Sustainable Energy Use in Mobile Communications - Aug 2007

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    Sustainable Energy Use in Mobile Communications - Aug 2007 - Presentation Transcript

    1. 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.
    2. 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 EAB-07:021801 Uen Rev B © Ericsson AB 2007 2 (23) Public
    3. Sustainable energy use in mobile communications 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. EAB-07:021801 Uen Rev B © Ericsson AB 2007 3 (23) Public
    4. Sustainable energy use in mobile communications 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). EAB-07:021801 Uen Rev B © Ericsson AB 2007 4 (23) Public
    5. Sustainable energy use in mobile communications 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. EAB-07:021801 Uen Rev B © Ericsson AB 2007 5 (23) Public
    6. Sustainable energy use in mobile communications 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. EAB-07:021801 Uen Rev B © Ericsson AB 2007 6 (23) Public
    7. Sustainable energy use in mobile communications 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. EAB-07:021801 Uen Rev B © Ericsson AB 2007 7 (23) Public
    8. Sustainable energy use in mobile communications 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. EAB-07:021801 Uen Rev B © Ericsson AB 2007 8 (23) Public
    9. Sustainable energy use in mobile communications 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. EAB-07:021801 Uen Rev B © Ericsson AB 2007 9 (23) Public
    10. Sustainable energy use in mobile communications 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. EAB-07:021801 Uen Rev B © Ericsson AB 2007 10 (23) Public
    11. Sustainable energy use in mobile communications 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. EAB-07:021801 Uen Rev B © Ericsson AB 2007 11 (23) Public
    12. Sustainable energy use in mobile communications 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. EAB-07:021801 Uen Rev B © Ericsson AB 2007 12 (23) Public
    13. Sustainable energy use in mobile communications 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 EAB-07:021801 Uen Rev B © Ericsson AB 2007 13 (23) Public
    14. Sustainable energy use in mobile communications • 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. EAB-07:021801 Uen Rev B © Ericsson AB 2007 14 (23) Public
    15. Sustainable energy use in mobile communications 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. EAB-07:021801 Uen Rev B © Ericsson AB 2007 15 (23) Public
    16. Sustainable energy use in mobile communications 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. EAB-07:021801 Uen Rev B © Ericsson AB 2007 16 (23) Public
    17. Sustainable energy use in mobile communications 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. EAB-07:021801 Uen Rev B © Ericsson AB 2007 17 (23) Public
    18. Sustainable energy use in mobile communications 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. EAB-07:021801 Uen Rev B © Ericsson AB 2007 18 (23) Public
    19. Sustainable energy use in mobile communications 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). EAB-07:021801 Uen Rev B © Ericsson AB 2007 19 (23) Public
    20. Sustainable energy use in mobile communications 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. EAB-07:021801 Uen Rev B © Ericsson AB 2007 20 (23) Public
    21. Sustainable energy use in mobile communications 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. EAB-07:021801 Uen Rev B © Ericsson AB 2007 21 (23) Public
    22. Sustainable energy use in mobile communications 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. EAB-07:021801 Uen Rev B © Ericsson AB 2007 22 (23) Public
    23. Sustainable energy use in mobile communications 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 EAB-07:021801 Uen Rev B © Ericsson AB 2007 23 (23) Public

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