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Tunnel Upgrade to Save Energy

02/05/2016

A planned upgrade of EastLink's 10 tunnel exhaust fans will incorporate variable speed drives and result in considerable direct energy savings, reducing greenhouse gas emissions by an estimated 6,441t CO2-e per annum.

The upgrade will also reduce vent stack fan noise in the adjacent community.

Update on 8/12/16:

  • Installation of the new fans is now 50% complete.

 

An energy optimisation study conducted in 2014 found the 10 exhaust fans consume about 65% of the tunnel's total energy.

Currently the exhaust fans take all tunnel air via the exhaust stacks during the day with each fan running full speed, using a lot of power. Variable speed drives on fans allow the fans to operate at a more efficient lower speed, therefore saving power and significantly reducing noise levels. With lower fan speeds some air from the tunnels will exit at road level with the air flow created by the flow of traffic within the tunnels. This air discharge at road level is known as portal emissions.

Currently, there are portal emissions overnight when the ventilation system is turned off, but there are no portal emissions from the EastLink tunnels during the day. To assist in achieving higher overall efficiencies, EastLink has applied to EPA Victoria for a licence amendment for the system upgrade and to permit partial portal emissions of 1.5 meters per second (approx. 30%) from the tunnels during the day with 70% continued to be extracted out the vent stacks. Air quality modelling undertaken has shown EastLink is able to achieve all of its air quality criteria with a 30% portal emission during the day.

EastLink will conduct air quality monitoring as we commence operating the new system to confirm no impact on community air quality.

Timing for project implementation will be:

  • Installation of new fans: second half 2016
  • Implementation of new control system and testing: first half 2017
  • Verification air quality monitoring during and post commissioning: mid 2017

Air quality reports and daily charts are available on the EastLink website here.

Updates on the implementation of this fan project will also be posted on the website.

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