The Carbon Footprint of Servers

What is the carbon footprint of your company’s servers? And how easy is it to find out? By sorting out a few questions regarding your company’s servers, you can get a rough estimate of your servers climate impact.

Last updated: 2024-08-27

There are two factors that you need to take into consideration when estimating the climate impact of your servers; 1. if the electricity used is green or not 2. if the servers are in the cloud or not.

When calculating the emissions from your servers, there are four categories to take into consideration to make a rough estimate. More categories could easily be constructed to achieve more precise estimations, but our goal is to make it as easy as possible to calculate the footprints. The four categories we ended up with are:

Cloud server using 100% green electricity: 160 kg CO2e / year and server
Cloud server using non-green electricity: 621 kg CO2e / year and server
On premise or data center-server using 100% green electricity: 320 kg CO2e / year and server
On premise or data center-server using non-green electricity: 1243 kg CO2e / year and servers

You find the calculations and assumptions for these numbers further down at this page

How do I know if the electricity our servers are using is 100% green?

With green electricity we mean fossil free electricity, so both renewable energy sources and nuclear energy are considered green – and are in our calculations considered having a zero climate impact. This is not 100% true since both renewable sources and nuclear sources have a carbon footprint from construction and maintenance, but the climate impact is negligible in comparison with electricity from fossil sources. Depending on where your servers are located, there are different ways of finding out if the electricity your servers use is green:

On premise-server – check your electricity contract or contact your electricity-provider
Data center-server – check your contract or contact your provider
Cloud servers - this is a bit more tricky. This table gives a short answer per provider, see the links underneath for a deeper understanding

Cloud server electricity

None of these runs to 100% on green electricity, it depends on the electricity source of the grid where they're located.

Cloud provider	Grade	Purchase of Green Energy	PUE & WUE
Google¹	A-	In 2019, 100% of all the electricity used was matched with regional, carbonfree sources. On an hourly basis 61% was matched.	1.07 > PUE > 1.19 WUE - N/A
Azure²	A-	By 2025 it will have Power Purchase Agreements for green energy contracted for 100 percent of carbon-emitting electricity consumed by all datacenters, buildings, and campuses. Swedish locations already match 100% with green energy.	1.12 > PUE > 1.4 0.03 > WUE > 2
AWS³	B+	In 2023, 100% of all the electricity used was matched with renewable energy sources. No hourly information found.	PUE - N/A WUE 0.18
Oracle⁴	B+	Committed to matching 100% renewable energy usage across its global platform by 2025. It reached 80% in 2022. No hourly information found.	1.13 > PUE > 2.33 WUE - N/A
IBM⁵	B-	74% of the electricity consumed in the data centers came from renewable sources in 2023. Globally, 28 data centers were matched 100% with renewable electricity.	PUE = 1.46 weighted average WUE - N/A

How do I know if my servers are in the cloud?

This might sound like an easy question, but there are many local providers that have smaller cloud-like solutions that might be as energy effective and utilize servers as good as the larger ones. So the question you should ask yourself here – if you are unsure if your servers can be considered being in the cloud or not – is if your provider can utilize servers about as effectively as the larger providers and if they can have the same energy efficiency as the larger ones.

Calculations and assumptions

An on-premises data center is 29 % less efficient in their use of power compared to a typical large cloud provider that uses top facility designs, cooling systems, and workload-optimized equipment. Source: Wikipedia: Power usage effectiveness We have decided to apply a simple factor of 0.5 for the energy consumption and server utilization of servers in the cloud. Amazon AWS claims a reduction of 84% in the amount of power required, but since we don’t have data for other providers we prefer to be a bit more conservative here. We have used the Nordic Residual Energy mix as the factor for CO2e emissions per kWh. The factor is 0,5241 kg CO2e / kWh (updated 2024). The reason for us using this is that most businesses using our calculator are expected to be in the Nordics. We have chosen to use data from a standard 2019 R640 Dell server. A high end but not unusual server being bought 2019. An exact server model for the ones you are using or your cloud server provider uses would give more precise data, but we believe this one gives a good estimation.

So, if we use these number and assumptions from above:

Emissions from production of servers for use on premise: 320 kg CO2e/year
Emissions from production of servers for use in cloud (since 50% is manufactured for use in cloud): 160 kg CO2e/year
Emissions from green power consumption: 0 kg CO2e/year
Emissions from non-green consumption for premise power or self-managed servers: 1760,3 kWh / year * 0,5241 CO2e / kWh = 923 kg CO2e
From non-green cloud power consumption: 1760.3 kWh / year * 0,5241 CO2e / kWh * 0,5 = 461 kg CO2e

This results in these factors for our four categories:

1. Cloud server using 100% green electricity: 160 kg CO2e / year and server 2. Cloud server using non-green electricity: 621 kg CO2e / year and server 3. On premise or data center-server using 100% green electricity: 320 kg CO2e / year and server 4. On premise or data center-server using non-green electricity: 1243 kg CO2e / year and servers.