Life cycle carbon analysis is like a silent conductor in the harmony of existence, revealing the carbon story of our creations. Every product and process follow a journey from creation to disposal, imprinting a lasting carbon footprint on the sustainability stage. With careful examination, this analysis exposes the play of emissions, from raw material extraction to disposal. Delving into the cradle-to-grave journey, this assessment becomes an indispensable tool for fostering informed decision-making and cultivating a harmonious coexistence with our planet.
- Global Construction Sector Emissions (2021):
- Total: 37% of global energy and process-related CO2 emissions.
- Breakdown: 27% energy-related emissions, 10% from materials used.
- Building Emission Reduction Targets:
- IPCC Target: 80-90% reduction by 2050.
- Near-Zero Energy: New construction to be fossil-free and near-zero energy by 2020.
- IEA’s Net Zero Pathway (2030):
- Overall Buildings Sector CO2 Emissions: Fall around 5 GtCO2 in 2030
- Reduction Target: 0.6 GtCO2 per year to achieve net-zero by 2050.
Embodied carbon and embodied water in building materials
Embodied carbon is sometimes ignored since it’s negligible in comparison to operational carbon and has, up to now, been mainly disregarded in regulations. The building and construction industry is responsible for around 40% of the world’s greenhouse gas emissions. Embodied carbon, or the greenhouse gases released during the extraction of raw materials for products that will be used in the building, their transportation to the factory, the manufacturing of the products, their delivery to the site, the building’s construction, and the building’s eventual deconstruction and demolition, accounts for 11% of these emissions.
The building industry uses 30% of the fresh water available worldwide, according to the United Nations Environmental Programme. A building’s embodied water is the sum of the water used during construction as well as the water used to extract and manufacture the materials utilized in the building.
The diagram lists their embodied carbon and embodied water of conventional building materials.
Conventional building materials, which are mostly made of finite resources, add a substantial amount to the carbon intensity of construction projects. By reducing embodied carbon, green building materials promote a sustainable mindset. They are usually produced locally, use less energy-intensive procedures, and come from renewable sources, all of which help to reduce emissions associated with transportation. Carbon efficiency, green building materials typically provide superior water conservation measures, demonstrating their comprehensive commitment to reducing the environmental effect of the construction sector. The below table provides few alternative solutions in choosing the building material which has very less embodied water and embodied carbon when compared to a conventional material.
Benchmarks of LCA
LCA measures impacts through a variety of metrics, such as global warming potential, acidification potential, eutrophication potential, smog formation potential, and ozone depletion potential. For construction sector the major environmental impact is GWP. Global warming potential (GWP) is the metric used to measure and track embodied carbon. Embodied Carbon of buildings many LCA benchmarking studies have been done and have come with the values as listed in the table.
Modules & Stages of LCA
EN 15978 defines the LCA calculation methodology, and it divides the life cycle of the building into different stages. A 1 – 3 covers production stage, A 4 – 5 construction process stage, B 1 – 7 use stage, C 1 – 4 end of life stage, D – reuse – recycling – recover stage.
- Product stage: Impacts and resource use during extraction, processing, manufacture, and transportation of materials between these processes, until the product leaves the factory gates to be taken to site.
- Construction process stage: Impacts and resource use during transport of materials/products to site, energy usage due to activities on site and the impacts associated with the production, transportation, and end of life processing of materials wasted on site.
- Use the stage: Impacts and resource use due to the use, maintenance, repair, replacement, refurbishment and operational energy and water while the building is in use. Module B4 (replacement) is often the focus of the use stage when embodied carbon is being considered.
- End of life stage: Impacts and resource use during decommissioning, stripping out, demolition, deconstruction, transportation of materials away from the site, waste processing and disposal of materials.
In the ever-evolving landscape of sustainability, the challenges surrounding life cycle carbon assessment in the future loom as formidable hurdles on the path to environmental stewardship. As industries strive to embrace greener practices, the complexity of global supply chains and the integration of emerging technologies pose significant challenges to accurately quantify and assess carbon footprints across the entire life cycle of products. Overcoming the challenges requires collaborative efforts, innovative solutions, and a commitment to refining methodologies to ensure that life cycle carbon assessment remains a reliable compass guiding us toward a sustainable and resilient future.
