By Imogen Hartmann, Journalist
Reliability and affordability of energy supply is a critical component of economies, and therefore top of mind when considering the longevity of urban infrastructure. With much of Sydney’s electricity transmission network dating back to the 1960s and 70s, and nearing the end of its serviceable life, TransGrid has undertaken a project to update the aging infrastructure and future-proof Sydney’s electricity supply.
TransGrid’s Powering Sydney’s Future project is set to deliver a major update to the city’s electrical infrastructure, and provide energy security to cope with increasing demands due to a growing population.
The project will allow aging cables to be retired by installing a new high-voltage connection. A 20km, 330kV underground transmission circuit will be installed between the Rookwood Road Substation in Potts Hill and the Beaconsfield West Substation in Alexandria.
Work at the substations involves upgrade works at the Rookwood Road and Beaconsfield West Substations to facilitate the new 330kV transmission cable circuit, as well as conversion works at the Beaconsfield West and Sydney South Substations to transition the existing Cable 41 from a 330kV connection to a 132kV connection.
The project is specifically targeted to secure safe, reliable and affordable electricity supply for the 800,000+ residents in Sydney’s CBD and inner suburbs.
Powering Sydney’s Future is the largest project TransGrid has undertaken in metropolitan Sydney in decades and is expected to create 140 new construction jobs, and inject $285 million into the New South Wales economy.
Fast-tracking for COVID recovery
The project was approved by the New South Wales Department of Planning, Industry and Environment (DPIE) on 14 May 2020, following the public exhibition and submission of the Environmental Impact Statement (EIS) from 11 October to 22 November 2019.
New South Wales Energy Minister, Matt Kean, said the upgraded infrastructure would provide additional security of supply during peak demand periods for more than half a million homes and businesses.
“Parts of Sydney’s transmission and distribution networks are reaching their end of life, so this project will play a crucial role in ensuring a continuous and reliable energy supply for our communities,” Mr Kean said.
TransGrid said that the studies that supported the EIS were prepared by independent experts and included assessments of potential impacts on the environment such as noise and vibration, heritage, air quality, amenity, and traffic and transport.
TransGrid also prepared a Submissions Report in response to questions and issues raised by the community and stakeholders.
As part of the approval, TransGrid will be required to minimise impacts to mature tree canopy, and plant at least two trees for every one removed during construction.
TransGrid is also working with local councils on a number of greening and bushcare initiatives along the cable route.
Powering Sydney’s Future is the 15th project to be determined through the Planning System Acceleration Program, which is fast-tracking project assessments to keep people in jobs and the economy moving during COVID-19.
TransGrid CEO, Paul Italiano, said, “The NSW Government has fast-tracked this project because Sydney’s peak electricity demand is expected to continue to grow, driven largely by the NSW Government’s record infrastructure investment and the city’s population growth.
“Powering Sydney’s Future will meet the energy needs of the nation’s largest economy.
“Sydney’s peak electricity demand has escalated since 2014 and even taking into account the current COVID-19 crisis, it is expected to continue to grow with major new transport infrastructure projects under construction –including Sydney Metro (City and Southwest), WestConnex and the Western Harbour Tunnel, and the recently opened Sydney Light Rail.”
Scope of works
As well as the underground cable installation and the substation upgrades, the project will also involve the installation of additional pipes so there is space for a second cable to be added in the future as demand increases, avoiding further disruption to local communities.
TransGrid examined more than 30 cable routes before identifying a route which would lower the construction impacts for local communities because it mainly follows low traffic roads, increasing productivity and minimising the need to work at night.
To cross waterways and rail lines, TransGrid will also construct special crossings, such as cable bridges or underbores (underground crossings).
In the first stage of the project, TransGrid will dig a trench around 1.6m wide by 1.6m deep, and then install pipes which will house the cable.
In the second stage, precast underground ‘joint bays’ and communication pits will be installed before the cable is pulled through the pipes in sections in the third stage.
The fourth stage will involve joining the cable sections together in the underground joint bays.
Lastly, TransGrid will conduct the permanent restoration of the road. TransGrid said this final stage will be guided by consultation with the relevant council/road authority.
TransGrid has also established a Community and Stakeholder Reference Group (CSRG) for the project to enable community participation in project delivery.
This is facilitated through forums for discussion between the project team (including TransGrid and its contractor Taihan) and local representatives, including community and stakeholder groups and local councils.
It is led by an independent chairperson. Main construction on the Powering Sydney’s Future project began in August 2020, and is due for completion by November 2022.
Main image shows the smoking ceremony which was conducted in August 2020 prior to the start of construction.