Network Carbon Intensity

Network carbon intensity measures the amount of carbon dioxide equivalent (CO₂e) emissions generated per unit of data transferred across network infrastructure. Since carbon emissions from network transfers cannot be directly measured, they must be estimated. Network carbon intensity is calculated using two factors:

• Network Energy Intensity (kWh/GB)
• Grid Carbon Intensity (g CO₂e/kWh).

Methodology#

The network carbon intensity methodology and data sources used by the Green Metrics Tool are documented in detail on our CO₂ Formulas page.

Relevance for the Green Metrics Tool#

The Green Metrics Tool aims to provide not just the energy consumption of the device, but also an estimated value for the carbon emissions resulting from network data transfer. To achieve this, it uses the network carbon intensity approach.

Although network emissions are not officially part of the Software Carbon Intensity (SCI) specification, the Green Metrics Tool includes them to offer a more complete view of your software’s carbon footprint.

Measurement Approach#

The Green Metrics Tool aggregates all network traffic from all containers and estimate CO₂ emissions using the CO₂-Formula. This approach assumes that all traffic is with external services. However, if your containers only communicate with each other and run on a single machine in production, the calculated emissions will significantly overstate the actual CO₂ impact.

We made this design choice because, during benchmarking, we can’t predict how your containers will be orchestrated in production. They might all run on one machine (resulting in zero network emissions), be distributed within a data center (with minimal emissions), or be spread globally (incurring the highest emissions). Since the Green Metrics Tool is meant to provide a baseline for optimization, we chose to report based on the worst-case scenario.

Configuration#

You can configure the network energy intensity as part of the SCI configuration in config.yml:

sci:
    N: 0.001875 # unit: kWh/GB

GMT calculates the network carbon intensity as:

network_data_transfer × N × I

The factor I is described in Grid Carbon Intensity.