Method
The carbon footprint of the two different alternatives for audiovisual
media distribution were assessed here by a screening Life
Cycle Assessment (LCA). LCA is the compilation and evaluation of
the inputs, outputs and potential environmental impacts of a
product system throughout its life cycle. (ISO, 2006a,b). The present
study was a screening LCA in the sense that easily available data
were used.
In performing LCAs, software programmes and databases
therein are often used. Here data were primarily chosen from the
Ecoinvent 2.2 database (Frischknecht et al., 2007), as provided in
SimaPro 7.2. For components not included in the database, data
were collected from the producer or assumptions were made with
help from personnel at telecommunications company TeliaSonera
and other sources.
The assessment focused on emissions of greenhouse gases (as
carbon dioxide equivalents), since these are often debated and are
in the interest of the stakeholders. Another reason was the availability
of data, as there were considerable data gaps for other
impact categories in some processes within the screening scope of
the study. The method chosen to model the results was classification
and characterisation with global warming potential (GWP)
from ReCiPe08 Midpoint (H) (Goedkoop et al., 2009).
2.2.1. Scope of the carbon footprint
The functional unit usedwas distributing andwatching a certain
movie (here defined as 2 h and 3 GB). The moviewas assumed to be
watched and distributed in Sweden, via one of the alternative
movie distribution systems studied. The moviewas also assumed to
be a popular movie that is available both for streaming via IPTV and
downloading via P2P. The description of the cases was based on
discussions within the project group (with personnel at KTH and
TeliaSonera).
In the IPTV case, the boundaries extended from the file with
DVD quality at a server or storage cluster to the end-user's TV. The
boundaries for the P2P system extended from the peers in the
network (see Section 2.1.2 for explanation) to the end-user's TV or
computer (the device on which the movie is watched). Production
and waste management of the end-user's devices were covered as
far as possible, depending on availability of data.
2.2.2. Data collection and allocations
The study examined movie distribution using the internet as far
as possible. For manufacturing, generic data from the Ecoinvent
database were mainly used, e.g. for production of the laptop, the