Analysis

Green telecoms - cutting energy demand

4G phone mast, Vodaphone

4G mobile broadband and cloud services require a lot of power. How can the power demand and its associated carbon demand be reduced? Andrew Wheen and Dave Tanner of Mott MacDonald offer some ideas.

Trends such as social networking are creating new demand for cloud, entertainment and mobile broadband services, and this is driving up the demand for power in telecommunication networks.

Emerging 4G services are likely to exacerbate the demand for power as smartphones are used to generate and access higher-bandwidth content that is stored on networks and downloaded repeatedly.

In 2010/11, BT consumed approximately 0.7% of all the electricity used in the UK. This means that BT is one of the top ten power users in the country. Clearly, the telecoms industry is a substantial user of power but, until recently, this was not regarded as a major issue.

Although telecoms traffic is growing rapidly, the rate of growth is actually falling. Forecasts by GreenTouch suggest that the Compound Annual Growth Rate (CAGR) of global wireline Internet traffic will decrease from approximately 45% in 2010 to 25% in 2020, while the CAGR for global mobile Internet traffic will decrease from approximately 170% in 2010 to 30% in 2020.

"If no action is taken, the level of power required by telecoms networks is likely to grow rapidly. The expansion of many network nodes and data centres is already constrained by the availability of power rather than by the availability of space, so telecoms desperately needs to become ‘greener’."

However, the key point here is that a CAGR of 25%-30% is still a dramatic rate of growth, so traffic in 2020 will still be doubling every three years.

If no action is taken, the level of power required by telecoms networks is likely to grow rapidly. The expansion of many network nodes and data centres is already constrained by the availability of power rather than by the availability of space, so telecoms desperately needs to become ‘greener’.

This white paper considers whether it would be possible to halt – or even reverse – the demand for power from the telecoms industry, whilst simultaneously reducing its carbon footprint.

To begin with, it is important to identify those parts of the network where substantial amounts of power are dissipated. In a fixed network, the access layer normally accounts for more than half the total power consumed, with a high proportion of this power being used on the customer site. In a mobile network, the majority of power is consumed in the base stations.

Some of the ways in which this power (and the associated carbon) might be reduced are listed below:

  • Switching to low-carbon electricity. This does not reduce power consumption, but it does reduce the carbon associated with that power.
  • Replacing legacy equipment. The active equipment in a network (routers, switches, management systems etc) often has a working life of less than five years before a ‘technology refresh’ is required, and this provides an opportunity to replace legacy equipment with more efficient designs.
  • Turning off unused or under-used parts of the network. This approach has already been very effective in data centres, and similar concepts can sometimes be used in telecom networks.
  • Improving data centre design. Data centres form an important part of most telecoms networks, and the techniques for designing more efficient data centres have advanced rapidly in recent years.
  • Improving the design of telecoms equipment. Further improvements have been identified, and the potential power savings are very significant.

In recent years, the massive traffic growth on both fixed and mobile networks has forced network operators to look far more carefully at all aspects of their operations.

Green issues are now firmly on the telecoms agenda, and organisations such as GreenTouch are helping to prevent any complacency by demonstrating just how much further there is to go. Identified improvements that have not yet been implemented are so significant that it should be possible to deliver very substantial power and carbon reductions in spite of the expected ‘data deluge’.

Andrew Wheen is xx at Mott MacDonald; Dave Tanner is xx at Mott MacDonald