Network Paradox Part IV: The Green Impact of Mobile Data

If there’s been one area in which the wireless industry has had an exemplary track record, it’s in the area of limiting greenhouse gas emissions. Considering the scope and the scale of the global wireless network, its impact on the energy footprint is relatively small. Most estimates put the greenhouse contribution of the entire information communications technology industry at 2% of all emissions, but most of that is accounted for on the computing side of the equation

Telecom’s portion of that energy consumption is a quarter of overall ICT energy consumption and within telecom, wireless accounts for one half of emissions. That’s one-quarter of a percentage point—not a bad track record for an industry that touches more than 4.6 billion people.

But as more and more data traffic moves onto the wireless network, mobility’s consumption of energy resources is set to explode. The industry isn’t just adding more subscribers as developing markets embrace wireless communications and subscribers in developed markets buy their second or even third connected devices. Mobile data is also driving more usage of mobile network resources, which in turn is driving more energy consumption. And even though the industry is quickly developing more energy efficient network and device technologies, those trends won’t keep up with the demands for data.

A study conducted by Alcatel-Lucent’s Bell Labs in June found that the mobile network is set to overtake the wireline access network as the most power consuming portion of the global communications system by 2012 or 2013, and overall power consumption attributable to the mobile network will continue to climb. By 2020, the total power per user attributable to telecom will have grown by a factor of 4 to 10, most of which due to growth in wireless data.

“That’s an order of magnitude increase in the power consumed by each user,” said Dan Kipler, a Bell Labs scientist and chairman of the GreenTouch Consortium technical committee. “This takes into account only the newest and most advanced equipment so it’s a best case scenario.”

The irony of the situation is that for the last few years, power consumption per user has actually been going down in many cases as vendors have developed more efficient radio technologies. New base station and power amplifier designs have boosted energy efficiency tremendously, and Bell Labs expects those gains to continue, improving base station efficiency by 15% each year until 2018. The move to new 3G and 4G technologies such as high-speed packet access (HSPA) and long-term evolution (LTE) along with new antenna designs such as multiple input-multiple output (MIMO) schemes allow networks to operate more efficiently, sending more bits per transmission but consuming the same amount of power.

The energy and operational efficiency of mobile networks is rapidly increasing, driving down the energy necessary to send a bit of traffic. The problem the number of bits transmitted is exploding—the improvement in network efficiency is far slower than the rate of overall traffic growth.

The impact of such a huge increase in power use isn’t just an environmental concern. It will have a big effect on how operators build new networks and charge for their services, Kipler said. “I don’t know any operator who can afford an order of magnitude increase in their power bills,” Kipler said. “Those added costs may mean that they won’t be able to deploy new networks allowing data to enjoy is natural growth. Or it might mean they’ll have to charge more for it.”

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