Improving the Energy Efficiency of Telephone Exchanges (Switching Centers)

Improving the Energy Efficiency of Telephone Exchanges (Switching Centers)

Keith Dickerson, David Faulkner, Paul Kingston
DOI: 10.4018/978-1-4666-8447-8.ch009
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This chapter discusses the environmental assessment of telecommunications switching centers (telephone exchanges), based on the experience gained by Climate Associates Limited (CAL) and K8T on contracts in the UK and Ireland over the last few years. CAL has been asked to assess the energy efficiency of telephone exchanges and make recommendation on how their energy efficiency could be improved. Although we are not able to disclose details that may be commercially in confidence, this chapter draws out some general principles on the energy efficiency of telecommunications switching centers, taking into account the electricity demand of the equipment, the energy performance of the buildings housing it, the air conditioning needed to cool it, and the electrical systems used to power it, with a focus on how this could be improved. Reference is made to assessment standards such as ITU-T L.1310 Energy efficiency measurement and metrics for telecommunication network and ITU-T L.1300 Best Practices for Green Data Centers. Dr. Keith Dickerson and Dr. David Faulkner have both been active in the development of standards for environmental assessment in the European Telecommunications Standards Institute (ETSI) and the International Telecommunications Union (ITU) over the past 10 years and hold leadership positions in these bodies. Dr. Paul Kingston has an excellent track record in the modeling and assessment of power consumption to optimize design of the built environment. Acknowledgement is given to BT for permission to publish the results of this study. The results are based primarily on the study of a single telephone exchange and may not be valid for all exchanges of this type in the UK.
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Telephone exchanges and their associated network infrastructure are a large (and steady) consumer of power in developed nations. At the same time, data centers, starting from a low base, are growing rapidly in size and number and are consuming ever more significant amounts of power, so that these are indirectly becoming major sources of GHG emissions in their own right. Therefore, the environmental impact of telecommunications equipment and data centers should be assessed and this should be carried out using standardized techniques which can then be used to compare GHG emissions from equipment performing similar functions in different countries and regions.

In the UK, BT as an organization consumes around 0.8% of all electricity generated, with almost three-quarters of its electricity consumed by the network (BT Group plc, 2014b). Therefore, any steps that BT take to reduce the energy consumption of their telecommunications switching and data centers could make a significant contribution to reducing the UK’s overall energy demand. This would help to meet carbon reduction targets such as those specified in the UK Climate Change Act 2008 (Parliament of the United Kingdom, 2008) to reduce GHG emissions by at least 26% compared to a 1990 baseline by 2020, and the EU target for GHG emissions to be 20% below 1990 emissions by 2020.

Sustainability is high on the list of BT’s priorities and the company has championed reductions in energy consumption for many years and continues to do so as part of its sustainability strategy (BT Group plc, 2014a). This has proved very successful and, as a result, the company topped the Telecommunications section of the Dow Jones Sustainability Index for seven years running. BT in common with many operators globally are replacing obsolescent Time Division Multiplex (TDM) equipment with more energy efficient IP-based equipment, and are also implementing low power modes for their DSL services. However, at the same time, customer demand for services using legacy network platforms is declining which makes it harder to justify further investment in the legacy platforms. Therefore, the less energy efficient network platforms are taking an increasing proportion of overall network energy consumption and threatening the operator’s energy savings targets.

Figure 1 shows BT’s worldwide energy consumption and carbon emissions from 2010-2014 (BT, 2014b). It should be noted that while energy consumption and carbon emissions have been falling in recent years, more to will need to be done if this reduction is to continue. This goal to cut carbon emissions is shared by many operators globally, most of which which set emissions reduction targets. Examples are given below:

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