The 'Craven Calculation' - DT06

Our sixth D&T was a presentation by one of the PDE tutors, Ben Craven, who is a fascinating personality. His talk focused on the benefits and the necessity of making quick calculations- often considering energy usage. For example, we worked out the inefficiencies of powering the GSofA Reid Building with water caught on the roof though various very rough approximations. Ben's blog Is a wonderful collection of such thought experiments.

It is very important in most projects to very early get a handle on engineering realities, these can be done as rough as necessary and are a very good way of whittling down silly ideas after the initial 'blue sky thinking' stages.

We are now tasked with coming up with our own 'Craven Calculations'. For mine I was inspired by a quote from B is for Bauhaus by Deyan Sujic, commenting on the amount of waste that our Phones save us from.

My first step was to find out the carbon footprint of one iPhone. This turns out to be, in the case of my iPhone 6, a whopping 95 kg of CO2. Most of which comes from the production process.

95 kg seems like a lot. Especially of CO2, which is a gas. At an atmospheric density of 1.225 kg/m3, that's 77m3, or 5% of a swimming pool. When you picture that as 'smoke' though it doesn't actually seem so bad.

When we consider however, what the Phone replaces, we see that we are quite well off really. Looking at the storage data for my iPhone; which is, naturally, full to the brim, we see there is a lot being stored.

6.13 GB of Photos, at 1.5MB a photo on average, is about 4,000 individual photographs. I'm not sure how I have 877MB of messages, but if we class this as 'multimedia' and compare it to a 56 page multimedia PDF of 5MB,

It works out at 0.1MP/page, effectively meaning that I have 8,770 pages of messages. If each page weighs 5g, then that's 44kg of messages I would have to carry around.

I also have 27MB of email. 

Compared to a plain text document, 3 pages at 100Kb, this works out as 0.03MB a page: 900 pages and 4.5kg of paper i'm sure the postman wouldn't want to deliver. 

Tallying up all of these sources of data storage, we get some very interesting results.

The results show that we have saved ourselves from 26,343 pages of paper. Apparently, the carbon footprint of 100,000 sheets is equivalent to 6,000kg of CO2, which works out as 0.06kg a sheet, and  a footprint of 1,581kg of CO2, or 3.44 swimming pools. Massive compared to the impact of one iPhone, in fact, equivalent to 16.64 iPhones.

Interestingly, I have 2GB of music on my phone, equivalent to 2.8 CD's, or at 250 individual songs, 31 vinyl records. This is a major source of data usage, but not actually that much in terms of carbon contribution when compared to the replaced paper figure. This is because a large amount of music (and video, of which I have none stored as hard data) can now be very easily streamed. This, the entire internet, and my mapping data, which is downloaded on-the-fly, points to the fact that my phone actually replaces even more physical material than may seem at first glance.

I think we should be very grateful of our phones and the functionality that they give us, especially as it is a new paradigm which has completely changed the way we live and socialise. I am not suggesting that we would have used this much paper if we didn't have phones, we would have simply done a lot less. Perhaps other revolutions in technology will actually massively enhance our capabilities while silently removing sources of emissions and energy usage.

We should also be very grateful of our ability to do these back-of-the-fag packet calculations, and incorporate them into our design processes as early as possible. Speed often beats precision, although there will be time for that later on in projects I'm sure.