Page 29 - ITU Kaleidoscope 2016

ICTs for a Sustainable World

Production

0.206

Channel
Playout

Coding &
Muxing

Transmitter Satellite
Network

Aerial & Aerial LNB
Amp
Figure 8: Emissions in kgCO 2 e from DTT without an aerial
amplifier.

DTT DST
Receiver Receiver
0.196

TV Display TV Display

Figure 7: DTT & DST distribution system

measures is not yet known but it is expected to be relatively slight
and certainly less than 10%. Additionally we have to be mindful
of the impact across the whole infrastructure because if the end
result is the addition of more powered head end/aerial amplifiers
in thousands of homes across the coverage area to compensate for
lower radiated field strengths, then the overall system power
saving might be easily negated. When trying to understand the
impact of carbon footprint of broadcasting we tend to use the
metric of per viewer-hour of TV consumed. This approach not
only allows us to include the impact of the audiences equipment
being in use but it also distributes the over head of fixed
infrastructure over the amount it has used. Figure 8 shows this Figure 9: Emissions from DTT with an aerial amplifier.
well because as you will note, BBC One, the BBC’s most popular
service, looks very efficient broadcast over DTT with audiences 8.45 x 10-4 kg CO 2 e/viewer-hour. The DTT system probably
frequently in excess of 6 million and emissions of 0.000265 kg consumes more power than this now, as many of the transmitters
CO 2 e/viewer-hour whereas the BBC’s Parliament service is far were increased in power during the digital switchover from
less widely viewed and its share of the infrastructure makes DTT analogue TV (which was completed in 2012). On the positive side,
look like a far less sustainable choice at 0.196 kg CO 2 e/viewer- this meant that the whole duplicate, analogue, infrastructure was
hour, so much so in fact that it’s way off the top of the scale used turned off, probably more than halving the power consumption of
in figures 8 & 9. In these TX means the proportion resulting from terrestrial TV in the UK.
Transmission and C&M from the Coding and Multiplexing.
When we get to the edges of DTT coverage, signal strength has 4.3 On-Line Delivery
dropped and the viewer needs to use an aerial amplifier to ensure
good pictures; we can see the impact of a small piece of
technology adding 9.85 x10-3 kg CO 2 e/viewer-hour and being The outlook for delivery over the Internet is far more complex, as
replicated across the 25 million homes in the UK as shown in many of the components are much harder to identify and when
figure 9. In fact the impact for BBC Parliament is that its overall they are, it is hard to know how much of their energy consumption
emissions only increase by 5% where as for the much more is due to delivering television pictures and sound.
popular BBC One the factor increases by 37 times. In figure 10 we see the simplified system diagram for the delivery
On the positive side the 2008 decision under the EU Ecodesign of video on demand [or VOD] TV. The only component common
Directive has reduced the energy losses in passive, standby and off with Figure 7 is the programme production element and once
modes of a broad range of TV products have been in recent years. again this is not included in this part of the analysis as it is not part
On average the BBC R&D white paper WHP 189 [10] concludes of the distribution system. The infrastructure elements are once
that in 2011 the DTT distribution for the UK emitted an average of again shown in darker grey than those in the home. The coding

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