The construction industry in India has been registering an impressive growth currently, overcoming the temporary setback witnessed during the Coronavirus pandemic. Once the pandemic got over, it seems that the industry is pursuing the growth path more vigorously. Almost all urban centres are throbbing with a variety of construction activities. Hectic construction of building physical infrastructure such as roads, highways, flyovers, metros is seen progressing simultaneously at different locations in various urban centres. At the same time, local newspapers are replete with advertisements seeking customer registrations in new launches of commercial and residential housing. The modernization of urban landscape with active participation of the construction industry is certainly a welcome development.
Currently, the Indian construction industry is ranked amongst the top five construction industries in the world. According to the Government of India’s “Invest India” platform, the Indian construction industry is expected to reach US$ 1.4 trillion by 2025. Certain futuristic projections about India’s urban sector indicate that the participation of building and construction would be crucial for its growth in coming years. The latest report of the Ministry of Environment, Forest and Climate Change projects that the urban Indian population is estimated to increase sharply from 377 million in 2011 to 600 million by 20301. Another report from the International Energy Agency (IEA) makes certain projections on the Indian scenario–2040. The IEA report reveals that an estimated 270 million people will be added to urban Indian population in the next two decades and that around 30 billion m2 of floor space will be required for accommodating these people2. This means that on an average, around 1,500 million m2 floor space needs to be built every year from 2020-2040! In addition to housing, suitable infrastructure in terms of additional roads, schools, hospitals, malls, water storage tanks, pipelines etc. is also required to be provided to the new entrants in the urban area. This is indeed a gigantic and challenging task.
Such massive construction in the current and the next decade would require a considerable amount of cement, concrete, steel and walling materials. Hence sustainability of construction would be of crucial importance. This is because all these materials would require enormous amounts of energy for their production on the one hand and the materials are produced mostly from non-renewable natural resources, on the other. Till recently, sustainability of construction was euphemistically connected with the green building rating systems. These may not suffice as the sustainability of construction is now closely getting linked with the reduction of carbon emissions from construction.
Carbon emission from the built environment is broadly divided into two categories, namely ‘operational carbon’ and the ‘embodied carbon’. Operational carbon encompasses emissions that arise owing to the energy-centric operations in buildings and construction such as heating, cooling, ventilation and lighting, etc. The simple tool to mitigate operational carbon is to reduce operational energy demand by undertaking all possible energy efficiency measures, use of passive architectural design and then the remaining energy requirements to be met with renewable energy in place of fossil fuel-based energy.
Embodied carbon is associated with the emissions of carbon during the five main stages of building’s/structure’s entire Life Cycle i.e. – product stage, construction stage, operation stage, deconstruction stage and beyond life cycle stage. It is reported that nearly 50% of embodied carbon is coming from the “Product” stage i. e. owing to the energy used in the raw material extraction, processing, transport, and manufacture (cradle to gate stage). It would be a good idea to tackle such reduction as much as possible.
In this context, we would like to draw the attention of our readers to the recent Special Issue of the Structural Engineering Digest on the theme Structural Engineering for Sustainable Development3, which incidentally was guest-edited by the present writer. We are re-publishing two technical papers from this Special Issue (under the category ‘Decarbonising Built Environment’) for wider dissemination of the concept of embodied carbon, its evaluation, mitigation, benchmarking, etc.
The first paper by paper by Er. Abhijeet Kulkarni and co-authors describe the major challenges faced in evaluating embodied carbon in the typical Indian context. The authors have covered topics such as the influencing parameters and complexities involved in such evaluation. The second paper by Dr V. V. Nori presents brief case histories of some integral bridges constructed in India during the past four decades. The paper also includes quantities of concrete and steel – major energy-intensive materials – used during construction and summarizes calculations of the embodied carbon. It can be seen that barring two outlier values, the average embodied carbon of integral bridges is just 473 kgCO2e. We do not have benchmarking data for comparison. However, prima facie, it seems that integral bridges present not only a structurally efficient, durable and cost-effective alternative but also the one having lower embodied carbon!
While sufficient technical guidance is now available from authentic literature on evaluation of embodied carbon of structures, it is high time that the civil engineering fraternity in India start the practice of evaluating embodied carbon for all new projects they are involved with. While it will take time to create national/regional benchmark values of embodied carbon under different categories of structures, it may be a good idea that the practice of creating benchmarks of embodied carbon for the projects executed are created by individual organizations in-house.
References
- India’s Long-Term Low Emission Development Strategy, Ministry of Environment, Forest and Climate Change, submitted to the United Nations Framework Convention on Climate Change (UNFCCC), November 2022,
- 2021. India Energy Outlook 2021. International Energy Agency. Paris, France. https://www.iea.org/reports/india-energy-outlook-2021
- Structural Engineering Digest, Theme ‘Structural Engineering for Sustainable Development’, Indian Association of Structural Engineers, Vol. 13, Issue No 1, Jan-Mar. 2023.