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A Deep Dive Into the Ecobilan Model
The FTTH Council’s goal in commissioning the Ecobilan
study was to start developing a standard approach for
evaluating FTTH solutions, using globally accepted life cycle
assessment (LCA) methodology. The study meets a set of
international standards called ISO 14040, for environmental
assessment based on consistent and relevant data, but it
does not cover all possible deployment scenarios. Use it as a
starting point for your own discussions.
FTTH Scenarios and Assumptions
The study models the entire network from the central office
(CO) to the user. It covers the passive components of the outside
plant fiber network (the cable and the hardware) as well
as the active equipment components in the access network.
It does not consider the infrastructure associated with the
metro or long-haul portions of the network, on the theory
that it is in place and would be expanded in any event. Thus,
it may slightly understate the impact of rural deployments
far from intercity fiber trunks, which require expansion of
the long-haul networks that might otherwise not take place.
On the other hand, it does not include the very latest versions
of FTTH equipment coming onto the market, with
lower energy consumption both in absolute terms and in
energy-per-bit efficiency.
The study integrates the environmental impacts associated
with the fiber networks from their construction to the
end of their useful life, excluding maintenance.
Based primarily on conversations with vendors and deployers,
Ecobilan made the following critical nationwide assumptions
to generate its “typical” GPON model. Network
deployers should make adjustments based on their individual
circumstances.
• Electricity is generated using 48.56 percent coal, 3.37
percent oil, 16.42 percent natural gas, 19.30 percent
nuclear, 7.49 percent hydro and 2.11 percent renewable
sources (data from the International Energy Agency).
• Passive equipment has a life of 30 to 50 years, while active
network elements last 5 to 10 years.
• LTA and CTC cable are used in equal amounts. A 72-fiber
LTA cable is mainly made of HDPE (high-density
polyethylene) and polyester with glass, while the CTC
cable of same fiber count is made mainly of HDPE, PVC
(polyvinyl chloride) and the glass fiber.
• Aerial cable is an outdoor cable consolidated with FRP
(glass and a polyester resin) and additional polyethylene.
• Buried cable is an outdoor cable armored with steel.
• Indoor cable is 24-fiber H-Pace, made mainly of LSOH
(low smoke zero halogen), which was modeled as if it
were polypropylene.
Network Life Cycle
Benefits of telecommuting, versus six major environmental impacts,
assuming no customer growth; the environmental cost of building
the network is paid back in six years. Most of a fiber network’s energy
impact is in construction, not operation.
The life cycle of a fiber-to-the-home network.
Assuming 25 percent customer growth, the payback is in four years.
32 | BROADBAND PROPERTIES | www.broadbandproperties.com | January/February 2009