Commencing operations in July, Western Australia’s 120 MW gas-fired Kwinana Swift power station can reach peak load in five minutes.
Following a dry autumn, Perth’s suburbs and outlying wheat belt were hit by a steady rain in mid-June, providing the region a much-needed drench. With just one month to go before final project completion, the rain wasn’t as welcome at Western Australia’s 120 MW Kwinana Swift, but Perth Energy’s wholesale general manager and project director, Patrick Peake, couldn’t complain.
“One part of our success has been the incredible dry time we’ve had in Perth, which has been really positive (for construction),” Mr Peake explained to Energy Source & Distribution from his Perth office.
Good timing and a fast response capability are an important aspect of the Kwinana Swift project. The installed capacity of the power station is 120 MW – enough power to supply around 80,000 homes. Located in one of 13 load areas in the South West Interconnected System (SWIS), of which the heavy industrial Kwinana has the highest annual average (over five years) peak demand growth rate, the project will sell into the competitive electricity market and assist in avoiding shortfalls in electricity supply during periods of peak demand.
The $130 million project uses two gas turbine engines similar to airline jets to drive a single generator, needing only five minutes to reach desired peak load. The gas turbine engines are model FT8 built by Pratt & Whitney Power Systems in the US while the generators are made in the UK by Brush Electrical. The gas turbine engines are based on the latest version of Pratt & Whitney’s JT8D turbo fan aircraft engine. The Swiftpac is termed an “aero-derivative” gas turbine.
The station provides increased reliability of supply during high demand periods and improved security of electricity supply during system emergencies or blackouts. For supply security, the gas turbines will be designed to run on dual fuel (natural gas and distillate), however distillate will only be used when gas is unavailable.
Bringing capital investment of up to $102 million in the Kwinana region, it employed up to 80 people during the construction phase. It will generally only run when demand is very high – about 1000 hours each year – and can start very quickly to cover for breakdowns of other generators.
“(Peak demand) has been increasing much faster than average demand. Demand for air conditioning, pool pumps, that sort of thing. The project’s around 110 MW (nominally) and the total market’s around 4000 at peak time. It’s about one year’s load growth I would say,” Mr Peake explains.
Further peak increases in the south-west region are expected to occur due to new iron ore mining developments. While much of the iron mining takes place in the north-west Pilbara region, energy-intensive mining facilities which grind iron ore into magnetite and are then magnetically separated have been discussed in the coming years. There has also been residential pressure as well, which Mr Peake estimates growing at about 4 per cent or so each year.
“(The project) has got two things. From a state perspective it’s supporting peak demand. It’s also a rapid response gas turbines, so they will be able to support wind power developments. For us it also supports our retail business. We have retail sales of around the 300 MW peak. It essentially gives us a cap in the market that allows us to reduce our risk in the retail business.”
Established in 1999, Perth Energy is majority owned by Infratil Limited, a New Zealand listed investment company, which owns a global portfolio of energy and infrastructure assets. A substantial share of Perth Energy is also owned by Western Australian private investors. As project director, Mr Peake’s main focus has been on Kwinana, but he has also been developing other products for Perth Energy. Originally with Western Power before moving to Perth Energy just over two years now, he is looking at a suite of projects to support their retail trading business.
“We’ve had a range of renewable energy offers come through to us but we seem to be struggling to get the finance to get those up. At the moment we had a wind farm project which looked very good. We were involved in a major solar project and then there have been other smaller renewable projects,” Mr Peake says.
The plant’s fast response capability will enable more renewable energy projects to be supported on the system. Given its characteristics, Perth Energy believes it will be ideal to be used to support and complement the renewable energy plant with intermittent fuel supply such as wind farms and landfill gas, and to meet peak and high shoulder load demands. It can increase and decrease output very quickly so it is ideal to support wind farms.
“It’s the first time that Pratt & Whitney’s have been used on the main land of Australia,” Mr Peake explains. “Aero- derivative engines are not particularly well used in Western Australia, there are a (small) number around.”
The project is expected to result in lower environmental impacts than those arising from conventional power generating facilities. It is located near its main customers, reducing line losses and resultant greenhouse gas benefits. The plant thermal efficiency exceeds the Australian Greenhouse Office (AGO) Technical Guidelines Generator Efficiency Standards (AGO 2006) for sent out thermal efficiency. Water injection are used to ensure the burners achieve NOx emissions of less than 25 ppm (dry at STP and 15 per cent O2) and the plant could be readily converted to combined cycle.
Water is taken from the Water Corporation and treated to a very high level of purity before being injected into the engines to reduce the emission of nitrous oxides (NOx). Waste water from the treatment plant is piped one kilometre to the Water Corporation’s Kwinana Water Recycling Plant (KWRP) for disposal. When operating on diesel, for around 100 hours per year, the plant uses ultra low sulphur to minimise emissions of sulphur oxides (SOx).
Perth Energy is a strong supporter of renewable energy and believes it is a pioneer in this energy field in the WA market. The company helped develop the generation of electricity from gas emitted by landfill and currently sells nearly all of the renewable energy into the south-west grid. Between 5 per cent to 10 per cent of Perth Energy’s current supply portfolio comes from renewable energy landfill gas generation.
“I think we’re all very excited here. I think it’s been a challenge both for us and the constructors. I think we’ve all learnt a tremendous amount and I think it’s a project we can all be proud of,” he said.
Mr Peake believes the station’s construction has shown the amount of support apparent within the Western Australia energy market.
“We’ve had tremendous support from government agencies, other utilities, construction companies. I think it’s shown the way the WA market is working as well too. We’re probably the first real merchant power plant onto the grid. It’s a sign of success for the electricity market. We also had good government support right the way through – both sides of government, Labor and Liberal. It’s been a very positive project all round.”