How green is my Mac?

The Mac is cool in a way it’s never been before. Whereas ten years ago, people were forecasting the demise of the platform and citing it, along with the Betamax video recorder, as an example of a better technology that simply got swept away by overwhelming market forces, today the Mac is doing surprisingly well in terms of market share and in winning new admirers across from Windows.

I have been using Macs since I started desktop publishing. In fact I switched straight from the venerable Amstrad PCW (1987-1993) to the Mac without ever owning a PC. Our household currently has four of the beasts and we’ve probably migrated through another four or five since getting my first one 15 years ago. Add in numerous screens, laser printers and other accessories, not to mention at least seven iPods at the last count, and you can see that Apple has done pretty well out of our household.

But that’s an awful lot of hardware and an awful lot of it is now defunct or nearing the end of its useful life. And recently, the spotlight has started to be shone directly at Apple to see how it stacks up environmentally. MacUser (19 Jan 2007) has an article entitled “How Green is Your Apple?” which takes a look at some of these issues.

The very basic question you might want to know the answer to is how much power does the computer consume? You’d think that somewhere in the control panels or system preferences it might tell you. But, if it does, I have never been able to find out where. There is a panel called About This Mac which has a page on System Power Settings. It has nothing about power usage. There is a System Preference window entitledEnergy Saver: it tells you how to put the computer and the display into Sleep Mode and lets you adjust how quickly you can do this, but there is no information about how much power you will save by doing this. To get this information, you have to trawl around the web and check out independent sources. The very fact that you have to do this shows how reluctant the manufacturers are to divulge this information. Can you imagine buying a light bulb and having to check on the web to find out what the wattage is?

In fact, one site run by Michael Bluejay, has the basic information I was looking for for the Mac I currently use, the iMac G5 with in-built 20” LCD screen (very nice it is too). It seems to vary from about 120 watts, doing stuff like watching a DVD or opening pictures, through 97 watts when very little is happening. The monitor consumes about 30 watts — LCD monitors use about half the power of the old CRT ones — and the computer itself about 60 or 70 watts. Putting everything into sleep mode cuts consumption right down to 3.5 watts. Interestingly, turning it off doesn’t completely cut out power usage: it still uses 1.5 watts. Only by unplugging it altogether does it stop using any power at all.

But another question arises. What is the embodied energy of my Mac? How much energy was consumed in building it? An academic at Arizona State University, Eric Williams, has attempted to work this out and has come to the conclusion that a desktop computer with a 17” monitor will consume 6400 megajoules in production. Put into a power unit more readily comprehensible (by me at least,) one megajoule is equivalent to 0.2778kilowatt hours, so 6400 megajoules = 1778kWh. That’s equivalent to around 20,000 hours computing time at 90watts an hour, which is probably two or three times longer than the typical desktop computer gets used for in its lifetime. Wow. That’s a lot. If you include this embodied energy into your calculations it means that every hour you run your computer it uses not around 90watts but 300 – 500 watts.

Why does it take so much power to produce a computer? Williams estimates that chip production is very energy intensive. A 32MB DRAM chip may only weigh 2 grams but it requires “1.6kg of fossil fuel, 72g of associate chemicals and a whopping 32kg of water to create.”

In addition, the manufacture of computers involves using lots of obscure and possibly dubious chemicals such as germanium, tantalum, mercury and even arsenic. It’s all resulted in Greenpeace running a campaign called Green My Apple. I’ll be honest: a lot of Greenpeace campaigns leave me cold, but this one is done with wit and style and it’s hard not to be won over by it. It’s good to shine the spotlight at what goes on in the dark underbelly of this industry.

But the real problem with computers in particular is that they are disposable. Computer companies depend on dreaming up new products all the time. The hardware companies do it. The software companies do it. The new software demands new hardware and the new hardware makes new software innovations possible. It’s been a very good development model for the past 25 years but maybe we have to start looking at a future where computers are built to last 20 years, not four. It’s been an industry subsumed by innovation and growth: maybe its time is up.