earlier Ericsson LCAs including information from major
suppliers like Intel, Texas Instruments, LSI, TSMC (used
also by Texas and LSI) and former ST-Ericsson. Based on
their input the total GHG emissions for production of ICs
including life cycle impact of ancillary materials for
smartphones are estimated to be in the range of 2.7 - 4.3 kg
CO2e per cm2 of good die (total GHG emissions are only
split on fully functional chip area, i.e. yield is considered).
The data show that the electricity consumption and
emission of gases with high GWP in the wafer factory are
two of the most important individual contributors,
corresponding to an average electricity consumption for
processors and ASIC’s of about 3 kWh/cm2 and about 2
kWh/cm2 for memories (yields included, i.e. allocated to
fully functional chip area).
The average GWP for overall production impacts of all
ICs for the assessed smartphone is about 3.5 kg CO2e per
cm2 - somewhat higher for the processors and ASICs (about
4 kg) and somewhat lower for the memories (about 3 kg) as
they consume less electricity per cm2 and have higher
production yields than processors and ASICs.
To put these figures into perspective, early, unpublished
Ericsson studies in the mid-90s showed wafer factory energy
consumption for different IC types 3-10 kWh/cm2 with yield
included (or 2-4 kWh/cm2 chip area without considering
yield). Mobile phone ASICs were found in the upper part of
this range. The electricity consumption of high end IC
components today is comparable to that of low end
components in 1995, and emissions of high-emitting GWP
gases have been reduced from around 1-1.5 kg CO2e/cm2
down to about 0.5 kg CO2e/cm2.
3) Display production
Another process that gained special attention during the
study was the display production for which the authors had
limited data regarding impact levels. Further, the display
production could be expected to be an important contributor
to overall impacts as it is known to require a very clean
environment and substantial inputs of water, gases and
chemicals.
According to the supplier, the electricity consumption in
the display manufacturing is about 0.1 kWh/cm2 (including
the touch layer). As for ICs the data shows that the impact
from input of water, gases and chemicals and from
supporting activities is large compared to other components.
The supplier data included information regarding the
production process, as well as LCA results for another
display type. Of these, the LCA results could not be used for
materials to avoid double counting with the materials data
acquired through materials declarations. Furthermore, the
material content represented a display intended for a TV with
different characteristics. However the LCA data was used to
modify the factory energy data for GWP to include support
activities. This could not be done for other impact categories.
Combining the factory data and the LCA leads to higher
uncertainty for the display than for other production
processes, especially since no prior data was available for
validation.
4) Part Transportation
Transportation types, weights and distances are obtained
from the suppliers through the questionnaire. This includes
inbound (both production and ancillary materials) and
outbound (parts and waste) transports. The primary data is
combined with models for the different means of
transportation that are based on secondary data.
Packaging weights have been included in the
transportation models.
5) Assembly
Final assembly of the smartphone is performed by Sony.
Data for the assembly processes are primary data collected
from a Sony assembly site and cover energy consumption,
generated waste, ancillary products, emissions to soil, air and
water and production related transportations.
6) ICT manufacturer support activities
ICT manufacturer support activities were estimated based
on primary data regarding energy consumption for main
offices and business travelling (not hotels) which were
allocated to the device based on sales volumes. It was
assumed that the need for supporting activities was the same
for all products.
7) Distribution
Transportation types, weights and distances for
distribution to retailers were built on internal Sony data.
Based on the main transportation routes to all continents, a
global average scenario was developed for air and road
transportation of the final product. The primary distribution
data were combined with secondary data for the models for
the different means of transportation.
Packaging weight has been included in the transportation
models but user travelling was not included.
D. Use
The use stage consists of usage of the device and
associated usage of the mobile network infrastructure. A
global energy mix has been adopted for the usage stage.
1) Smartphone use
The smartphone energy consumption is based on a
reasonable usage scenario (described below) which is
assumed to be the representative case, based on Sony data
for charging time and energy consumption during charging
and for chargers in stand-by.
Two other scenarios, assumed to represent heavy and
light users, were developed for the sensitivity analysis. The
user scenarios differ with respect to the battery charging
cycles and lifetime. A representative user is considered to
charge the device once every two days whereas the heavy
and light users charge every day and every 3rd
day
respectively, as shown in Table III. The phone energy
consumption includes the daily power consumption of the
device based on chargers and power consumption of battery
while charging and in standby-mode power consumption. A
charging time applicable to Z5 and Z3 conditions is
embodied in the figures. It was also assumed that the
representative user would change phone every 3 years, while
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