Located 30 kilometres west of Perth, the $400 million base load 320 megawatt (MW) gas-fired power station, was built for the NewGen venture comprising Babcock & Brown Power and ERM Power, by Alstom.
Officially opened in October 2008 by Western Australia Minister for Energy and Resources Peter Collier, the plant was completed seven weeks ahead of schedule and under budget. At the opening Mr Collier said “This will ensure that the state will be well covered this summer and for many years to come.”?
Mr Collier said that the project would ensure reliable power supplies to industry and underpin the state’s ongoing economic growth. Base load power will be supplied to Western Power under a 25 year contract, while output from the station has been contracted to government-owned Synergy.
Gas for the power station is delivered through the Dampier to Bunbury Natural Gas Pipeline from the North West Shelf.
The power station is a combined-cycle operation, harnessing and using steam from waste heat in the gas turbine’s exhaust to run a turbine. The operation reduces greenhouse gas emissions by up to half of those from a conventional plant in addition to consuming 90 per cent less water.
Alstom designed and supplied the GT13E2 gas turbine and the 160 MW steam turbine. The company also supplied the condenser, heat recovery steam generator, step-up transformers, plant control systems, high voltage switchyard, civil works and the general balance of the plant. The gas turbine, at the centre of the plant, produces the highest open cycle efficiency in its class.
The project had a peak combined workforce in excess of 350 people, including employees from design contractors WorleyParsons, construction contractor Alstom, and Smithbridge Australia who also undertook construction works.
Environmental and community considerations
One of the main challenges experienced by the engineering team was to create a design for the outfall trench excavation. This needed to meet the environmental requirements for minimising water temperature rise and construction impacts on the delicate environment in the Cockburn Sound, an inlet of the Indian Ocean on the coast of Western Australia.
Sheet-pile cofferdams were used to significantly reduce turbidity in the inlet, creating a significantly reduced environmental impact compared with traditional dredging methods. By working from a stable, temporary bridge it was possible to ensure that the backfill operation was carried out precisely and the finished level was maintained within very tight tolerances. The use of these methods meant that the environmental impact was limited to between one fifth and one tenth of the disturbance created by traditional dredging trench methods.
Two years prior to the project’s construction, a three-stage community consultation process was undertaken, including initial stakeholder identification and contact at a preliminary briefing; a formal stakeholder provision and a response process; and, finally a formal response to stakeholder comments. Issues raised included the closure of a local horse exercising beach during construction, material residue on the beach that could damage the aesthetics of the local environment, and cultural heritage matters. Where possible, these issues were addressed, such as the concern about the horse exercising area, which was incorporated into the design of the outfall so as to not leave any permanent works or obstacles in the area.
Cultural heritage matters
Works involved excavation through a sensitive dune zone, which had high heritage value. An Aboriginal Heritage Review was undertaken to determine potential outfall impact on Aboriginal archaeological objects.
A small number of possible impacts were identified and consultation and on site surveys were carried out with local Aboriginal people, including the traditional owners and the South West Aboriginal Land and Sea Council, to identify any areas of unrecorded archaeological and ethnographic significance.
As a result, all site excavations had cultural heritage monitors to observe the works and ensure culturally significant materials were preserved.
Saving energy with an eco-friendly power station
Kwinana has started its production life both ahead of schedule and under budget, whilst employing various eco-friendly and energy saving methods. Set to supply Western Australia with 10 per cent of its energy requirements, the power plant will not only ease the strain on the Western Australian power grid, but will help the state reduce its greenhouse gas emissions.