I am posting this to save others from the bill trauma we experienced.
We had our solar installed In December '16 but due to some delay the bi-directional meter was not installed til March '17(we had old spinning disc meters).
On the day of solar instal the installer cheerfully showed us that the solar was working because the meter was running backwards..
On the face of it , this sounds good because theoreticaly we were sending power back at the same cost rate as we were consuming it.
This is not so.
If the meter runs back to a figure less than the last meter reading it causes problems with the calculation of your consumption.
Apparently AGL's computor algorithm cannot digest negative readings.
In our case the solar was installed and energised early in the Dec-March quarter but the b/d meter was installed approx. 6 weeks later, plenty of time to drive the meter into negative territory.
If our meter had not gone negative it may have gone unnoticed.
As a result of this we received a bill for $1070 when it should have been approx. $400.
After several contacts with AGL,they thankfully revised the bill to $360 thus ending a few weeks of stress (we are on a limited budget so couldnt afford a large bill like this)
AGL said the problem was due to the solar being turned on incorrectly.
Arising from this issue I decided to find out what the "correct." is.
I assumed that AGL or Ausgrid would have procedural documentation concerning this (they have procedures for everything else).
After much trawling on the net (a direct approach to Ausgrids office got nowhere) I found three documents which fully explain the "do's and don'ts" and the consequences and penalties.
1. Ausgrids ES3 part A
Connecting solar is briefly mentioned in section 2.7 paragraph 7 as follows.
"All all Bi-Directional Metering must be installed prior to the energising of the new or altered embedded generation system"
This means that the solar system must not be turned on til the b/d meter is installed.
2. S.A Power Networks Industry News
Being a South Aust. document,it may not be totally relevent to NSW, but it seems to spell out the situation clearly on page 4 section3.
3. Electricity Act 1996 section 85
This exerpt from the Electricity Act , explains the rules and who would be held responsible (you, as the owner of the installation)
It is quite clear that a solar system should not be turned on until a b/d meter (or smart meter I suppose) is installed.
So when your solar system is installed make sure your installer leaves it off til the meter upgrade is done.
However, if you are prepared to take the risk, make sure your meter doesnt run backward in to negative territory.
Disclaimer!!! I do not condone allowing your meter to run backward, as this would amount to electricity theft, wouldnt it !
It has taken a lot of deep digging to find this info, (they dont make it easy) but if this saves others from this trauma then it has been worthwhile
When our meter was installed, the installer explained that I should leave it turned off till the new meter is installed because if it goes negative I could get a large bill. Glad I had the installer I did or I would have been in the same boat as you were
Here is some more info on the subject. Main point being, know your last proper meter read and dont let it go below that.