ADVA Optical Networking products are part of the global Internet, or ICT sector. As such, they are part of a sector who contributes approximately 2% of the global greenhouse-gas (GHG) emissions. On the other hand, this same sector potentially enables GHG emissions abatement that is seven times higher than its own emissions. This is sometimes also referred to as Green-by-ICT.
The global ICT sector can be split into three areas: data centers, networks, and end-user devices. The networks segment in turn splits into two approximately equally large parts, wireline and wireless networks. Our products, incl. DCI solutions, mainly fall into the wireline networks category (the ICT data-center segment mainly consists of servers and switches). The impact of the wireline networks segment on global ICT GHG emissions is shown in the following picture.
Figure 1. Global ICT emissions [GeSI SMARTer 2020, 12/2012]
Figure 1 shows that energy consumption in the networks segment is predicted to grow significantly over the next couple of years. In many cases of network equipment, the entire product environmental footprint is even dominated by the use-phase energy consumption. This necessitates to continuously optimizing the impact of the related products via respective eco design.
The environmental footprint is calculated by life-cycle analysis (LCA, e.g., according to ISO14040/14044), which considers all phases of the entire product life. This ranges from extraction of raw materials via production and distribution to the use phase and finally the product end of life (i.e., reuse, recycling or landfill). Consequently, eco design must consider the aspects of material usage / composition, size / weight, energy efficiency, and design for reuse and recycling.
Today, LCA cover a substantial part of our product portfolio (approximately, the commercially most relevant 90%). All LCA consistently show that several environmental-impact factors – most notably CO2 and ozone depletion – are clearly dominated by the products’ use phase. This is true for WDM equipment as well as Ethernet equipment. The common reason behind is that this equipment is typically used in telecommunications networks for quite a long time and in 24/7 always-on mode (since deactivation would cause network outages). In particular the WDM equipment, but also substantial parts of the Ethernet portfolio, have long lifetime, often approaching 10 years. A WDM LCA example is given in the following diagram.
Figure 2. Simplified WDM LCA showing the use-phase dominance on environmental impact
This analysis has been done for a typical configuration of our FSP 3000 product, an amplified multi-channel DWDM transport system. For this LCA, a product lifetime of 8 years has been considered (which is typical for WDM). It shows that CO2 (Global Warming), several ecotoxicity aspects, acidification and abiotic resource depletion are dominated by the products’ use phase. All other life-cycle phases are summarized in the light-gray “Other” bars.
The use-phase dominance to date is the main guideline for our WDM eco-design focus. Since use-phase energy consumption clearly is the main environmental-impact driver, we are constantly reducing the energy consumption to the best achievable extent. As a result, the energy efficiency of our WDM products (measured in watts per Gb/s) increased strongly.
The energy-efficiency gain is accompanied by the ICT trend of exponentially increasing bit rates. Since this bit-rate increase is faster than the energy-efficiency increase, WDM generations tend to consume increasing energy over time. This is despite the fact that all measures are taken to increase efficiency. In other words, to date no technologies are known that would allow overcompensation of the bit-rate increase. This is a common trend in telecommunications today, it can be seen, e.g., for core IP routers as well. This is shown in the following figure for our WDM equipment and for third-parties core routers.
Figure 3. Development of core-network-equipment energy efficiency
The figure shows energy consumption in dependence of router throughput (left diagram, data taken from Vereecken et al., IEEE COMMAG, Vol. 49, No. 6, 2011) and WDM channel-card bit rate (right diagram, based on own data). In both cases, the x-axis also represents the time axis. In the case of our WDM equipment, efficiency developed to less than 0.4 W / (Gb/s). At the end of 2016, this was best practice in energy efficiency in WDM transport.
Between 1996 and 2016, WDM channel bit rates increased on average at a CAGR of ~34%. This can be derived from the picture above, considering that WDM channel rates of 2.5 Gb/s were introduced commercially around 1996. In this period, total global IP traffic also grew at CAGR of 34% and higher, according to the Cisco VNI 2016. Toward 2020, IP-traffic growth is projected to have CAGR of ~22% [The Zettabyte Era: Trends and Analysis, Cisco White Paper, June 2016]. On the other hand, the GHG emissions in the ICT network segment have a CAGR of ~4% only, see the following picture [GeSI SMARTer 2020]. These numbers again show that efficiency has been improved drastically.
Figure 4. Wireline network-segment GHG emission growth [GeSI SMARTer 2020]
The trend of bit-rate increase outpacing gains in energy efficiency is ubiquitous in the global ICT networks segment. It means that currently, no technologies are known that would allow decreasing the total energy consumption of WDM equipment (or core routers, aggregation switches, etc.) from generation to generation. This must be considered when evaluating and rating improvements of any related eco-design efforts. One possible solution to this problem consists of applying some sort of Internet-growth-aware metrics. Such a metric may be applied as long as no new, disruptive, still unknown technologies appear which drastically increase energy efficiency.
It must also be noted that ICT enables GHG abatement outside the ICT sector which is substantially higher than the ICT energy consumption itself. Hence, ICT – including the energy-consumption-critical network segment – can be regarded as one of the few enablers of decreasing global GHG emissions.
Regarding the energy-consumption relevance, it must be noted that the European power sector aims at a 50% reduction of its GHG footprint by 2030. This will decrease the LCA use-phase dominance. With decreasing relevance of the use phase, the next relevant life-cycle phases must be considered for the improvement of the environmental impact of telecommunications equipment. Figure 5 shows a more detailed zoom into the LCA example from Figure 2. It reveals that the next relevant phase following the use phase is the manufacturing phase (which contains the contributions from the supply chain). This is followed by the development phase (called “Sites” here, since it contains all contributions related to the manufacturer’s sites), distribution / transport, and the end-of-life (EoL) treatment.
Figure 5. Details of WDM LCA example. Note that use-phase bars are truncated at 40%.
The newly considered life-cycle phases require different measures each for further environmental-impact reductions. The manufacturing phase requires improvements in the supply chain (components suppliers’ sites, material selection). Regarding the development phase (“Sites”), the contribution of the systems manufacturers’ sites must be considered. In the distribution phase, the transport mode must be optimized (reduction of air freight). Finally, for the EoL phase, the respective treatment must be optimized (optimized recycling).
Dedicated considerations that reduce raw-material intake and support the recycling are integrated into our product-design processes, in the form of a product eco design guide (called DfR3, Design for Reduction, Reuse, and Recycling).
The DfR3 guide splits into two parts, one focused at energy efficiency, the other looking at different aspects that lead to Design for Circular Economy. The energy-efficiency part summarizes those steps in a process document which have been followed earlier already. It contains high-level guidance regarding components, save modes, thermal design, and others. The Circular Economy part splits into several chapters. These address the following areas of Circular-Economy-related product design:
- Lifetime extension and upgradeability
- Manual disassembly (avoidance of glue, rivets, etc.)
- Material efficiency, selection, and composition
- Dedicated design criteria for printed circuit boards and plastic parts
- Labelling (of materials)
These design rules limit the number of materials and material combinations, and they also limit the choices for connections between different parts, sub-units, etc.
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