Australia is getting its biggest reciprocating engine power plant so far, and it will run on Wärtsilä's newest large-bore gas engine. The Finnish group announced on 30 September that it will supply 13 Wärtsilä 46TS-SG engines for a 300 MW plant in Australia. Neither the customer nor the site has been named. Wärtsilä booked the order in the third quarter; the engines are to be delivered in early 2029 and the plant is expected to be in full operation in 2030.
The plant's job is grid balancing and system security. Wärtsilä presents it as fast-starting, flexible capacity that lets the grid take more wind and solar without giving up security of supply, and says the modular layout allows the plant to be extended as the renewable share grows.
The 46TS On A Power Plant Order
According to pv magazine Australia, each 46TS-SG gives up to 23.4 MW of mechanical output, with a peak electrical efficiency above 51.3 %. A unit reaches full load in about two minutes, can be started and stopped without limit and has no minimum up or down time. The engines run on natural gas and biogas and, today, on hydrogen blends of up to 25 % by volume; Wärtsilä speaks of a route to fully sustainable fuels later.
Thirteen engines for 300 MW is a small unit count for a plant of that size. Fewer, bigger units mean fewer auxiliaries to maintain and a smaller footprint, but each engine taken out for overhaul removes a larger slice of the capacity. For a balancing plant, where the operator sells availability as much as energy, that trade-off is usually settled long before the order.
Which Site?
Wärtsilä keeps the location to itself. pv magazine Australia points out, without linking the two, that the Western Australian government is studying a state-run gas-fired station of about 300 MW at Naval Base / Kwinana, south-west of Perth, to be developed by the state utility Synergy and aimed at operation in 2030. That project has been referred to the state's Environmental Protection Authority for assessment and is opposed by Greenpeace Australia Pacific. Until the customer is named, any connection is speculation.
Many Starts, Hot Afternoons
A plant built to follow wind and solar does not run like a baseload station. It may start several times a day, sit warm on standby for hours, then be asked for full output within minutes when the clouds come in or the wind drops at dusk. Every start is a thermal cycle for the engine and for everything around it: lube oil and jacket water heating, the charge-air circuit, the cooling system that has to come up with the engine and be ready for full heat rejection almost at once.
In Australia that full output is often wanted on the hottest days of the year, when demand peaks and solar output is already falling in the late afternoon. Anyone specifying such a plant should make sure the rating is held at the site's real summer conditions, not at a standard reference temperature. The same logic applies to the engine power plants now being built next to U.S. data centers.
Sources: Wärtsilä, pv magazine Australia
