In 2008, construction of the Uranquinty Power Station was completed. Located on the Moomba to Sydney Gas Pipeline southern lateral near Wagga Wagga, the power station has significantly increased gas demand on this section of the New South Wales transmission system, and required expansion pipeline infrastructure to meet the increasing demand.

Since then, gas usage for the power station has continued to increase and a decision to further increase to the capacity of the Young to Wagga Pipeline was made in October 2009. This will remove capacity constraints on the Moomba to Sydney southern lateral, and provide additional gas storage capacity for the Uranquinty Power Station.

The existing Young to Wagga Pipeline, constructed in 1981, provides gas supply to towns in central south New South Wales including Griffith, Cootamundra, Young and Wagga Wagga. In 1998, the 18 inch Interconnect was built connecting Bomen (Wagga Wagga) and Barnawatha in Victoria, which enabled gas to flow between the two states. The Young to Wagga Looping project is designed to additional provide flexibility of supply, security of supply and gas storage.

Stage 1 of APA Group’s Young to Wagga Looping project involves the construction of 61 km of 18 inch diameter gas transmission pipeline from Bomen north to Bethungra. The looping pipeline will be positioned 7 m away from the operating Young to Wagga Pipeline, with line valves at Wantiool and Bethungra, and cross tie-ins at Bethungra and Bomen.

Construction contractor WDS Ltd has mobilised approximately 115 people to work towards the project’s completion, expected by mid-November 2010. Construction commenced on 25 May 2010 and has been affected by weeks of rainfall.

APA has also commenced the formal approvals process for Stage 2 of the looping project, which entails looping of the Bethungra to Young section of the Young to Wagga Pipeline, and will be in a position to commence construction in approximately October 2011 if necessary.

Navigating new project approval regulations

The Young to Wagga Looping is the first APA pipeline project to go through the new NSW major projects approval Part 3A regulations under the Environmental Planning and Assessment Act 1979.

“APA has gone through a very detailed approval process including the approval process for the Construction Environmental Management Plan (CEMP). We have also had to appoint an independent Environmental Representative for the project,” said Manager Projects New South Wales, Australian Capital Territory and Western Australia Prakash Mehta.

The Part 3A approval process required preparation and submission of the Environmental Assessment Report (EAR). The EAR was placed on public exhibition, and the submissions received from the New South Wales Department of Planning were responded to in the Submissions Report.

The project was approved with conditions of approval which were incorporated into a CEMP, and are being implemented during construction of the project.

Construction underway

Construction crews targeted a production rate in the order of 2 km of pipeline per day.

Temporary facilities for the project include site office and work areas for material and equipment, workshop for equipment maintenance, a dam to store water for hydrostatic testing and borrow pits to source additional fill material if required.

Access tracks and additional gates have been constructed to access the pipeline easement and work areas and existing roads, access tracks and disturbed areas have been used to minimise disturbance to the surrounding areas.

Installing compressors in Victoria: the Wollert Compressor Station upgrade

APA is also undertaking an upgrade of the Wollert Compressor Station, designed to expand capacity on the Wollert to Euroa Pipeline on the northern section of the Victorian Transmission System.

The Wollert Compressor Station upgrade involves the installation of two Solar Centaur 50 Low NOX emission gas turbine driven compressors, fin fan after coolers, gas filters and all associated services and piping. Construction commenced with earthworks in December 2009, with completion of the upgrade scheduled for early November 2010.

The two Centaur 50 compressors will supersede the existing three Saturn compressors. With each Centaur machine having more than five times the capacity – 6,102 horsepower each – of the older units, the station’s overall capacity will be increased by over three times. Provision has also been made for further compressors in the future.

Following completion of the Wollert Compression project and the maximum allowable operating pressure pipeline upgrade project, the pipeline’s pressure limit will be 8,800 kilopascals (kPa). The new Wollert station has been designed for 10,200 kPa for potential future pressure requirements.

3D modelling software was used to virtually assemble the project before construction. APA Manager Projects Victoria Tom Carroll said “The use of 3D modelling software has allowed for the entire project to be assembled in the virtual world before any construction began.”

“The benefits of this technology were apparent from early in the design phase– allowing the end users to review the entire project easily and have their input – through to construction, with the minimisation of site work as a result of highly accurate design drawings,” he said.

The design of the Wollert Compressor Station was influenced by APA Asset Management and Engineering’s strategy to standardise designs nationally across all of APA’s future installations. Under the new strategy all compressor stations will be standardised across key deliverables, site layout, diverging plant configuration and equipment purchase.

Overall the project will involve the installation of ten major equipment items, 20 km of instrument and electrical cable, 2.5 km of piping and 40 tonnes of structural steel. Approximately 10,000 tonnes of reclaimed soil and 12,000 tonnes of imported select fill were used to complete site levelling.

Keeping safe

Part of the design concept was to locate the new station in a greenfield site, outside the existing Wollert Compressor Station’s operating assets, thereby minimising the risk of construction personnel working in the vicinity of live plant. This had the combined benefit of allowing APA operations personnel to continue with their activities with minimal impact from construction personnel.

APA’s permit-to-work system was incorporated into the project, which included completing a job safety analysis for each job task prior to any work commencing. Weekly toolbox meetings are held with the contractors, co-ordinated by the project specific safety officer, to ensure any site issues are addressed promptly and allowing a direct line of communication between the work crews and APA supervision.

Using local labour

For all construction activities, local labour was utilised and the majority of plant, materials and equipment has been procured from local suppliers. However, the specialised nature of some equipment meant that some items and raw materials were sourced from outside Australia.

The main piping contractor, Skinner Engineering, is located in Epping, approximately 15 km from Wollert, allowing for a greater degree of connectivity to the site.

Hanson also supplied the imported crushed rock from a local quarry, which meant deliveries were timely and transport costs were reduced.

Avoiding the hot tap challenge

Although tie-in works were planned carefully to avoid any hot tap works, a station shutdown proved unavoidable. The shutdown plan required approval from multiple stakeholders prior to any work commencing on site.

Gas needed to be sourced from New South Wales to maintain the gas supply commitments and the opening of valves to ensure security of supply to the distribution companies. The works were completed early in 2010 before the higher demand for gas brought on by the colder months.