To bury or not to bury...
In rolling out fibre-optic cable to 90 per cent of Australian homes,
workplaces and schools, there are two main choices for the mode of deployment:
underground cabling and aerial cabling. The committee strongly believes that
this issue requires greater scrutiny by the government, industry and the
Australian people; consequently this chapter is dedicated to this crucial
To provide optical fibre cables aerially, the NBN Co will need to either
use existing electricity utility infrastructure, or to build their own poles
where there are none in existence. Aerial cabling is most likely to be used in
existing, or 'brownfield' areas, where telecommunications and other
infrastructure already exists. Extrapolating from that assumption, and taking
guidance from the Tasmanian roll-out, the committee believes that aerial
cabling may be deployed over the vast majority of the 90 per cent FTTP
Deployment requirements and issues
To the casual observer, the option of utilising existing power poles to
carry the fibre optic cabling required for the FTTP project seems an obvious
and efficient solution. The infrastructure is already there, so all that might
be required would be the technical slicing and stringing of cables between
poles to connect each premises.
This was the assumption made during the planning of the tasCOLT pilot
that connected several small pockets of homes in Tasmania to a FTTP network
utilising existing infrastructure. The pilot objectives were to create a FTTP
network using Passive Optical network technology, deployed mainly via overhead
cables owned by Aurora Energy, and delivering network services capable of
average speeds up to 100Mbps. The completed tasCOLT network passes approximately
1200 premises, connecting approximately 600 of those. Over half of the
connected premises have subscribed to the full range of services available
under the project.
However, the final report of the tasCOLT project provides evidence that
aerial cabling was not the quick-fix that planners had anticipated. The
rollout of the pilot was expected to take six months, but actually took almost
two years, with the report noting that 'installing optic fibre in
"brownfield" areas is complex.'
The reported reasons for the massive overrun on the project timeframe were:
The requirement to obtain local government approvals for aerial
cable deployment, including an environmental impact study and approvals from
the Tasmanian Heritage Council, where applicable;
The integration of the optical fibre system with Aurora Energy's
existing infrastructure, which involved:
compliance with OH&S standards;
compliance with Australian Engineering standards;
possible reconfiguration of existing poles and cabling; and
possible replacement of some poles and cabling.
The availability and affordability of skilled installation
The requirement of approvals from landlords to connect the drop
cable to each property.
In a revealing admission, the report made the statement that:
Local government is a key player in the deployment of optic
fibre networks and should be included as a partner in any project.
General aerial issues
The documented lessons from the tasCOLT project validate the concerns
expressed by several witnesses in relation to the use of aerial cabling. Mr
Peter Downey, Chairman of Cables Downunder, gave evidence and also provided a
written submission jointly with Dr Ross Kelso elaborating on several of the issues
identified in the tasCOLT report.
When discussing the impact of aerial construction, the submission noted
that electrical safety codes require power lines and optical fibre cables to be
at separated, predetermined and standardised heights. An example of the impact
of these codes from tasCOLT is illustrated at figure 2, with a photo of a
typical pole at figure 3. The submission states that cable heights must also
comply with road traffic regulations, with the lowest cable being no less than
five metres above the crown of the road.
Figure 2: Representation of aerial
The submission states that during the Hybrid Fibre Coaxial (HFC)
deployment by Telstra and Optus between 1995 and 1997, utilities companies
determined that existing pole infrastructure was insufficient, and that
existing poles had to be replaced or strengthened. The photo at Figure 3
illustrates efforts to strengthen and heighten a pole in a Brisbane suburb. Mr
Downey explained that height clearance issues are exacerbated in hilly, or even
mildly sloping, street scapes.
Mr Downey gave evidence that by deploying aerial cables Australia would
be putting itself further behind international efforts, where 'the majority of
communications and electricity cables are underground.'
As an example, Germany began burying telegraph cables in
1845, London began burying electricity cables in 1882, followed by New York in
1888. We have found that many third world countries, such as Rwanda and Somalia
in Africa, have underground fibre optic and electricity networks. Today UK is
85 per cent underground and Europe is 70 per cent and rising.
Mr Downey also noted the lack of public awareness that aerial cabling is
likely to be the mode of the NBN's deployment in many urban areas.
At this stage I do not believe that the general public are
aware that the NBN will be erected overhead. At various functions I have
attended recently at which I have raised the issue there has been stunned
silence followed by comments such as, 'You are kidding, aren't you?' ...
It does not matter what size the overhead cable is, it will
be the fact that it is an overhead cable that raises the ire of the public.
Even if aerial cabling is proven to be more efficient than underground
cabling to deploy, there are legacy issues with aerial cabling that will remain
a burden to governments for the life of the aerial cabling. One obvious cost is
in keeping trees trimmed and well away from aerial cabling. The subsequent
'mutilation' of trees will continue to increase the visual pollution of aerial
cabling, in addition to the annual cost of labour to prune the trees.
A further bottleneck that was caused by the use of aerial cabling in the
tasCOLT project was the lack of skilled technicians. In order to rollout
aerial cabling, technicians with electrical, communications and fibre optic
slicing skills are needed.
If the government wishes to pursue aerial cabling, it will need to address this
issue immediately and ensure that the additional time of training is factored
in – as was clearly illustrated during the tasCOLT pilot.
Figure 3: Visual impact of aerial
cabling with required spacing
Typical example of a pole that has
been extended and strengthened to support additional HFC cables.
Picture taken by Ross Kelso
There is also a concern that aerial construction of the NBN 'will
seriously degrade service reliability.'
Despite all efforts to keep power lines free from obstructions, power lines and
aerial optical cables are frequently brought down by severe storm conditions
across the nation – again with ongoing repair costs.
For example, Mr Downey pointed to the threat to service reliability
caused by bushfires every year across Australia. This was most evident in the
tragic Victorian bushfires in February 2009:
Many Victorian communities were put at risk simple because
the overhead cabling that provided them with communications and power was
destroyed long before those communities were aware of their peril.
Conversely, the protection offered by below-ground infrastructure which
escaped destruction was discussed by Mr Brad Wynter from the City of
Whittlesea, which was devastated in those fires. Whittlesea council had been
proactive in planning the installation of fibre conduits in greenfields
estates. When asked whether underground services in the town had been any
better off than the aerial cabling, Mr Wynter replied:
Without a doubt, the underground infrastructure was
preserved. At Strathewen, which is a neighbouring municipality, the only
infrastructure that was damaged was the exchange, the above-ground
infrastructure. In that case, Telstra brought in a portable exchange on the
back of a truck and basically connected that up and had those services
operating within one day.
A further negative aspect of aerial cabling is the damage caused by
traffic accidents between vehicles and power poles, both to surrounding
businesses as a result of interruptions in communications and electricity
services, and more importantly to individual health and life. There is also of
course the cost of repairing both the pole and the cabling.
Underground cabling (undergrounding) is a more labour-intensive option
for deploying the FTTP network. High labour costs consequently increases in the
cost of deployment. Undergrounding costs are minimised in greenfield estates,
where the cabling ground works can be undertaken as part of establishing the
overall infrastructure of the greenfield area. This also minimises the impact
of trenching on traffic, businesses and utility services to the community, as
it can be completed prior to the area being populated.
Retrofitting of underground cabling is much more costly than greenfields
undergrounding, due to the need to trench along and subsequently repair roads
and footpaths, in close proximity to existing underground infrastructure. In
highly built-up areas there is the requirement of using horizontal trenching
methods to minimise road closures and traffic disruption.
The Tasmanian government imported from Germany the latest in
trench-digging machinery for laying fibre optic cables. This machinery was used
in Hobart, which was the first time it had been used in Australia. The giant
wheel-saw can cut through road surfaces with minimal disruption to traffic and
minimal damage to existing road or footpaths.
The details of this new horizontal trenching technology were discussed
by several witnesses. For example, Mr Downey explained that the technology is
capable of 'trenchless' deployment of underground cables. By using a horizontal
boring head with imbedded sonar detection, Mr Downey explained that:
...you basically dig a hole two foot by three foot ... at your
entry point and then put another at your exit point and you just drill a
[horizontal] hole underground.
Mr Downey went on to explain that a worker with a sonar wand walks along
the street, able to detect where the boring head is, and hence steers the head
to avoid other underground infrastructure. This technique can be employed to
lay cable under a busy intersection, avoiding any traffic disruption. Although
understandably more expensive that trenching, this could minimise the
disruption to businesses that would otherwise occur during the trenching works,
also allow the continuity of other utility and communication services.
Improvement in planning
The need for planning and consultation at the local government level is
crucial for the deployment of underground cabling in both greenfield and
brownfield estates. Issues that require consideration for greenfields were
outlined by Mr Wynter from the Whittlesea Council at the Melbourne hearing.
The Whittlesea Council identified that the future retrofitting of fibre
in greenfield estates would be very difficult, as all infrastructure is underground.
The Council recognised that it could address this in future greenfields
development planning by mandating that an additional conduit be laid for the
future provision of fibre to the premises. As the council did not have a
carrier's licence, and consequently could not lay the fibre themselves, they
lobbied developers to provide a subsidy for licensed carriers who wanted to lay
the fibre. The council now has two estates that are FFTP connected and
providing 100Mbps services.
Commenting on the cost saving of laying conduit at the time of
development, Mr Wynter said that:
We know that the cost of putting the conduits in at the time
of subdivision is about half the cost of doing retrospectively – the main
reason being that [developers] open up the trenches to put in all the other
services, but to retrofit they have to bore under roads and footpaths ...
The benefits of laying conduit at the time of development were also
highlighted to the committee by Professor Walter Green, and are detailed in the
committee's first Interim Report. Professor Green not only outlined the
economic efficiencies, but also highlighted the crucial need for improved
coordination of infrastructure planning across all tiers of government and the
private sector developers. In fact, Professor Green seemed to pre-empt the
government's thinking when he stated that:
State and Federal governments should in fact be mandating,
for new estates or greenfield estates, that provision for the fibre
infrastructure should be made.
Professor Green was also able to provide the committee with examples
where improved coordination between governments and developers had provided
improved outcomes in major state infrastructure projects, including the
recently completed Perth to Mandurah railway:
...[W]here state planning has...been lucky is in terms of the
Perth to Mandurah railway line. I...proposed...or motivated to get the conduit next
to the railway line. Putting fibre in there is having an impact on broadband...
Lack of standards and regulation
A critical issue raised by Mr Wynter was the lack of applicable
standards for underground networks:
We had some work done in getting a commercial developer to
develop some standards so that the conduit would be suitable for any type of
fibre technology, because there is a range of fibre technology, some of which
require more space than others, and we built some standards around that conduit
network to ensure it could be future-proof and could cater for any type of
The committee is concerned by this lack of standardised practice, and
urges the government to bring forward the development of standards that would
be applicable nationally to greenfields conduit networking. The committee notes
that although there are various current standards for the retrofitting of
aerial cabling, the government needs to ensure there are national standards for
the retrofitting of underground cabling.
Mr Wynter also noted the lack of regulation at the federal level, which
became evident when the Whittlesea Council came to enter into agreements with
carriers to ensure they provided FTTP services on an open access basis:
The conduit belongs to council, and it is our mechanism of
ensuring that we get our three policy objectives met ... open access, scaleable
infrastructure and a rich mix of services on a competitive basis. ...
Currently, because there is no regulation at the federal level, we are the ones
that have to regulate the open access, and [retaining ownership of the conduit]
is our mechanism for doing so.
Comparative advantages and disadvantages
It is apparent that the government is desperate to demonstrate progress
on the NBN, particularly with the commencement of an election year in 2010. The
Committee is concerned that the Government is looking to implement aerial
cabling in as large an area as quickly as possible to serve this need.
Despite the government refusing to release the full report of the Panel
of Experts, their negotiations with the Tasmanian Government were a clear
indication that the Expert Panel thought there was merit in the Tasmanian
Government bid for the FTTN RFP process. This bid no doubt would have aimed to
leverage the experience and lessons gained during the tasCOLT pilots, the
majority of which involved retrofitting aerial cabling in brownfield estates.
The main advantage of deploying aerial cabling is in the apparent
time-saving use of existing infrastructure. However, as evidenced by the
experience of the tasCOLT pilots, this anticipated expediency did not eventuate
If aerial deployment is effectively planned to ensure the required
approvals and skill shortages do not cause bottlenecks, aerial cabling may be
more cost effective. This in turn could enable the NBN Co to more quickly
become commercially viable. However, the ongoing maintenance and repair costs
would be a continual burden for the operator.
The benefits of underground cabling are numerous and long term, as has
been outlined above. These benefits include:
underground cabling is a future proofed, long term solution;
immediate economic stimulus of increased employment across a
broader section of local communities;
lack of visual pollution;
consequential increase in property values;
lack of impact from climatic extremes, including bushfires and flooding;
consequential increased reliability;
decreased maintenance costs;
decreased associated costs of pole replacements (due to motor
no need for street tree mutilation;
decreased OH&S issues;
decreased electrical transmission losses with consequential
decrease in greenhouse gas emissions;
smart deployment technologies will enable skills development
while minimising disruption to telecommunication and utility services; and
decreased negative impact on local businesses during deployment.
Deploying the NBN fibre optical cables underground will result in a long
term, future proofed solution. Initial increased deployment cost and time
frames can be mitigated by the overall decrease in ongoing costs over the life
of the fibre. This will provide a pathway for the long term commercial
viability of the network.
Cables Downunder went further in their submission to advocate that the
government should utilise the NBN opportunity to embark on burying all aerial
utility infrastructure as a long term, truly nation building project.
The submission quoted a comprehensive study undertaken around 1998 'into the
practical options for retrospectively undergrounding both aerial electricity
lines and telecommunication cables throughout urban and suburban Australia.'
Included in the study were all urban and suburban localities with a
population over 30,000, which then equated to around 90 per cent of the
population. The average cost of retrofitting underground utilities was then
estimated at $5516 per household. However, with today's innovative design,
installation improvements and economies of scale, the submission states that
figure could be closer to $4900 per household in today's figures.
Dearth of information
The committee is concerned at the dearth of current information relating
to comparative costs of aerial versus underground deployment of the NBN,
despite the best efforts by the committee to source that information. Witnesses
generally pointed to the companies manufacturing and/or deploying fibre currently
as the logical source of that information.
However, when the committee sought that information from Aurora Energy,
the partner in the NBN Tasmania venture, the major infrastructure supplier and
owner refused to reveal likely costs. They instead referred the committee's
question to the NBN Tasmania. The response was eventually provided was
completely unhelpful, devoid of any dollar value, noting only that:
In general terms installing optical fibre cable on overhead
structures is substantially cheaper than installing the same infrastructure in
a new underground environment.
The committee also highlights that tender documents released by Aurora
Energy for the Tasmanian roll-out confirm that 560km of the 580km of cable will
be aerial. This is with little consultation with the general community that
will be impacted by the aerial cabling, nor with the local councils in which
the roll-out is to occur.
The committee remains concerned that the perceived short term benefits
of aerial deployment will over-ride sound business practices, which should
dictate that major national infrastructure is built seeking long term benefits.
The committee strongly cautions against expediency where it would
clearly not be in the long term interest of public investment. The short term
cost efficiency gains that may result in short term political benefits need to
be weighed against the long term efficiencies of underground cabling. As
submitted by Cables Downunder:
It would be foolish to embark on a nation-building exercise
based on such a short term approach to construction cost and roll-out speed.
Additionally, as can be seen in the previous photograph, the outcome is
far from ideal, and is certainly not 'future-proofed'. Australia is already
more than a century behind major international competitors that have buried the
vast majority of their electricity and telecommunications cables.
The committee highlights that the aerial deployment of the NBN merely
provides a quick-fix, bandaid solution that is not worthy of an infrastructure
project of this magnitude.
The committee therefore urges the government to favour underground
cabling in the remainder of the 90 per cent FTTP footprint, ensuring long term,
future proof benefits for the network, its investors and its consumers.
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