The hidden cost of the NBN street cabinets

The 60,000 cabinets that make up the Coalition’s NBN pose significant complications with regards to power consumption and maintenance costs. But you probably won't hear much from the Opposition on that, not yet anyway.

The 60,000 cabinets needed to bring the Coalition’s NBN to fruition may not be prettiest piece of paraphernalia coming to a street near you, but there are a few more pressing considerations about these mini-exchanges than their visual appeal.

Among the passionately put opinions filling this and other journals, scant attention has been given to the running costs of the Coalition’s NBN proposals, and to maintenance. On initial calculations, the running costs of the FTTN approach are very large, with significant power consumption implications.

There are two key strengths with fibre optic technology.

Firstly, with every fibre optic cable is able to easily carry all known communication frequencies. The spectrum used for wireless internet, 3G and the proposed 4G telephony, all television and all broadcast radio, AM, FM and shortwave, can be carried several time over in just one optic fibre cable.

And secondly, it is a passive technology, meaning it requires little external power to drive it. Modern glass fibre is so transparent – and its transparency is improving all the time – that the lasers used to carry the signals need use only tens of milliwatts of power to carry a signal 100 kilometres or more. That’s a small fraction of the power consumed by a hand torch and much less than just one in-home wireless internet connection.  

The energy savings are enormous, but only if the optic fibre cable runs all the way to the premises. Covering the last few hundred metres on wireless, copper or HCF is hugely wasteful in terms of the energy consumed.

The 60,000 nodes required to implement the Coalition’s model are power guzzlers. Some may use solar power; however it is more likely that most of the 60,000 additional nodes will be drawing power from the grid.

For arguments sake, let’s say each node consumes 100 watts – a fairly modest figure, as much as an incandescent light bulb in a largish room.

Now the nodes run all day all night, seven day a week, 365.25 days a year, or 8,766 hours. Multiply the two and the nodes for the Coalition’s NBN model will consume 52,596 megawatt hours of electricity per year, all baseline load.

Seems to me the Coalition’s model should have included the cost of expanding our baseline electricity generation capacity in its NBN cost calculations. Then there are the greenhouse emissions and the maintenance of the aging copper network. The first isn't recognised in the policy the other flick-passed in the background papers.

Dr Vincent O'Donnell is the media policy editor at Screen Hub and an executive producer and presenter of Arts Alive. 

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