Sunday, 10 April 2011

Carbon footprint for reading a newspaper on an iPad

Making paper (even recycled), printing it and transporting it uses a lot of energy and generates carbon emissions. However e-readers such as the iPad or the Kindle also have a carbon cost for manufacturing. In my book I explore the payback time for reading books on a Kindle and I reckon, depending on your assumptions, it comes to about 70 books – which in my case would be a couple of years reading. However, newspapers consume a huge amount of paper too, and can just about sensibly be read now with something like an iPad. If you read a newspaper every day, how long would it take to pay back the initial carbon emissions from the iPad?

According to Apple, the total CO2e(1) emissions for the iPad are 130kg, of which 30% is customer use, over a 3 year lifetime (2). That means the consumer emissions are 0.25 kg/week and everything else comes to 91kg.

You might be an avid news reader, consuming a 'quality' paper like the Guardian or the Observer every day, or maybe you read something smaller like the Sun. I shall assume the Guardian reader takes an hour every day and on average pulls 50 pages each day. The Sun reader takes 30 minutes each day and only pulls down 25 pages. Or you might just read the Observer on Sundays.

Here's the calculations:





Guardian/
Observer every day
Sun every day
Observer only


1
iPad embodied CO2e
91
91
91
kg
2
Paper newspaper CO2e (3)
7.6
2.8
1.8
kg/week
3
Energy consumption by iPad when reading (4)
0.026
0.013
0.008
kWh/week
4
Energy consumed by newspaper servers generating web pages (5)
0.21
0.11
0.03
kWh/week
5
Total energy consumed (row 4 + 5)
0.24
0.12
0.04
kWh/week
6
Carbon footprint of this energy (545g/kWh)
0.13
0.06
0.02
kg CO2e/week
7
Add in carbon footprint for normal use – 0.25 kg (2)
0.38
0.31
0.27
kg CO2e/week
8
Overall savings/week (row 2 - 7)
7.2
2.5
1.5
kg CO2e/week
9
Payback time (row 1/8)
13
37
59
weeks.

Reading on the iPad generates far less carbon emissions than buying the news on paper and the more you read the quicker the payback time. The Guardian reader starts making net carbon savings in only 4 months while the Sun reader takes 9 months. However, if you only read the newspaper on Sundays, then it will take a bit more than a year to pay back the initial carbon emissions (59 weeks). If you ignore the carbon footprint for normal use the paybacks are a little better but still 51 weeks for the Sundays only case).


(1) CO2e is the overall greenhouse gas emissions in CO2 equivalent units.
(2) From Apple
(3) Guardian/Observer 0.8kg weekdays and 1.8kg weekends; Sun 0.4kg/day from How Bad are Bananas from Mike Berners-Lee
(4) 60 minutes/day for Guardian/Observer, 30 minutes/day for Sun reader. The iPad is mostly idle so 3W and the power adapter is 80% efficient see (2)
(5) Assume each page takes twice as much energy as a google page fetch so 0.0006 kWh/page (Google says 0.0003 kWh/page ). Guardian reader pulls 50 pages/day, Sun reader pulls 25.

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