Origin has officially opened Australia’s largest combined cycle gas-fired power station, the 630 megawatt Darling Downs Power Station located near Dalby, in southern Queensland.
The station comprises three 120 MW GE Frame 9E turbines and a 270 MW steam turbine, which is driven by steam raised from the three gas turbines’ waste heat.
Origin acquired the development and regulatory approvals for a gas-fired power station in the Darling Downs region in February 2007, as a result of the acquisition of Sun Retail from the Queensland Government.
A consortium of GE and CH2M Hill constructed the project, which created approximately 1,000 jobs during the construction phase.
Greener power
Darling Downs is one of Australia’s most efficient base load gas-fired power stations, capable of supplying enough energy to power more than 400,000 homes each day. Origin Energy Managing Director Grant King said that the project “is a $1 billion investment by Origin in electricity generation technology that can help Australia start to meet its objectives of reducing carbon emissions.”
The station’s green credentials are laudable. As a gas-fired power station, it will emit less than half the greenhouse gas of a typical water-cooled coal-fired power station of the same capacity. In addition, the power station will be air-cooled, meaning it only uses 200 megalitres of water per year (ML/a), approximately 2–3 per cent of the 8,500 ML/a of water used by a typical water-cooled coal-fired power station.
Part of a bigger picture
Darling Downs is part of Origin’s focus to become a vertically integrated company – “using our own power stations, fired by our own fuel sources.”
The station is fuelled by coal seam gas (CSG), sourced primarily from the Spring Gully gas fields in the Surat Basin, in tenements owned by Australia Pacific LNG, a joint venture between Origin and ConocoPhillips.
The CSG is processed at Origin’s Spring Gully gas processing plant, then transported through existing pipeline infrastructure to Wallumbilla. A 205 km gas pipeline transports the gas from the Wallumbilla Gas Hub near Roma to the power station.
The Wallumbilla to Darling Downs Pipeline was constructed by Nacap, who completed construction in October 2009, and provides 44 petajoules per day of gas to Darling Downs Power Station.
Although Spring Gully was already producing gas, Darling Downs underwrote phase five of the development. The phase five development included an additional 60 wells, the expansion of the Strathblane gas plant, and an additional gas processing plant.
The Wallumbilla to Darling Downs Pipeline also passes via the Talinga Gas Plant in the Walloon coal seams, another significant development for Origin.
Origin has also purchased a 77 hectare block adjacent to the current Darling Downs Power Station for possible future expansion of the project.
