The 660 megawatt (MW) Colongra open-cycle gas-fired power plant is located at Munmorah, 120 kilometres north of Sydney. The plant will provide power during peak demand periods in the area, generating enough electricity to supply 600,000 homes.

“The new facility will include four open-cycle gas turbines and will be a ‘peaking plant’ operating at times of peak demand such as very hot days or cold nights,” said Alstom site manager Leo Cooper.

In addition to providing peaking capacity, the power plant is to provide ‘black start’ capability, which refers to the process of restoring a power station to operation without relying on external energy sources. This is set to provide system security, stabilisation and emergency response to the Colongra turbine. A black start generator will be installed, as well as distillate fuel and demineralised water storage units, a gas compressor and an evaporative inlet air cooling unit.

Tonnes of turbine

Proponent Delta Electricity awarded Alstom a $500 million contract for the design, supply, installation and commissioning of the entire power plant, including 4 x GT13E2 gas turbines, step-up transformers, plant control systems and balance of plant. Alstom said that the power plant’s peaking capacity will benefit from the high flexibility of the GT13 engine.

Alstom is currently undertaking the placement and installation of largely pre-fabricated plant equipment. Other on site construction activities to be undertaken involve earthworks and site preparation, construction of concrete footings and pads, and installation of associated pipework, controls, power and other ancillary services.

Delivering the gas turbines to site proved a challenge, as a road train of over 122 metres long as needed to carry the four turbines – weighing 343 tonnes each – from Port Newcastle to Munmorah. In addition, four generators – each weighing 230 tonnes – and four slightly smaller loads carrying generator step up transformers – weighing 155 tonnes each – were delivered to the site.

The road train consisted of three prime movers pulling from the front, with two 14-axle trailers and two prime movers pushing from the rear. A police escort and a convoy of 20 vehicles, including an emergency support truck carrying approximately 20–30 spare tyres and other spare parts, accompanied the delivery.

Alstom began work on the Colongra project in October 2007 and is expected to complete works by November this year.

Executive Vice President Philippe Joubert said “Our industry-leading technology and capacity to integrate power plant components allows Alstom to offer Delta Electricity the most innovative and efficient solution to meet its growing power needs.”

The contract is the company’s fifth in Australia since 2005 for the supply of turnkey gas turbine plants, meaning that the company has provided a total of eleven turbines to the country for either peaking, cogeneration or combined cycle applications.

The Colongra power plant will be built next to Delta’s existing coal-fired plant at Munmorah, which Alstom supplied with the original 4 x 350 MW steam turbine generators units in the mid-1960s.

Storage pipeline requirement

The project also requires the construction of a lateral gas pipeline connecting the gas turbine facility to the Sydney-Newcastle Pipeline. Jemena completed construction of the 42 inch diameter pipeline in January, installing Australia’s largest onshore diameter gas pipeline.

The lateral pipeline connects the Colongra power station into the Sydney-Newcastle Pipeline at Wyee and consists of a compressor station, 3.5 km of 10 inch feeder pipeline, 9 km of looped 42 inch storage pipeline and a let-down station.

Gas for the future

New South Wales Minister for Energy Ian Macdonald said the Colongra project “provides an environmentally responsible way to meet our state’s growing demand for electricity. Gas-fired plants produce about 40 per cent less greenhouse gas emissions when operating compared to coal-fired power plants.

“This is great news for the Central Coast, great news for our environment and great news for electricity consumers in New South Wales.”