Bridging methodological gaps in building life cycle assessment: a case study in the Indian context

India’s building sector contributes approximately 25% of the nation’s GHG emissions, with 45% from material manufacturing and the remainder from building operations. As India’s floor space is projected to double in the next two decades, emissions are expected to rise. Current Indian policies primarily target reducing operational carbon, but addressing embodied carbon across the building lifecycle is equally crucial for comprehensive decarbonisation of the sector.

Life Cycle Assessment (LCA) considers emissions from manufacturing of materials/ building products, use phase, and end-of-life, guiding key design decisions to reduce overall emissions. While there is a growing interest in LCA of buildings in the Indian context, many of the studies face challenges due to inconsistent embodied carbon data for building materials and products, with different datasets often using different LCA analysis boundaries or geographic-specific data, which undermines the reliability of their results. These inconsistencies are further exacerbated by lack of standardised guidelines on data sources and assumptions, as well as the unavailability of comprehensive data across the lifecycle of buildings given the long life of the asset.

This study reviews existing literature on the life cycle assessment (LCA) of buildings both in the Indian context and globally, compiling the best available data on embodied carbon and methodologies for estimating emissions across different life cycle stages. A case study is developed for a small commercial office building in the Indian context using the identified methodologies and sources of data.

The results are compared with those from commonly used commercial LCA software (One Click LCA) to analyse gaps arising from the lack of India-specific data and uncertainties in estimating emissions at various life cycle stages. Additionally, the study explores how LCA can guide building design and material choices by evaluating both embodied and operational carbon emissions for conventional and low-carbon construction materials.

This study adds value by collating the best available methods and data from the literature to estimate emissions across different life cycle stages in the Indian context, aiming to reduce methodological inconsistencies and improve the accuracy of LCA results.

Preliminary results indicate that operational energy emissions constitute 85% of total building lifecycle emissions, while embodied carbon emissions account for 15%. Material analysis reveals that cement contributes 39% of lifecycle embodied carbon, followed by steel at 23% and aluminium at 12%.

This assessment bridges the gap between theoretical LCA methodologies and practical implementation in India’s building sector, promoting more sustainable building designs.