Found the topic fun to engage with. So why not have some wise words on the subject from someone that see the bigger picture.
Not sure why out of all thing one can do, one try and save on the environment on a personal computer. Like honestly any savings done here will be ruined by the countless of stuff happening around you.
Like as said above by others. First thing to check is the screen your using. (for most people) Then the computer itself. Wasted energy is HEAT. And in some ways I like some heating in my room thank you! So even that is not very wasteful here in winter time. But a computer (laptop from say 2008) not used heavily will not be very power hungry. But put a big work load on it, IT WILL be wasteful compared to a modern machine. Since trying to cope with the non intended use of the machine ruins the power usage. A modern machine evolved with the need of the heavier workload. (not true but close enough)
But monitors are always wasteful, and that is part of the design. They are converting electricity into something we humans can interact with (light) so it is very wasteful when it comes to power. And really if your compiling ports then stop doing that to XD Someone has already done that for you. Or rather spent energy on it.
It should be quite obvious. But CPU's are in essences TINY TINY mechanical things moving fast. And the waste of energy is really low due to the small size of it. But the less you use it the better. And if you need to use it then a better and more efficient CPU give more bang for the power use. As they become smaller and smaller as we progress in the tech. Less movement the less HEAT created.
Even old hardware is not bad. The power savings of getting a new board is going to be nothing when comparing the material and energy needed to create and get the new PC, and then get rid of the old computer is doing harm too.
It is just a matter of how much computing you need. The more you need the better a modern computer gets. At least in theory. But being happily using a slow but highly efficient modern ARM thing is best of both words. But do not think the OS or the Hardware is a big factor in saving the environment. It simply is better to go back to a more basic usage of tech. Like 70s and 80s. Nothing fancy but lean and fast.
Solar power made from your own panels. Now THAT will blow the environment friendliness sky high. Well compared to running on money electricity that is. Since the electricity likely is produced in a environment negative way. In the name of PROFIT. So that is a very recommended approach to feel better about computer usage.
Sell green power to buy cheap bad power. No joke this is what happens around the world. Do not trust environment nonsense from companies. They make a green good power source "for free" but opt to make money out of it instead. Since that is what they do. Big industry next to me do just this exact thing. Buy Coal power and sell Green power. Make them allot of money. They waste energy since they are being PAID for creating GREEN power. But they do not use it but exchanging it for money. There power bill is being paid off and getting a profit from it. Instead of you know.. Using the power they created for there own production on the spot.
Really that is the messed up world we live in. Waste energy and getting paid good for it too. At that place they run everything on electric, all lamps are on all year around. Not trying to conserve power in any way. They are Environment Friendly company? Yes. Just happen to create green power without them even trying. A bioproduct at it's finest. Think about that before buying a electric car running on "green" power. It is just as "green" as YOU yourself make it. Same with computers or tech in general.
Really unless you need a computer the "Environmentalist" thing to do is ditching technologies for the most part. Really only thing to use it for is to avoid traveling. And so then if that is the reason to use a computer. Well... It is more about networking that you should be concerned about and not the computer your using. Well with a intent in Environmentalist actions being the number 1 thing.
Do not just focus on what happens on your computer. Think the hole process you embark on when being online. As with everything in life. Think!
It is better being on a computer VS driving to a friend to talk with them and such. It's better watching YouTube then going on a holyday in a car or airplane. But the energy and hardware (and therefor pollution) from being online is no joke. But it dose not have to be. But anything fun or whatever draws you to being on the web is BAD for the environment. It is to avoid needing to travel that is GOOD.
But just 1 other human being on the planet not taking "Environmentalist" actions will ruin anything you do anyways. And to bring the point home fully think about this one. ANY criminal* money making scheme is going to pollute and ruin the earth so much more then a million ordinary people running a computer. At least if they are just sending email's and peer to peer data transfers.
But that's the problem. We are not peer to peer data sharing. We are feeding big servers data. That's no good for multiple reasons. As why they do not charge us for this is simple and open facts. They use our data and run computer intensive (power intensive) things on it. For as you might know already, profit. Training AI's or selling it to put ads on us. (good use of electricity ye?)
I like to give a idea of how pointless the focus on a OS or hardware really is in the big picture. So that is why I bring this stuff up. There is so much more productive things to focus on
Like not letting servers suck up power from you watching cats on the web. Do something IRL like grow your own food. Use the web to learn about that stuff. That is what I love about the internet. Knowledge.
Now instead of peer to peer data transfers (a good way to moved data around) we use Facebook, YouTube etc with a middle man server. Witch if you think about it means one extra set of power draining appliances for data transfers as a minimum. They spend more electricity on stuff on there servers then what the home computers uses do. They simply are doing so much in the background compared to if you just had talked directly with however you where interacting with online. (peer to peer computing) FreeBSD server we download files from are doing the least amount of efforts to deliver the files to us. But other servers do all kinds of crazy stuff. For what reason? Profit? Most likely.
Literally ANY peer to peer data transfers are seen as criminal actions today. (more or less) You are going to be challenged why your sending encrypted or non encrypted messages peer to peer. Since it looks suspicious. Even now there are legit reason for it.
And it also is simply a hard thing to do. That is probably the big reason really. Much harder to learn or care about it when you can just go online on a forum like this one. Or Instagram. That is why the changes are not happening. Convenience. To really do anything worthwhile from a Environmentalist standpoint the changes to how we do things need to change. (did not see that one coming did ya all?)
A forum like this are grate! But what else do you do on the web? Might you rethink having them get more data to process?
Not just change the hardware or OS we run will do anything. It is the software and services we run on top of it. Trying to be smarter about what we do in our lives.
The big picture is difficult to grasp. But the point is to limit what actions you take and how much you rely on people with there motives being always about money.
Same with vehicle transport, food, ANYTHING really. Doing as much as you can on your own is the key. You find out what is good or bad for the Environment simply by what you can accomplice on your own or in your community close by. What dose nature support basically is the key to saving the Environment. And working together as small communities this called "internet" can still exist but for real practical reasons. Educations etc. Not Netflix...
So really to be environmentally good, limiting networking and sending and retrieving as little as possible is more important then you might expect. Meaning your basically not going to be using a computer in the way of 2020. But rather just for emails and stuff that really is just sending small files around. That is less impactful then sending snail mails or driving around in a car. So it works out as a positive thing even now it dose pollute. Agene using the computer to avoid traveling with vehicles are A GOOD THING. But that's about it. It is wasteful since it is not necessary or vital in life to be on a computer as we do now.
Avoiding internet and computers plays well in with a low powered ARM based devices. Since in essence if you only do need a low range PC, well you then have changed the way you do thing too. Still you can be online and watch a movie or YouTube. But it is so much more valuable to think about what impact it has outside of your eye sight. Same as how coal burning has such a damaging impact. It is outside of eye sight the problem occurs, always. It is not "free" being online. At least not for the Environment. The cost are huge but better then a airplane trip for "fun".
Literally a tiny ARM or RISC board will draw nearly nothing. The monitor will be the big power consumer. Then the network transfers and anything happening out there on the web. That should be the concern. What dose it take to create this tech, and keep the internet running. That is the real pollution maker.
So to be frank there are better things to look into before looking at whatever power saving measures can be done on OS level. It is more about whatever that OS is doing and what it is communicating with. (and how much)
Like look at that Pi keyboard with a built in computer. You can still watch YouTube on it. But the problem is YouTube. That is the power hungry thing. As is basically anything but the most old school internet usages. Like when we used phones to communicate peer to peer. That is the kind of data transfers that are ethical to be using. And they where SLOW. But did something useful with little impact to anything.
Like I do not even think FreeBSD is the best OS for this task of power saving. (nor Android) Efficient use of electronics are the key for a Environmentalist caring person. Just as avoiding running unnecessary lights in your home (LED ones ofc).
FreeBSD I think is to fancy. XD But I mean sure it is not that bad. You just need to learn so much about computers to get anywhere with it. I think Linux or Pi OS is better suited. Simply more support for the goals of a OS for basic web stuff. FreeBSD is a hobby or a server OS. Or someone that likes to be more in tune with the computer and like them to be powerful and awesome.
If the question was about saving battery life and extend usage time. Then yea looking into hardware and OS is the main thing to do. Since any reason to use the battery is to get something done. For fun or work.
But that was not the question. So happy Environment saving. ? I recommend something like a Pine phone. Mobile and can be charged by a solar panel easily. Can connect to a monitor making it a grate computer also. I really dig the idea of getting one of them. Simply for the reasons I have said in the post. It is a good device since the goals line up with so much of or mere mortals needs.