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Discrepancy between solar inverter power generation and the AGL app

Switched-on

Hi There, I've been monitoring my 5kw Fronius inverter and the kwh produced each day. July 26th was an ok day and reading via the Fronius solarweb app was 18.0kwh produced. Yet on the AGL App for the same day it states just 7.22kwh sold to the grid and 21.01kwh bought from the grid. The figures don't stack up. 

 

Thanks

Kevin

5 REPLIES 5
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Re: Discrepancy between solar inverter power generation and the AGL app

AGL Moderator

Hi Kevinh99,

 

Welcome to the AGL Community!

 

As you've mentioned, your inverter records the amount of power your system generates, whereas your meter records the power you export to grid. Based on the figures you've provided, If your system generated 18kWh and exported 7.22kWh, the difference of 10.78kWh would've been used within your property during daylight hours. The 21.01kWh imported from the grid would've been used during non-daylight times, or during the day when your system was unable supply enough power to meet the demand within your property.

 

Kind regards,

 

Jayden

If I’ve helped in anyway, please mark my post as SOLVED!

This helps our Community know the answer to common questions.

Re: Discrepancy between solar inverter power generation and the AGL app

Conductor

I have long read my meters twice a day (morning and at sundown) and find there is a difference of 3 to 4 k/watts  from what my panels produce to what my smart meter tells me I have exported. I have put this down to the fridge running and occasional power I use during the day. This backed up by energy I import during the day at best 0.4 k/w and if I or my wife does cooking during the day up to 8k/w during the day, overnight we can use at best 5 k/w if all the cooking is done before sundown and have an early night. Hence with using power from the panels and overnight usage with minimal power usage would be about 5 k/w day or night. Of this is rare as we mostly cook after sundown. I find the ducted air con the biggest user of power and hence it is rarely used (heating or cooling) I got the ducted system as a deal with the new house but regret that now and should have gone for individual room a/c units.

To get back to the question at hand I still check with the AGL site what the readings are and they are never the same as my readings from the meter (only out by 1 or 2 k/w), now this is a smart meter it should read the same as the AGL meters I can only put it down to when the meter is read but if it is after sundown (which it should be to get the full solar reading) then why the difference. AGL cover themselves by stating their reading are estimates ( or as their put only indicative of the true reading) and I will find out when the bill comes in.

Sorry for being so long winded.

 

Re: Discrepancy between solar inverter power generation and the AGL app

Dynamo

Kim,

I am fairly new to AGL and in fact have just completed my first billing cycle with AGL and 16 days into my 2nd.

Now I was very disappointed that my bill was FOUR cents out from what I calculated.

I have a spreadsheet that I fill out daily using the CSV supplied by either my Electricity Supplier or the horrible AGL csv file.

AGL do not supply in NEM format but SA Power Networks supplies the data in NEM format but do not always get the correct data. So I have to add offsets into my programme to allow for missing days.

 

Not a problem as long I read my Meters at 23:30 to get the true Values then compare my reading to the reading produced up to the my meter read date.

 

I have written a programme that converts the AGL csv file into NEM format.

Also written a programme that converts NEM format files into something completely usable.

 

DatePeakExportedSolar GenUsedMeter Solar
Carried Fwd001579.9 1038.3483209.208
1-Aug2.9636.7219.42.681041.3113215.929
2-Aug4.1309.02213.03.981045.4413224.951
3-Aug4.5625.3799.23.821050.0033230.330
4-Aug6.69719.00824.45.391056.7003249.338
5-Aug6.35721.8126.34.491063.0573271.148
6-Aug4.31515.26619.44.131067.3723286.414
7-Aug5.2486.3139.73.391072.6203292.727
8-Aug5.4116.21210.94.691078.0313298.939
9-Aug6.69214.86919.84.931084.7233313.808
10-Aug4.67813.40919.66.191089.4013327.217
11-Aug6.00814.23320.76.471095.4093341.450
12-Aug4.81112.12215.93.781100.2203353.572
13-Aug3.80220.73124.53.771104.0223374.303
14-Aug3.51625.88229.53.621107.5383400.185
15-Aug4.02516.22319.53.281111.5633416.408
16-Aug4.4799.90515.25.301116.0423426.313

 

Above is the sheet that I use to keep track of my usage and my ACTUAL POWER METER from the data supplied by AGL and my solar inverter. The used column is what I have used of the SOLAR generated for the day.

I do not have anything that uses Controlled Load or Off peak so do not have that in my sheet.

 

Do you have electric hot water, is that using your power.

We have a heat pump and set that to run from 11:00 to 17:00 each day (thus using Solar).

That uses about 3kw of our average daily consumption of 4.8 used from our solar output.

As I have said I am 16 days into our next bill.

Meter Readings
Peak MeterOff Peak SolarDATE
1038.34803209.20831-Jul-19
1077.953 3298.9398-Aug-19
1116.137 3426.31816-Aug-19
UsedUsedProducedDays
77.7890.00217.11016
Averages Per Day 
4.86013.57 
Cost Per Day $            0.22

 

I won't go into great details but the COST PER DAY is inclusive of all electricity used by our house and includes our supply charge.

We are still getting overcast days here and rain (Adelaide SA).

We pay including GST 41.58 cents per KW and 91.3 cents per day for Supply Charges, 20 cents per Kw for Solar generated. If my average  Solar / used is greater than 3.00 then I do not pay a bill.

 

At the moment it is 2.792 which equates to 21 cents (3- 2.792)*100.

 

To go further at my current use and supply averaged out to when my next bill is due. My bill will be

Bill Due 29/10/2019
Current Bill
No Discount (Estimate)
Supply $           74.70
Peak $         165.40
Total $         240.10
+GST $           24.01
  $          264.11
Solar Feed in $         244.25
Total Payable $         19.86
Payment Required Per Fortnight Pay on Time $             4.00
Credit $            71.05
Cost Per Day $              0.22
DUE DATE29/10/2019

 

Here is a CSV sample of what my programme produces in regard to the CSV file supplied by AGL (then converted to nem format) and then run through my MeterRead programme.

 

NMI 20013969096   <-->   Meter #U260000657   <-->   NMI ID=E1   Interval Mins=30

DATENMITYPED/Total00:00>07:0007:30>18:0018:30>23:0023:30>00:00
20190801E1General2.9631.4670.3991.020.077
20190802E1General4.131.2450.81.9530.132
20190803E1General4.5622.0880.8121.4840.178
20190804E1General6.6972.181.0453.3550.117
20190805E1General6.3572.5542.0521.6450.106
20190806E1General4.3151.7430.7481.730.094
20190807E1General5.2482.0431.5041.6410.06
20190808E1General5.4111.751.8451.6850.131
20190809E1General6.6922.170.9483.3060.268
20190810E1General4.6781.5941.4331.5080.143
20190811E1General6.0082.2042.1721.4530.179
20190812E1General4.8112.3390.7921.5580.122
20190813E1General3.8021.7120.2261.7390.125
20190814E1General3.5162.1730.3430.8810.119
20190815E1General4.0251.3350.4112.1060.173
20190816E1General4.4792.3590.6241.4960
Total:E1General77.69430.95616.15428.562.024
DATETYPENMILast DataMeter ReadDay Avg  
20190816SolarB19.9053441.18212.771  
20190816GeneralE14.4791122.7344.57  
20190816ControlledE2000  

 

As you can see I can manipulate the data any way I like

DATENMITYPED/Total

Are default settings

I then can add up to 10  additional queries for any times that I want to add using a configuration file

You can see at a glance that we are having cloudy days due to the high usage between 7am and 6pm

Electronic meters are "read" at midnight but using nem file and a bit spread sheet know how. You can take a meter reading anytime (well at the hour or half past) and going from you last meter read (from your bill)  add up all the daily usages plus the part day up to when you read your meters confirm you meter reading.

Solar is easy, if your are not producing power then the meter is correct for that night (after sunset) or if before dawn then the night before.

If you know what you are doing you can check your SMART meter to see how many amps you are using and how many amps you are putting back into the grid..

Simply multiply the amps by 250 to get the watts (close approximation). If you are putting 20 amps into the grid (20*250=5000 watts or 5Kw) then you are producing the maximum out from your solar system.

Yes you may have a 6.6Kw system but your inverter is limited to 5Kw (and will reduce further on hot days)

 

Hope this helps but I have been using a smart meter and my programmes for some time and the only fault I have found is that our meter runs on Vic time not SA time.....

 

Hence my 4 cents wrong on my bill average usage between 23:30 and 00:00 is 0.1265 watts at the moment so unless I change my programme to run on VIC time it will be 5 cents out this time.

Cheers

Neil

 

 

 

 

Tags (3)

Re: Discrepancy between solar inverter power generation and the AGL app

Conductor

Thanks Neil for such an in-depth analysis and far more accurate recording and spreadsheet setup than I am capable of. I am happy with what I record and my simple spreadsheet is set up to tell me how much I make per day and how much I use per day and the difference. Here in Queensland I haven't been able to find a program on the AGL website to record these and I don't think I am capable enough to convert it from cvs to nem format (even if I knew what they were). I have tried to add up the cost from the information I have gathered and I would be happy if I could come as close as 4 cents difference.

 

Simply put as long as I make more solar power than I use then I am happy. The true test will be if I can work out when the next bill comes if I come any where near what AGL has calculated. Having said I want to make more than I use, this might change during the summer months when using the a/c will be a necessity due to Queensland hot/ humid weather. At present we have homestay students and providing them with comfortable conditions for their studies is a priority. If it was myself and my wife I would take advantage of shopping centres and libraries using their a/c.

I do have solar hot water and I believe it has a pump to circulate the water between the tank at ground level and the roof panels but it apparently it automatically heats up when the water get below a certain temperature, 50 degrees I believe. So I am not sure what power it uses and again with students if and when it heats up, if it was just my wife and myself I don't believe it would need the boost. Here in Queensland we are blest with generally sunny days but  I believe once the temp gets above 25 degrees the panels are less effective again I am happy with what I am producing at most so far this winter the best was 22.602 k/w for my 4.3 /k/w system, I was impressed with you getting a couple of 26 k/w on a few days. I have to remain below 5 k/w system or I will lose my 52 cents feed in tariff a carry on from the old system on the house we knocked down to rebuild a new one. 

Once again Thank you for your reply it sure has enlightened me to how other systems work and in different states with their different weather zones. Keep up your recording and calculations your dedication may help others as much as it helped me. I will be interested in what your summer reading will be compared to here with mine. I would pass on some of my readings from my spread sheet if I knew how.

Kim Harley

Re: Discrepancy between solar inverter power generation and the AGL app

Dynamo

Kim,

When you log in on the page you can see your icon and settings.

Third icon on the right is E-Mail.

You can send personal messages via that.

Cheers Neil