Origin Energy’s Darling Downs Power Station is set to take advantage of coal seam gas (CSG) reserves held by Australia Pacific LNG (APLNG), a 50:50 partnership between Origin and ConocoPhillips, in southwest Queensland, predominantly in the area around Roma and Chinchilla.
Originally to be developed at APLNG’s Spring Gully CSG Field, the power station site has been relocated to Dalby, where the plant is being constructed adjacent to ERM Power’s Braemar 1 and 2 power stations. Fuel for the station will come from APLNG’s CSG fields and processing facilities in the region will then be transported through a recently constructed gas pipeline to the Wallumbilla Gas Hub.
The plant consists of three General Electric (GE) 9E class gas turbines, each with a capacity of 120 megawatts (MW), and a 270 MW capacity steam turbine that utilises an air-cooled condenser for the plant’s primary cooling system. The plant is fuelled by CSG and natural gas.
Darling Downs Power Station Project Director Paul Farnworth said “The power station will be air-cooled, meaning it only uses 200 megalitres of water a year, around two to three per cent of the water used by a typical water-cooled coal-fired power station.”?
Construction in the works
Construction on the plant began in August 2007, with the power station expected to be commissioned in the fourth quarter of 2009 and fully operational by early 2010.
CH2M Hill and GE Energy were awarded a $780 million engineering, procurement and construction contract for the power station.
CH2M Hill is performing the engineering, design and procurement of the balance of plant equipment for the project, integrating with the three GE-supplied Frame 9E gas turbine generators, the D11 steam turbine generator, the plant control system, and three heat recovery steam generators.
The company is also partnering with Laing O’Rourke Australia for execution of the project’s site works as well as supplying equipment, components and materials.
Key features stipulated by Origin had to be taken into consideration when completing the design of the project. These included:
- Low water consumption for the plant
- Very low plant noise level
- A highly automated plant to ensure reliability and security.
“The timing, equipment supply and its sources were tailored at the time of contracting to achieve the owner’s required outcomes and price requirements,”? said CH2M Hill National Manager for Power John Elkins.
The company said that co-ordination of the international procurement efforts has required significant logistics planning, heavy haul planning and co-ordination, very regular phone conference calls, expediting lists, schedule tracking and reporting.
In addition, a significant procurement team has been established in Australia to support local procurement and compliance with local requirements.
Where possible, the company has endeavoured to employ local construction and operational Darling Downs staff with a peak local staff rate of 25 per cent. Local storage areas, accommodation and contractors have also been used.
Multiple shift work has been established to maintain the construction program. The construction of the power station has required a large skilled workforce, which has allowed CH2M Hill to accelerate critical erection and pre-assembly. Multiple commissioning teams have also been used to expedite the commissioning process.
Ensuring a safe workplace
CH2M Hill said that a focused effort is put into safety techniques at Darling Downs, with a detailed safety campaign implemented for all of those working at the construction site.
Mr Elkins advised that the site has just completed one million construction hours without a lost time injury.
The zero harm safety target required considerable effort from the site team to achieve the high standards. These measures included additional safety officers, repeated and lengthy inductions, safety banners, toolbox talks and frequent audits.
Australian opportunities
CH2M Hill said that Australia has significant growth opportunities for gas-fired generation in the future and hopes to be a part of that growth.
“This project is CH2M Hill’s first large effort in Australia, bringing its experience to the Australian power industry. CH2M Hill intends to build on this experience with other projects using its global procurement reach to offer clients high quality, competitively priced plants”? said Mr Elkins.