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





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.














Thanks for the no reply.


Now lets work out why you added solar.

Simple, you added solar to reduce the cost of your electricity usage.


The big question is did you do your sums before you invested in your Solar.

You didn't did you. Hence your question.


I answered your question but no response. I gave you a reasonable answer


Could I say to you,

"With all the tech knowledge & data that is available today on computers, I think that users should fully look at the Pro's and Con's before making any investment and understand that any change should be fully analysed over a period before jumping to some conclusions on what data should be presented."


I would suggest that you re-read my response and take all that has been presented to you in the generalisation that it been presented.


I am sure that if you only used 5.712 Kw per day and generated exactly 21.563 a day and used none of the power you generated that you could predict with 100% accuracy your bill.


AGL tries to give you a reasonable estimate based on your last thirty days usage, because as you well know generation of solar energy is dependant on the daily conditions (overcast, rain, smoke haze etc) and also the time of year ( 12 hours of sunlight in Summer and 6 hours in winter).


Try this site "" to see what  the sun is doing for the month.

By the way I suggest you change it to your own local due to "tech knowledge & data that is available today on computers".


By the way in the THREE weeks that you have ignored this my current bill is :

Bill Estimate 
Supply $            74.70
Peak $          193.09
Total $          267.79
+GST $            26.78
Total $          294.57
Solar Feed in $         414.98
Total Payable-$        120.40
Payment Required Per Fortnight-$           21.00
Cost Per Day-$              1.34



So we have been lucky, even though we have less sunlight, the sun has been nice to us and given me $0.01 cents more a day, The only problem is that our water bill has increased due to the fact that we are not getting any rain.


Just to remind you this is AGL's current prediction.


Updated 13 Apr 2020 using your last 30 days of data.

Bill projection $-99.99


and to save you looking it up


Updated 23 Mar 2020 using your last 30 days of data. 
Bill projection $-71.81
So my prediction went from -$        119.71
to                                               -$        120.40
Whilst AGL's went up by $28.18
As I have stated before it is a guide, on the day that my bill is due I will be within cents of the correct amount.
You know why!
"Because of all the tech knowledge & data that is available today on computers and I use it"


For A start "Neil" i don,t know who you think you are ,but i do know how to read data for a  start & this is the first message i received from you as i have been down on my computer , so before you start advising people on how great you are, treat people with a bit of respect & yes i do know why i got solar & yes i have had solar for a number of years. so please impress someone else


hi sorry that you seem to have taken offence at what i thought was a reply to your original request i answered as best as i could to explain that the information you get is relevant to a particular period, this is the third message that i have sent to you, obviously you already knew the answer as you have not acknowledge either of my previous responses nor requested any further information only more complaints


ong Again, as usual.


Meant to say ,Wrong Again,as usual.