Energy-efficiency and net-zero trade-offs in rural biomass heating: A comparative assessment of centralized and decentralized approaches

: This study presents a quasi-experimental, multi-criteria comparison of centralized Biomass-Based Distirct Heating System with an installed capacity of 1,000 kW versus a decentralized, nine Individual Biomass Boilers with a total of 1,020 kW capacity. The solutions for heating public buildings in two climatically and socio-economically similar Romanian mountain municipalities. The novelty of this study lies in the analysis of near-parallel implementations (2020–2023) to combine detailed technical metrics, dynamic cash-flow economics, and life-cycle-based environmental assessment into a single evidence base. Technical results show higher boiler and plant performance for the centralized plant (boiler efficiency ≈89.9%; overall plant energy-use efficiency ≈81%) versus average IBB boiler efficiencies ≈85–86%, with grid heat losses in the BBDHS limited to ∼5%. Quantitatively, the BBDHS substitutes 2,098.6 MWh/year of fossil fuels and saves 489.3 t CO 2 -eq/year; the IBB portfolio substitutes ∼2,198.7 MWh/year and saves 455.2 t CO 2 -eq/year (aggregated), while delivering smaller per-unit energy savings (132.3 vs. 121.3 MWh/a, total fuel-input basis). Economically, the centralized solution outperforms: total CAPEX 810,261 EUR (≈810 EUR/kW) vs. 1,011,741 EUR for IBBs (≈992 EUR/kW); payback 4.63 years, NPV 352,728 EUR and IRR 13.05% for the BBDHS versus 9.56 years and NPV 267,660 EUR for IBBs. Operational staffing and maintenance costs are lower for the centralized plant. Policy-relevant conclusion: where public buildings are spatially clustered and governance is coordinated, centralized biomass district heating offers superior energy efficiency, faster economic payback, and greater lifecycle GHG reduction; decentralized boilers remain valuable for phased investments, resilience and dispersed contexts.