Improving the Energy Efficiency of Telephone Exchanges (Switching Centers)

Background

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: