Renewable Electricity in German Multi-Family Buildings: Unlocking the Photovoltaic Potential for Small-Scale Landlord-to-Tenant Power Supply

The implementation of photovoltaic and home storage systems in multi-family houses (MFHs) in Germany lags significantly behind their development in single-family houses. The Landlord-to-Tenant (L2T) power supply model is meant to reduce this gap, yet few projects have been implemented to date. In th...

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Main Authors: Mauricio Celi Cortés, Jonas van Ouwerkerk, Jingyu Gong, Jan Figgener, Christian Bußar, Dirk Uwe Sauer
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Energies
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Online Access:https://www.mdpi.com/1996-1073/18/5/1213
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author Mauricio Celi Cortés
Jonas van Ouwerkerk
Jingyu Gong
Jan Figgener
Christian Bußar
Dirk Uwe Sauer
author_facet Mauricio Celi Cortés
Jonas van Ouwerkerk
Jingyu Gong
Jan Figgener
Christian Bußar
Dirk Uwe Sauer
author_sort Mauricio Celi Cortés
collection DOAJ
description The implementation of photovoltaic and home storage systems in multi-family houses (MFHs) in Germany lags significantly behind their development in single-family houses. The Landlord-to-Tenant (L2T) power supply model is meant to reduce this gap, yet few projects have been implemented to date. In this model, the landlord must fulfill the tenants’ power demand through a combination of photovoltaic generation and storage and electricity from the grid, for which the landlord pays an auxiliary electricity price that greatly influences the financial viability of a project. Our contribution focuses on the impact of electricity price variations and recent policy changes on the financial viability of small-scale L2T concepts. We considered component investment costs, building sizes, photovoltaic yields, and future developments. Recent policy changes have improved the financial viability of L2T projects, increasing the maximal auxiliary electricity price for which an investment is viable by 13 ct/kWh for a four-party MFH. Minimal auxiliary electricity prices justifying the installation of home storage systems (HSSs) decreased by 9 ct/kWh from 2020 to 2023. Autarky rates are substantially different across the considered scenarios, with the autarky rate being defined as the percentage of consumption of self-generated energy relative to the total energy consumption. For a 22-party MFH the autarky rate decreases by 17% compared to a 4-party MFH. HSSs have the potential to increase autarky rates while maintaining the financial viability of L2T projects.
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spelling doaj-art-e989633b0f49481ebbfbf1a767d8365d2025-08-20T02:05:24ZengMDPI AGEnergies1996-10732025-03-01185121310.3390/en18051213Renewable Electricity in German Multi-Family Buildings: Unlocking the Photovoltaic Potential for Small-Scale Landlord-to-Tenant Power SupplyMauricio Celi Cortés0Jonas van Ouwerkerk1Jingyu Gong2Jan Figgener3Christian Bußar4Dirk Uwe Sauer5Electrochemical Energy Conversion and Storage Systems, Institute for Power Electronics and Electrical Drives (ISEA), RWTH Aachen University, 52074 Aachen, GermanyElectrochemical Energy Conversion and Storage Systems, Institute for Power Electronics and Electrical Drives (ISEA), RWTH Aachen University, 52074 Aachen, GermanyElectrochemical Energy Conversion and Storage Systems, Institute for Power Electronics and Electrical Drives (ISEA), RWTH Aachen University, 52074 Aachen, GermanyElectrochemical Energy Conversion and Storage Systems, Institute for Power Electronics and Electrical Drives (ISEA), RWTH Aachen University, 52074 Aachen, GermanyElectrochemical Energy Conversion and Storage Systems, Institute for Power Electronics and Electrical Drives (ISEA), RWTH Aachen University, 52074 Aachen, GermanyElectrochemical Energy Conversion and Storage Systems, Institute for Power Electronics and Electrical Drives (ISEA), RWTH Aachen University, 52074 Aachen, GermanyThe implementation of photovoltaic and home storage systems in multi-family houses (MFHs) in Germany lags significantly behind their development in single-family houses. The Landlord-to-Tenant (L2T) power supply model is meant to reduce this gap, yet few projects have been implemented to date. In this model, the landlord must fulfill the tenants’ power demand through a combination of photovoltaic generation and storage and electricity from the grid, for which the landlord pays an auxiliary electricity price that greatly influences the financial viability of a project. Our contribution focuses on the impact of electricity price variations and recent policy changes on the financial viability of small-scale L2T concepts. We considered component investment costs, building sizes, photovoltaic yields, and future developments. Recent policy changes have improved the financial viability of L2T projects, increasing the maximal auxiliary electricity price for which an investment is viable by 13 ct/kWh for a four-party MFH. Minimal auxiliary electricity prices justifying the installation of home storage systems (HSSs) decreased by 9 ct/kWh from 2020 to 2023. Autarky rates are substantially different across the considered scenarios, with the autarky rate being defined as the percentage of consumption of self-generated energy relative to the total energy consumption. For a 22-party MFH the autarky rate decreases by 17% compared to a 4-party MFH. HSSs have the potential to increase autarky rates while maintaining the financial viability of L2T projects.https://www.mdpi.com/1996-1073/18/5/1213prosumer modelingMieterstromLandlord-to-Tenant power supplyMILPresidential solar systemshome storage systems
spellingShingle Mauricio Celi Cortés
Jonas van Ouwerkerk
Jingyu Gong
Jan Figgener
Christian Bußar
Dirk Uwe Sauer
Renewable Electricity in German Multi-Family Buildings: Unlocking the Photovoltaic Potential for Small-Scale Landlord-to-Tenant Power Supply
Energies
prosumer modeling
Mieterstrom
Landlord-to-Tenant power supply
MILP
residential solar systems
home storage systems
title Renewable Electricity in German Multi-Family Buildings: Unlocking the Photovoltaic Potential for Small-Scale Landlord-to-Tenant Power Supply
title_full Renewable Electricity in German Multi-Family Buildings: Unlocking the Photovoltaic Potential for Small-Scale Landlord-to-Tenant Power Supply
title_fullStr Renewable Electricity in German Multi-Family Buildings: Unlocking the Photovoltaic Potential for Small-Scale Landlord-to-Tenant Power Supply
title_full_unstemmed Renewable Electricity in German Multi-Family Buildings: Unlocking the Photovoltaic Potential for Small-Scale Landlord-to-Tenant Power Supply
title_short Renewable Electricity in German Multi-Family Buildings: Unlocking the Photovoltaic Potential for Small-Scale Landlord-to-Tenant Power Supply
title_sort renewable electricity in german multi family buildings unlocking the photovoltaic potential for small scale landlord to tenant power supply
topic prosumer modeling
Mieterstrom
Landlord-to-Tenant power supply
MILP
residential solar systems
home storage systems
url https://www.mdpi.com/1996-1073/18/5/1213
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