Today my attention was drawn to a widely-covered (link, link, link) MusicTank energy report with an alarming headline statistic – Streaming media could have larger carbon footprint than plastic discs – and, specifically, streaming an album 27 times could use more energy than producing and shipping the physical product.
Wow, sounds alarming. Could that be true?
Digging into the actual report I found the quote on p14: “…streaming or downloading 12 tracks, without compression, just 27 times by one user would, in energy terms, equate to the production and shipping of one physical 12-track CD album.”
Ok, so there’s a major caveat in there – “without compression” – which almost never happens in the real world and overstates the case seven-fold. But even so, downloading the same MP3 album ‘just’ 189 times (27 x 7) supposedly uses as much energy as physical production and shipping… still hugely surprising.
Where did these figures come from? Page 13 of the report shows some comparisons in the form of equivalent “light bulb hours”. Apparently a CD takes 38 “light bulb” hours worth of energy to produce and ship, while an uncompressed 12 track WAV download consumes 88 “light bulb” seconds.
Converting those to the same units gives (38hrs x 60 mins x 60 secs =) 136,800 seconds for the CD, and 88 seconds for the uncompressed 12 track download.
Wait a minute, wasn’t the CD supposed to consume just 27 times the energy of an uncompressed album download? From the reports own figures it looks like the CD uses 1,555 times more energy (136800 / 88)!
Is the whole report based on a calculator slip? If the uncompressed WAVs instead consumed 88 light bulb minutes their figures would have been roughly right (38hrs x 60 = 2280 mins… divided by 88 mins =) 26 times bigger…. very close to the 27 times of the report. But that would be equating minutes to seconds, putting the whole comparison out by a huge magnitude.
I’m still ignoring the potentially confounding flaw in the comparison – the source of the energy cost figures isn’t clear but it looks like they’re based on data from 2010 at best. By the reports own admission, the energy required to transmit 1GB of data halved between 2008 and 2010.
Since data transmission rates historically improve on an exponential curve against broadly flat energy usage, it’s fair to assume that the energy cost to transmit an album will be much lower today. And even lower tomorrow.
The twisted conclusion that the report is trying to reach is that everyone having “all the worlds music” stored on a memory card may soon be more efficient than transmitting that music over the air.
Apart from being based on figures which are just plain wrong, this conveniently ignores several points:
1. The majority of music purchased is new/current music, which would have to be downloaded to the memory card in the first place. The report suggests that all new music could be downloaded to each user ‘only once’, but this would be even more wasteful – by the reports own admission we’re talking about roughly 342 years of non-stop music to date, and there are years-worth of new tunes being recorded every week.
2. It would be more efficient to stream music constantly from the users birth to death than it would be to transmit hundreds of years worth of listening updates that a particular listener will never consume.
3. As data networks improve, more and more mobile listening is to ‘live’ channels – 1,000′s of global radio stations, Podcasts, etc. This type of listening doesn’t fit the download once, listen forever model.
4. The ‘store everything’ model of the report assumes AAC compression. Using the same level of compression on the downloaded versions (as almost every online music download currently does) would yield a seven-fold improvement – i.e. downloads being 10,000 times more energy efficient than CDs.
I could go on, but hopefully that’s a start. MusicTank – would you care to comment?
Update (14 Sept): Following my blog post, MusicTank have withdrawn the original report and replaced it with a version with 88 seconds changed to minutes. This makes the numbers square but, as noted in my comment below, it still puts their figures out of step with other comparable figures by more than an order of magnitude.