As cloud providers and hardware manufacturers are becoming more environmentally aware, more hardware is being reused and recycled. This reduces the embodied emissions of cloud computing, because it reduces the need for raw material extraction and the manufacture of new hardware. This lowers the overall quantity of emissions associated with each hardware component. It is important to account for this when calculating embodied emissions, to produce more reliable results, and to encourage cloud providers to further their efforts towards responsible end of life processes.
However, calculating accurate disposal figures is challenging. It is impossible to track a hardware component to its end-of-life journey. Without providing data to support this claim, AWS states that it:
‘sends all functional, sanitized, retired server racks and components to its reverse logistics hubs. There, server racks are securely demanufactured, and components are repaired and tested for reuse in our data centers.’
All hardware may be sent to the recycling hubs, but AWS does not specify what percentage of this hardware is then reused. Azure is more specific, reporting that they reuse or recycle 89.4% of their cloud hardware.
Tailpipe matches this data with the most comprehensive emissions analysis of data center hardware to be published to date: the 2019 Dell R740 Server Life Cycle Analysis. This report details the embodied and operational emissions produced by a single R740 server, broken down into detailed analyses of each hardware component and the additional transport, assembly, and disposal processes required across the product’s lifetime.
Dell calculates that the end-of-life recycling and reuse of hardware components results in an approximate 1.8% reduction in the overall emissions associated with the server. This is based on an 82.32% recycling rate for the server electronics, and a 100% recycling rate for the server’s aluminum and steel casing. Azure and AWS do not specify which proportions of electronics and metals are recycled from their hardware, so Tailpipe considers the Dell figure to represent a valid industry standard.
Tailpipe therefore factors this 1.8% reduction into its embodied emissions methodology.
