Cove.tool optimizes the process for selecting building products with embodied carbon in mind.
What is Embodied Carbon?
Embodied carbon (kgCO2e) refers to the Greenhouse Gases (GHGs) emitted during the extraction, manufacture, transportation, construction, replacement, and deconstruction of building materials, together with the end of life emissions. This is different from Carbon Emissions (also known as Operational Carbon), and one of the many metrics used to understand your building's Carbon Footprint. Embodied carbon is usually expressed at the product level in kgCO2e (kilograms of CO2e), and at the building level in 1,000 kgCO2e (Tonnes of CO2e). Carbon allows for a tangible measurement, in unit-kilogram, to compare and analyze the environmental impact, direct and indirect, of every choice and resulting environmental reaction.
According to the UN Environment Program, the construction and operation of buildings account for 39% of energy-related carbon dioxide emissions annually. In New York City, buildings emit 70% of GHGs, requiring immediate demand for stringent updates to design and construction regulations. In the coming decade, we need to radically decarbonize the industry if we are to avoid the disastrous consequences of crossing the 1.5°C threshold.
Life Cycle Assessment (LCAs)
When calculating embodied carbon it is crucial to keep the assessment period consistent as every step of the product's life cycle emits some amount of GHGs. Typical assessment periods include cradle-to-gate, cradle-to-site, cradle-to-end of construction, cradle-to-grave (LCAs), and cradle-to-cradle. The typical embodied carbon assessment is cradle-to-gate (aka 'product phase' or 'A1-A3'), which is a partial life cycle assessment from resource extraction (cradle) to the factory gate (i.e., before it is transported to the consumer). Embodied Carbon can represent any phase of the building life cycle, but only a full assessment from A1 (extraction) to A7 (end-of-life) is called an LCA or Life Cycle Assessment. The diagram below shows the 7 stages of the LCA: the extraction, manufacture, transportation, construction, replacement, and deconstruction of building materials, together with the end of life emissions.
Conducting a full scope Life Cycle Assessment is an incredibly costly and time-consuming study to undergo and typically requires hiring a full-time Life Cycle Consultant to conduct over a period of several months. At the moment, the most accessible form of calculating embodied carbon is calculating Tonnes kgCO2e for only the Product Phase. This is also Embodied Carbon users will calculate in cove.tool in the next section.
How does cove.tool optimize for Embodied Carbon?
Cove.tool has added embodied carbon as an optional property input in the change option tabs as a new column category in the Optimization Tool. In the former users can add embodied carbon values for each product, and in the latter can analyze the embodied carbon in CO2e (tonnes) for each available bundle option. Read more about optimization here.
What do I need to optimize for Embodied Carbon?
To add embodied carbon to your building performance analysis, you only need the kgCO2e value and multiplier unit of the building product which the user would like to evaluate. These inputs are not yet automated by cove.tool, but can be found through the product's manufacturer website, on a products EPD certificate, or through the EC3 portal. The last option is available through cove.tool as the Building Transparency button at the top on each Change Options Page. Read this article to see how you can use the EC3 Database to locate your building products' embodied carbon value.
Where else can I find Embodied Carbon Values?
If the EC3 Tool did not contain the product you were looking for, the next best resource is going to be finding your products, or a similar product's, Environmental Product Declaration (EPD). EPDs are a standardized assessment of a product or building system's effect on the environment. The assessment includes declaring the product's or building system's global warming potential (embodied carbon), energy and resource depletion, chemical makeup, waste generation, and more. Learn more about EPDs in this article about Greenhouse Gases. Example EPD tables are shown below.
Why do I need to calculate embodied carbon in the early stages?
Buildings contribute to 40% of all CO2 emissions worldwide. Most of this is due to the energy required to operate existing buildings, however, between now and 2060 the world’s population is expected to double the amount of building floor space. Carbon Emissions will soon be outpaced by Embodied Carbon — the emissions associated with building construction, including extracting, transporting, and manufacturing materials. Over the past two decades, we’ve made significant progress in reducing carbon emissions associated with operating buildings. However, according to Architecture 2030, “new research from the IPCC, the UN, and the scientific community stresses the critical importance of a 2030 milestone: if we do not achieve a 45-55% reduction in total global emissions by 2030 we will have lost the opportunity to meet the 1.5/2 ℃ warming threshold and climate change will become irreversible. The immediate focus for embodied carbon reductions must, therefore, be in the next decade. Annually, the embodied carbon of building structure, substructure, and enclosures are responsible for 11% of global GHG emissions and 28% of global building sector emissions. Eliminating these emissions is key to addressing climate change and meeting Paris Climate Agreement targets.”
Read more about the Carbon Leadership initiative here.
Table (above) from the University of Washington’ Embodied Carbon Benchmark Study: LCA for Low Carbon Construction - Part 1. Find your use-type to learn more about a typical kgCO2e benchmark.