Green software development

On The Poker Copilot blog, Steve has pointed out a discussion on Stack Overflow about what software developers can do to be more environmentally friendly. The points are more or less what you would expect; switching equipment off when not in use, not printing stuff, buying eBooks rather than printed books and so on. But how much energy do these measures actually save, and how much CO2 does that equate to?

“I suspect that as a vegetarian programmer you could leave your monitor on 24 hours a day and print out every e-mail you get, and still have far less negative impact on the wider environment that your omnivore colleague who follows the bandaid tips above.” – Steve McLeod, The Poker Copilot blog

I suspect the key word in Steve’s comment is “Vegetarian”. According to scientists at the National Institute of Livestock and Grassland Science in Japan, on average the production of 1Kg of beef has a CO2 impact equivalent to going on a three hour drive while leaving all the lights on at home. (published in New Scientist 18th July 2007).

Vegetarianism/Omnivorism aside, how much of an impact can we have with making incremental improvements?

How much do I consume?

Except when I’m in the middle of a piece of work, I always switch off my main desktop machine overnight and monitors too. While working for me my desktop computer consumes between 150 to 350 watts of power, my office lighting is four wall-mounted dimmable 40 watt bulbs, two desk lamps at 40 watts each plus an air conditioning unit (for the hot days) and an electric fan heater (for the cold days), and central heating. I have a fairly big sound system which although sounding beautiful it rather annoyingly uses 50 watts of power even when I’m not listening to anything. My main monitor uses 59 watts of power and my secondary monitor uses 48. So I’m up to around 540-700 watts of power just doing my job. I haven’t added any peripherals, printers, UPS supplies, etc. I make my instant coffee with a fast boiling kettle that uses 1500W, so that should give you some idea of my consumption.

I also have a server, which needs to run 24×7. It’s the same server that I blogged about here, and I built it to be energy efficient, so it consumes between 15 and 50 watts of power (seriously!).

Further to this, I have a dedicated server in a data center, fully air conditioned with backup power. I don’t know the electricity/CO2 cost for that.

How much can I save?

I took a trip to IKEA and for a few quid I replaced all the wall mounted bulbs with compact fluorescent bulbs, saving 29 watts per bulb (116 watts total). These aren’t dimmable, but they aren’t as yellow as I expected and still give out enough light to work with. I replaced one of my desk lamps with an an energy efficient desk lamp, saving another 29 watts – but I’ve kept my 40 watt halogen desk lamp (saving 145 watts). The simple step of replacing in descant and halogen lighting with compact fluorescent lighting has reduced my power consumption rate by 145 watts, or 24%. Of course this result is non-scientific but I’m hoping this will make a noticeable difference to the energy bills and hence the environment. Both my monitors have energy saving modes, I don’t use a screensaver as I power down the displays instead. At night when I power down my desktop, the main Dell monitor goes immediately into standby mode, however the secondary CiBox continues to bleed light (!) and draw power even when it’s switched off at the power button. I consider both Creative (for the Gigaworks S750 power consumption) and CiBox to be serious offenders to the environment and my electricity bill.

Regarding avoiding paper, I’ve recently signed up for a 10 day trial of O’Reilly Safari Books Online. Basically, you can read all of their titles (and more in some cases) online for a monthly subscription. The monthly subscription for a virtual 10-book shelf is less than I currently pay for my books, however as I do most of my reading on the sofa (where I don’t want a laptop), in bed (where a bright display would burn out my eyes) and in the bath (where I really don’t want a laptop) – I’ll just be sticking with the printed books. However there is a market for PDF eBooks which I could read on my PDA. But at the moment, eBooks are just too expensive for what they are.

Work in your own office. Meet your customers online.

I don’t drive much for business, Back in 2005 I drove a peak of around 800 miles a week, fairly constantly. That’s now down to an average 3 miles a week. A busy commute and a traffic jam for me would be when both of my cats are coming up the stairs when I want to go down. Face to face meetings are important, but I don’t understand the business need for software developers to be in a continually consultative face to face approach (also known in the industry as “bum on seat”). Although email has largely replaced the sending of letters, us knowledge workers still clog up the motorways and public transport systems. All of my clients (yes, all) still receive a face to face consultancy as and when required, but it’s not often required. It’s also more expensive, so they save money, I save money and time, the environment saves, and it’s all win.

My comment on the issue (with copious apologies to Steve McLeod!)

I suspect that as a non-commuting programmer, you could leave all your equipment (and air conditioning) on 24 hours a day and print out every e-mail you get and still have far less negative impact on the wider environment than your commuting colleague who follows the tips above.

Indeed, I suppose a non-commuting vegetarian programmer who works from home, using only a laptop while working in a naturally aspirated environment (like outdoors!) would win the CO2 contest. Perhaps we all need something to aspire towards 🙂

Further reading

Act on CO2 (Direct.gov): http://campaigns.direct.gov.uk/actonco2/home.html

Top suggestions for saving energy (as a software developer):

• Switch off your monitor when not in use
• Switch off your computer when not in use
• Buy a OneClick gang socket
• Use standby or hibernate more often
• Don’t use a screen saver (see bullet 1)
• Switch off your second/third/fourth screen when not in use
• Declock your GPU or processor
• Don’t print stuff < /li>
• Buy more ebooks
• Get John Skeet to null your carbon footprint