Open Access

ARTICLE

Assessment of Energy Self-Consumption and Potential Participation in Renewable Energy Community through a 3 kWp Photovoltaic System: Case Study of a Condominium Apartment

Giuliana Daniela Foti^1,*, Alexandra Catalina Lazaroiu², Mariacristina Roscia¹
1 Department of Engineering and Applied Sciences, University of Bergamo, Dalmine, Italy
2 Department of Electrical Engineering, National University of Science and Technology POLITEHNICA Bucharest, Bucharest, Romania
* Corresponding Author: Giuliana Daniela Foti. Email:
(This article belongs to the Special Issue: Renewable Energy Community (REC) Engineering towards Sustainable Development and Energy Poverty Reduction)

Energy Engineering https://doi.org/10.32604/ee.2026.087000

Received 09 June 2026; Accepted 12 August 2026; Published online 17 September 2026

Abstract

Residential photovoltaic (PV) systems can reduce grid dependence and support renewable-energy sharing within Renewable Energy Communities (RECs). However, their effectiveness in condominium buildings is often constrained by the temporal mismatch between electricity generation and demand, seasonal variability, local shading, and limited installation space. This study evaluates the technical feasibility of a 3 kWp PV system serving a condominium apartment in Peschiera Borromeo, Italy, with the objectives of improving energy performance, increasing self-consumption and self-sufficiency, and assessing the potential contribution of surplus renewable electricity to a REC. Unlike studies focusing exclusively on building retrofit, photovoltaic performance, or energy sharing, this work integrates energy-efficiency measures, site-specific PV assessment, hourly electricity-demand modeling, battery-storage operation, and REC participation within a single apartment-scale framework. An energy diagnosis was conducted to identify effective envelope and system retrofit solutions, and five electricity-demand scenarios were developed by combining heating, cooling, domestic hot-water production, and household-appliance loads. PV generation was estimated using PVGIS and an independent site-specific hourly analytical model accounting for solar geometry, module temperature, and local shading. The best retrofit configuration improved the apartment’s energy rating from class F to A3 and reduced primary energy demand by 82.05%. Annual PV generation was estimated at 4022.01 kWh by PVGIS and 3671.38 kWh by the analytical model. With a 5 kWh battery, the highest self-consumption and self-sufficiency rates reached 78.64% and 77.33%, respectively, while the most efficient complete-demand scenario achieved 72.99% self-sufficiency. PV generation fully covered monthly electricity demand in July and August, whereas grid dependence remained significant during winter because of reduced solar availability and higher thermal loads. The results demonstrate that the proposed configuration can substantially reduce grid withdrawals and generate renewable-electricity surpluses suitable for collective self-consumption within a REC, although PV integration alone cannot ensure year-round energy independence.

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Keywords

Residential photovoltaic systems; building energy retrofit; self-consumption; energy self-sufficiency; battery energy storage; renewable energy communities (RECs); shading assessment; condominium buildings

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