Offering Mieterstrom in 2026: A Guide for Landlords and Commercial Property Owners

Owners of multi-unit or commercial buildings can deliver solar power from their own roof directly to the users inside. Since Solarpaket I, two routes lead there: classic Mieterstrom (landlord-to-tenant power supply) with a surcharge, and gemeinschaftliche Gebäudeversorgung (GGV, shared on-site building supply) under Section 42b EnWG. They differ fundamentally in obligations and funding, and many outdated guides only know the first.

Route 1: Classic Mieterstrom with the Mieterstrom surcharge

Under the classic model, the system operator (or a contracted service provider) becomes the tenants' electricity supplier: full supply including residual power, billing, supplier obligations. In return, the EEG pays the Mieterstrom surcharge (Section 21(3) EEG) on top of every directly delivered kilowatt hour.

The key parameters:

• System size: up to 100 kWp per system.
• Surcharge: tiered by size; for systems commissioned between February and July 2026, roughly 2.3 to 2.6 ct/kWh depending on tier. A further degression step took effect on 1 August 2026; for the current window, the figures published by the Bundesnetzagentur are binding. Paid for 20 years from commissioning.
• Price cap: the Mieterstrom price may not exceed 90% of the local default supplier tariff.
• No grid transit: the electricity must be consumed in the immediate spatial vicinity.

New since Solarpaket I: the surcharge is no longer limited to residential buildings. Purely commercial properties and auxiliary structures are also eligible, provided the operator and the supplied end consumers are not affiliated companies. For business parks with multiple tenants, this opens up a model that was legally blocked until 2024.

Route 2: Gemeinschaftliche Gebäudeversorgung (GGV)

GGV under Section 42b EnWG, introduced with Solarpaket I, allocates the solar power arithmetically to the participants in the building without the operator becoming a full supplier:

• No supplier obligations: each participant keeps their own residual power contract. The operator delivers only the building's solar power.
• Virtual balancing meter model: allocation runs on quarter-hour values from smart metering systems; a physical balancing meter is no longer mandatory.
• No Mieterstrom surcharge: GGV forgoes the EEG funding. Its advantage is the radically lower operating effort.
• Surplus: flows into the grid as ordinary feed-in, remunerated at the current EEG rates.

Which route for whom?

Rule of thumb: those who want to offer full supply as a product and run administration at scale (housing companies, urban quarters) get more out of the surcharge. Those who simply want to distribute the solar power within the building without becoming an energy supplier travel lighter with GGV. Energy Sharing (Section 42c EnWG) is envisaged as a third option that crosses building boundaries; for investment decisions, the two established routes remain what count.

What this means economically

For the owner, Mieterstrom combines two revenue streams: the sales revenue from directly delivered kilowatt hours (below the 90% cap, but above generation cost) and the feed-in remuneration for surpluses. At building level, the model competes with a simple roof lease: less effort, but also less value creation. The choice of model follows the same logic as in the comparison of operator models; the economics of the system itself are covered in Is photovoltaics worth it for commercial roofs in 2026?

NEXA models both routes for multi-unit and commercial properties, including the metering concept and the economics of each variant. The starting point is the address: Start your analysis