Digital products: how are calculated my emissions?

• General methodology - direct access
• Devices - direct access
• Networks - direct access
• Servers - direct access
• Services & APIs Used - direct access
• Add an Emission Factor - direct access

 

General methodology

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The Carbo method is based on research, publications from laboratories, and insights from companies specialising in electricity consumption and the carbon impact of digital technologies.
The calculation methodology is consistent across websites, mobile apps, SaaS applications, and APIs. However, the questions asked vary to make it easier to assess your emissions based on the information you have available.
The CO₂e emissions from your digital services are generated by the electricity consumption of three distinct sources:

Devices (computers or phones) that consume your services and content via your website or app
Networks through which data is transmitted to your users
Data centres that host your data and code, and respond to user requests

Thus, the impact of your websites, APIs, and mobile apps is the sum of the impact from devices, networks, and hosting.

Devices

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Your website, app, or SaaS software’s traffic data helps determine the screen time consumed.
Depending on the devices used, the type of application, and the content consumed, we determine an electricity consumption coefficient per minute of use.
We can then calculate the total electricity consumption linked to the use of your sites and applications, and thus the CO₂e emissions associated with this electricity consumption (based on the energy mix of the country or countries involved).

• If the majority of users are in France, use: 90% France Emission Factor + 10% Europe Emission Factor
• If the majority of users are in Europe, use: 10% France Emission Factor + 70% Europe Emission Factor + 20% International Emission Factor
• If the majority of users are in the USA, use: 5% France Emission Factor + 10% Europe Emission Factor + 70% USA Emission Factor + 15% International Emission Factor
• If users are international, use: 100% International Emission Factor
  
  

Electricity Consumption Coefficients per Minute of Use

• Website usage electricity consumption: 0.13 Wh/min (Source: Greenspector)
• Mobile app usage electricity consumption: 0.315 mAh/sec (Source: Greenspector)

 

Website Consumption Calculation Details

The average electricity consumption for visiting a website is calculated based on usage from both computers and mobile devices:

(0.20 + 0.06) / 2 = 0.13 Wh/min

Mobile website visit:

0.20 Wh/min = (15.85 mAh/min × 3.83 V) / 1000

15.85 mAh/min: Energy consumption of a mobile device using Google Chrome (Greenspector)

3.83 V: Mobile device voltage

Desktop website visit:

0.06 Wh/min = (18.9 mAh/min × 10.8 V) / 1000

10.8 V: Voltage of a computer, assuming a common battery capacity of 4400 mAh (48 Wh), with 6 cells at 10.8 V (Source)

Mobile App Consumption Calculation Details

0.315 mAh/sec × 60 sec = 18.9 mAh/min (Source: Greenspector) – Electricity consumption of a mobile app.

 

Networks

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For a website or SaaS application, the number of page views and their size allow you to calculate the amount of data transmitted over networks when using the service.

For a mobile app, its size, the number of downloads, and the amount of data consumed during usage allow you to calculate the amount of data transmitted over networks when using the service.

Electricity intensity coefficient for data: 0.43 kWh/GB (Source)

Servers

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If your hosting provider directly supplies your CO₂e emissions data, you can enter this information during your data collection process. This is the most accurate method for estimating the impact of your hosting.

If not, we can estimate your emissions using other collected data. Traffic information and the amount of data stored, combined with the processing time per request on your servers, allow us to estimate the average number of servers used within a cloud infrastructure—or the number of servers you own/lease—to handle the calculated load and traffic.

Details about your hosting provider help determine the energy efficiency of the data centre and the electricity mix powering your servers. This enables us to calculate the CO₂e emissions generated based on the number of servers in use.

The calculation for the number of servers required to manage your site’s traffic differs depending on whether you have your own infrastructure or share a large data centre’s infrastructure via the cloud. The energy efficiency of servers also depends on their location.

 

 

For each hosting provider, we have estimated a carbon intensity per euro spent, based on their revenue and carbon footprint reports. The formula is as follows:

Carbon intensity (kgCO₂e/€) = Total scope emissions (kgCO₂e) / Revenue (€)

Equinix
2020 Revenue: $5,999,000,000 = €4,910,961,370 (Exchange rate as of 21/12/2020: 1 USD = 0.81863 EUR)
GHG Emissions: 3,968,300 tCO₂e
Scope 1: 55,100 tCO₂e
Scope 2 (location-based): 2,280,200 tCO₂e
Scope 3: 1,633,000 tCO₂e
Source: Equinix, June 2020 – "Sustainability Report Highlights FY2020"

AWS (Amazon Web Services)
2019 Carbon Footprint: 60,640,000 tCO₂e
2019 Revenue: €316,031,434,185 (Exchange rate as of 31/12/2020: 1 EUR = 1.2216 USD)
Renewable Energy: 50% of data centre energy consumption (Source: Amazon, December 2020 – "Amazon Sustainability Report: All In")

Google Cloud Platform
2019 Carbon Footprint / 2019 Revenue: Data not specified
Renewable Energy: 61% of data centre energy consumption (Google purchases renewable energy certificates to cover 100% of energy needs)
Source: Google, September 2020 – "24/7 by 2030: Realizing a Carbon-free Future"

OVH
2019 Revenue: €600,000,000
2019 Carbon Footprint: 106,658 tCO₂e
2017 Revenue (by server count): €400,000,000
2017 Carbon Footprint (ADEME platform): 67,406 tCO₂e
Per Server (2017): 0.2246866667 tCO₂e/server (300,000 servers)

Scaleway
2020 Carbon Intensity: 0.26 kgCO₂e/€
2020 Emissions: 21,398 tCO₂e
2020 Revenue: €81,972,600

Our calculations take into account the proportion of renewable energy used by the hosting provider.

• AWS: Global average: 50% renewable energy used by their data centres. Source: Amazon, December 2020 – "Amazon Sustainability Report: All In".
• Google: Google purchases Guarantees of Origin to match 100% of its energy needs with renewable energy (equivalent to a green energy offer). 61% renewable energy consumed by their data centres. 
• Source: Google, September 2020 – "24/7 by 2030: Realizing a Carbon-free Future".

The following emission factors (FE) are averages calculated by our Data team:

• Elsewhere in the cloud – average
• On your own servers – average
• Microsoft Azure – average

For the full methodology guide on calculating the CO₂e impact of digital usage, click here.

 

External services & APIs used

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For external services and APIs, we base our estimates on the monetary emission factor from ADEME.

This is a monetary emission factor. To understand what this means and how it is calculated, click here. You can also access ADEME’s full methodology.

Add an emission factor

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Would you like to request the addition of a specific emission factor for your activity? Read this article.