EAB-07:021801 Uen Rev B
Sustainable energy use in mobile
communications
August 2007
White Paper
How to achieve energy-efficient, sustainable
mobile communications through network
optimization, site optimization and alternative
energy sources.

Sustainable energy use in mobile communications
Contents
1 Executive summary ............................................................................... 3
2 Introduction............................................................................................ 4
3 Energy-optimized network.................................................................... 6
3.1 Assessing true network needs................................................................. 6
3.2 Energy and Total Cost of Ownership....................................................... 6
3.3 Real-life cost savings............................................................................... 7
4 Site optimization .................................................................................... 9
4.1 Energy efficient radio equipment ........................................................... 10
4.2 Site energy efficiency ............................................................................ 12
4.3 Remote sites.......................................................................................... 13
4.4 Remote power network.......................................................................... 14
4.5 Advanced core network equipment ....................................................... 14
4.6 High-efficiency power modules.............................................................. 15
5 Alternative energy sources................................................................. 16
5.1 Solar power ........................................................................................... 16
5.2 Wind power............................................................................................ 17
5.3 Fuel cells ............................................................................................... 17
5.4 Biofuels .................................................................................................. 17
6 Lifecycle assessment.......................................................................... 19
7 Conclusion ........................................................................................... 22
8 Glossary ............................................................................................... 23
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1 Executive summary
Protecting the environment and combating climate change are two of the most
pressing challenges facing humankind. As energy prices soar, network operators
are increasingly scrutinizing their environmental and social responsibilities … and, of
course, their energy bills.
It is worth pointing out that mobile communications – like fixed telecoms – is itself a
relatively low-impact industry when it comes to energy usage and carbon dioxide
(CO2) emissions, despite its rapid growth.
From our own lifecycle assessment studies, and other published data sources, we
estimate that approximately 0.14 per cent of global CO2 emissions and
approximately 0.12 per cent of primary energy use are attributable to mobile
telecom. This compares with 20 per cent of CO2 emissions and approximately 23
per cent of primary energy use for travel and transport, for example. The annual
CO2 footprint of the average mobile subscriber is around 25kg – which is
comparable to driving an average car on the motorway for one hour, or running a
5W lamp for a year.
Many telecom operators have about the same energy consumption today as they
did in 1995, but with twice as many total subscribers. Technology improvements
have kept energy usage very low, and there are still great opportunities for the ICT
industry to reduce CO2 emissions. For example, smart use of telecom, intelligent
homes and offices, and travel substitution could all have a dramatic effect on energy
usage and CO2 footprint.
Ericsson itself has conducted lifecycle assessments of mobile networks for more
than a decade. These studies have consistently found that it is the energy
consumption in the ‘use phase’ of radio access networks that has the most
significant impact on the environment out of all the company’s products (radio
access products are the company’s highest-volume product and account for 75 per
cent of indirect CO2 emissions).
Energy optimization in mobile communications is a three-step process.
First, mobile communication networks need to be dimensioned with as few
equipment sites as possible, while maintaining the desired coverage, capacity and
quality.
Second, the energy efficiency of individual products – as well as that of entire sites –
must be optimized, for examples through the deployment of small, efficient sites
where large cells are impractical, such as in hilly terrain or to serve small
populations in isolated areas.
Third, there needs to be ongoing research and development into the use of
renewable energy sources, such as solar, wind and biofuels.
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2 Introduction
Mobile communication is one of the most important technologies for contributing to
social and economic development around the world. Many studies have pointed to
the contribution of mobile communications to GDP growth and the UN Millennium
Development goals highlight ICT as key to sustainability.
Optimizing energy efficiency will not only reduce environmental impact, it will also
cut network costs and help to make communication more affordable for everyone.
Finding new efficient energy solutions also helps spread access to communications
by opening up more options for the siting of radio sites in a sustainable, low-impact
way.
Mobile network efficiency starts with good design, and continues with excellent
individual core and radio site performance. Utilizing alternative sources of energy
such as solar, wind and biofuels will make communications more accessible and will
reduce reliance on fossil fuels and further reduce environmental impact. It will also
help address the energy challenge that operators face when building out networks
where electricity grids are unavailable or unreliable.
There is a continuing need to develop solutions that reduce operating costs and
environmental impact by improving energy efficiency. Taking the customer
perspective, Ericsson has used site, network, climate, and traffic statistics from real
operator networks to accurately estimate enhancements to energy consumption.
Based on these, new network design methodologies, radio techniques and site
technologies have been developed to reduce energy consumption across the board:
from radio equipment, through climate systems and radio access networks
(especially during roll-out), to existing networks (during operation).
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Ericsson’s lifecycle assessment of its own products shows that in GSM and
WCDMA mobile networks, it is the radio access network (and particularly the Radio
Base Stations (RBSs)) that are the highest contributors of CO2 emissions – a well-
established measure of overall environmental impact – in the use phase. RBSs
account for roughly two-thirds of the total CO2 emissions in the use phase, which is
itself responsible for two-thirds of the total energy-related environmental impact of a
mobile communications network.
Therefore, it makes sense that any serious attempt to make mobile communications
more energy-efficient should focus on the performance of the radio network, while
also continuing to make improvements in other areas, such as the core network.
This paper outlines the network design methodology, technical solutions and
alternative energy sources that can be used to optimize the energy-efficiency of a
mobile communications network.
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3 Energy-optimized network
At the heart of any efficient, sustainable network is good design. By far the best way
to achieve an optimized, energy-efficient network is to build it on good foundations,
based on sound design principles. No amount of energy efficiency at the component
level can make up for an inefficiently designed network, in which the number of radio
sites could potentially be double what it needs to be to achieve the same coverage
with the same quality.
A thorough understanding of all the cost elements associated with operating a
cellular mobile network is needed, and efficient network design should be
considered long before the RFP is issued by the operator. In many cases, a design
has already been put together, and the RFP issued with the aim of obtaining a
certain number of sites at the lowest possible cost. For example, by getting
experienced network designers involved from the start of the process, operators can
typically reduce the number of radio sites needed overall by between 30 and 50 per
cent.
The following sections describe how this is achieved.
3.1 Assessing true network needs
Before getting into considerations of individual sites and equipment specifications, it
pays to consider exactly what coverage, capacity and quality are required from the
network. Does coverage need to be contiguous, or will spot coverage suffice? What
grade of service is really required – is 1–5 per cent grade of service acceptable? Will
congestion cause a problem? How important is voice quality and call set-up time to
subscribers?
At the same time, the current and future business environment needs to be
considered. Are competitors on the same market ahead, behind or at the same
level? Will increasing capacity requirements mean reduced coverage? Will it be
possible to expand or rebuild sites in line with capacity demand?
Only once all these factors have been considered should an operator begin the
network design process, and that should start with a thorough examination of the
total cost of ownership (TCO) of the alternative design options.
3.2 Energy and Total Cost of Ownership
Capital expenditure (CAPEX) typically represents a very small proportion of TCO.
So while the network equipment required to achieve efficient design is typically more
expensive to buy in the first place – box versus box – the long-term savings from
site reduction and efficient operations mean TCO can be greatly reduced. A knock-
on benefit is a significant reduction in energy consumption.
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TCO is the annual amount the operator must spend to keep the network operating at
the level of performance needed to sustain and build a business, based on the roll-
out of a defined coverage area or capacity expansion. It includes costs such as
operation and maintenance (O&M), site rental, power, transmission and spares,
support and training. It also encompasses depreciation of capital equipment
including radio equipment, site equipment, civil works and network roll-out. A TCO
model designed to identify the total annual cost of network operations and
depreciation (OPEX plus CAPEX) is shown in Figure 1.
Figure 1. Total Cost of Ownership model.
Adding together the total annual OPEX and depreciation provides the annual TCO.
This approach can illustrate how operator investments in cheap or poor-quality
network equipment can ultimately result in an unintended consequence: higher TCO
and higher energy bills. This is because poor-quality equipment often requires more
sites and more OPEX than an investment in high-performance equipment would.
The long-term TCO and energy savings provided by thorough network design and
advanced equipment are not just theory: they have been proved in real-life
networks.
3.3 Real-life cost savings
The results of efficient network dimensioning and advanced coverage- and capacity-
enhancing features can be seen from a real-life network, rolled out in a new
coverage area in a developing market.
In this case, TCO analysis was used to evaluate various radio network designs, from
a basic ‘combined’ design to one incorporating a number of advanced features,
including Transmitter Coherent Combining (TCC), four-way receiver diversity
(4WRD), and modular high-gain antenna (MHGA). The optimized network design
not only provided slightly more coverage with half the number of radio sites, it also
reduced power consumption by ten per cent through radio network efficiency alone,
as shown in Figure 2. Taking all other factors into account, including the reduction in
transportation and site visits, energy consumption was reduced by half. Considering
that the average lifetime of radio equipment is 10–20 years, these savings can be
significant.
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Figure 2. Reduced overall energy consumption through better network design.
The higher overall costs for radio and site equipment were more than offset by
savings in transmission equipment, civil works, network roll-out, operation and
maintenance, site rental, transportation, and spares, support and training.
With an optimized network, operators can then address the optimization of individual
sites.
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4 Site optimization
Today, some 25 years after the introduction of the first mass-market mobile phones,
you might think that core, transmission and radio network equipment have become
commodity items. However, while equipment is quite mature and readily available
from many suppliers, it’s still true that total network solutions are greater than the
sum of their parts. Optimizing solutions for minimum TCO involves rethinking the
entire design, and engineering each component to contribute optimally to the overall
equation. Merely combining the best or cheapest components in a package does not
necessarily produce the best results.
In the radio network, for example, as well as the radio base station (RBS) and
transmission equipment, the typical radio site today also includes battery back-up
units (BBUs), air conditioning equipment to secure battery lifetime, and diesel
generators to charge the batteries during longer power disruptions or where direct
connection to the electricity grid is impossible. The relative energy consumption of
the various components at an RBS site is shown in Figure 3.
Figure 3. Energy consumption at a typical macro RBS site (normalized).
An array of technologies and techniques are now available to reduce OPEX through
energy efficiency at individual radio sites. Together, these can reduce energy
consumption by 30 per cent or more.
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4.1 Energy efficient radio equipment
RBS systems may have been around for decades, but new techniques are
constantly being developed to enhance output performance and improve energy
efficiency, as shown in Figure 4.
Figure 4. Continuous reduction in CO2 (Mtonne) through improved RBS design.
One way energy efficiency can be improved is through the Main Remote solution –
also known as tower top-mounted radios, which can reduce energy consumption by
two-thirds.
In traditional RBSs, all equipment is located in a shelter or in an outdoor RBS on the
ground. The radio units are connected to the antennas using feeder cables, which
can be several tens of meters long. Typically half of the emitted power from the
radio transmitters is lost in the feeders.
Thanks to integration and miniaturization, the Main Unit can now, as an alternative,
be housed in an outdoor casing adjacent to the Remote Radio Unit(s) on the tower
(as shown in Figure 5). This means that either the input power can be halved, or the
output power can be doubled for the same input. In addition, both site planning and
installation are greatly simplified, as the RBS has virtually no footprint. Cooling
systems are also eliminated, as the Main Unit can be cooled through natural
convection.
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Figure 5. Main Remote configurations.
The Main Remote solution opens up opportunities for alternative energy sources. As
an illustration, a tower top mounted RBS – such as a four-transceiver (TRX) RBS
providing 33dBm at the antenna or a two-TRX RBS providing 43dBm at the antenna
– consumes less than 200W per radio unit. The RBS can, when applicable, be split
into two sectors (cells). This implies a site energy consumption of ~600W (plus
transmission). With such low energy consumption, solar or combined solar–wind
energy solutions (plus batteries) become viable for off-grid sites.
Another way in which radio equipment can be managed to reduce overall energy
consumption is through stand-by modes. RBS sites are dimensioned to cope with
peak hours. In a typical three-sector cell, with four TRXs per sector, this means that
12 TRXs are active all the time, when often they are not all needed. By introducing
advanced power management schemes, one TRX per sector could be put into
stand-by mode during quieter periods. When one considers that each idling TRX
consumes 40–60W, the potential energy savings across a network of hundreds of
RBSs could be huge (as shown in Figure 6). Today it is possible to make 10–20 per
cent overall energy savings in this way without any impact on service quality.
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Figure 6. The effect of GSM base station power-saving feature.
If the entire installed base of Ericsson GSM base stations was to apply this
software-upgradeable feature, CO2 emissions could be cut by 1 million tons per year
– the equivalent of the emissions from 330,000 cars each traveling 16,000km per
year.
4.2 Site energy efficiency
A number of energy management techniques can be deployed at RBS sites to
improve their energy efficiency. Redundant units or resources not needed during low
traffic hours could be shut down using sleep mode functions, for example.
For new indoor sites with multiple RBSs, conversion between 24V and -48V should
be avoided. Avoiding unnecessary DC/DC conversion typically saves around 15 per
cent in energy consumption and cost. It is more energy-efficient to have a separate
rectifier and back-up system for the different voltages. However, if the power
consumption for one of the voltages is minor – as with transmission – there is no
advantage in having a separate rectifier and back-up system.
An outdoor combined RBS and BBU forms a streamlined site with a common
cabinet/shelter that minimizes hardware and energy consumption. Such a solution
offers long battery back-up of up to 12 hours. Similar performance can be achieved
even in a shelter solution when the air conditioning system can be replaced with
simple fans or passive heat exchangers – with the battery compartment in the
shelter cooled separately. With this solution, the upper temperature performance of
the RBS can be utilized. To save on CAPEX, the RBS internal power system should
be used, as it manages efficient battery charging and is tolerant of power
fluctuations.
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While the power consumption of the RBS is falling significantly – the most efficient
outdoor three-sector RBS consumes only 500W – other parts of the site become
significant. It is important to reduce the power consumption of transmission
equipment, mast warning light and other equipment with power consumption in the
same range.
Using an outdoor combined RBS and BBU solution is advantageous at sites with
generator back-up, as the power generator can be downsized considerably. Many
operators still begin running their generators a short time after a mains power break:
often within 30 minutes. The reason could be that they do not want to invest in a big
battery bank or they might be afraid to wear out the batteries too quickly. With
correct dimensioning, and by using the correct battery type, battery life can be
extended to four years or more. After analyzing the mains outage data, an optimized
battery dimension can reduce the number of starts and generator running time by
more than half. This saves fuel, extends generator life and reduces maintenance.
4.3 Remote sites
For remote sites, where the electricity grid is unavailable or unreliable, local power
solutions are needed.
Peak power and start-up currents are very important factors for dimensioning the
power converter, usually a diesel generator.
For off-grid installations, continuous generator operation is common. To secure
operation, two generator sets are used, often with each working half the time. One
will also act as a redundant unit for the other. After a limited lifetime, both generators
have to be replaced, which affects OPEX.
In hybrid operation, one generator is replaced by a large battery bank, the cost of
which is roughly equivalent to that of the generator. The generator can also be
complemented with alternative energy sources to reduce diesel consumption.
Assuming the battery bank is dimensioned correctly, there should not be any
particular maintenance needs from the batteries: only when they need replacement.
Maintenance is limited to one generator rather than two. As the battery charging
requires additional power, the generator can operate at a higher load for the running
period – eliminating the time the generator needs to run with ‘dummy’ loads. This
operating mode is more fuel-efficient and so reduces fuel consumption.
Energy efficiency can be optimized by running the RBS from battery power during
the quiet night-time period, say between midnight and six o’clock in the morning.
The batteries are recharged by the generator during the day-time. Running the
generator at higher loads like this extends its maintenance period and overall
lifetime as it suffers from less build-up of deposits – leading to an approximately 50
per cent reduction in energy-related costs.
In remote areas, handset charging stations are needed. They can be arranged as:
• stand-alone units, usually sun generator with battery back-up
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• adjacent to a base station – connected to the site power
• distributed to the village using remote power distribution.
4.4 Remote power network
Remote power schemes enable several sites to be powered from one central point,
as a result of advances in power transmission technology.
The user sites could be RBS sites, handset charging stations or village power.
The central site produces power using generator sets and distributes it to other RBS
sites over specially-designed low-cost, copper-free cable in star, ring or chain
configurations, over several tens of kilometers.
The central site generators are dimensioned for cluster consumption, providing
power trunking efficiency. The remote sites have no need for generators or batteries
on site.
4.5 Advanced core network equipment
While the potential energy savings in a typical radio network of hundreds or
thousands of base station sites are huge, the scope for savings in the core network
should not be overlooked.
Overall, the shift to IP-based routing and switching systems has improved the
efficiency of the core network substantially over the past decade or so. This is
especially true for the transmission of voice, where digital compression techniques
have provided a 60–70 per cent reduction in transmission capacity requirements.
Today’s Mobile Switching Centre Server (MSC-S) consumes around 35 per cent
less power per subscriber than its predecessor. A single MSC-S node, capable of
serving 1.3 million subscribers, can now be housed in one cabinet (occupying less
than half a square meter of floor space) – where historically, several cabinets would
have been needed – reducing floor space, cooling and energy needs. MSC Pooling
– where MSCs are combined to cover larger areas, especially where different areas
have complementary load patterns (residential and business areas, for example) –
also provides large potential savings in overall transmission capacity requirements.
Similar improvements in energy-efficiency have been made in other core network
nodes, including the Mobile Media Gateway (M-MGw) and GPRS Support Nodes
(GSN). The latest generation of Serving GSN (SGSN), for example, consumes half
the power per subscriber of its predecessor.
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4.6 High-efficiency power modules
The efficiency and reliability of all electronic equipment is underpinned by the
performance of its power supply system. New digital control techniques used in an
on-board power supplies are delivering every-improving efficiency, reduced total
cost and advanced system power management.
Digital power techniques in power conversion applications are now an extremely
viable and attractive option and deliver capabilities and performance levels at both
the power supply and system levels that are simply not possible with analog
techniques. Benefits include improved efficiency; improved reliability due to higher
integration of digital control circuitry; reduced system cost as a result of there being
fewer decoupling capacitors, due to enhanced load transient response of adaptive
digital control; increased power supply power density due to smaller digital control
circuitry; tighter output voltage tolerances owing to enhanced initial set point
trimming; lower overall cost of ownership resulting from all the above improvements.
The cost parity between digital and analog control implementations means these
benefits are ‘free’ to radio network equipment designers and manufacturers. There
are real advantages in using the digital interface to power supplies during the
system design, development and evaluation phases. The communications bus
enables complete customization – reducing design time, facilitating power
management and reducing time-to-market. A single power supply ‘part number’ can
serve several purposes, so reducing parts inventory and sourcing time.
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5 Alternative energy sources
Where sites are beyond the reach of an electricity grid, or where the electricity
supply is unreliable – and are remote enough to make the regular maintenance and
refueling of diesel generators prohibitive – there are now a number of cost-effective
alternative energy sources available.
The importance of these alternative energy sources is increasing as the costs of
expanding into remote areas grow – for example, to cover road and infrastructure
development, fuel transport and security. Energy-related expenditure can be as high
as 50 per cent of the total OPEX in some markets, and cost of fossil fuels continues
to rise.
As radio sites have become less energy-intensive, it has become more economically
and technically feasible to use alternative energy sources,
The choice of alternative energy source will depend on local conditions.
5.1 Solar power
For low- and medium-capacity sites, or repeater sites, solar power can be used to
provide virtually free energy, at least in terms of OPEX. While the initial CAPEX per
kilowatt is higher for such solutions, they can provide a positive business case
compared with diesel generators within one or two years of operation.
Solar power is a mature technology and has been used to power RBS sites for
many years. While CAPEX is still the major issue, costs have come down as new
production capacity becomes available and new manufacturing technology matures.
Also, as sites are more energy-lean today than in the past, it is no longer necessary
to have solar panels covering large areas. A site with one average outdoor base
station today only requires 50 square meters of panels, compared with 200 square
meters five years ago.
By using the latest-generation RBSs – specifically the Main Remote solution –
small-to medium-capacity RBS sites can be solar-powered in many of the world’s
emerging markets.
Apart from having very low environmental impact, solar-powered sites also have the
advantage of being very low-maintenance, with a technical lifetime of 20 years or so,
and much more reliable than diesel generator-powered systems. Reliability is often
the deciding factor when choosing an energy system for high-capacity radio
transmission installations, such as trunk radio sites.
Also, solar power scales with the load, so the size of the solar installation can be
matched to actual needs without unnecessary capacity.
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The downsides are the need for more site space and higher energy storage capacity
(to cope with seasonal variations in sunshine, for example), compared with diesel
generator-powered sites.
However, the energy-optimized site of the future might combine a number of
alternative energy sources to account for seasonal and climatic differences.
5.2 Wind power
As with solar power, wind power can provide virtually free energy. The wind power
industry is, however, moving towards very large wind turbines, and the challenge is
to find a cost-effective solution for an RBS site.
The big advantage of wind power is that a turbine can support a traditional macro
RBS site without too large an impact on cost. On the downside, there is the erratic
nature of wind, which means that a small diesel generator or other power source is
likely to be needed for fill-in power during periods of low, or no, wind. Currently, wind
power also demands extra site space, because of the need for an extra mast or
tower to house the wind turbine.
5.3 Fuel cells
Fuel cells are increasingly being considered as a viable alternative site energy
solution for telecoms. They can be deployed in place of diesel generators, and partly
replace batteries, at remote sites with long back-up requirements. In addition to
improving energy efficiency, they can also improve network up-time and reliability.
Fuel cells are highly reliable and efficient, and have the advantage of being load-
following, which means sizing is not an issue, other than for hydrogen storage.
Currently, fuel cells provide an alternative to battery banks and diesel generators for
back-up purposes in markets with a stable power grid. For telecoms networks with
unstable power grids and longer periods of local power generation, the technology
still needs to prove itself, especially as the refueling requirement is just as much of
an issue as for diesel generators.
5.4 Biofuels
Biofuels include fuels such as biodiesel, vegetable oils, ethanol, methanol, biogas
and other fuels derived from biomass. Biodiesel can be produced from a number of
feedstocks including cold-pressed vegetable oils, waste vegetable oils (used frying
oils from restaurants), animal fats and fish oils.
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In theory, biodiesel can be used in a regular diesel generator engine without
modification – however, this needs to be confirmed with the generator vendor. The
advantage of using vegetable oil is that the production step for processing of
biodiesel can be omitted, which results in lower fuel costs and easier logistics. The
disadvantage of vegetable oil is that the diesel engine must be modified – or another
type of engine used – because of the oil’s higher viscosity.
Biodiesel is cheaper than petro-diesel in some countries (depending on excise tax
and tax exemptions) and the commercialization of biodiesel is heavily linked to the
escalation of the price of petro-diesel. Biodiesel reduces dependency on fossil fuels,
with their fluctuating prices and negative impact on national economies. If the
biodiesel is produced locally, the cost of delivery is also reduced. Furthermore, the
local micro-economy is stimulated through local job creation which, among other
benefits, may reduce the risk of theft of fuel and equipment.
It is important that biodiesel meets the EN 14214:2003 or ASTM D6751 quality
standard.
The environmental benefits of biodiesel include a reduction in emissions of carbon
dioxide (78 per cent) and sulfur dioxide, and a reduction in particulate matter and
hydrocarbons, as a result of cleaner burning and reduced delivery logistics.
Biodiesel is free of lead and sulfur, non-toxic and bio-degradable within a matter of
21 days if spilled.
A few important factors to bear in mind when considering the production of biofuel
crops include: the requirement for fertilizers and pesticides; the potential
displacement of food crops; the use of the biofuel crop as a ‘break crop’ for later
food production; and the need for machinery-intensive production.
Biodiesel production can be controversial if, for example, rain forests are cleared for
widescale biodiesel plantations or if food crops are taken out of the food chain.
However, in the case of telecoms, this can be avoided through the use of small,
localized production close to the site and at the local community level, and through
the use of non-food crops such as jatropha. It is important to consider environmental
guidelines, such as the sustainability criteria developed by UNEP, as well as the
total energy gain, or saving, against the environmental impact of each potential
energy source.
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6 Lifecycle assessment
Lifecycle assessment (LCA) can be used to analyze the total potential
environmental impacts associated with a product or service. LCA can provide a
holistic overview of the relative significance of the different phases of a life cycle,
and can be used as a tool to provide guidance on improvements.
We’ve seen how optimized network design and site solutions can reduce energy
consumption and overall TCO for the operator. Ensuring that such developments
provide long-term, sustainable benefits means taking a holistic view and
understanding network energy consumption end-to-end. Understanding the
relationship between energy, OPEX and carbon dioxide emissions is critical to be
able to reduced total cost of ownership, and to develop efficient products and
innovative sustainable energy solutions.
It is worth saying that mobile communications is a relatively low-impact activity when
it comes to CO2 emissions. The annual CO2 footprint of the average mobile
subscriber is around 25kg – which is comparable to driving an average car on the
motorway for one hour, or running a 5W lamp for a year. This has come down from
over 150kg of CO2 per year for first-generation mobile systems in the late 1980s (as
shown in Figure 7).
Figure 7. Evolution of total lifecycle CO2 per average mobile subscriber per year
(source: Ericsson).
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The lifecycle assessment for mobile communications carried out by Ericsson
includes everything from concrete foundations to mobile handsets, over their
lifetime. It covers four main lifecycle phases: supply chain (manufacturing and office
sites, transport, raw materials and chemicals); vendor (transport, office and
manufacturing sites, business travel; use phase (products’ energy consumption,
offices and stores and vehicle fleet); and end-of-life (recycling, collection/treatment,
landfill and resource depletion).
For the use phase, we have been able to gather field data from over one-third of all
GSM networks worldwide. These studies have found that the largest individual
contribution to most environmental impact categories comes from equipment
operation (as shown in Figure 8) – although normalizing the results to the global
average impact per head gives very low values.
Figure 8. Lifecycle assessments of mobile networks.
The materials and energy consumed by the RBS function have fallen continually
over the past 20 years. In the late 1980s, the typical analogue macro RBS could
only serve 21 simultaneous voice calls (0.2Mbit/s), with two tonnes of equipment
consuming 5kW of power in its own building or shelter. Today, a WCDMA Main
Remote RBS can serve up to 150 simultaneous users, with up to 3x3.6Mbit/s
(11Mbit/s) voice and data, with just 100kg of equipment, consuming 0.5kW, and no
need for its own building or shelter.
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As stated above, LCA can be used as a tool to analyze the total potential
environmental impacts associated with a mobile network in operation. Ericsson has
used LCA for more than a decade to understand the relative significance of the
different phases of a mobile network in use. This has guided us in setting aggressive
energy targets for our largest-volume products, the radio base stations.
Ambitious goals for products have reduced consumption rates considerably. New
RBS products from 2006 onwards with lower energy consumption will save about
two million tons of CO2, over their average ten-year life span.
Combining LCA with a TCO approach results in a comprehensive understanding of
energy issues, OPEX issues and CO2 impacts of the products and services we
deliver.
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7 Conclusion
Large volumes of telecom equipment will continue to be deployed to meet traffic
growth, both in the radio network and the core network. Continued energy-efficiency
improvements will reduce energy consumption and provide a competitive
advantage.
In addition, the need to offset physical transportation to combat climate change will
likely lead to an increase in telecom applications and services. What is more,
increasing consumer awareness of environmental issues, as well as the energy
availability challenges in rolling out telecom networks to remote areas, will result in
growth in alternative power sources such as solar, wind and biofuel.
Energy efficiency is a key challenge for operators that want to reduce OPEX as well
as meet their environmental obligations. Delivering long-term, sustainable energy
savings means taking a holistic approach that encompasses the three main pillars of
an energy-efficient, sustainable network:
• end-to-end network design
• individual site performance
• alternative energy sources.
Advanced TCO modeling, extensive field measurements and practical experience of
advanced technology solutions have all shown how attention to optimized network
design, efficient site solutions and use of alternative energy sources such as solar,
wind and biofuels can lead to dramatic improvements in the energy efficiency of
mobile networks. Furthermore, this approach will make communications more
accessible, reduce reliance on fossil fuels and further reduce environmental impact.
Ericsson is committed to ensuring that its solutions lead the way in helping operators
reduce the overall TCO of their operations, and encourage sustainable development
and access to communications for all around the world.
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8 Glossary
4WRD Four-Way Receiver Diversity
BBU Battery Back-up Unit
CAPEX Capital Expenditure
CMOS Complementary Metal Oxide Semiconductor
GDP Gross Domestic Product
GPRS General Packet Radio Service
GSM Global System for Mobile communications
GSN GPRS Support Node
ICT Information & Communication Technology
LCA Lifecycle Assessment
M-MGw Mobile Media Gateway
MHGA Modular High-Gain Antenna
MSC Mobile Switching Centre
O&M Operations & Maintenance
OPEX Operating Expenditure
RBS Radio Base Station
RFP Request For Proposal
RRU Remote Radio Unit
TCC Transmitter Coherent Combining
TCO Total Cost of Ownership
TRX Transceiver
WCDMA Wideband Code Division Multiple Access
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