown on your Overview page (the page shown when you log onto the Web)


Now from my spreadsheet it reports.



Below is my expected bill based on  usage up to Midnight on the 21st March 2020 using the formulas above on my real data supplied by AGL


Current Bill 
No Discount (Estimate) 
Supply $           74.70
Peak $         205.10
Total $         279.80
+GST $           27.98
  $          307.78
Solar Feed in $         427.49
Total Payable-$        119.71
Payment Required Per Fortnight-$           20.00
Cost Per Day-$              1.33


Don't forget the whole prediction can go to poop easily by having a stack of overcast days or hot days where you ran the AC all night etc.


So I would say that their prediction is not too bad as my figures are based on 51 days while they only use the last 30 days to give a better estimate.


With my spreadsheet the closer I get to the due date the more accurate it becomes.