ᐅ Is it possible to sell self-generated electricity to tenants in a multi-family building?

I own a house built in 1994 with four rented apartments. So far, heating has been provided by individual gas boilers. Now, I want to add insulation, install a photovoltaic system, and switch to a heat pump. An energy consultant has prepared everything. Only now have I understood that the electricity generated by the photovoltaic system can only be used to operate the heat pump. Any electricity not needed by the heat pump (in summer) must be fed back into the grid for 8 cents per kWh. Until now, I thought I could also sell this surplus electricity to the tenants – for example, at 15 or 20 cents per kWh. That would seem like a win/win situation. However, the tenants keep their own electricity meters and continue to purchase their household electricity from their own suppliers.

I am concerned that, in the end, a lot of electricity will be fed back to the grid at a low rate, since the main electricity production is in summer, when the heat pump is needed the least (only for hot water). Or is there another solution?

Of course, there are other ways to do this. However, as is often the case in Germany, the process is very complex and complicated. Search for tenant electricity models.

The other solutions seem too complex to me. I wonder if the west-facing photovoltaic system makes sense at all without a battery storage. How does the heat pump know that it should run best when the sun is shining?

It is possible, but involves some effort, and you will need to evaluate whether it makes financial sense. Since the solar package 2 (or even 1), a much simpler method with virtual summation meters has been available: balances are created instead of having to count everything twice. The easiest to use will be metering concept 13.

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Problem: All meters must be smart meters (iMSys), and the metering service providers often hesitate because it means additional work for them. Essentially, in this metering concept, the electricity generated by the rooftop system is allocated among all meters between Z1 and Z2 according to a predefined distribution key. Anything remaining is fed into the grid. Then, software creates a balance for each 15-minute interval and billing is done accordingly.

Solution: You will definitely need an electrical contractor accredited by your metering service provider. You should find a list on their website, select one from it, and get advice. Depending on the required modifications, you may, like many before you, conclude that direct feed-in is more economical. Alternatively, you could set up four separate systems and assign each to an individual apartment, similar to a balcony solar system but somewhat larger and installed on the roof.

It is possible that there will be no revenue at all for feed-in next year.

I’m wondering if it’s even worth it anymore.

Rental building, 4 apartments of about 75 sqm (800 sq ft) each, built in 1994.

Option A: Continue heating with individual gas boilers and add insulation to the exterior walls, estimated cost: around €10,000.

Option B: Install a central heat pump, without a photovoltaic system, estimated cost after subsidies: around €75,000.

Option C: Install a central heat pump with a photovoltaic system of about 9 kWp, facing west, estimated cost after subsidies: around €90,000.

How would you decide?