Three phase Electricity Net Metering

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fastbike

212 posts

Master Geek

#318172 23-Dec-2024 11:00

I have three phase power and solar.

If I have my car plugged in, charging on one phase which is importing a small amount of power, while the other two phases are exporting - does the meter offset so I get a small net export. Or does it (as I suspect) have two completely separate registers and charge me for the import (at 30 cents) while simultaneously crediting me for the export (at 17 cents) ?

NB: the inverter cannot see the connection that the car is plugged into so is not capable of increasing the supply to the phase with the car charger - they are 30m separate.

Otautahi Christchurch

k1w1k1d

1519 posts

Uber Geek

#3323595 23-Dec-2024 12:09

Probably a good question to ask your power provider.

SomeoneSomewhere

1802 posts

Uber Geek

Lifetime subscriber

#3323656 23-Dec-2024 13:07

This has been discussed previously, and the answer is the current metering code requires the lines company to meter and charge you for export and import on different phases. See e.g. this thread: https://www.geekzone.co.nz/forums.asp?topicid=311834

richms

28168 posts

Uber Geek

Trusted

Lifetime subscriber

#3323663 23-Dec-2024 13:31

There is also no way to make a charger in a car take more or less power from certain phases, which makes it even harder to deal with.

Richard rich.ms

fastbike

212 posts

Master Geek

#3324081 24-Dec-2024 09:01

SomeoneSomewhere:

This has been discussed previously, and the answer is the current metering code requires the lines company to meter and charge you for export and import on different phases. See e.g. this thread: https://www.geekzone.co.nz/forums.asp?topicid=311834

Thanks, the key message I got from the discussion is covered by this sentence

Therefore, each revenue meter essentially has two counters per phase, one for import, one for export. Each counter can only ever count up. If you are exporting on one phase and importing on another, those counters will be increasing and you will be billed for import and credited for export in the given time period, even if the total power in the time period is zero.

I think I will need to set up some automation rules to ensure the EVSE never exceeds the power available on a single phase.

Otautahi Christchurch

fastbike

212 posts

Master Geek

#3324083 24-Dec-2024 09:03

richms:

There is also no way to make a charger in a car take more or less power from certain phases, which makes it even harder to deal with.

The car only as a single phase charger built in, so a moot point.

I will speak to a transformer engineer to see if I can get a 400v two phase to 230v single phase transformer, at an affordable price, to feed the EVSE. This would then allow power from 2/3 of the inverter output to be used.

Otautahi Christchurch