Self Photovoltaic and energy metering

Good evening.

I plan to buy a self PV as allowed in Germany with 600VA maximum.

With old Ferraris meters I got a well solution with ai on the edge (thanks to the community for help)

Well, problem with self PV is, I need to use the energy on the fly, otherwise it’s given to the net for free.

The energy companies are forced to assemble digital meters, but consumers only able to read values by public cloud.

So my idea (house with some flats) is

+Main Meter counts only bought energy
+> meter for common energy of shared rooms for all
+> meter for used energy of my flat
__+> meter for produced energy (technically sadly after my meter)

So main meter needs to be bidirective one, no idea how to read out :frowning: one direction maybe works with ai on the edge
The other two needs to be mid compliant.

But I didn’t found any mid-compliant meter could be read out directly. All working only with mbus:(

For produced energy I looked for a Shelly 4pm, but that one don’t need to be mid conform.

Any good ideas or devices could work well? With Wi-Fi, lan, or wmbus and mid conform?

There are energy meters with MID certificate and Modbus interface. MID is mainly about stability of readout and hardness towards resetting of counted values. M-Bus is very convenient way as it standardizes reporting of data making billing process straight while Modbus does not. Hence it is easier to find electric meter with MID which comes with M-Bus, but there are other meters which come with variants. You can look at inepro or socomec three phase meters or some of Jantiza products. I know inepro have (or had) MID certificate for bidirectional Modbus meter, socomec is fairly popular in industrial usecases. Inepro modbus is quite painful, but Jantiza just worked and reported proper float values out of the box.

Not sure if 600VA is a problem, if so you might look for indirect meter.

Typical structuring I saw so far:

  • Main
    – Shared
    – Apartment 1
    – Apartment 2
    – Apartment 3
    – PV (optionally)
    – Charging stations (optionally)

Two additional meters on the list come for situations where you have several tenants. Shared electricity is divided between them while PV could be used to reduce overall bill. Charging stations must be substracted from overall electricity as charging stations are usually billed individually.
A separate PV meter with MID might be necessary for situations where you want to aggregate yield information from several inverters in a reliable way. It will also tell you net production before going to the grid. Otherwise you don’t have a proof of how much power you had in installation and just see some of it going to the grid.

If you look for a ways to get the PV energy utilized… go with AC, thing like Askoma or car charging station. These three can take most, if not all, of the yield you get from home owner PV installation.

Best,
Łukasz

Thank you Łukasz,

just a question: how to get mbus work with openHAB best way?

I saw a lot of meters with mbus, but no idea how to integrate to openHAB :see_no_evil:

I don’t think there is a straight way for OH. I was hopping to get project for that but it was delayed already several times. For customer deployments I used ta.co.at equipment with ta binding I wrote, however this is not a valid MID path.

I think the straight and typical OH way would involve calls to mbus command line utility (ie. GitHub - rscada/libmbus: Meter-bus library and utility programs) and transformation through json or xpath expressions.

As PV Operator myself and seeing your idea, I strongly advise you to consult the https://www.photovoltaikforum.com/.

To my knowledge, only one “Balkonkraftwerk” is allowed per meter. You’ll get a new bidirectional meter from your MSB (Messstellenbetreiber, Meter operator) because of your notice of installation to your VNB (Verteilnetzbetreiber, Grid operator). As Ferrais is phased out, you (should) get a digital one where you can use the smartmeter binding together with Hichi’s optocoupler (Lesekopf bei Heise getestet - volkszaehler.org - Photovoltaikforum)

Oh, just forgot: it’s financially sad for you if you export energy for free (you may of course get the Einspeisevergütung!) but for the sake of getting rid of fossils, your neighbor will be consuming the energy.

Hi,

this Optodevice looks exactly like what I looked for.

Do you know if it supports bidirectional smart meters too? (kWh?)

Sure it does. I’m using it with the Iskra meter MT175.

Also keep in mind you need to unlock the meter for detailed values (Wh instead of kWh) using your PIN. You’ll get it from your MSB for the meter.

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