Comparative Lifecycle Assessment of Renewable Energy Investments in Public Buildings: A Case Study of an Austrian Kindergarten Under Atypical Operational Conditions

This paper investigates the environmental and economic impacts of energy-efficient renovations, specifically focusing on the integration of photovoltaic (PV) systems in a public kindergarten. Leveraging the VERIFY platform, this study employs Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) methodologies to evaluate building performance over a 25-year analysis period under three distinct scenarios: a low-usage period during the COVID-19 pandemic (2021), a normal-usage period under post-pandemic conditions (2024) with the realized investment, and a hypothetical scenario with a PV installation size that allows for appropriate reductions alongside favorable financial outcomes. The pandemic-induced occupancy reduction led to atypical energy demand patterns, with lower self-consumption and increased electricity exports to the grid, affecting the financial viability of PV investments. By incorporating post-pandemic operational data, a meaningful comparison of energy efficiency measures under constrained and stable operating conditions is conducted, addressing the impact of fluctuating demand on long-term energy investment sustainability. The results highlight that system sizing and energy reconciliation policies (net metering, net billing) significantly influence financial outcomes. The PV system achieved a Levelized Cost of Electricity (LCOE) of EUR 0.0811–0.0948/kWh, with payback periods ranging from 6.01 to 14.66 years, depending on operational intensity. The findings demonstrate that while PV systems contribute to emission reductions and cost savings, their economic feasibility depends on occupancy stability and policy frameworks. This study provides insights for optimizing renewable energy investments in public buildings, demonstrating the importance of considering dynamic operational conditions in lifecycle assessments.