Information and communication technologies (ICTs) and ... - ITU

• Sharing equipment between utilities and TSPs
• Having a longer equipment life cycle before replacement
The above principles can be applied to both wireline and mobile networks. In Ghana, mobile networks have
many times more users than wireline networks and user adoption is growing at a much faster rate,
therefore these are covered first in the sections below as measures taken here have the potential to have a
more significant impact on reducing emissions. However, the use of fibre optic networks is increasing as
broadband services are rolled out, and so the energy efficiency of these must also be considered. Broadcast
services and private circuits are also growing rapidly and emissions from these could become significant in
the future.
4.1 Mobile services and energy efficiency
“Irbaris estimates that mobile industry emissions were 90 mega-tonnes of carbon dioxide equivalent (Mt
CO2e) in 2002 rising to 245 Mt CO2e by 2009. During this period, the industry grew from 1.1 billion to
4.6 billion connections, whilst GSM network coverage increased to over 90 per cent of the world’s population
in 2009 from 50 per cent in 2002 and a new generation of mobile broadband networks, 3G HSPA (High-
Speed Downlink Packet Access), began to be built out. Emissions per connection actually fell by 30 per cent
from 2002 to 2009 113 ”.
The use of the network accounted for 71 per cent of emissions, and devices for 4 per cent. Embodied (i.e.
non-use phase) emissions of the network component were 13 per cent whilst embodied emissions of the
devices were 12 per cent. The embodied emissions are understood to be an annualised figure with handsets
being replaced every two years. Some effort has been made to use recycled materials, including plastics.
However, the report notes that the take-back rates are low as research shows that old mobile phones are
typically kept by customers.
Base Transceiver Stations (BTS or base stations) typically consume around 65 per cent of a mobile TSP’s
energy usage (e.g. for Vodafone globally it is 62 per cent 114 ). However, the type and level of demand for
mobile services is key to the energy demand of the base station.
With 2G (International Mobile Telecommunications 2000), it was normal for a base station to run at around
800W power consumption. In 2011, this has been typically reduced to around 500W-650W (38-19 per cent
reduction). Vodafone has shown that the adoption of a number of power-reduction techniques, such as
remote radio heads, optimising the design of the antenna and radio frequency stages, and use of free air
cooling, can reduce this to around 200W for a 2 transceiver GSM site 115 (75 per cent reduction from average
rates in the year 2000).
International Mobile Telecommunications-Advanced (IMT-Advanced) have much higher power consumption
due to growing demand for bandwidth for mobile data and applications. The advent of smartphones implies
that data usage is likely to grow from around 700MB/month/user in 2010 to 2.5GB/month/user in 2015.
Therefore, base stations will be running at full demand for a greater period of time and will normally
consume up to 1000W per base station (25 per cent more than an average 2G base station). IMT-Advanced
base stations are required to run at maximum power for at least 50 per cent of the time due to LTE data
throughput requirements. LTE was designed with a higher modulation complexity and the peak power
consumption increases as a result. Fortunately, there are potential solutions to this through, for example,
high accuracy tracking enabling high efficiency power amplifiers 116 .
If the energy consumption of a BTS could be reduced to 200W or less, then it would be practical to run a
BTS from off-grid renewable sources for at least part of the day. This would reduce demand on the
62