Dampier to Bunbury Natural Gas Pipeline

The idea of a pipeline to transport gas from the North West Shelf to the south-west of Western Australia had its origins in 1975, following the discovery of large offshore reserves by WAPET and Woodside Petroleum. Around this time, the State Energy Commission of Western Australia (SECWA) reviewed the state's future gas requirements in conjunction with the partners in the North West Shelf consortium. The developers of the North West Shelf were in the preliminary stages of planning a system of production facilities based on the Rankin and Goodwyn fields (located about off the coast of Dampier), linked to a liquefied natural gas processing plant and a domestic gas plant situated at Withnell Bay. As the state government had access to more attractive interest rates than the commercial venturers, the state agreed to fund and build (through SECWA) a gas pipeline to transport the output from the domestic gas plant. In addition, SECWA entered into long term (20-year) take-or-pay contracts with the North West Shelf partners, in which SECWA agreed to pay for fixed volumes of gas which exceeded the market demand for gas in the south west. Engineering design commenced in 1979. and the pipeline was constructed between 1983 and 1984, Construction involved the welding of 127,000 sections of pipe. Gas first flowed into the pipe on 16 August 1984. Following the disaggregation of SECWA in 1995, the pipeline came under the ownership and control of the government's gas utility, AlintaGas. As part of a government policy of privatisation, Alinta sold the pipeline in 1998 to Epic Energy, a consortium of two US pipeline companies (along with three Australian institutional shareholders) at a price of , equivalent to in . Epic Energy owned and operated the pipeline for six years, eventually selling the pipeline in October 2004 to Dampier Bunbury Pipeline (DBP) Ltd, which is the trading name of the DBNGP group of companies. DBP had two institutional shareholders: D.U.E.T. (Diversified Utilities and Energy Trusts) (80%) and Alcoa (20%) up until 2017. The DBNGP is currently owned and operated by Dampier Bunbury Pipeline (DBP), part of the Australian Gas Infrastructure Group (AGIG), Australian Gas Infrastructure Group is owned by various consortia of Hong Kong-based entities listed on the Hong Kong Stock Exchange. The consortia include CK Asset Holdings (CKA), CK Infrastructure Holdings (CKI), Power Assets Holdings (PAH) and CK Hutchison Holdings (CKH). == Throughput ==

When first constructed, the capacity of the system was . A $150-million enhancement carried out in 1991 increased the capacity to . The pipeline The expansion project consists of two types of upgrade. Several of the pipeline's compressor stations will be upgraded with higher capacity gas turbines, thus increasing the actual pressure of the gas inside the line. In addition, the expansion involves a process of 'looping' the pipeline. This is the installation of additional lengths of pipe alongside, and connected to, the existing pipeline. The effect of looping is to provide additional capacity at critical sections of the main trunkline, thus increasing the total possible throughput. == DBP expansion projects ==

The DBNGP underwent a range of expansion projects under previous ownership structures. However, the most advanced have been undertaken by the current owners, who have invested in three major expansion projects since acquiring the asset, these projects are known as Stage 4 (constructed by Nacap Australia Pty Ltd), Stage 5A (constructed by Saipem) and the most recent, Stage 5B (as constructed by McConnell Dowell). These three projects were carried out in direct response to increasing demand for gas in the south-west of Western Australia. The owners worked closely with major gas customers to deliver the capacity required within the timeframes needed to support those customers' projects. Increasing the gas haulage capacity of the pipeline was crucial in supporting economic growth in Western Australia. The expansions were designed and built to meet DBP's contractual obligations. As a result of the expansions, 83% of the pipeline has now been duplicatedeffectively creating a second pipeline. This was achieved via a process known as looping. Looping involves installation of pipe lengths parallel to the existing asset. The expansion projects also required upgrade works on the pipeline's compressor stations, control and communications systems and metering equipment. The three expansions have increased the capacity of the pipeline by over as well as enhancing the reliability of the pipeline and improving security of supply for customers. The Stage 4, Stage 5A and Stage 5B expansion projects have seen the pipeline owners inject $1.7billion into the DBNGP. In The works include: • flow testing of all station pipework at design flows; • the completion of the Fortescue River Crossing; • modifications and completion of traffic and flow management at all stations; • ongoing environment restoration and subsidence repairs of the Right of Way. == Pipeline corridor ==

The pipeline's corridor runs near and crosses the North West Coastal Highway to near the Yannrie river where it passes inland, east of the Kennedy Range National Park crossing the Murchison River near Mulla Mulla flat, moving south to cross the Midlands Road east of Dongara. ==References==