Roma to Brisbane Pipeline Access Arrangement Submission
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September 2016 roma to brisbane pipeline access arrangement submission. attachment 5-2 – forecast capital expenditure project documents business case urban risk reduction RBP RISK MITIGATION - PROTECTIVE BARRIERS AND PRESSURE REGULATION Business Case – Capital Expenditure RBP Risk Mitigation - Protective Barriers and Pressure Regulation Business Case Number AA-02 – REVISION 1 1 Project Approvals TABLE 1: BUSINESS CASE – PROJECT APPROVALS Prepared By Jennifer Ward, Pipeline and Asset Management Engineer, APA Group Reviewed By Francis Carroll, Engineering Services Manager Queensland, APA Group Approved By Craig Bonar, Manager East Coast Grid Engineering, APA Group 2 Project Overview TABLE 2: BUSINESS CASE – PROJECT OVERVIEW Description of The DN250, DN300 and DN400 metropolitan sections of the Roma Brisbane Pipeline (RBP) Issue/Project operate at risk levels that have become acceptable, due to urban encroachment. This risk is due to the threat of external interference in high consequence areas, causing damage to the pipeline, leading to potential rupture and resulting fatalities and injuries within the measurement length. It is of particular concern to the RBP due to its age and its construction which is less resistant to damage than modern pipelines. The AS 2885 safety management process requires APA to carry out an options study to reduce the risk to demonstrably ALARP where there have been land use changes around an existing pipeline. The ALARP study assessed a range of options and identified a preferred solution. As part of a long term strategy, operating pressure regulation is being implemented in addition to complementary protective barrier slabbing in identified critical areas in order to reduce the risk of pipeline rupture and improve public safety. Options Considered The following options have been considered: 1. Option 1: Do Nothing Option – retain the existing unacceptable risk level 2. Option 2: MOP Reduction to fully meet code compliance for maximizing the critical defect length of the pipeline, by installing additional regulating stations upstream of the metropolitan area and additional compression in the metro area to maintain supply; 3. Option 3: Pipe Replacement – total replacement of non-compliant pipe with modern pipe, meeting the code requirements for damage resistance, in the metropolitan area [metro looping] in combination with pressure reduction or abandonment of original line; 4. Option 4: Physical protection - Increased physical protection by the installation of barriers such as concrete slabs, encasement or similar, at all locations accessible by excavators and augers in the high consequence areas. This does not achieve the ‘no rupture’ or energy release rate code requirements but reduces the likelihood of mechanical damage occurring. 5. Option 5: Procedural measures only – increased patrol frequency; signage; landowner and 3rd party liaison; APA considers that all effective procedural measures are already in place and this would have limited additional effectiveness. 6. Option 6 (preferred): Combined MOP reduction and physical protection – combination of option 2 and 4, where the preference is to undertake MOP reduction where feasible, as it removes the highest consequence (rupture) and is generally more cost effective. Where MOP reduction is impractical, physical protection is to be installed to minimize the likelihood of mechanical damage. This option was the recommended outcome of the ALARP study. Estimated Cost $10.97 million RBP RISK MITIGATION - PROTECTIVE BARRIERS AND PRESSURE REGULATION ROMA BRISBANE PIPELINE 1 RBP RISK MITIGATION - PROTECTIVE BARRIERS AND PRESSURE REGULATION Consistency with The completion of this risk reduction work complies with the new capital expenditure criteria in the National Gas Rule 79 of the NGR because: Rules (NGR) • it is necessary to maintain and improve the safety of services and maintain the integrity of services (Rules 79(2)(c)(i) and (ii)); and • it is such as would be incurred by a prudent service provider acting efficiently, in accordance with accepted good industry practice, to achieve the lowest sustainable cost of providing services (Rule 79(1)(a)). Stakeholder The primary stakeholder consideration in this project is for landowner impacts from third party Engagement interference in urban encroachment areas. Other stakeholders are the Queensland Department of Natural Resources and Mines, Brisbane City Council and other local authorities, and APA’s shippers on the RBP and commercial operations. 3 Background 3.1 Description of relevant pipeline The RBP was constructed in 1969 to provide gas from the Roma Gas Fields to supply domestic and industrial consumers in Brisbane. The pipeline is approximately 440 km long and has been expanded since original construction to now consist of fully looped sections of DN250 and DN400 pipeline between Wallumbilla and Brisbane. The Brisbane metropolitan section of the RBP comprises a DN300 pipeline, partially duplicated for 6 km by the Metro Looping 1 (MLP1) project, and a DN200 pipeline supplying Gibson Island. There are also laterals to Swanbank power station and Lytton (Caltex) refinery. In its determination for the 2012 to 2017 access arrangement the AER accepted the APA proposal in relation to the capacity expansion of the RBP. This expansion involved the installation of an additional compressor at the Dalby Compressor Station, duplication of a 6 km section of the Roma Brisbane Pipeline in the metro section and a MOP upgrade of the DN400 pipeline. This project represented the first phase of the Metropolitan looping project (MLP1). At the time of the last AA submission APTPPL noted that the capacity of the RBP is likely to be constrained at some point by the capacity of the metro section and there would be a need to construct metro looping phase 2 and 3. Had this project gone ahead the additional capacity provide by the looping would have permitted a pressure reduction on the current metro section whilst still meeting the capacity needs of Brisbane users. However, current forecasts do not support an economic case for the construction of metro looping phase 2 and 3 in timeframes consistent with the resolution of issues raised by urban encroachment and associated third party interference risks. 3.2 Urban encroachment The original Roma to Brisbane Pipeline DN250, DN300 and DN200 pipelines were constructed in 1969. The DN400 looping pipeline up to Looping 6 was constructed between 1988 and 2002. At the time of construction, the pipeline traversed mostly rural areas, and was designed accordingly to the applicable standards of the time. Prior to 2007, design codes did not require retrospective consideration of high-consequence areas. Since the time of construction, significant development has occurred particularly in the Brisbane outskirts, so that parts of the pipeline that were originally in rural areas are now surrounded by dense urban areas. To a lesser extent, growth in the towns along the pipeline such as Dalby and Toowoomba has also changed the land use within the measurement length. This means that in addition to the original ‘Metro’ DN300 and DN200 pipeline segments, significant portions of the DN250 and DN400 pipelines are now located in high-consequence built up areas. As can be seen in the satellite image below, the metro section is located in dense, established suburbs of Ipswich and Brisbane, including Karalee, Riverview, Redbank, Collingwood Park, Camira, Forest Lake, Sunnybank, Eight Mile Plains, Wishart, Mansfield, Carindale, Carina, Tingalpa and Murarrie. A high proportion of the pipeline is located in road reserve, and therefore more exposed to other utility construction and maintenance threats, than in comparable pipelines in other major Australian cities. RBP RISK MITIGATION - PROTECTIVE BARRIERS AND PRESSURE REGULATION ROMA BRISBANE PIPELINE 2 RBP RISK MITIGATION - PROTECTIVE BARRIERS AND PRESSURE REGULATION Key pipeline details are provided in the following table, including the lengths of pipeline segments assessed to be located in High Consequence Areas (location class of T1, T2, S, I or HI for consequence escalation). The location class requirements are defined in AS 2885.1-2012, assessed through the SMS and Location Class review process and the ALARP study, and described further below. Pipeline DN200 DN250 DN300 DN400 Commissioning Date 1969 1969 1969 1988 - 2002 Length of pipeline 2 km 399 km 38 km 404 km MAOP 9300 kPa Wallumbilla – 4612 kPa Bellbird Condamine Park – Mt Gravatt 4200 kPa 7136 kPa 9600 kPa 4200 kPa Mt Condamine to Gravatt – SEA Swanbank/ Ellengrove Outside diameter 219.1 mm 273.1 mm 323.9 mm 406.4 mm Wall thickness 4.78 / 5.19 / 6.35 5.7* / 6.8 / 8.1 / 4.78 mm 5.19 mm mm 8.85 / 9.5 / 9.7mm Pipe specification API 5L X60 / X70 / API 5L X46 API 5L X46 API 5L X42 X80 RBP RISK MITIGATION - PROTECTIVE BARRIERS AND PRESSURE REGULATION ROMA BRISBANE PIPELINE 3 RBP RISK MITIGATION - PROTECTIVE BARRIERS AND PRESSURE REGULATION 12.6 kW/m2 radiation 102 m 166 m 159 m 288 m contour 4.7 kW/m2 radiation contour (Measurement 167 m 272 m 261 m 472m Length) Length in High 2.1 km 35.3 km 27.5 km 61.8 km Consequence Areas * Note that due to the staged construction of the DN400 pipeline over many years, several wall thickness and grade combinations exist. It should also be noted that the Lytton Lateral and Metro Looping 1 pipelines are not in the scope of this Business Case, as they were designed and constructed in accordance with AS 2885.1-2007 or later with full cognisance of high-consequence area requirements. 3.3 Design standards and legislation 3.3.1 Petroleum & Gas (Production & Safety) Regulations 2004 APTPPL is licensed to operate the RBP under the Queensland Petroleum & Gas (Production & Safety) Act and Regulations 2004. Schedule 1 to the regulations sets AS2885 as a preferred standard under the Act. Under regulation 7 this means that pipeline construction and operation is mandated to comply with AS2885. 3.3.2 Australian Standard AS 2885 Hydrocarbon transmission pipelines such as the RBP have an Australian Standard for their design and construction, AS 2885.1.