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Discussion on: Why “dark mode” is more energy-efficient: How to calculate image energy-cost

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moopet profile image
Ben Sinclair

That research is a decade old now - transfer costs have presumably continued to improve since then.

It's also very awkward to define. They're trying to come up with some global average, but it clearly doesn't take the equivalent of three space heaters to move a movie from one hard drive to another. Numbers like 5KW aren't useful unless they have a time component (this is why you get charged in "kilowatt-hours")

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Mads Stoumann • Edited

In general, "the cost of the internet" is difficult to measure, I guess.
The number 416.2twH pops up as "this is what the internet costs", but that's just the electricity to drive data-centers etc. There's also the cost of building data-centers (in terms of CO2 emissions, where 1kg cement === 1kg CO2) and the infastructure around it. And if we need to calculate the cost of downloading data to a device, we also need to measure the costs of our routers, modems, and ... it's ... difficult!

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GrahamTheDev

Difficult is landing a rocket on the moon, calculating the actual cost of the internet is impossible I would say as we don't have enough data 😋🤣

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madsstoumann profile image
Mads Stoumann

Not to mention all the different energy-units! We're measuring emissions in CO2, but the energy that creates them in KwH/TwH, eV ... even calories! In meat-production, a cow needs to eat 6 calories to produce the meat-equivalent of 1 calorie for us to eat - but we measure the end-result in CO2 - phew!

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GrahamTheDev

Haha - we should measure everything calories...I mean I don’t have a chance as I live in the UK so we measure food in calories, temperature in Celsius, oven temperatures in “Gas Marks”, fuel usage in miles per gallon....you get the idea!

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GrahamTheDev • Edited

Yes the numbers vary wildly, websitecarbon.com/how-does-it-work/ gives 1.8kwH / GB - which means you need to save around 55kb a page - still easy for most sites.

And yes the numbers are imperfect but the idea of this was to show a) how little power screens actually use today (which I find astounding!) and b) show that saving kb is the way to be greener and the one that most people can do.

This doesn't take anything away from dark mode, I am currently using the site in dark mode and I am a big fan, but designing a site with darker colours to try and save the planet is not fruitful.

Also I love that Mads took the time to design an image calculator for working out the energy usage - I would love to see that integrated in a site like PSI as he said!

In fact I would love for Google to do it for a whole site including the background colours etc. It wouldn't be that hard to do either as they already gather screenshots for the site to calculate the “Speed Index” that are low resolution - so pixel sampling them in a similar way to how Mads did it could give the answer for "battery life saving" and "kwH used".

ps.s I always get confused on power usage units so thanks for pointing that out!