General Question about Energy dashboard - Energy returned in relation to Mini-PV

Hello guys,

I have a question about “energy returned” in relation to solar production.

I use a Mini-PV with 600WP and so I get a little bit of energy back when the sun shines. The Mini-PV is plugged into a normal German “Schuko” socket. The socket is connected to phase C.

Phase C doesn’t have many things plugged into it so the consumption is often lower than the production.

HA then shows this energy as returned to grid. Although I have consumption in the house itself which is higher than the production.

Should HA then not simply deduct this value from the other phases as well?

In this case I didn’t return any energy to the grid as far as I understand it.

Where is my thinking error - can you help me?

How this work for me, is that my electricity meter doesn’t care what I’m doing on which phases; as long as there is more being consumed than produced, I take from the grid. If I produce more than I use (again regardless of what happens on each phase), I deliver to the grid. The meter is incapable of both taking from the grid and delivering to the grid, over separate phases.

So by measuring the grid out at the meter, I do not experience the issue that you describe.

Where do you measure energy from grid?

I got a Shelly3EM which has a clamp, one over each phase.

So when on phase c more is produced than consumed it simply counts backwards - thus counts it as returned to the grid.

Although on phase a and b are normal consumers which should use the provided power from the PV.

So there should be no value in “energy returned”

But when you produce on a different phase than you consume on, you are not actually grid independent; you still need energy from the grid to those phases. So what the 3EM is reporting is correct, right?

If you do not pay / get paid for these three phases separately, but as one total meter, I would suggest either measuring at that meter (like the situation I described), or using the three 3em meters to produce a total sum, which should give you the same result.

To do that, you can create a template sensor that sums the three phases on the 3em. If you then have a negative reading on one phase (returned to grid) and positive readings on the other, they will even out and give you the number that I think you are looking for.

That would look something like this (replace the sensor names):

sensor:
  - platform: template
    sensors:
      grid_meter:
        friendly_name: "Grid meter"
        unit_of_measurement: 'kWh'
        value_template: "{{ states('sensor.em2phase1')|float + states('sensor.em2phase2')|float +states('sensor.em2phase3')|float }}"

This will give you an accumulating sensor for grid consumption that you can use in the energy dashboard.

Hope this helps!

1 Like