Carbon accounting in the Cloud: a methodology for allocating emissions across data center users

TL;DR

This paper introduces a detailed methodology for allocating energy consumption and carbon emissions among data center users, enabling accurate carbon reporting for cloud services like Google Cloud and Workspace.

Contribution

It presents a novel, granular approach combining resource reservation data, real-time usage, and location-specific carbon intensity to improve large-scale cloud carbon accounting.

Findings

Enhanced accuracy in carbon emission allocation

Integration of resource reservation and real-time usage data

Use of location-specific carbon intensity estimates

Abstract

This paper presents a methodology for allocating energy consumption to multiple users of shared data center machines, infrastructure, and software. Google uses this methodology to provide carbon reporting data for enterprise customers of multiple Google products, including Google Cloud and Workspace. The approach documented here advances the state-of-the-art of large scale Cloud carbon reporting systems. It uses detailed, granular measurement data on machine energy consumption. In addition, it uses physical factors for allocating energy consumption and carbon emissions--preferred by the Greenhouse Gas Protocol's Scope 3 Reporting Standard. Specifically, the approach described here allocates machine energy consumption based on a combination of data center resource reservations and hourly measured resource usage. It also accounts for Google's own internal use of shared software services, reallocating energy use to the users of those shared services. Finally, it uses hourly, location-specific estimates of carbon intensity to precisely measure carbon emissions of users in a global fleet of data centers.