Real-world examples of green coding achievements
Software engineers have many responsibilities, including > social and environmental concerns.
Green coding should be part of every software project.
So far the environmental footprint of a software product is only known of a few:
Software applications with measured environmental footprint
Climate Product Leaders provide a list of case studies:
https://climateproductleaders.org/case-studies/
Reduction of 59 t CO2 per month by removing a 20 kB JavaScript dependency
In January 2020 Danny van Kooten removed a 20 kB JavaScript dependency in Mailchimp for WordPress. He estimated that this removal saves an estimated 59,000 kg CO2 per month.
https://www.dannyvankooten.com/blog/2020/website-carbon-emissions/
Note on the calculation:
Danny used the factor 0.5 kWh/GB data transfer, sourced from the study @Pihkola.etal.2018.EvaluatingEnergyConsumption. 0.5 kWh/GB is the estimated average energy consumption of a 4G LTE network in Finland in 2016. As Danny himself admits in the blog post, it is "hard to come up with a good estimate that works globally". Nevertheless, it is important to note that kWh/GB is a bad metric in general.
Image optimization on a UK local authority website
By reducing their front page from 20 MB to 2.6 MB just by doing some quick image optimization, they estimated that it saved 1.2 tones of CO2 per year or the same as boiling water for 57,000 cups of tea.
https://open-innovations.org/blog/2021-05-28-council-website-emissions
Note on the calculation:
The estimation used websitecarbon.com in 2021.
Sunsetting PHP library Faker
François Zaninotto (marmelab) was sunsetting the PHP library fzaninotto/Faker in October 2020. One reason was, that he released Faker has probably emitted more than 11 Metric tons of CO2 over the years.
https://marmelab.com/blog/2020/10/21/sunsetting-faker.html
Image from Wikipedia was downloaded 78 Mio times per day by accident
The mysterious photo of a purple flower that receives 78 million hits each day - Rest of World
Switch of the keyboard on Android saves 18 %
It is possible to save nearly 18% of energy by replacing the most used keyboard in Android by the most efficient one.
Games
To summarize, we are saving 15% on our power consumption without any impact whatsoever to the player experience. The result is invisible to the player. Once we developed a functional change, we were able to prove that we could work together and earn the trust of our leadership team.
β https://learn.microsoft.com/en-us/gaming/sustainability/case-studies/case-studies-halo
Fortnite's team found it possible to make a significant difference with a small development effort. You can read more about how this was achieved in Epic's dedicated white paper: Reducing Fortnite's Power Consumption:.
As a result of these changes, we estimate around 200 MWh per day of savings across Fortnite's total player base, or 73 GWh per year
β https://learn.microsoft.com/en-us/gaming/sustainability/case-studies/case-studies-fortnite
Since 2021, ESO has an energy footprint well into the tens of millions of kilowatt hours just on Xbox consoles. During the first week when these changes were rolled out, we saw a 5% improvement in energy efficiency. This means that these improvements on Xbox, over the next 3 years could save the equivalent of nearly 1 million pounds of burned coal or more than 2 million miles driven by an average gas-powered vehicle.
β https://learn.microsoft.com/en-us/gaming/sustainability/case-studies/case-studies-elder-scrolls-online