Photovoltaic deployment strategies for net-zero commercial buildings in India: A climate-zoned benchmarking approach

Decarbonizing the energy-intensive building sector requires systematic integration of on-site renewable generation with building energy performance evaluation. This study develops and applies a structured Photovoltaic Energy Generation–Net Zero Energy (PVEG-NZE) assessment framework to comparatively evaluate rooftop-mounted and façade-integrated photovoltaic (PV) systems for low-rise commercial buildings across four tropical climate zones in India. Building energy simulations are coupled with detailed PV performance modeling to quantify annual electricity generation, energy performance improvements under national code-compliant scenarios, and net-zero energy (NZE) offset potential. A key contribution is the formalization and validation of the Photovoltaic Energy Generation Intensity (PV-EGI) metric, defined as annual PV output per unit installed area (kWh·m −2 ·yr −1 ), enabling area-normalized benchmarking and climate-based preliminary performance prediction for defined PV deployment strategies. Results indicate that façade-integrated PV systems generate 33–39% higher total annual electricity due to larger deployable surface area, whereas rooftop PV systems demonstrate superior per-unit-area performance. Validation against measured data from real-world case-study installations demonstrated prediction errors of approximately 16–20% with correlation coefficients (R 2 ) ranging from 0.60 to 0.78, indicating reasonable agreement between predicted and measured photovoltaic performance, thereby supporting the applicability of the proposed framework for preliminary performance assessment. By integrating photovoltaic generation modeling with building energy demand assessment, the study establishes a climate-zoned benchmarking approach for evaluating net-zero energy offset potential in Indian commercial buildings, supporting the transition toward net-zero buildings and near-term decarbonization objectives.