At least 80% of carriers' total power cost is consumed in the network. Like everyone else, operators are seeking ways to cut their soaring electricity bills.
Ovum research director John Madden said CTOs were under pressure from their CEOs and shareholders to cut power cost and consumption. They are also influenced by the push for CSR and green IT, "but the motivating factor initially is to take out cost," he said.
Already EU operators have developed a code of conduct on energy efficiency of ADSL and VDSL equipment that is aimed at halving electricity consumption of broadband networks between now and 2015.
Anne Larilahti, head of environmentally sustainable business for Nokia Siemens Networks, said energy-saving was "pretty much on the minds of all the operators today because of the oil prices."
Mobile operators were mainly focused on cutting the escalating power cost of running their radio networks, she said.
"If you look at the really big guys, they have energy bills of $1 billion annually, so that makes it quite interesting for them.
For vendors like NSN, it's one of the next big business opportunities.
"If the operators' energy bill is $1 billion, and 85% is going on networks, and we can lower power consumption in the base station by 1% per year, we are already saving them millions in power costs."
NSN estimates that the energy cost of running 3G networks could be cut by as much as 40%. How to do it‾
It's first about network design, so that a minimum number of base stations are deployed.
"That makes a huge difference," Larilahti said. "We have done calculations where you end up with 70% savings through optimal design and planning with energy efficiency in mind."
It also helps if the network is operating in lower frequency ranges - the lower frequencies can support bigger cells, meaning fewer towers need to be deployed.
The second is the power consumption on-site, where air-conditioning typically takes 30% of the power load.
"We have been going back and changing the temperature at the sites; our equipment can often run at 40 degrees. That's probably the biggest thing you can do on the site level."
The other is the actual base station equipment itself. Like a number of other vendors, NSN has introduced its own range of low-powered equipment.
It is also pushing network equipment powered by renewable energy, which is especially attractive for rural areas of developing countries.
NSN expects renewable energy will be the biggest source of power for remote networks by 2011.
"If we look at renewable energy, we think some countries will be 100% renewable," she said.