The calculation of the energy consumption and environmental impact of Microsoft's public cloud

After the Paris Agreement, with increased attention on climate change and measures taken by governments to reduce carbon emissions, the environmental impact of IT systems is increasingly in the spotlight. Several studies have shown that the cloud also offers significant benefits in terms of sustainability and provides companies with the possibility of reducing the environmental impact of IT services, thus contributing to a more sustainable future. To evaluate the real impact, it is advisable to apply measurements and controls. This article describes the methodology designed to calculate the carbon emissions associated with the use of Microsoft Azure resources.

Microsoft provides tools to monitor and manage the environmental impact of carbon emissions, based on the methodology described in this article, which is constantly evolving and improving. Such tools, specific to the Azure cloud, allow to:

  • Get the visibility you need to promote sustainability, taking into account both emissions and carbon use.
  • Simplify data collection and emissions calculations.
  • Analyze and report more efficiently the environmental impact and progress of a company in terms of sustainability.

This methodology used by Microsoft is constantly updated to include science-based approaches as they become available and relevant for assessing the carbon emissions associated with the Azure cloud.

Standards used for calculation

Microsoft shares its greenhouse gas emissions (GHG) into three categories (scope), sticking to Greenhouse Gas Protocol, a globally recognized standard for the methodology for calculating and reporting greenhouse gas emissions (GHG).

Scope 1: direct emissions – emissions deriving from combustion and industrial processes

Greenhouse gas emissions in this category include emissions from the combustion of diesel and emissions from the use of refrigerants for cooling data centers.

Scope 2: indirect emissions – emissions resulting from electricity consumption, heat or steam

Greenhouse gas emissions in this category include emissions from the consumption of electricity used to power Microsoft data centers.

Scope 3: other indirect emissions – the emissions generated during the production phase and at the end of the product life cycle

Greenhouse gas emissions include emissions from the extraction of raw materials, from component assembly and end-of-life management of hardware devices (for example: recycling, landfill or compost), such as servers and network equipment, used in Microsoft data centers.

Figure 1 – Examples of types of scope carbon emissions 1, 2 and 3 in the Microsoft cloud

In this context, it should be borne in mind that the 2020 Microsoft has reaffirmed its commitment to integrating sustainability into all of its businesses. In fact,, announced an ambitious goal and plan to reduce and ultimately eliminate carbon emissions. Under this plan, Microsoft has set itself the goal of becoming a company “carbon neutral” by 2030, and is adopting various strategies to reduce its carbon emissions, including the purchase of renewable energy sources, optimizing the energy efficiency of its data centers and supporting the transition to a low-carbon economy.


Microsoft bases its calculation methodology also relying on widely accepted ISO standards in the industry:

  • Carbon emissions related to materials are based on ISO standard 14067:2018 (Greenhouse gases – Product carbon footprint – Quantification requirements and guidelines).
  • Operational emissions are based on ISO standard 14064-1:2006 (Greenhouse gases – Part 1: Organization-wide specifications and guidelines for quantifying and reporting GHG emissions and removals).
  • Verification and validation are based on the ISO standard 14064-3:2006 (Greenhouse gases – Part 3: Specifications with guidance on validating and verifying greenhouse gas claims).

Calculation methodologies

Scope 1 and 2

Greenhouse gas emissions related to the use of electricity for scopes 1 and 2 are usually divided into categories such as Storage, Compute and Network. The quantification of the emissions of these scopes is based on the time of use of the individual categories. The methodology used to calculate emissions in Scope 1 and 2 is generally based on a lifecycle analysis present in a Microsoft study, available at this address. This methodology for the Scope 2 includes calculation of energy impact and carbon emissions for each specific data center, considering factors such as data center and server efficiency, the emission factors, renewable energy purchases and infrastructure energy usage over time.

Scope 3

Calculation of emissions relating to the Scope 3 is summarized in the following figure:

Figure 2 – Methodology for calculating emissions relating to the Scope 3

It starts with the assessment of the life cycle of the materials used in the data center infrastructure and the related carbon emissions are calculated. This sum is then segmented based on customer usage of each data center.

This methodology for emissions related to the Scope 3 calculates the energy and carbon footprint for each data center over time, taking into consideration the following:

  • The most common materials used for the construction of the IT infrastructure used in data centers.
  • The main components that make up the cloud infrastructure.
  • The complete list of all assets in Microsoft data centers.
  • Carbon factors for cloud infrastructure at all stages of the lifecycle (extraction of raw materials, component assembly, use and disposal at the end of the life cycle).

Validation of the Microsoft methodology for scope 3 is published at this link.

Common definitions

This section contains definitions of the most frequently used terms relating to the impact of emissions:

  • mtCO2e: is the unit of measurement used to express the impact of greenhouse gas emissions on the global greenhouse effect. It takes into account not only carbon dioxide emissions (CO2), but also of other greenhouse gases such as methane (CH4), nitrous oxide (N2O) and fluorinated gases (F-gases). mtCO2e is used to measure global greenhouse gas emissions and to set emissions reduction targets.
  • Carbon emissions (mtCO2e) from Azure: carbon emissions (mtCO2e) for the Azure cloud refer to the amount of greenhouse gases, mainly carbon dioxide (CO2), emitted into the atmosphere due to the use of Microsoft Azure cloud computing services. This value includes Microsoft Scopes (1, 2 it's the 3).
  • Carbon intensity (mtCO2e/usage): the carbon intensity index provides a ratio between carbon dioxide emissions and another variable. For Green SKU, this is the total carbon dioxide equivalent emissions per hours of use, measured in mtCO2e/hour. The purpose of this index is to provide visibility into carbon emissions related to the use of Azure services.
  • Carbon emissions expected at the end of the year (mtCO2e): Projected end-of-year cumulative carbon emissions allocation based on current year's cloud resource usage projection and previous year's trends.


To identify the benefits to the IT environment of deploying applications on Azure, it is important to educate customers about the environmental impact of their IT assets and provide them with the tools to govern that impact. This must be done with the intention of improving, setting specific and realistic sustainability objectives. Such an approach benefits both the business and society.

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