The IP (Internet Protocol) core network operated by TeliaSonera in Sweden has been studied according to a described definition (system boundary) and extrapolated to a national level for Sweden. A top-down and a bottom-up data collection approach have been used to quantify network equipment and energy consumption. The electricity consumption of the IP core network was about one fourth of the total energy consumption of the connected mobile and fixed access networks. The use stage results for the Swedish IP core network is about 0.08 kWh per GB (Gigabyte) of data traffic corresponding to about 19 g CO2e/GB when applying a Swedish electricity mix. If instead a global average electricity mix is used, the resulting greenhouse gas emission would be about 64 g CO2e/GB. A method is also proposed where the amount of data traffic is used to allocate the IP core network on different usage. The method is exemplified by the 3G mobile broadband data traffic in Sweden.
There is a need for verification of the sustainability potential of an increasing number of smart city initiatives. This paper discuss a set of requirements necessary to consider when developing a methodology intended to evaluate the environmental and socioeconomic sustainability impact of Information and Communication Technology (ICT) solutions at a city level. A smart city definition is chosen and a model of the city is proposed, dividing the city into service sectors where ICT solutions are expected to be implemented. Requirements on a quantitative methodology for assessing the sustainability potential of ICT solutions in cities are listed, including transparency in selection of city boundary and results, and the importance of setting realistic scenarios and using publicly available data. The methodology activities presented include defining system boundaries, building scenarios and assessing the solution at a city level, and scaling the solution between cities.
The presented LCA-based method can be used when assessing the potential CO2e emission reduction from introducing an ICT-based service. The method was used to analyze the CO2e emissions from the communication networks in Sweden as well as on the effects of introducing smart work solutions at TeliaSonera. For TeliaSonera the CO2e reductions resulting from smart work sum up to about 40% per employee, or over 2.8 ton CO2e per employee and year. The total reduction potential due to smart work in the world was estimated to be 2 % - 4% of global CO2e emissions, if reductions of 20% - 40% can be achieved per employee in a 10 - 20 year timeframe.
Use of life cycle assessment (LCA) methodology for information and communications technology (ICT) equipment, networks, services and organizations is growing in importance. The complexity of conducting LCA for ICT has led to several initiatives (e.g. by ITU-T and ETSI) to develop standardized methodologies. LCA is an important methodological platform for understanding environmental impact of various product systems and is found to provide a good basis for prioritization of a company's environmental work. However, results of an LCA are always model-based representations of the real environmental impact, and the absolute impact of a certain equipment, network, service or organization is beyond reach. LCA results are only valid under the assumptions of the study and are still associated with substantial uncertainty, which needs to be considered to the extent needed to understand the study results. This paper demonstrates that by examples related to uncertainty and variability of scenarios and data.
This article quantifies the global carbon footprint of mobile communication systems, and discusses its ecological and economic implications. Using up-to-date data and life cycle assessment models, we predict an increase of CO2 equivalent emissions by a factor of three until 2020 compared to 2007, rising from about 86 to 235 Mton CO2e, suggesting a steeper increase than predicted in the well-known SMART2020 report. We provide a breakdown of the global carbon footprint, which reveals that production of mobile devices and global radio access network operation will remain the major contributors, accompanied by an increasing share of emissions due to data transfer in the backbone resulting from rising mobile traffic volumes. The energy bill due to network operation will gain increasing importance in cellular business models. Furthermore, technologies to reduce energy consumption are considered a key enabler for the spread of mobile communications in developing countries. Taking into account several scenarios of technological advancement and rollout, we analyze the overall energy consumption of global radio access networks and illustrate the saving potential of green communication technologies. We conclude that, conditioned on quick implementation and alongside other "classical" improvements of spectral efficiency, these technologies offer the potential to serve three orders of magnitude more traffic with the same overall energy consumption as today.