Carbon footprint of images on the web

Talk prepared for Toronto Web Performance Group meetup:
In Commission to No Emissions: Conversations on Kb, Kw and Climate
https://www.meetup.com/Toronto-Web-Performance-Group/events/283332963/

Some stats from ImageEngine

Transcript

1. VP
   a
   t im
   a
   geengine.io | @im
   a
   geCDN
   Carbon footprint of images
   Jon Arne Sæter
   å
   s
   

   @jon
   a
   rnes
   

   View Slide

2. of CO2 eq s
   a
   ved by Im
   a
   geEngine in December 2021
   243 tonnes
   Same as from burning almost 900 barrels of gasoline
   
   
   or
   
   
   planting 4018 trees and let them grow for 10 years
   

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3. How to calculate Co2 footprint?
   1. Find the kWh needed to transmit 1GB
   
   
   • Numbers ranging from 0.06kWh to 7kWh
   
   
   • What to include (storage, processing, cooling…)?
   
   
   2. Find the CO2 emitted to produce 1 kWh
   
   
   • Where/How is the electricity produced?
   
   
   • Norway: 22g CO2/kWh
   
   
   • India: 718g CO2/kWh
   
   
   • Globally 200-500 CO2/kWh
   • 1 GB require 1 kWh
   
   
   • 1 kWh produces 500g CO2
   My estimate from 2019
   

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4. The system
   Mobile
   Desk/Laptop
   2G
   3G
   4G
   Wi
   fi
   /ether
   Internet plumbing
   Processing
   Storage, backup
   0.08 kWh/GB
   37 kWh/GB
   2.9kWh/GB
   0.5 kWh/GB
   0.08 kWh/GB
   0,0316 kWh/GB
   0,072 kWh/GB
   0,0128 kWh/GB
   Shift Project: 36% 29% 35%
   

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5. ImageEngine
   Mobile
   a
   nd connectivity
   25 %
   75 %
   4G
   3G and less
   20 %
   80 %
   Mobile connectivity
   Non-mobile
   49 % 51 %
   Mobile connectivity
   Non-mobile
   Globally India Connectivity, India
   

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6. • 12 image variants are required to serve 95% of your
   users with the best image. (3 variants cover 75%)
   0
   20
   40
   60
   80
   100
   120
   1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65
   Variants
   • 21% of requests have the “Save Data”/“Lite mode”
   enabled.
   21 %
   

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7. • Converting JPEG → WEBP = >90% savings
   • Optimising JPEG → JPEG = >80% savings
   
   
   JPEG
   WEBP
   0 25 50 75 100
   JPEG
   JPEG (o)
   0 25 50 75 100
   • The byte saving potential of images is between
   60-90%
   Original
   Optimized
   0 25 50 75 100
   

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8. • Optimising PNG → WEBP = >95% savings
   

   (why do we still use PNGs?)
   • Optimising PNG → PNG = >85% savings
   

   (why do we still use PNGs?)
   PNG
   WEBP
   0 25 50 75 100
   PNG
   PNG (o)
   0 25 50 75 100
   GIF
   aWEBP
   MP4
   0 25 50 75 100
   • Converting a GIF to MP4 instead of WEBP is
   30% more e
   ff
   ective (and >90% better than the
   original GIF)
   

   View Slide

9. • JPEG2000 in many cases perform better than WEBP and AVIF
   • AVIF?
   
   
   • Jury is still out… It’s a tradeo
   f
   between visual quality, byte size and
   encoding/decoding e
   ff
   i
   ciency.
   

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10. Bec
    a
    use it h
    a
    s to be tr
    a
    nsferred
    a
    nd stored
    Reduce Payload!
    Data centres may be “green”, but what’s the alternative use if that electricity?
    

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11. 🍀Please consider the environment and print this email in stead of storing it in the clouds forever
    

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12. References
    • https://www.carbonbrief.org/factcheck-what-is-the-carbon-footprint-of-streaming-video-on-net
    fl
    ix
    
    
    • https://www.mdpi.com/2071-1050/10/7/2494/htm
    
    
    • https://www.epa.gov/energy/greenhouse-gas-equivalencies-calculator
    
    
    • https://app.electricitymap.org/
    
    
    • https://www.iea.org/reports/global-energy-co2-status-report-2019/emissions
    
    
    • https://theshiftproject.org/en/home/
    
    
    • https://energyinnovation.org/2020/03/17/how-much-energy-do-data-centers-really-use/
    
    
    • https://www.cmswire.com/digital-experience/calculating-the-pollution-e
    ff
    ect-of-data/
    
    
    • https://www.mdpi.com/2078-1547/6/1/117/htm
    
    
    • https://onlinelibrary.wiley.com/doi/10.1111/jiec.12630
    
    
    • https://www.wholegraindigital.com/blog/website-energy-consumption/
    

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