Saving Energy – One Web Page Color At A Time
I was tired of the bright white screen flashing in front of my eyes every time I visited Google. So here is what I wrote to Google team.
I have an analysis on my blog post on how the brighter colors displayed on screen make difference in power consumption of monitor.
Since www.google.com is visited worldwide daily by infinite number of people, it would make a huge difference if the default color of google home page is changed from bright white to something dark. Ideally white text on black background. CRT monitor consumes 43% more power when displaying bright white screen than when displaying dark black screen.
A quick calculation – a white google to black google will help reduce 10-15 watts per 17% crt monitor. Using Alexa.com (which says google reaches 25% people and average page views per person approx 5) and using http://www.internetworldstats.com/stats.htm, which says about 1 billion people use Internet,
About 250 million users (25% of 1 Billion), say visit 5 pages each, and stay on each page for 5 seconds. So you have 250 x 5 x 5 = 6250 million page seconds on Google.
Assuming you take out 1250 million page seconds LCD monitors, because they behave differently, still you have 5000 million page seconds.
Assuming 17″ monitors are most common, for each page displayed black instead of white, you will save about 10-15 Watts seconds. Say 10 for simpler calculation (which is actually on lesser side). So we have 50,000 million Watt Seconds saved. That means 50 million Kilo Watt Second saved. That means 50,000,000/3600 = 13,888 Kilo Watt Hour electricity saved. 14 MegaWatt Hour energy saved. That also mounts to saving a few tonnes of CO2 from going into atmosphere.
If you don’t want to make it default dark black, you could give users a choice and let them know that by setting default color to black, they can save energy as well as help environment. Give an option of energy saving google color scheme.
I forgot to add the money benefits in the email I sent to google. The money Google users will save is rather small, but companies like Google who have teams of people working on optimizing and squeezing bits and bytes of network performance and processor speed should not overlook this fact. If Google switches to black and saves of order of 15 MW per day, it would mean saving about $2000 per day for all Google users at about $0.12/KWH. Mind you this amount is considering the utility rates same as USA all over the world, which is not the case. In almost all countries, electricity costs a lot more than that in USA. This money saved is directly available disposable income.
Over the period of one year, this goes to $700,000. Agreed, this amount is peanuts when talking about the world. But at the end of the day, where would Google like people to spend $700,000 ? Pay to utility company? Or to have that as disposable cash and use it to buy the merchandise advertised by Google Adsense, using Google checkout?
Also I have said at other places, but I will say it here again. Conservation measures have very strong synergy between them. When your monitor emits less heat, your air conditioner has to work less to pump out that heat and so on. So when you attempt to save 1$ by conserving energy, you end up saving $1.12 or something like that.
If you liked this idea, pick a website and contact them yourself. I am going to write to Yahoo and CNN when I get time. But tonnes of more websites are there who for some reason think bright white is good. Either they should change the default scheme, or provide an alternative theme for environment minded people like us.
Here is how to calculate it.
1. Visit http://www.alexa.com and find out the web traffic details of the website you picked. They give you percentage reach, which is the fraction of total Internet users visiting that website on that day. So assuming total Internet users = 1 billion, calculate the number.
2. Then multiply that number by pages visited per user number (also available on Alexa).
3. Then multiply this number by 5 (assuming user stays on that page for 5 seconds), to get total “user page seconds.”
4. Then from my earlier posting one-monitor-at-a-time, change from black to white makes difference of 15 W for 17 inch CRT, which is most common. So multiply the above number by 15. Now you have Watts second.
5. Divide it by 1000 to get KW second.
6. Divide it by 3600 to get KWH.
7. This is the energy difference per day in KWH.
8. Assume $0.12 / KWH to calculate monetary savings per day. This is the amount of money that comes back into economy as disposable income, thus creating more jobs and growth.
9. Assume 1.15 lb CO2/KWH for calculating pollution savings per day. This is the amount of CO2 stopped from escaping into atmosphere, thus maintaining blue sky blue and fresh air fresh.
Several times you will arrive at not so impressive figures for individual websites. But hey, if they all start doing it, it would make really big difference.