To reverse utility meter

[Langjan]

Running a Growatt 5 KW hybrid inverter, 3,3L-C1 lithium battery and 6x CS365W Mono panels, will the system enable me to reverse-feed into the old-type revolving disc utility meter during low usage times to effect more savings?

 

[Johnson]

Running a Growatt 5 KW hybrid inverter, 3,3L-C1 lithium battery and 6x CS365W Mono panels, will the system enable me to reverse-feed into the old-type revolving disc utility meter during low usage times to effect more savings?

That would require permits and is potentially dangerous.

 

[Langjan]

That would require permits and is potentially dangerous.

Technical advice asked for please.

 

[meetyg]

If you don't consume the energy your inverter produces, then yes, it will go back to the grid (unless the inverter has a limiting function using a CT clamp for example).

As for your meter going backwards, yes, most old meters will go backwards if backfeeded. But even some old mechanical type meters might have some sort of protection. Also note, that some meters are not aware of the direction the energy flows, and might actually go forward even when backfeeding, causing you to pay for the excess energy going to the grid.

As mentioned, backfeeding into the grid in most regions is illegal (without a contract with your electricity supplier). You should check your local regulations before doing this.

Your other option is to simply supply some of your loads using an off-grid system.

 

[Langjan]

If you don't consume the energy your inverter produces, then yes, it will go back to the grid (unless the inverter has a limiting function using a CT clamp for example).

As for your meter going backwards, yes, most old meters will go backwards if backfeeded. But even some old mechanical type meters might have some sort of protection. Also note, that some meters are not aware of the direction the energy flows, and might actually go forward even when backfeeding, causing you to pay for the excess energy going to the grid.

As mentioned, backfeeding into the grid in most regions is illegal (without a contract with your electricity supplier). You should check your local regulations before doing this.

Your other option is to simply supply some of your loads using an off-grid system.

Many thanks for the useful and informative input. At the recent Kragdag expo near Cullinan the guys apparently in the know were confident that feedback into the grid will be legalised soon, even encouraged for obvious reasons.

 

[Zil]

No. Feed back will likely never be allowed by electric utility companies. Certainly not 'soon'.
It is far too dangerous to workers out on the grid.
The grid is not able to control un-regulated power.

 

[robby]

It won't be legalized and if you do it you will get audited!
Anytime the power company see's a significant change in energy usage for over 90 days they will flag the account and send someone over to inspect the system. If they find that meter running backwards or even see the solar panels it will trigger a second report. In a few days they will be back and if they find you have an illegal grid tie and are running the meter backwards they will either bill you based on your highest monthly usage for those 90+ days and require that all connections be removed and change your meter to a digital meter that will only add more to your bill if you feed the power to it. Worst case scenario is they disconnect the meter or disconnect the power lines from the poll that run to your house. Anyway I see your in South Africa and I know the Grid over there is a complete disaster.
I hear it's 8 hours of power per day per household, depending on where you live.

 

[Langjan]

It won't be legalized and if you do it you will get audited!
Anytime the power company see's a significant change in energy usage for over 90 days they will flag the account and send someone over to inspect the system. If they find that meter running backwards or even see the solar panels it will trigger a second report. In a few days they will be back and if they find you have an illegal grid tie and are running the meter backwards they will either bill you based on your highest monthly usage for those 90+ days and require that all connections be removed and change your meter to a digital meter that will only add more to your bill if you feed the power to it. Worst case scenario is they disconnect the meter or disconnect the power lines from the poll that run to your house. Anyway I see your in South Africa and I know the Grid over there is a complete disaster.
I hear it's 8 hours of power per day per household, depending on where you live.

It's not nearly as bad here in SA as you seem to think, we have load shedding from time to time. Fortunately we are pre-warned most of the time and the outages are usually between 120 and 140 minutes once or twice a day. Unscheduled outages also do occur, usually due to mismanaged municipal systems but also fortunately not very regularly in most areas.

 

[meetyg]

It's not nearly as bad here in SA as you seem to think, we have load shedding from time to time. Fortunately we are pre-warned most of the time and the outages are usually between 120 and 140 minutes once or twice a day. Unscheduled outages also do occur, usually due to mismanaged municipal systems but also fortunately not very regularly in most areas.

Just so you know: If you have power outages, the grid tied system won't produce electricity either. This is required by law, in order to prevent electricity workers from getting shocked when working on the lines.

It seems you will benefit more from an off-grid system. It's legal, and can give power during outages.

Some inverters are also AC-DC battery chargers (in case you don't get enough solar), and can act as an automatic transfer switch, when the grid goes down.

 

[Hedges]

If an inverter is designed for backfeed, e.g. implements UL-1741 for the US market, then it will safely feed power intro the grid, and shut down if the grid goes down.
The utility may detect it and come knocking (ask me how I know), but it is safe, doesn't endanger the linemen. So long as it is designed, tested, certified for that purpose.

I don't know about your particular growatt. Some may have grid feed features, while others do not.
You would NOT connect output AC terminals to the house wiring that is fed by grid.
Only input AC terminals.

Some inverters have a "zero export" option, where you put current transformers on wires feeding house from grid, and will backfeed power to household loads, but not into the grid.
Those would work without spinning meter backwards.
But I wouldn't trust them to be safe unless suitably certified, like UL-1741, to detect broken utility grid an shut off. Otherwise could deliver hazardous voltage to lineman.

 

[Hedges]

You might want to use a timer to shift some loads to hours of the day when PV produces power.
For instance, an electric water heater - don't let it run at night, rather wait for middle of day.
(An alternate way to address "low usage times")