New gas network powering ahead

A ‘ jack of all trades’ infrastructure company, Jemena not only owns and operates a number of significant gas, water and electricity networks, but also manages more than $5 billion worth of Australian utility assets.
The company, owned by Singapore Power, was formed from the sale of Alinta Limited in 2007, and operates four business platforms for its assets: owning and investing; developing; managing; and servicing.
Through Jemena’s 50 per cent interest in ActewAGL, the company works with ACTEW Distribution Limited to develop and operate gas, water and electricity networks in the ACT.
Jemena also has a 34 per cent interest in United Energy, the owner of the electricity distribution network that supplies electricity to about 630,000 people in Melbourne’s south-eastern suburbs and the Mornington Peninsula.
In its management role, Jemena operates Multinet’s Victorian gas distribution network, which supplies gas to Melbourne’s inner and outer eastern and south-eastern suburbs.
Altogether, Jemena operates more than 2000km of gas transmission pipelines and associated facilities, and more than 30,000km of gas mains throughout
Queensland, Victoria, Tasmania and NSW.
With extensions under way, natural gas is one of the fastest-growing facets of the Jemena business.
The company’s wholly-owned assets include the 9km Colongra Gas Transmission and Storage Pipeline, which is the largest onshore gas pipeline in Australia; and the Queensland Gas Pipeline, which carries gas from the Surat and Bowen basins and the Denison Trough to major clients including Rio Tinto, Queensland Alumina, Orica and Queensland Magnesia in Gladstone and Rockhampton.
The Eastern Gas Pipeline, another of Jemena’s main assets, transports gas from Victoria’s Gippsland Basin to Sydney, Wollongong and Canberra, with the VicHub
Interconnect Facility acting as a transmission centre between the Eastern Gas Pipeline and the Victorian gas transmission system.
Expanding the network
Of all its current assets, the 25,000km Jemena Gas Network (JGN) is the one that Jemena is most eager to develop.
The JGN supplies about 100 petajoules per annum of natural gas to more than one million homes and businesses in Sydney, Newcastle, Wollongong and more than 20 regional centres in NSW.
With rising population figures and an increased demand for natural gas as NSW electricity prices rise, Jemena has seized the opportunity to extend and upgrade the network, establishing plans to invest more than $800 million between 2010 and 2015.
Jemena general manager of gas and water networks Peter Harcus explained that the investment was necessary to cater for anticipated growth, both in future demand for gas and the company’s client base.
“Each year we add another 30,000 customer sites to the gas network and since 2005 to 2006, the total number of customer sites connected to the JGN has increased by 160,000,” he said.
“Each year we lay about 200km of gas mains and over the past six years Jemena has significantly expanded the gas network in New South Wales by laying over 1100km of new gas mains, making it easier for residential and business customers in the state to connect to natural gas.”
The investment includes a number of extension and development projects Jemena claims are aimed at improving the reliability, integrity and safety of NSW’s natural gas supply.
“When it comes to reliability, gas supply problems have reduced from 1.832 per 1000 customers in 2005 to 2006 to 1.229 per 1000 customers in 2010 to 2011: an improvement of 33 per cent,” Mr Harcus said.
“When it comes to integrity and safety, reported gas leaks on the network have reduced from 5.5 per 10km of mains in 2005 to 2006 to 4.9 per 10km of mains in 2010 to 2011: an improvement of 10.9 per cent.”
Completed projects
Jemena has already completed several of its planned projects, including the construction of a primary regulating station (PRS) and new primary and secondary gas mains at Lane Cove in Sydney.
According to Mr Harcus, the new PRS, together with the North Ryde PRS and Willoughby PRS, will link the city’s northern suburbs to the secondary distribution link, ensuring continuity of gas supply to homes and businesses on the existing Lane Cove distribution network as well as new customers in the northern districts.
“The Lane Cove project, together with the Wakehurst Parkway project which involved upgrading the existing gas main between Frenchs Forest and North Narrabeen, is aimed at ensuring security of gas supply to 43,000 customers in the Manly-Warringah area and 17,000 customers in the Pittwater area,” he said.
Another important development in Jemena’s expansion of the JGN was the construction of a new primary gas main from Penrith to Emu Plains in the Blue Mountains.
A new PRS was also built at Emu Plains to ease pressure on Jemena’s existing gasnetwork as population and demand in the region grows.
Perhaps the most challenging of the expansion projects so far, the Emu Plains development required Jemena to excavate a 3.2km trench through Woodriff Gardens and horizontal directional drill through 8m of cobblestone beneath the Nepean River to reach the site of the new PRS.
Project manager Matthew Good said the team employed ingenuity to overcome the issue of drilling through the dense rock.
“The actual trajectory of the drill meant that up to 50m of these cobblestone and boulder layers had to be penetrated before we could start our horizontal directional drilling,” he said.
“Attempts to drill across the Nepean River through the cobble and boulder layers had been made on a number of occasions in the past, resulting in failure.”
Mr Good said the team overcame the problem by pushing a 700mm steel casing through the layers, which prevented the cobblestones and boulders from collapsing around the drill head.
One of Jemena’s most recently completed projects involved the construction of a new trunk regulating station (TRS) at Albion Park in Wollongong.
The TRS aims to improve the supply of natural gas to about 13,000 homes and businesses in the area, and is in part preparation for the extra 30,000 people
expected to inhabit the area in 40 years’ time.
According to Mr Harcus, the next 12 months will see further growth of the JGN under Jemena’s $800 million investment plan.
“This investment is aimed at expanding the network to ensure more homes and businesses can enjoy the benefits of natural gas, upgrading the network to meet growing demand for natural gas, and improving the reliability and integrity of gas supply to the existing 1.1 million customer sites in New South Wales that are connected to the Jemena Gas Network,” he said.
“Calendar [year] 2013 will see Jemena continue with its capital works program of investing more than $800 million over a five-year period to upgrade, extend
and improve the reliability and integrity of gas supplied via its 25,000km-long Jemena Gas Network.”

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