ESS connected to two grid lines

Q&A and troubleshooting
, , , ,
1

Dear Community,

we are planning a solar installation on a double house with 10 apartments each. The house has one roof and one facade, but is historically technically divided, including the grid lines coming into the two house parts.

What are my possibilities? As it seems to me, there are only two:

  1. cut house B from the grid, route it to house A, where the ESS is installed.
  2. divide the solar system and the ESS into two systems, each for one half of the house.

It would be nice if I could have two grid meters connected to the Cerbo, which is accumulating these two for regulating the ESS. But aggregation of grid meters in cerbo is not possible, is it?

If this would be possible, it would ease the installation tremendously, because in Germany there is the possibility to bond several grid meters together into one virtual grid meter, exactly for these purposes, to get one invoice for several lines. But these grid meters cannot communicate with the Cerbo…

What’s you opinion on this?

Thanks, Martin

2

What is not possible is accepting two grid sources at the same time on a system.
Can we assume they are separted do to an import current limit? Or loading a separate phase?

Does there need to be battery back up (grid blackout support) for both halves of the system?

This is probably the simplest all round

3

They are both three phase and have capacity to spare, since warm water was done with electricity and is now done centrally. So you are right, the reason for division was a) the two houses and b) separate the loads. It is not necessary anymore, and solar/battery/blackout support should be available in both house parts.

4

Metering each section is the easy part.
Combining the two feeds is the only way
Unless you split the system as you already noted.
How big does it make the system if it is one system for both?

I guess the simple answer is → it always comes down to cost.