Page 8 - European Energy Innovation - Winter 2016 publication
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8 Winter 2016 European Energy Innovation

The Core-Network Energy-
Efficiency Challenge

By Dr. Klaus Grobe, Director Global Sustainability, ADVA Optical Networking SE, Germany

INTRODUCTION                                             on technology. With Passive Optical                                                                                     is confirmed in so-called Life-Cycle
Bit rates in the Internet are growing                    Networks, growth can be kept to a                                                                                       Analysis (LCA), where various impact

exponentially. So is the negative                        minimum.                                                                                                                aspects like GHG production, Ozone

environmental impact of the global ICT                                                                                                                                           depletion and others are calculated

sector, albeit somewhat slower. This is                  Relevant core-network components                                                                                        over the entire equipment life, from

primarily driven by the Internet energy are IP/MPLS core routers and high-                                                                                                       extracting raw materials via production,

consumption and the associated                           capacity transport. The latter is based                                                                                 transport, use-phase up to end-of-

greenhouse gases (GHG). It holds as                      on Wavelength-Division Multiplexing                                                                                     life (recycling, landfill). A simplified

long as electricity is not fully based on                (WDM). In WDM, multiple wavelengths WDM LCA example is given in Figure

renewable energy.                                        are used in optical fibers, each carrying 2, which shows the dominance of the

                                                         digital information.                                                                                                    use-phase.

ICT energy consumption splits into

core and access networks, data centers, This started approximately 20 years                                                                                                      The energy efficiency of core-network

and end-user equipment. There is a                       ago with per-wavelength bit rates                                                                                       equipment, in particular core routers

significant difference between core-                     of 2.5 Gb/s, the latest generation                                                                                      and WDM, has been substantially

networks and data centers on the                         is carrying up to 200 Gb/s per                                                                                          increased in the last two decades.

one hand, and end-user equipment                         wavelength. Although the WDM                                                                                            Unfortunately, the bit-rate increase –

on the other. In the recent years, the                   contribution to global ICT electricity                                                                                  throughput in core routers and WDM

energy consumption of end-user                           consumption is comparatively low,                                                                                       transport capacity – has grown even

equipment decreased globally, which                      WDM is one of the areas where growth faster. For both equipment categories,

was primarily driven by improvements                     is predicted. This is shown in Figure 1,                                                                                one can approximately derive

in flat-panel displays and (laptop)                      where WDM contributes to Networks.                                                                                      duplicated energy consumption for

computers. On the other hand, core-                                                                                                                                              10-fold bit-rate increase. This is shown

network and data-center energy                           ICT AND THE CORE-NETWORK                                                                                                in Figure 3 for typical routers and WDM
consumption is commonly predicted                        CONTRIBUTION                                                                                                            gear. It is relevant to note that the latest
to grow significantly. Broadband                         The main environmental impact from                                                                                      numbers in both equipment categories

access networks are also predicted                       core-network equipment results from                                                                                     are only achieved by combining the

to grow, but growth rate depends                         its use-phase energy consumption. This most energy-efficient measures in

                                                                                                                                                                                 all equipment aspects. This includes

Figure 1. Internet energy consumption in Germany                                                                                                                                 latest chip sets, optimized voltage

[Hintemann et al., EGG 2016+, Berlin, September 2016                                                                                                                             supply, deactivation of unused parts,

Energy Consumption [GWh/Year]  40                                                                                                                                                etc. In other words – even if the best
                                                                                                                                                                                 technologies are combined today, the
                                                    WDM LCA Example (FSP 3000)resulting efficiency increase is slightly

                               30 lower than the bit-rate increase. This

                                                                                                                                                                                 behavior is different as compared to

                               20 other equipment, e.g., computers, TV
                                                                                                                                              sets etc.

                               10 Figure 2. Simple WDM LCA example.

                               0              2015       2020                                                                                                   2025        CO2  Other   Use Phase
                                      2010                                                                                                                                        Other   Use Phase
                                   Smartphones, Tablets        Networks                                                                                               Depletion

                                   Computers                   Data Centers                                                                                                      0% 20% 40% 60% 80% 100%

Hintemann et al., EGG 2016+, Berlin, September 2016]                                                                                                                           

                                                                                                          © 2016 ADVA Optical Networking. All rights reserved.
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