Renew Magazine is a publication of Australia's Alternative Technology Association (ATA) and is a wonderful resource of information about "technology for a sustainable future." The current issue includes a fascinating article by Lance Turner on low-power, low-cost computing. He notes that if you live off-grid, this can be a big issue:
The needs of computer users vary widely—some need higher processing power whereas others, who do everything in a web browser, need far less. The same applies to energy consumption. If you live with a small renewable energy system, your main priority may be to minimise energy consumption.
Phones and tablets
Most [phones and] tablets are simply not repairable by the average user and when the battery fails (after a few years at best) most users will simply junk the device and buy a new one. When you factor in the environmental cost of manfacturing a new tablet every few years as well as the cost to the consumer of paying several hundred dollars for each new device, tablets are actually an expensive computing option.
Perhaps. But everybody has a phone, and if you can make it work as your computer then you are using one less device and using it a lot more, getting real value out of it. I have been experimenting with this, and have used my iPhone 4s and a bluetooth folding keyboard and find that for basic writing, it's just fine; Apple now gives away their Pages word processor and it works well across all my devices. I have a VGA output adaptor and can hook my phone up to my monitor if I want. This should not be discounted as a green way to go, maximizing the use of one device.
Laptops and notebooks
Lance looks at the laptop option and concludes with a very good point:
If you don't need a portable device then buying a laptop doesn't really make sense as you are paying for a battery and associated components when you have no use for them. this costs you and the planet when the batteries inevitably die, particularly if the batteries are difficult to replace, resulting in the same outcome as with many tablets- unnecessary upgrading.
It's true that you can pay a big premium for portability, although Lance doesn't look at the new and cheap Chromebooks as an option.
These were the rage among hobbyists a few years ago, the little packaged PCs with the soldered-on chips. They can do almost anything a regular PC can do, and use very little power; according to Zotac, this little thing has "desktop-class processing power that sips miniscule amounts of energy." At idle it sucks 11 watts and under full load, 28 watts. I used to build my own computers and always claimed that it was better to keep your components separate, spilling your coffee on a keyboard is a very different thing when it is in a notebook. Lance says much the same thing:
Environmentally, it makes a lot more sense to keep the components separate and upgradeable/ repairable, and desktop PCs are in a class of their own when it comes to this ability.
It's also easier to get the ergonomics right, and to get better keyboards and displays. Lance points to new low power monitors that Philips is selling that burn only nine watts; they don't even have a power supply, getting the juice they need through the USB port.
Finally, given that this is under the DIY section of the magazine, Lance looks at the Raspberry Pi, the wondrous and cheap as dirt computer that runs Linux. He notes that there is now a wide range of free software for the PI, including desktop publishing, office suites and GIMP, a photoshop substitute, although you can do all of that in the cloud now. He makes it sound easy as pi.
It is a fascinating article that shows open-source, inexpensive and really low-power alternatives to the iWorld that I have moved into in the last few years. I cannot comfortably edit a post on TreeHugger on my iPhone or iPad, but could easily do so on a Raspberry Pi that costs less than any of them. It's a real eye-opener.
The article isn't online yet, but you can buy a PDF or paper copy here.