A Calculation Method of Embodied Carbon-energy for Low-carbon Products

This paper was aiming at creating an effective way to calculate product's carbon emissions at the perspective of products themselves rather than the whole system boundary. In order to calculate the carbon emissions in the manufacturing stage and usage stage, as the two largest contributors in life cycle, we propose a calculation method of "embodied carbon-energy (ECE)" of products/components/parts. The ECE took carbon footprint as a metric for estimating energy and materials variation occurring in various phases of products. First, we divided the activities happened in products' life cycle into two types, i.e. active energy activities and auxiliary energy activities. Then, we discussed the two main phases in detail. In the manufacturing stage, the increment of ECE was increased due to energy variation in manufacturing processes. Therefore, the active energy activities were the processes providing for components or parts, containing mass-reducing processes, mass-unchanging processes and joining processes; the auxiliary energy activities provided support for processes. Similarly, in the usage stage, the increment of ECE was increased caused by different functions needed to be realized. The active energy activities were energy consumption by using products; the auxiliary energy activities were manly caused by various subcomponents of products. The total ECE was the sum of initial ECE and the ECE of activities in these stages. Finally, an example of honing machine and its critical components validated the feasibility of the proposed method. The method provided a novel insight into the calculation of carbon emissions in the main life cycle phase of products and laid a foundation for low-carbon design from the perspective of products themselves for further study.