During the rainy season roads are washed away, and diesel has to be helicoptered
to mobile base stations not connected to the electrical grid, so it's easy to
understand the communications industry's growing interest in energy-efficiency
and renewable energy sources.

All mobile carriers are currently investigating how to improve energy efficiency,
according to Gartner analyst Martin Gutberlet.

"The main driver is to reduce the cost of running mobile networks, but
then you also get to reduce CO2 emissions as a bonus," he said.

Just recently Vodafone
announced it would reduce its carbon-dioxide emissions by 50 percent by 2020.
The push makes sense from an environmental and business point of view, according
to CEO Arun Sarin.

Vodafone started looking at energy efficiency two years ago, but as evidence
has mounted of how carbon-dioxide affects the environment the company felt it
was time to do more.

"Succeeding will be a big challenge, and today we don't know exactly how
to do it," said Ulrich Blau, senior manager Site Infrastructure & Energy,
at Vodafone Group.

The primary focus should be on the mobile base stations, since they consume
almost 70 percent of all energy in a mobile network, according to Ericsson.

There are a number of ways for mobile operators to become more energy efficient.

One way is to increase the temperature at which equipment will work, which
reduces the energy needed for air conditioning. Instead operators can use free
cooling, which uses outside air.

Raising the temperature from 25 degrees Celsius to 40 degrees Celsius reduces
required energy by up to 30 percent, according to Nokia
Siemens Networks.

Another method is to reduce energy consumption during off-peak hours by adapting
the energy use of the base station according to the level of calls, just like
a laptop goes into sleep mode when it isn't used. A feature from Ericsson,
called Base Transceiver Station Power Savings (BTS Power Savings), does just
that and can lower energy use by 15 percent to 25 percent.

A more spectacular way of reducing carbon-dioxide is Ericsson's radio base
station site concept Tower Tube, which looks like something from a science-fiction
movie, designed to require no active cooling. It is built using concrete instead
of steel, which lowers emissions by up to 40 percent.

Nokia Siemens has set a target to reduce energy use of typical GSM (Global
System for Mobile Communications) base stations by 20 percent by 2010, from
the 2007 level of 800W, and 3G (third-generation) base stations by 40 percent
from 500W, during the same period.

In 2008 Ericsson exceeded its target to lower energy use in a 3G base station
by 50 percent compared to 2005 levels. Later this year it will introduce future
targets.

As the need for power decreases, the use of renewable energy, like solar and
wind power, becomes more viable. A base station that needed 200 square meters
of solar panels five years ago, today needs 50 square meters, according to Ericsson.

Wind and solar power have advantages and disadvantages. Wind is more efficient,
if you find a spot with enough speed and wind occurrence, according to Blau.

But there is more data -- about where the sun shines, and for how many hours
-- about where you can use solar power, according to Ericsson's Linda Ekener
Mägi, marketing manager, Communications Expander.

At the same time, solar-power technology has disappointed in recent years --
it isn't evolving as fast as Ericsson and Vodafone had hoped.

In the end, considerations about lowering carbon-dioxide emissions and using
renewable energy come down to cost. Currently any Vodafone investment needs
a pay-back time of two years at the most.

Vodafone Germany was the first operator to upgrade its network to support BTS
Power Savings. "I am keen to get it in other networks as well, but the
software upgrade is really expensive," said Blau.

From a technical standpoint, there are also challenges. The best way to decrease
carbon-dioxide emissions is to use fewer base stations. But building a network
with high data speeds requires using more base stations.

Vodafone acknowledges the paradox.

"The radio guys want to build the best network in the world, and I want
to lower energy use, so we'll have to try to find a compromise," said Blau.

» posted by abennett

IDG News Service

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