Page 47 - European Energy Innovation - Spring 2016 publication
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Spring 2016 European Energy Innovation                          47


Improved energy efficiency in
WDM network elements

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

INTRODUCTION                                 Power Consumption [W]1000  10 W/Gb/s
The internet as a whole, the number                                100
of its connections, their bit rates,
throughput – all of this is exponentially                           10
growing now for decades. So is the                                                                                          0.1 W/Gb/s
negative environmental impact of the
ICT sector. From an estimated 2% of                   1                                                                                 1000
the worldwide electricity production,                      1 10 100
ICT is predicted to grow toward
10% beyond 2020. The increasing                                                   WDM Channel Bit Rate [Gb/s]
energy consumption creates a dual-           Figure 1: Increase of WDM energy efficiency over time
fold problem. Firstly, and as long as
electricity production hasn’t been           A STORY OF IMPROVING WDM                  energy efficiency. One can derive from
fully converted to renewable energy,         ENERGY EFFICIENCY                         the figure that our most-recent 400-
it contributes to CO2 production.            ADVA Optical Networking started           Gb/s technology exceeds 0.5 W/(Gb/s)
Secondly, in the recent decades,             developing WDM gear in 1994.              efficiency, which for the time being is
the average energy-cost trend was            For certain operational reasons –         record-breaking. This was enabled, on
exclusively increasing.                      avoidance of the hot spots in data        the basis of long-term research and
                                             centers already mentioned – energy        development, by combining latest
THE INTERNET AND WAVELENGTH-                 efficiency has always been a primary      chip-sets, ever increasing power-
DOMAIN MULTIPLEXING                          concern. This is reflected by the fact    supply efficiency, optimized voltage
Today, Wavelength-Domain Multiplexing        that, to first approximation, the same    distribution within the WDM shelves
(WDM) is the basis of all broadband          number of WDM channels always             and smallest form factor (the latter
wireline connectivity. Without it, the       fit into one shelf, irrespective of the   leading to less shelf overhead).
internet as we know it would not             channel bit rate. This was only possibly
exist. It is based on independently          by massively increasing the per-bit-      CONCLUSION
using multiple wavelengths, each             rate energy efficiency (expressed in      Improvements in ICT energy efficiency
one carrying digital information,            W/(Gb/s)). Research enabling this         are crucial. If all relevant aspects
for capacity increase in fiber-optic         improvement has been supported            are considered and combined, the
transmission. Although its contribution      by several EU projects, among them        results necessary to avoid internet’s
to global ICT electricity consumption        the projects C-3PO and the more           energy-consumption explosion can
is comparatively low (routers and end-       recent and ongoing CEEOALAN.              be achieved. On top, proper use of
user equipment cater for the majority),      These projects supported specific         the internet will help reducing energy
it must improve in efficiency, too. This is  photonic-components and high-speed-       consumption elsewhere. l
driven by several facts.                     modulation aspects with special regard
                                             to energy efficiency.                       CONTACT DETAILS
The internet’s ever-increasing
bandwidth appetite requires similar          One result of the continuous WDM            Dr. Klaus Grobe
development in efficiency (otherwise,        energy-efficiency improvement is            ADVA Optical Networking SE
internet’s energy consumption                demonstrated in Figure 1. It shows, over    Fraunhoferstr. 9a
would be exponentially increasing).          bit-rate generations and that is, over      82152 Martinsried, Germany
Then, without improvements, WDM              time, and for typical WDM transport
equipment like some other gear as            configurations, the development in
well could easily create hot spots
in data centers and similar places.
Finally, it is well-known from Life-Cycle
Analysis, that the majority of green-
house gas and some other relevant
environmental-impact factors (like
ozone depletion) is determined by the
use phase, and that is, by the energy
efficiency during the lifetime of the
respective network elements.
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