Why not optimize for CO2 emission instead ?
We can estimate the emissions caused by crypto-currency as that is almost entirely CPU-bound by about the same amount (or an easy to estimate average) per unit. The costs of transmission and storage are going to be relatively minor.
For images the compression cost, while the process is similarly CPU-bound, is pretty small unless you are doing something small like compressing to hundreds/thousands of algorithm/parameter combinations and picking the best result (perhaps by some heuristic more complex than final file size). Also transmission and strorage costs are difficult to estimate because for any given image how do you guestimate how many times it will move and be copied?
Having said that, the article's statement that: “[as] bandwidth savings from overly lossy image codecs will become meaningless, [] the CPU/user time and battery or grid energy spent on complex decompression steps will be wasted.” implies that energy use is at least a coincidental consideration here. Though image quality is by far the primary concern, and that despite being subjective is probably an easier metric to measure in this case, with compression time likely to be ahead of energy use too.
Main problem with the grid in California is when it sets fire to things or windstorms cause an outage. The generation side is holding up pretty well.
Also, renewable energy doesn’t mean infinite/limitless energy. It often means there are more limitations than non-renewable counterparts. Eg: storing energy is still not a solved problem without really toxic (environmentally and politically) materials.
Storage at this point is plentiful. Most people can live just fine with 1 TB of it, which is trivially found in both HDD and SSD forms. Using less saves you nothing, as the media is still there.
Bandwidth is also plentiful and available 24/7. It's also very bursty -- you only download your game once, while you may play it a lot. So saving 50% download time makes no difference energy-wise.
What we can control a lot is CPU power usage. We now have 16 core consumer CPUs that are designed to sleep when not in use, so difference in power usage at runtime can be dramatic.
So an algorithm that trades disk space for decoding efficiency is probably the best way to save power.
So on my current connection, that's maybe 2-5 seconds of download time. Meanwhile, the router is on constantly anyway, so whether it's 200 MB or 400MB makes next to zero difference energy-wise.
Okay, say you're on a 10 Mbps connection. That update takes you what, 5 minutes? Yeah, that's an annoyance, but that's time for a coffee or a bathroom break. Most games don't update daily or anywhere close to it, so your download time is still going to be <1% of your play time for most people.
If your hardware/connection is really awful, yeah, maybe downloading the latest DOOM isn't a great experience, but luckily there's no lack of smaller things to play.
Either way, it's completely irrelevant carbon/energy-wise. Your power usage is going to be dominated by a game trying to render 3D graphics at 60 FPS, not by the tiny increase of the power draw of a router during an update download.
https://expressiveaudio.com/blogs/audio-advent/audio-advent-...
https://www.extremetech.com/gaming/189268-digital-game-downl...
https://arstechnica.com/science/2022/05/discs-vs-data-are-we...
for one thing there is the question of how to attribute carbon emissions for all the "middleboxes" that are drawing tiny amounts of power throughout the whole process but could add up to a lot.
I myself live in western Europe and I can't do cloud backups because it would take me about two weeks of 24/7 uploading which then constantly interferes with every other internet connection I want to use and makes things like streaming videos, zoom sessions or online gaming impossible. Game updates usually mean I won't be gaming that evening. And that's already the better connection after switching providers.
The actual optimization here would be fewer updates and games releasing in a finished state.
So, in what plausible scenario would a gamer's CO2 output (which is mostly power use) be significantly influenced by download time?
The vast majority of people spend a lot more time playing than downloading. If your connection is really bad, then you're probably going to buy physical media or play something smaller.
There's no plausible scenario I can think of in which a significant amount of people sits there waiting for an hour for a game to download, on a daily basis, and where the amount of power consumption caused by that is significant when compared to what's consumed by actual game play.
Yeah, I get that giant updates might be annoying to you personally. But the discussion is about CO2.
I have two ADSL connections that can download at 20 Mbits/s with a load balancer.
With my XBOX ONE I don't really have a choice of physical media, even if I have physical media I'd expect to download between 2-40 GB of patches or additional content. It is definitely a hassle but not prohibitive, generally I install a game before I expect to play it and keep up on downloads ahead of time.
For PC games it is similar except most of the games I play I get off Steam I don't even know if physical media is available at all.
At 20 Mbps, 40GB takes a bit over 4 hours to download. Supposing you have an idle power draw of 60W, that's 0.240 KWh. I think that's reasonable. Downloading is almost effortless for a modern computer, and I'll assume that you're not getting any more use of it, so the monitor turned itself off.
Now compare that to a CPU easily having a TDP of 100W, plus a GPU drawing 180W, plus the rest of the computer, plus a monitor, etc, you can easily reach 400W. That'll blow through the power you consumed to download in half an hour.
Also I don't think anyone releases 40GB patches on a daily basis, so if you game for say, 3 hours a day for a week, the costs of the download is already down to 3%.
Which again is what I was getting at: you should optimize the biggest sources of waste first. Anything that makes your actual gameplay more efficient and consume less CPU or CPU resources will decrease your consumption far more noticeably than almost any optimization you can do to downloading stuff.
How if you don’t know where the electricity comes from powering the hardware your image decoder runs on.
But watch out for induced demand (the user turning the graphics settings up because you made the FPS better.)
The best way to "optimize for CO2 emission" is to just stop living.